2019-27545. Approval of Air Quality Implementation Plans; California; Ventura County; 8-Hour Ozone Nonattainment Area Requirements

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing to approve, or conditionally approve, all or portions of two state implementation plan (SIP) revisions submitted by the State of California to meet Clean Air Act (CAA or “the Act”) requirements for the 2008 8-hour ozone national ambient air quality standards (NAAQS or “standards”) in the Ventura County, California (“Ventura County”) ozone nonattainment area. The two SIP revisions include the “Final 2016 Ventura County Air Quality Management Plan,” and the Ventura County portion of the “2018 Updates to the California State Implementation Plan.” In today's action, the EPA refers to these submittals collectively as the “2016 Ventura County Ozone SIP.” The 2016 Ventura County Ozone SIP addresses the nonattainment area requirements for the 2008 ozone NAAQS, including the requirements for an emissions inventory, attainment demonstration, reasonable further progress, reasonably available control measures, contingency measures, among others; and establishes motor vehicle emissions budgets. The EPA is proposing to approve the 2016 Ventura County Ozone SIP as meeting all the applicable ozone nonattainment area requirements except for the contingency measure requirement, for which the EPA is proposing conditional approval. In addition, the EPA is beginning the adequacy process for the 2020 motor vehicle emissions budgets in the 2016 Ventura County Air Quality Management Plan through this proposed rule.

DATES:

Written comments must arrive on or before January 21, 2020.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-R09-OAR-2018-0146 at https://www.regulations.gov. For comments submitted at Regulations.gov, follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the FOR FURTHER INFORMATION CONTACT section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/​dockets/​commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT:

John Kelly, Air Planning Office (AIR-2), EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105, [phone], or by email at [e-mail].

SUPPLEMENTARY INFORMATION:

Throughout this document, “we,” “us,” and “our” refer to the EPA.

Table of Contents

I. Regulatory Context

A. Ozone Standards, Area Designations, and SIPs

B. The Ventura County Ozone Nonattainment Area

C. CAA and Regulatory Requirements for 2008 Ozone Nonattainment Area SIPs

II. Submissions From the State of California To Address 2008 Ozone Requirements in Ventura County

A. Summary of Submissions

B. CAA Procedural Requirements for Adoption and Submission of SIP Revisions

III. Evaluation of the 2016 Ventura County Ozone SIP

A. Emissions Inventories

B. Emissions Statement

C. Reasonably Available Control Measures Demonstration

D. Attainment Demonstration

E. Rate of Progress Plan and Reasonable Further Progress Demonstration

F. Contingency Measures

G. Motor Vehicle Emissions Budgets for Transportation Conformity

H. General Conformity Budgets

I. Other Clean Air Act Requirements Applicable to Serious Ozone Nonattainment Areas

IV. Proposed Action

V. Statutory and Executive Order Reviews

I. Regulatory Context

A. Ozone Standards, Area Designations, and SIPs

Ground-level ozone pollution is formed from the reaction of volatile organic compounds (VOC) and oxides of nitrogen (NO_X) in the presence of sunlight.^[1] These two pollutants, referred to as ozone precursors, are emitted by many types of sources, including on- and off-road motor vehicles and engines, power plants and industrial facilities, and smaller area sources such as lawn and garden equipment and paints.

Scientific evidence indicates that adverse public health effects occur following exposure to ozone, particularly in children and adults with lung disease. Breathing air containing ozone can reduce lung function and inflame airways, which can increase respiratory symptoms and aggravate asthma or other lung diseases.^[2]

Under section 109 of the CAA, the EPA promulgates NAAQS for pervasive air pollutants, such as ozone. The NAAQS are concentration levels that, the attainment and maintenance of which, the EPA has determined to be requisite to protect public health and welfare. In 1979, the EPA established the 1-hour ozone NAAQS of 0.12 parts per million (ppm) (referred to herein as the “1-hour ozone NAAQS”).^[3] Section 110 of the CAA requires states to develop and submit SIPs to implement, maintain, and enforce the NAAQS.

Under the CAA, as amended in 1977, the EPA designated all areas of the country as “nonattainment,” “attainment,” or “unclassifiable” with respect to each NAAQS, and in so doing, designated Ventura County (excluding the Channel Islands) as a nonattainment area for photochemical oxidant (later ozone).^[4] States with nonattainment areas are required to submit revisions to their SIPs that include a control strategy and technical analysis to demonstrate how the area will attain the NAAQS (referred to as an “attainment demonstration”), and the EPA took action on a number of related SIP revisions submitted by the California Air Resources Board (CARB) in the late 1970s and 1980s for Ventura County.^[5] Under the 1977 CAA Amendments, nonattainment areas were to have attained the 1-hour ozone NAAQS no later than 1987. By 1990, however, like many other areas throughout the country, Ventura County had not yet attained the 1-hour ozone NAAQS, and the CAA was amended to include new SIP requirements and new attainment deadlines.

Under the CAA Amendments of 1990, Ventura County (excluding the Channel Islands) was classified as a “Severe-15” nonattainment area for the 1-hour ozone NAAQS based on a 1-hour ozone design value of 0.17 parts per million (ppm).^[6] As a Severe-15 ozone nonattainment area, Ventura County was required to attain the 1-hour ozone NAAQS no later than November 15, 2005 and was subject to additional SIP planning requirements, including a revised attainment demonstration.

In the wake of the classification of Ventura County as a Severe-15 nonattainment area for the 1-hour ozone NAAQS, CARB submitted a number of SIP revisions for Ventura County that contained an attainment demonstration for the 1-hour ozone NAAQS and other SIP elements, and that relied on a combination of mobile source control measures adopted by CARB and stationary source control measures adopted by the Ventura County Air Pollution Control District (VCAPCD or “District”). In connection with these submittals, the EPA took the following actions:

• 1994 Air Quality Management Plan for Ventura County and related State Strategy—The EPA approved the control measures, the 15 percent rate of progress demonstration and attainment demonstration, among other elements, for the 1-hour ozone NAAQS at 62 FR 1150 (January 8, 1997);
• Ventura County 1995 Air Quality Management Plan Revision—The EPA approved the revised rule adoption and implementation schedule at 62 FR 1150 (January 8, 1997);
• Ventura County 1997 Air Quality Management Plan—The EPA approved certain commitments to adopt and implement control measures at 63 FR 19659 (April 21, 1998).

As noted previously, Ventura County was required to attain the 1-hour ozone NAAQS no later than 2005, and in 2009, the EPA determined that Ventura County had attained the 1-hour ozone NAAQS by the 2005 applicable attainment date.^[7] Since 2005, 1-hour ozone design values in Ventura County have decreased from 0.12 ppm in 2005 (based on 2003-2005 data) to 0.10 ppm in 2018 (based on 2016-2018 data) and are consistent with continued attainment of the 1-hour ozone NAAQS.^[8]

In 1997, the EPA revised the NAAQS for ozone, setting it at 0.08 ppm averaged over an 8-hour timeframe (referred to herein as the “1997 ozone NAAQS”) to replace the existing 1-hour ozone NAAQS of 0.12 ppm.^[9] In 2004, the EPA designated and classified Ventura County (excluding the Channel Islands) as a “Moderate” nonattainment area for the 1997 ozone NAAQS but later granted CARB's request to reclassify Ventura County to “Serious” nonattainment for the 1997 ozone NAAQS.^[10] Serious ozone nonattainment areas were required to attain the 1997 ozone NAAQS as expeditiously as practicable, but no later than June 15, 2013. In 2012, the EPA determined that Ventura County attained the 1997 ozone NAAQS based on the ambient data for years 2009-2011.^[11] Since 2011, the eight-hour ozone design values for Ventura County have decreased from 0.083 ppm in 2011 (based on 2009-2011 data) to 0.078 ppm in 2018 (based on 2016-2018 data) and are consistent with continued attainment of the 1997 ozone NAAQS.^[12]

In 2008, the EPA lowered the 8-hour ozone NAAQS to 0.075 ppm (referred to herein as the “2008 ozone NAAQS”) to replace the 1997 ozone NAAQS of 0.08 ppm.^[13] In 2012, the EPA designated Ventura County (excluding the Channel Islands) as nonattainment for the 2008 ozone NAAQS and classified the area as Serious.^[14] Areas classified as Serious must attain the NAAQS within 9 years of the effective date of the nonattainment designation.^[15] The SIP revisions that are the subject of today's proposed action address the Serious nonattainment area requirements that apply to Ventura County for the 2008 ozone NAAQS.

B. The Ventura County Ozone Nonattainment Area

The Ventura County nonattainment area for the 2008 ozone NAAQS consists of the Ventura County portion of California's South Central Coast Air Basin, excluding the Channel Islands. Ventura County encompasses approximately 2,200 square miles and has a population of approximately 874,000 (in 2018); it is located west of Los Angeles County and is bordered by Kern County to the north, Santa Barbara County and the Pacific Ocean to the west, and the Pacific Ocean and Los Angeles County to the south. Ozone in the Ventura County nonattainment area is caused by both locally generated emissions and transport from the South Coast Air Basin.^[16] Ocean-going vessels calling on Port Hueneme or the ports of Los Angeles or Long Beach and transiting vessels passing through southern California waters, but without calling at the ports, also impact Ventura County's air quality.

C. CAA and Regulatory Requirements for 2008 Ozone Nonattainment Area SIPs

States must implement the 2008 ozone NAAQS under title I, part D of the CAA, including sections 171-179B of subpart 1 (“Nonattainment Areas in General”) and sections 181-185 of subpart 2 (“Additional Provisions for Ozone Nonattainment Areas”). To assist states in developing effective plans to address ozone nonattainment problems, in 2015, the EPA issued a SIP Requirements Rule (SRR) for the 2008 ozone NAAQS (“2008 Ozone SRR”) that addressed implementation of the 2008 standards, including attainment dates, requirements for emissions inventories, attainment and reasonable further progress (RFP) demonstrations, among other SIP elements, as well as the transition from the 1997 ozone NAAQS to the 2008 ozone NAAQS and associated anti-backsliding requirements.^[17] The 2008 Ozone SRR is codified at 40 CFR part 51, subpart AA. We discuss the CAA and regulatory requirements for the elements of 2008 ozone plans relevant to this proposal in more detail below.

The EPA's 2008 Ozone SRR was challenged, and on February 16, 2018, the U.S. Court of Appeals for the D.C. Circuit (“D.C. Circuit”) published its decision in South Coast Air Quality Management District v. EPA^[18] (“South Coast II”) ^[19] vacating portions of the 2008 Ozone SRR. The only aspect of the South Coast II decision that affects this proposed action is the vacatur of the alternative baseline year for RFP plans. More specifically, the 2008 Ozone SRR required states to develop the baseline emissions inventory for RFP plans using the emissions for the most recent calendar year for which states submit a triennial inventory to the EPA under subpart A (“Air Emissions Reporting Requirements”) of 40 CFR part 51, which was 2011. However, the 2008 Ozone SRR allowed states to use an alternative year, between 2008 and 2012, for the baseline emissions inventory provided that the state demonstrated why the alternative baseline year was appropriate. In the South Coast II decision, the D.C. Circuit vacated the provisions of the 2008 Ozone SRR that allowed states to use an alternative baseline year for demonstrating RFP.

II. Submissions From the State of California To Address 2008 Ozone Requirements in Ventura County

A. Summary of Submissions

In this document, we are proposing action on all or portions of two SIP revisions, which are described in detail in the following paragraphs. Collectively, we refer to the relevant portions of the two SIP revisions as the 2016 Ventura County Ozone SIP.

1. VCAPCD's 2016 Air Quality Management Plan

On April 11, 2017, CARB submitted the Final 2016 Ventura County Air Quality Management Plan (February 14, 2017) (“2016 Ventura County AQMP”) to the EPA as a revision to the California SIP.^[20] The 2016 Ventura County AQMP addresses the nonattainment area requirements for Ventura County for the 2008 ozone NAAQS.

More specifically, the 2016 Ventura County AQMP includes a base year emissions inventory,^[21] reasonably available control measure (RACM) demonstration, RFP demonstration, attainment demonstration, contingency measures, motor vehicle and general conformity emissions budgets, and it also addresses the emissions statement requirement. The appendices to the 2016 Ventura County AQMP provide documentation for the emissions inventories, RACM demonstration, and the photochemical modeling conducted in support of the attainment demonstration. Further support for the attainment demonstration is provided in Appendix J (“Ventura County Unmonitored Area Analysis”) and Appendix K (“Ventura County Weight of Evidence Assessment”). The April 11, 2017 SIP submittal of the 2016 Ventura County AQMP was accompanied by public process documentation at both the County and State levels.

Since submittal of the 2016 Ventura County AQMP, CARB has replaced or supplemented certain elements of the 2016 Ventura County AQMP (such as the RFP demonstration and contingency measure element) through a SIP revision submittal dated December 5, 2018 and discussed in more detail in the following subsection. In addition, by letter dated August 29, 2019, CARB has provided some additional information related to the motor vehicle emissions budgets in the 2016 Ventura County AQMP.^[22]

2. CARB's 2018 Updates to the California State Implementation Plan

On December 5, 2018, CARB submitted the 2018 Updates to the California State Implementation Plan (“2018 SIP Update”) to the EPA as a revision to the California SIP.^[23] CARB adopted the 2018 SIP Update on October 25, 2018. CARB developed the 2018 SIP Update in response to the court's decision in South Coast II vacating the 2008 Ozone SRR with respect to the use of an alternate baseline year for demonstrating RFP and to provide additional information pertaining to the contingency measure requirement in the wake of the court decision in Bahr v. EPA.^[24] The 2018 SIP Update includes an RFP demonstration using the required 2011 baseline year for Ventura County for the 2008 ozone NAAQS. The RFP demonstration in the 2018 SIP Update for Ventura County supersedes and replaces the RFP demonstration in the 2016 Ventura County AQMP.^[25]

The 2018 SIP Update includes updates for 8 different California ozone nonattainment areas. We have already taken action to approve the San Joaquin Valley and South Coast portions of the 2018 SIP Update.^[26] In today's document, we are proposing action on the Ventura County portion of the 2018 SIP Update. Also, to supplement the contingency measure element of the 2016 Ventura County Ozone SIP, in a letter dated August 30, 2019, CARB forwarded to the EPA an August 16, 2019 letter of commitment from the District.^[27] In its letter, the District commits to modify at least one of three existing rules to create a contingency measure that will be triggered if the area fails to meet an RFP milestone or to attain the 2008 ozone NAAQS and to transmit the rule, as amended, to CARB for submittal to the EPA.^[28] In the August 30, 2019 letter, CARB commits to submit the revised District rule or rules to the EPA as a SIP revision within 12 months of the effective date of the EPA's final conditional approval of the contingency measure element of the 2016 Ventura County Ozone SIP.

B. CAA Procedural Requirements for Adoption and Submission of SIP Revisions

Sections 110(a) and 110(l) of the CAA require a state to provide reasonable public notice and opportunity for public hearing prior to the adoption and submission of a SIP or SIP revision. To meet this requirement, every SIP submittal should include evidence that adequate public notice was given and an opportunity for a public hearing was provided consistent with the EPA's implementing regulations in 40 CFR 51.102.

Both the District and CARB have satisfied the applicable statutory and regulatory requirements for reasonable public notice and hearing prior to the adoption and submittal of the SIP revisions that comprise the 2016 Ventura County Ozone SIP. With respect to the 2016 Ventura County AQMP, the District provided two public review periods: One for the initial draft 2016 Ventura County AQMP and a second for the final draft 2016 Ventura County AQMP. Combined, the public review periods lasted 43 days. The District published notices of the two public review periods on its website and in a local newspaper. The District also published notice of a public hearing to be held on February 14, 2017, for the adoption of the 2016 Ventura County AQMP. On February 14, 2017, the District held the public hearing, and, through a minute order, adopted the 2016 Ventura County AQMP and directed staff to forward the plan to CARB for inclusion in the California SIP.

CARB also provided public notice and opportunity for public comment on the 2016 Ventura County AQMP. On February 17, 2017, CARB released for public review its Staff Report for the 2016 Ventura County AQMP and published a notice of public meeting to be held on March 23, 2017, to consider adoption of the 2016 Ventura County AQMP.^[29] On March 23, 2017, CARB held the hearing and adopted the 2016 Ventura County AQMP as a revision to the California SIP, and directed the Executive Officer to submit the 2016 Ventura County AQMP to the EPA for approval into the California SIP.^[30] On April 11, 2017, the Executive Officer of CARB submitted the 2016 Ventura County AQMP to the EPA and included a public comments log entry indicating that there were no public comments during the Board hearing held on March 23, 2017.^[31]

With respect to the 2018 SIP Update, CARB also provided public notice and opportunity for public comment. On September 21, 2018, CARB released for public review the 2018 SIP Update and published a notice of public meeting to be held on October 23, 2018, to consider adoption of the 2018 SIP Update.^[32] On October 23, 2018, through Resolution 18-50, CARB adopted the 2018 SIP Update. On December 5, 2018, CARB submitted the 2018 SIP Update to the EPA.

Based on information provided in each of the SIP revisions summarized above, the EPA has determined that all hearings were properly noticed. Therefore, we find that the submittals of the 2016 Ventura County AQMP and the 2018 SIP Update meet the procedural requirements for public notice and hearing in CAA sections 110(a) and 110(l) and 40 CFR 51.102.

III. Evaluation of the 2016 Ventura County Ozone SIP

A. Emissions Inventories

1. Statutory and Regulatory Requirements

CAA sections 172(c)(3) and 182(a)(1) require states to submit for each ozone nonattainment area a “base year inventory” that is a comprehensive, accurate, current inventory of actual emissions from all sources of the relevant pollutant or pollutants in the area. In addition, the 2008 Ozone SRR requires that the inventory year be selected consistent with the baseline year for the RFP demonstration, which is the most recent calendar year for which a complete triennial inventory is required to be submitted to the EPA under the Air Emissions Reporting Requirements.^[33]

The EPA has issued guidance on the development of base year and future year emissions inventories for ozone and other pollutants.^[34] Emissions inventories for ozone must include emissions of VOC and NO_X and represent emissions for a typical ozone season weekday.^[35] States should include documentation explaining how the emissions data were calculated. In estimating mobile source emissions, states should use the latest emissions models and planning assumptions available at the time the SIP is developed.^[36]

Future baseline emissions inventories must reflect the most recent population, employment, travel and congestion projections for the area. In this context, future “baseline” emissions inventories refer to emissions estimates for a given year and area that reflect rules and regulations and other measures that are already adopted and that take into account expected growth. Future baseline emissions inventories are necessary to show the projected effectiveness of SIP control measures. Both the base year and future year inventories are necessary for photochemical modeling to demonstrate attainment.

2. Summary of State's Submission

The 2016 Ventura County AQMP includes base year (2012) and future year baseline inventories for NO_X and VOC for the Ventura County ozone nonattainment area. Documentation for the inventories is found in Chapter 2 (“2012 Baseline Emissions Inventory”) and Appendix A (“Ventura County Emissions Inventory Documentation”) of the 2016 Ventura County AQMP. Because ozone levels in Ventura County are typically higher from May through October, these inventories represent average summer day emissions. The 2012 base year and future year inventories in the 2016 Ventura County AQMP reflect District rules adopted prior to July 2015, and CARB rules adopted by November 2015.^[37] The mobile source portions of both base year and projected future year inventories were developed using California's EPA-approved mobile source emissions model, EMFAC2014, for estimating on-road motor vehicle emissions.^[38]

Emissions estimates of VOC and NO_X in the 2016 Ventura County AQMP are grouped into two general categories: (1) Stationary and area-wide sources, and (2) mobile sources, which are comprised of on-road motor vehicles and other mobile (off-road) sources. Stationary sources refer to larger “point” sources that have a fixed geographic location, such as power plants, industrial engines, and oil storage tanks, and that are subject to District permits. Area-wide sources are emissions sources occuring over a wide geographic area such as consumer products and architectural coatings. The emissions inventories for the 2016 Ventura County AQMP account for smaller permitted stationary sources in the area source categories. The mobile sources category is divided into two major subcategories, “on-road” and “off-road” mobile sources. On-road mobile sources include light-duty automobiles, light-, medium-, and heavy-duty trucks, and motorcycles. Off-road mobile sources include aircraft and boats.

For the 2016 Ventura County AQMP, point source emissions for the 2012 base year emissions inventory are based on reported data from facilities using the District's annual emissions reporting program, which applies under District Rule 24 (“Source Recordkeeping, Reporting and Emissions Statements”) to all stationary sources in Ventura County that emit more than 25 tons per year (tpy) or more of VOC or NO_X. Area sources include smaller emissions sources distributed across the nonattainment area. CARB and the District estimate emissions for area sources using established inventory methods, including publicly available emission factors and activity information. Area source methodologies are described in Appendix A of the 2016 Ventura County AQMP. To improve and update the emissions inventory, District staff evaluate the data and methods used on an annual basis. CARB and District staff coordinate the update process through the State's Emissions Inventory Technical Advisory Committee.

On-road emissions inventories in the 2016 Ventura County AQMP are calculated using CARB's EMFAC2014 model ^[39] and the travel activity data provided by the Southern California Association of Governments (SCAG) in “The 2016-2040 Regional Transportation Plan/Sustainable Communities Strategy.” ^[40] CARB provided emissions inventories for off-road equipment, including construction and mining equipment, industrial and commercial equipment, lawn and garden equipment, agricultural equipment, ocean-going vessels, commercial harbor craft, locomotives, cargo handling equipment, pleasure craft, and recreational vehicles. CARB uses several models to estimate emissions for more than one hundred off-road equipment categories.^[41] The District estimates aircraft emissions based on information provided by the airport operators in Ventura County.

The 2016 Ventura County AQMP distinguishes between emission sources within Ventura County, which includes coastal emissions (including marine vessel emissions) within three miles of the coastline, and emissions sources operating outside the county but within 100 nautical miles of the coastline. The latter are included in the Outer Continental Shelf (OCS) category. The base year emissions inventory reflects only those emissions sources that operate within the nonattainment area (i.e., within the three miles of the coastline), but OCS emissions sources affect ozone concentrations in the nonattainment area and thus are included in the emissions inventories used for the attainment demonstration in the 2016 Ventura County AQMP.

Future emissions forecasts in the 2016 Ventura County AQMP are primarily based on demographic and economic growth projections provided by SCAG (i.e., the metropolitan planning organization (MPO) for Ventura County), and control factors developed by the District in reference to the 2012 base year. Growth factors used to project these baseline inventories are derived mainly from data obtained from SCAG.^[42]

Under EPA's SIP regulations for nonattainment new source review (NSR) programs, a state may allow new major stationary sources or major modifications to use emission reductions credits (ERCs) that were generated through shutdown or curtailed emissions units occuring before the base year of an attainment plan. However, to use such ERCs, the projected emissions inventory used to develop the attainment demonstration must explicitly include the emissions from such previously shutdown or curtailed emissions units.^[43] The District has elected to provide for use of pre-base year ERCs as offsets by explicitly including such ERCs in the 2020 attainment year inventory. The ERC set-aside in the attainment year (2020) amounts to 1.72 tons per day (tpd) of VOC and 0.82 tpd of NO_X.

Table 1 provides a summary of the District's 2012 base year and future attainment year baseline emissions estimates in tpd (average summer day) for VOC and NO_X. These inventories provide the basis for the control measure analysis and the attainment demonstration in the 2016 Ventura County AQMP. Based on the inventory for 2012, stationary, area and mobile sources contribute roughly equally to county-wide VOC emissions, whereas mobile sources are the predominant sources of NO_X emissions. The inventory for 2012 also shows the extent (about 40 percent) to which OCS sources contribute to the overall anthropogenic NO_X emissions total used for attainment modeling purposes.

Table 1—Ventura County 2012 Base Year and 2020 Attainment Year Emissions Inventories

[Summer planning inventory, tpd]

Category	2012		2020
	VOC	NOX	VOC	NOX
Stationary	8.55	2.08	8.67	1.87
Area Sources	11.57	0.95	10.91	0.62
On-Road Mobile Sources	8.54	12.62	4.21	6.01
Other (Off-Road) Mobile Sources	8.14	8.78	6.63	7.25
ERCs			1.72	0.82
Total for Ventura County Nonattainment Area	36.81	24.44	32.14	16.57
OCS Sources	0.96	16.11	1.37	15.49
Total Anthropogenic Emissions Used for Attainment Demonstration	37.76	40.55	33.50	32.06
Source: 2016 Ventura County AQMP, Appendix A, tables A-7 and A-8. The sum of the emissions values may not equal the total shown due to rounding of the numbers.

Following the South Coast II decision, CARB submitted the 2018 SIP Update to the EPA to, among other things, revise the RFP demonstration in the 2016 Ventura County AQMP based on a 2011 RFP baseline year (i.e., rather than 2012).^[44] Our analysis of the emissions inventories for the 2011 RFP baseline year and RFP milestone years 2017 and 2020 can be found in section III.E below.

3. The EPA's Review of the State's Submission

We have reviewed the 2012 base year emissions inventory in the 2016 Ventura County AQMP and the inventory methodologies used by the District and CARB for consistency with CAA requirements and EPA guidance. First, as required by EPA regulation, we find that the 2012 inventory includes estimates for VOC and NO_X for a typical ozone season weekday, and that CARB has provided adequate documentation explaining how the emissions are calculated. Second, we find that the 2012 base year emissions inventory in the 2016 Ventura County AQMP reflects appropriate emissions models and methodologies, and, therefore, represents a comprehensive, accurate, and current inventory of actual emissions during that year in the Ventura County nonattainment area. Third, we find that selection of year 2012 for the base year emissions inventory is appropriate because it is consistent with the 2011 RFP baseline year (from the 2018 SIP Update) because both inventories are derived from a common set of models and methods. Therefore, the EPA is proposing to approve the 2012 emissions inventory in the 2016 Ventura County AQMP as meeting the requirements for a base year inventory set forth in CAA section 182(a)(1) and 40 CFR 51.1115. In addition, although the requirement for a base year emissions inventory applies to the nonattainment area, we find that the District's estimates of OCS emissions out to 100 nautical miles (i.e., beyond the nonattainment area boundary that extends 3 miles offshore) are reasonable and appropriate to include in the 2016 Ventura County AQMP given that such emissions must be accounted for in the ozone attainment demonstration for this nonattainment area.

With respect to future year baseline projections, we have reviewed the growth and control factors and find them acceptable and conclude that the future baseline emissions projections in the 2016 Ventura County AQMP reflect appropriate calculation methods and the latest planning assumptions.

Furthermore, we note that the future year baseline projections take into account emissions reductions from adopted State and local rules and regulations. As a general matter, the EPA will approve a SIP revision that takes emissions reduction credit for such control measures only where the EPA has approved the control measures as part of the SIP. Table 1 in the EPA's memorandum dated September 11, 2019, to the docket for this rulemaking lists District VOC and NO_X rules that the 2016 Ventura County AQMP relied upon in developing future year baseline emissions projections. Table 1 also includes information on EPA approval of these rules and shows that emissions reductions for stationary sources assumed by the 2016 Ventura County AQMP for future years are supported by rules approved as part of the SIP.^[45] With respect to mobile sources, the EPA has taken action in recent years to approve CARB mobile source regulations into the California SIP.^[46] We therefore find that the future year baseline projections in the 2016 Ventura County AQMP are properly supported by SIP-approved stationary and mobile source control measures.

B. Emissions Statement

1. Statutory and Regulatory Requirements

Section 182(a)(3)(B)(i) of the Act requires states to submit a SIP revision requiring owners or operators of stationary sources of VOC or NO_X to provide the state with statements of actual emissions from such sources. Statements must be submitted at least every year and must contain a certification that the information contained in the statement is accurate to the best knowledge of the individual certifying the statement. Section 182(a)(3)(B)(ii) of the Act allows states to waive the emissions statement requirement for any class or category of stationary sources that emit less than 25 tpy of VOC or NO_X, if the state provides an inventory of emissions from such class or category of sources as part of the base year or periodic inventories required under CAA sections 182(a)(1) and 182(a)(3)(A), based on the use of emission factors established by the EPA or other methods acceptable to the EPA.

The 2008 Ozone SRR provides that nonattainment areas are subject to the requirements of subpart 2 of part D of title I of the CAA that apply for that area's classification.^[47] For all areas classified under subpart 2, the emissions statement requirement under CAA section 182(a)(3)(B)(i) applies. The preamble of the 2008 Ozone SRR states that if an area has a previously approved emissions statement rule for the 1997 ozone NAAQS or the 1-hour ozone NAAQS that covers all portions of the nonattainment area for the 2008 ozone NAAQS, such rule should be sufficient for purposes of the emissions statement requirement for the 2008 ozone NAAQS.^[48] The state should review the existing rule to ensure it is adequate and, if so, may rely on it to meet the emissions statement requirement for the 2008 ozone NAAQS. Where an existing SIP-approved emissions statement rule is adequate to meet the requirements of the 2008 Ozone SRR, states can provide the rationale for that determination to the EPA in a written statement in their SIP submittal for the 2008 ozone NAAQS to meet this requirement. States should identify the various requirements and how each is met by the existing SIP-approved emissions statement program. Where an emissions statement requirement is modified for any reason, the state must provide the revision to the emissions statement rule as part of its SIP.

2. Summary of the State's Submission

The 2016 Ventura County AQMP addresses compliance with the emissions statement requirement in CAA section 182(a)(3)(B) for the 2008 ozone NAAQS by reference to District Rule 24 (“Source Recordkeeping, Reporting and Emissions Statements”).^[49] District Rule 24 requires, among other things, emissions reporting from all Ventura County stationary sources of NO_X and VOC, but provides for waiver of the requirement by the Air Pollution Control Officer for sources that emit less than 25 tpy.^[50] The EPA approved District Rule 24 as a revision to the Ventura County portion of the California SIP in 2000.^[51] The District determined in the 2016 Ventura County AQMP that the existing provisions of District Rule 24 meet the emissions statement requirements for the 2008 ozone NAAQS.^[52]

3. The EPA's Review of the State's Submission

For this action, we have reviewed VCAPCD's evaluation of SIP-approved District Rule 24 for compliance with the specific requirements for emissions statements under CAA section 182(a)(3)(B). We agree with the District that District Rule 24 applies within the entire ozone nonattainment area and that the nonattainment area is the same for both the 1-hour and 2008 ozone NAAQS; applies to all stationary sources of VOC and NO_X, except those emitting less than 25 tpy for which the District has waived the requirement (consistent with CAA section 182(a)(3)(B)(ii)); and requires reporting, on an annual basis, of total emissions of VOC and NO_X. Also, as required under CAA section 182(a)(3)(B), we note that District Rule 24 requires certification that the information provided to the District is accurate to the best knowledge of the individual certifying the emissions data.

Therefore, we propose to approve the emissions statement element of the 2016 Ventura County AQMP as meeting the requirements of CAA section 182(a)(3)(B) and the 40 CFR 51.1102.

C. Reasonably Available Control Measures Demonstration

1. Statutory and Regulatory Requirements

CAA section 172(c)(1) requires that each attainment plan provide for the implementation of all RACM as expeditiously as practicable (including such reductions in emissions from existing sources in the area as may be obtained through implementation of reasonably available control technology), and also provide for attainment of the NAAQS. The 2008 Ozone SRR requires that, for each nonattainment area required to submit an attainment demonstration, the state concurrently submit a SIP revision demonstrating that it has adopted all RACM necessary to demonstrate attainment as expeditiously as practicable and to meet any RFP requirements.^[53]

The EPA has previously provided guidance interpreting the RACM requirement in the General Preamble for the Implementation of the Clean Air Act Amendments of 1990 (“General Preamble”) and in a memorandum titled “Guidance on the Reasonably Available Control Measure Requirement and Attainment Demonstration Submissions for Ozone Nonattainment Areas.” ^[54] In short, to address the requirement to adopt all RACM, states should consider all potentially reasonable control measures for source categories in the nonattainment area to determine whether they are reasonably available for implementation in that area and whether they would, if implemented individually or collectively, advance the area's attainment date by one year or more.^[55] Any measures that are necessary to meet these requirements that are not already either federally promulgated, or part of the state's SIP, must be submitted in enforceable form as part of the state's attainment plan for the area.^[56]

2. Summary of the State's Submission

For the 2016 Ventura County AQMP, the District, the Ventura County Transportation Commission (VCTC) and CARB each undertook a process to identify and evaluate potential RACM that could contribute to expeditious attainment of the 2008 ozone NAAQS in Ventura County. We describe these efforts in the three sections below. To determine what RACM may be necessary, the District compares, in the 2016 Ventura County AQMP, the projected 2019 emissions inventory to the 2020 attainment year. Comparing the levels of VOC and NO_X in these two years, during which emissions are declining, allows a simple subtraction to determine what amount of emissions reductions would result in 2020 attainment year-level emissions in the year 2019. Since levels of VOC are identical in both 2019 and 2020, no reduction was necessary to achieve the attainment year VOC emissions level. However, for NO_X the difference was 2 tpd, so the RACM analyses of the 2016 Ventura County AQMP appendices E, F and G focus on determining whether one or more control measures would be potentially reasonable and would result in a 2 tpd reduction of NO_X emissions prior to the 2020 attainment year.

a. District's RACM Analysis

The District's portion of the RACM demonstration for the 2008 ozone NAAQS focuses on stationary source controls and is described in the 2016 Ventura County AQMP on pages 54 and 55, and in Appendix E (“Ventura County Stationary Source Reasonably Available Control Measure Assessment”). Appendix E contains analyses of all potential stationary source control measures in the District's jurisdiction.

As background, the District notes that Ventura County was nonattainment for all prior ozone NAAQS, therefore the District's RACM analysis builds upon a foundation of District rules developed for earlier ozone plans. We provide a list of the District's NO_X and VOC rules approved into the California SIP in Table 1 of our September 11, 2019 memorandum to the docket for this proposed action.^[57] The 48 SIP-approved District VOC or NO_X rules listed in Table 1 of our September 11, 2019 memorandum establish emission limits or other types of emissions controls for a wide range of sources, including use of solvents, refineries, gasoline storage, architectural coatings, oilfield drilling operations, various types of commercial coatings, boilers, steam generators and process heaters, marine coating operations, dry cleaning, and others. These rules have already provided significant and ongoing reductions toward attainment of the 2008 ozone NAAQS by 2020. In describing its stationary source controls, the District also notes the EPA's 2015 approval of its reasonably available control technology (RACT) SIP and our finding in that action that District rules that apply to ozone precursor emissions fulfill RACT requirements for the 2008 ozone NAAQS.^[58]

For the stationary source RACM demonstration, the District evaluated the VOC and NO_X rules that were not fully addressed in the District's 2014 RACT SIP for potential RACM emissions reductions. The District compared that subset of District rules to analogous rules adopted by other air districts having nonattainment areas with higher ozone nonattainment classifications (i.e., South Coast and San Joaquin Valley, which are both “Extreme” nonattainment areas for the 2008 ozone NAAQS), as well as certain other air districts such as the Bay Area Air Quality Management District, to evaluate whether control technologies available and cost-effective within other areas would be available and cost-effective for use in Ventura County. The District also identified a few rules from other air districts that apply to unregulated source categories in Ventura County. Tables E-2 and E-3 in Appendix E of the 2016 Ventura County AQMP list the rules that the District evaluated for the RACM demonstration. Table E-2 includes 13 rules that the District has previously adopted that were compared to rules in other areas. Table E-3 includes five source categories the District evaluated, where there is no corresponding rule for that source category in Ventura County.

The District provides an evaluation of the controls it reviewed for RACM purposes in Appendix E of the 2016 Ventura County AQMP. The evaluation includes the following: Description of the Ventura County sources within the category or sources that would be subject to the rule; potential NO_X and VOC emissions reductions expected from implementing the rule in Ventura County for the source category affected by the rule; discussion of the current requirements of the rule; and discussion of potential additional control measures. This includes comparison of each District rule to analogous control measures adopted by other agencies.

Among the 13 existing District NO_X or VOC rules that the District compared to rules in other areas, the District found that eight of the VCAPCD rule emission limits were as stringent as those found in analogous rules adopted by the other districts or were not applicable for the purposes of comparison. The District estimated the emissions reductions for the remaining five rules that could be made more stringent to match the most stringent of the other district rules' limits.^[59] Among the five source categories for which the District has no current rules, the District identified four categories for which other districts have adopted rules that could be adopted for Ventura County.^[60]

The District estimated the potential emissions reduction associated with revisions to the five existing District rules and adoption of the four new rules to be approximately 0.5 tpd of VOC and 0.01 tpd of NO_X. Based on the District's threshold of 2 tpd of NO_X as the minimum reduction necessary to advance attainment by one year, the District concluded that its current set of VOC and NO_X rules represent all RACM within regulatory jurisdiction, and that no further RACM are necessary to meet the RACM requirement for the 2008 ozone NAAQS. We note that the new stationary source control measures in the 2016 Ventura County AQMP include revisions to two existing District rules, Rule 74.2 (“Architectural Coatings”) and Rule 74.22 (“Natural Gas-Fired, Central Fan-Type Furnaces”), and adoption of one new rule, proposed new Rule 74.32 (“Compostable Material Handing and Conversion Operations”), that are part of the RACM analysis. However, the purpose of these stationary source control measures in the 2016 Ventura County AQMP was not to meet the RACM requirement but to provide emissions reductions for the 2015 ozone NAAQS and to fulfill State air quality requirements.

b. Local Jurisdiction's RACM Analysis and Transportation Control Measures

Transportation Control Measures (TCMs) are projects that reduce air pollutants from transportation sources by reducing vehicle use, traffic congestion, or vehicle miles traveled. Appendix B (“Ventura County Transportation Control Measure Commitments”) of the 2016 Ventura County AQMP lists the current TCMs identified by SCAG and the District as committed TCMs. “Committed” TCMs are subject to the timely implementation requirement in CAA section 176(c)(2)(B). For the 2016 Ventura County AQMP, the District and VCTC worked together to determine whether additional TCMs are necessary to meet the RACM requirement. The TCM RACM component of the 2016 Ventura County AQMP is found on page 55 of the AQMP and in Appendix F (“Ventura County Transportation Control Measures Reasonably Available Control Measure Assessment”).

First, the District prepared a list of candidate RACM using the CAA's list of TCMs in section 108(f)(1)(A) by reviewing the TCMs in the 2008 Ventura County AQMP, and other air district and planning agency plans, such as the 2012 South Coast AQMP, 2007 San Joaquin Valley Ozone Plan, 2013 Sacramento Regional 8-Hour Ozone Attainment and Reasonable Further Progress Plan, and the 2004/2007 Metropolitan Washington Council of Governments SIP. Second, the District, along with staff of the VCTC, sorted the candidate TCMs based on their feasibility or infeasibility for implementation in Ventura County.^[61] Table F-1 of Appendix F of the 2016 Ventura County AQMP summarizes the results of the sorting process. Justification is provided in Table F-1 for those candidate TCMs deemed by the District and VCTC to be infeasible. All candidate TCMs are organized in Table F-1 according to the sixteen categories specified in section 108(f)(1)(A) of the CAA.

The District found that the majority of TCMs that were deemed to be feasible in Ventura County were already being implemented, or had been implemented in the county, and that implementing all additional feasible TCMs in the county would not advance attainment by a year. Based on its comprehensive review of TCM projects in other nonattainment areas or otherwise identified, the District determined that the TCMs being implemented in Ventura County are inclusive of all RACM.^[62]

c. CARB's RACM Analysis

Source categories for which CARB has primary jurisdiction for reducing emissions in California include most new and existing on- and off-road engines and vehicles, motor vehicle fuels, and consumer products. CARB's RACM assessment is contained in the 2016 Ventura County AQMP, Appendix G (“Ventura County Mobile Source Reasonably Available Control Measures Assessment”). In the 2016 Ventura County AQMP, CARB has also provided a general description of CARB's key mobile source regulations and programs and a comprehensive table listing on- and off-road mobile source regulatory actions taken by CARB from 1985 through 2016.^[63] The RACM assessment contains CARB's evaluation of mobile source and other statewide control measures that reduce emissions of NO_X and VOC in Ventura County.

Given the need for substantial emissions reductions from mobile and area sources to meet the NAAQS in California nonattainment areas, CARB established stringent control measures for on-road and off-road mobile sources and the fuels that power them. California has unique authority under CAA section 209 (subject to a waiver by the EPA) to adopt and implement new emission standards for many categories of on-road vehicles and engines, and new and in-use off-road vehicles and engines.

CARB's mobile source program extends beyond regulations that are subject to the waiver or authorization process set forth in CAA section 209, to include standards and other requirements to control emissions from in-use heavy-duty trucks and buses, gasoline and diesel fuel specifications, and many other types of mobile sources. Generally, these regulations have been submitted and approved as revisions to the California SIP.^[64]

In the RACM assessment, CARB concludes that there are no additional RACM that would advance attainment of the 2008 ozone NAAQS in Ventura County. As a result, CARB concludes that California's mobile source programs fully meet the RACM requirement.^[65]

3. The EPA's Review of the State's Submission

As described above, the District already implements many rules to reduce VOC and NO_X emissions from stationary sources in Ventura County. For the 2016 Ventura County AQMP, the District evaluated a range of potentially available control measures. We find that the process followed by the District in the 2016 Ventura County AQMP to identify additional RACM is generally consistent with the EPA's recommendations in the General Preamble, the District's evaluation of potential measures is appropriate, and the District has provided reasoned justifications for rejection of measures deemed not reasonably available.

With respect to mobile sources, CARB's current program addresses the full range of mobile sources in Ventura County through regulatory programs for both new and in-use vehicles. With respect to TCMs, we find that the District's and VCTC's process for identifying additional TCM RACM and the District's conclusion that the TCMs being implemented in Ventura County (i.e., the TCMs listed in Table B-1 in Appendix B of the 2016 Ventura County AQMP) are inclusive of all TCM RACM to be reasonably justified and supported.

Based on our review of these RACM analyses, the District's and CARB's adopted rules, and SCAG's committed TCMs, we propose to find that there are, at this time, no additional RACM that would advance attainment of the 2008 ozone NAAQS in Ventura County.^[66] For the foregoing reasons, we propose to find that the 2016 Ventura County AQMP provides for the implementation of all RACM as required by CAA section 172(c)(1) and 40 CFR 51.1112(c).

D. Attainment Demonstration

1. Statutory and Regulatory Requirements

An attainment demonstration consists of the following: (1) Technical analyses, such as base year and future year modeling, to locate and identify sources of emissions that are contributing to violations of the ozone NAAQS within the nonattainment area (i.e., analyses related to the emissions inventory for the nonattainment area and the emissions reductions necessary to attain the standard); (2) a list of adopted measures (including RACT controls) with schedules for implementation and other means and techniques necessary and appropriate for demonstrating RFP and attainment as expeditiously as practicable but no later than the outside attainment date for the area's classification; (3) a RACM analysis; and (4) contingency measures required under sections 172(c)(9) and 182(c)(9) of the CAA that can be implemented without further action by the state or the EPA to cover emissions shortfalls in RFP plans and failures to attain.^[67] This subsection of today's proposed rule addresses the first two components of the attainment demonstration—the technical analyses and a list of adopted measures. Section III.C, Reasonably Available Control Measures Demonstration, of this document addresses the RACM component, and section III.F, Contingency Measures, addresses the contingency measures component of the attainment demonstration in the 2016 Ventura County AQMP.

With respect to the technical analyses, section 182(c)(2)(A) of the CAA requires that a plan for an ozone nonattainment area classified Serious or above include a “demonstration that the plan . . . will provide for attainment of the ozone [NAAQS] by the applicable attainment date. This attainment demonstration must be based on photochemical grid modeling or any other analytical method determined . . . to be at least as effective.” The attainment demonstration predicts future ambient concentrations for comparison to the NAAQS, making use of available information on measured concentrations, meteorology, and current and projected emissions inventories of ozone precursors, including the effect of control measures in the plan.

Areas classified Serious for the 2008 ozone NAAQS must demonstrate attainment as expeditiously as practicable, but no later than 9 years after the effective date of designation to nonattainment. Ventura County was designated nonattainment effective July 20, 2012, and the area must demonstrate attainment of the 2008 ozone NAAQS by July 20, 2021.^[68] An attainment demonstration must show attainment of the standards for a full calendar year before the attainment date, so in practice, Serious nonattainment areas must demonstrate attainment in 2020.

The EPA's recommended procedures for modeling ozone as part of an attainment demonstration are contained in “Modeling Guidance for Demonstrating Attainment of Air Quality Goals for Ozone, PM_2.5, and Regional Haze” (“Modeling Guidance”).^[69] The Modeling Guidance includes recommendations for a modeling protocol, model input preparation, model performance evaluation, use of model output for the numerical NAAQS attainment test, and modeling documentation. Air quality modeling is performed using meteorology and emissions from a base year, and the predicted concentrations from this base case modeling are compared to air quality monitoring data from that year to evaluate model performance.

Once the model performance is determined to be acceptable, future year emissions are simulated with the model. The relative (or percent) change in modeled concentration due to future emissions reductions provides a Relative Response Factor (RRF). Each monitoring site's RRF is applied to its monitored base year design value to provide the future design value for comparison to the NAAQS. The Modeling Guidance also recommends supplemental air quality analyses, which may be used as part of a Weight of Evidence (WOE) analysis. A WOE analysis corroborates the attainment demonstration by considering evidence other than the main air quality modeling attainment test, such as trends and additional monitoring and modeling analyses.

The Modeling Guidance does not require a particular year to be used as the base year for 2008 ozone NAAQS plans.^[70] The Modeling Guidance states that the most recent year of the National Emissions Inventory may be appropriate for use as the base year for modeling, but that other years may be more appropriate when considering meteorology, transport patterns, exceptional events, or other factors that may vary from year to year.^[71] Therefore, the base year used for the attainment demonstration need not be the same year used to meet the requirements for RFP.

With respect to the list of adopted measures, CAA section 172(c)(6) requires that nonattainment area plans include enforceable emissions limitations, and such other control measures, means or techniques (including economic incentives such as fees, marketable permits, and auctions of emission rights), as well as schedules and timetables for compliance, as may be necessary or appropriate to provide for timely attainment of the NAAQS.^[72] Under the 2008 Ozone SRR, all control measures needed for attainment must be implemented no later than the beginning of the attainment year ozone season.^[73] The attainment year ozone season is defined as the ozone season immediately preceding a nonattainment area's maximum attainment date.^[74]

2. Summary of the State's Submission

a. Photochemical Modeling

The 2016 Ventura County AQMP includes photochemical modeling for the 2008 ozone NAAQS. The South Coast Air Quality Management District (SCAQMD) performed the air quality modeling for the 2016 Ventura County AQMP. The modeling relies on a 2012 base year and demonstrates attainment of the 2008 ozone NAAQS by the applicable Serious area attainment year (i.e. 2020).

The modeling and modeled attainment demonstration are described in Chapter 5 (“Attainment Demonstration”) of the 2016 Ventura County AQMP and in four appendices. Appendix H (“Protocol for Photochemical Modeling of Ozone in Ventura County”) of the 2016 Ventura County AQMP is the modeling protocol and contains all the elements recommended in the Modeling Guidance. Those include: Selection of model, time period to model, modeling domain, and model boundary conditions and initialization procedures; a discussion of emissions inventory development and other model input preparation procedures; model performance evaluation procedures; selection of days; and other details for calculating RRFs. Appendix H of the 2016 Ventura County AQMP also provides the coordinates of the modeling domain and thoroughly describes the development of the modeling emissions inventory, including its chemical speciation, its spatial and temporal allocation, its temperature dependence, and quality assurance procedures.

The modeling analysis used version 5.0.2 of the Community Multiscale Air Quality (CMAQ) photochemical model, developed by the EPA. To prepare meteorological input for CMAQ, the Weather and Research Forecasting model version 3.6 (WRF) from the National Center for Atmospheric Research was used. CMAQ and WRF are both recognized in the Modeling Guidance as technically sound, state-of-the-art models. The areal extent and the horizontal and vertical resolution used in these models were adequate for modeling ozone in the southern California domain, including Ventura.

The performance of the WRF meteorological model was assessed through a series of simulations, and the SCAQMD concluded that the daily WRF simulation for 2012 provided representative meteorological fields that well characterized the observed conditions. The SCAQMD's conclusions were supported by hourly time series graphs of wind speed, direction, and temperature.^[75]

Ozone model performance statistics are described in the 2016 Ventura County AQMP Appendix I (“Ventura County Community Multiscale Air Quality Model Performance Analysis”), which include tables of statistics recommended in the Modeling Guidance for 8-hour daily maximum ozone for Ventura County. Hourly time series are presented, as well as density scatter plots and plots of bias against concentration. Note that only relative changes are used from the modeling, therefore the overprediction or underprediction of absolute ozone concentrations does not mean that future concentrations will be overestimated or underestimated.

After model performance for the 2012 base case was accepted, the model was applied to develop RRFs for the attainment demonstration. This entailed running the model with the same meteorological inputs as before, but with adjusted emissions inventories to reflect the expected changes between 2012 and the 2020 attainment year. The base year or “reference year” modeling inventory was the same as the inventory for the modeling base case. The 2020 inventory projects the base year into the future by including the effect of economic growth and emissions control measures. The set of 153 days from May 1 through September 30, 2012, was simulated and analyzed to determine daily 8-hour average maximum ozone concentrations for the 2020 emissions inventory. To develop the RRFs for the 2008 ozone NAAQS, only the top 10 days were used.

The Modeling Guidance addresses attainment demonstrations with ozone NAAQS based on 8-hour averages. For the 2008 ozone NAAQS, the 2016 Ventura County AQMP carried out the attainment test procedure consistent with the Modeling Guidance. The RRFs were calculated as the ratio of future to base year concentrations. The resulting RRFs were then applied to 2012 weighted base year design values ^[76] for each monitor to arrive at a 2020 future year design value.^[77] The highest 2020 ozone design value is 0.072 ppm at the Simi Valley site; this value demonstrates attainment of the corresponding 2008 ozone NAAQS of 0.075 ppm.

The 2016 Ventura County AQMP modeling also includes a WOE demonstration in Appendix K (Ventura County Weight of Evidence Assessment) prepared by CARB. To complement regional photochemical modeling analyses included in the 2016 Ventura County AQMP, the WOE demonstration includes detailed analyses of ambient ozone data, county level precursor emissions trends, population exposure trends, and a discussion of conditions that contribute to exceedances of the 0.075 ppm 2008 ozone NAAQS. Further, the rate of progress toward air quality goals was evaluated by considering trends in ozone design values, precursor emissions reductions, and the relationship between ozone air quality and past emissions reductions.^[78]

Finally, the 2016 Ventura County AQMP includes an unmonitored area analysis for the 2008 ozone NAAQS to assess the attainment status of locations other than monitoring sites.^[79] The Modeling Guidance describes a “gradient adjusted spatial fields” procedure along with the EPA software (i.e., Modeled Attainment Test Software) used to carry it out.^[80] The unmonitored area analysis in the 2016 Ventura County AQMP shows concentrations below the 2008 ozone NAAQS for all locations.^[81]

b. Control Strategy for Attainment

The control strategy for attainment of the 2008 ozone NAAQS in the 2016 Ventura County AQMP relies on emissions reductions from baseline (i.e., already-adopted) measures. The baseline control measures include the District's stationary source rules, including those specifically included in the emissions inventories prepared for the 2016 Ventura County AQMP,^[82] and CARB's mobile source and consumer product rules adopted through 2016 as listed in Appendix D of the 2016 Ventura County AQMP.

c. Attainment Demonstration

Table 2 below summarizes the attainment demonstration for the 2008 ozone NAAQS by listing the base year (2012) emissions level, the modeled attainment emissions level, and the reductions that the District and CARB estimate to achieve through baseline control measures taking into account growth and the District's ERC balance. As shown in Table 2, baseline measures are expected to reduce base year (2012) emissions of NO_X by 21 percent and VOC emissions by 11 percent by the 2020 attainment year, notwithstanding growth and the ERC balance, and to attain the 2008 ozone NAAQS in Ventura County by that year.

Table 2—Summary of Ventura County 2008 Ozone NAAQS Attainment Demonstration

[Summer planning inventory, tpd]

	NOX	VOC
A 2012 Base Year Emissions Level a	40.55	37.76.
B—2020 Modeled Attainment Emissions Level a	32.06	33.50.
C Total Reductions Needed from 2012 Base Year Levels to Demonstrate Attainment (A-B)	8.49	4.26.
D Reductions from Baseline (i.e., adopted) Measures, net of growth and ERC balance	8.49	4.26.
E 2020 Emissions with Reductions from Baseline Control Strategy (compare to Row B)	32.06	33.50.
Attainment demonstrated?	Yes	Yes.
Notes and sources:
a 2016 Ventura County AQMP, Appendix A, tables A-6 and A-7. Includes emissions out to 100 nautical miles from the coast. Year 2020 Modeled Attainment Emissions Level includes ERC balance.

3. The EPA's Review of the State's Submission

a. Photochemical Modeling

To approve a SIP's attainment demonstration, the EPA must make several findings. First, we must find that the demonstration's technical bases, including the emissions inventories and air quality modeling, are adequate. As discussed above in section III.A of this document, we are proposing to approve the base year emissions inventory and to find that the future year emissions projections in the 2016 Ventura County AQMP reflect appropriate calculation methods and that the latest planning assumptions are properly supported by SIP-approved stationary and mobile source measures. These are the same inventories used for the attainment demonstration, and thus, we find that the emissions portion of the attainment demonstration is adequate.

With respect to the photochemical modeling in the 2016 Ventura County AQMP, based on our review of the 2016 Ventura County AQMP, the EPA finds that the modeling is adequate for purposes of supporting the attainment demonstration. First, we note the extensive discussion of modeling procedures, tests, and performance analyses called for in the Modeling Protocol (i.e., Appendix H) and the good model performance. Second, we find the WRF meteorological model results and performance statistics, including hourly time series graphs of wind speed, direction, and temperature for the southern California modeling domain, to be satisfactory and consistent with our Modeling Guidance.^[83]

The model performance statistics for ozone are described in the 2016 Ventura County AQMP, Appendix I. The analysis evaluated how well the photochemical model for the 2016 Ventura County AQMP was able to predict 8-hour ozone concentrations at each monitoring site in the county compared to observed 8-hour ozone concentrations at those same monitoring sites and is based on the statistical evaluation recommended in the Modeling Guidance. The base year average regional model performance was evaluated for May through September 2012 for days when maximum 8-hour ozone levels were at least 60 ppb.^[84] Ozone measurements from air quality monitors in Thousand Oaks, Piru, Ojai, Simi Valley, and El Rio were compiled for the analysis. To develop the RRFs for the 2008 ozone NAAQS, only the top 10 days were used. This is consistent with EPA guidance, which recommends the use of only the top 10 days in the RRF calculation because the modeling capability to predict high concentrations is more important than the prediction of low concentrations.^[85]

The 2016 Ventura County AQMP's unmonitored area analysis showed concentrations below the 2008 ozone NAAQS for all locations. This analysis adds assurance to the attainment demonstration that all locations in Ventura County will attain the 2008 ozone NAAQS by the 2020 attainment year. In addition, the WOE analyses presented in the 2016 Ventura County AQMP provide additional information with respect to the sensitivity to emission changes and improve the understanding of the model performance. We are proposing to find the air quality modeling in the 2016 Ventura County AQMP adequate to support the attainment demonstration for the 2008 ozone NAAQS in Ventura County, based on reasonable meteorological and ozone modeling performance, and further supported by the unmonitored area and WOE analyses.

b. Control Strategy for Attainment

Second, we must find that the emissions reductions that are relied on for attainment are creditable and are sufficient to provide for attainment. As shown in Table 2 above, the 2016 Ventura County AQMP relies on baseline measures to achieve all the emissions reductions needed to attain the 2008 ozone NAAQS by 2020. The baseline measures are approved into the SIP and, as such, are fully creditable.

c. Attainment Demonstration

Based on our proposed determinations that the photochemical modeling and control strategy are acceptable, we propose to approve the attainment demonstration for the 2008 ozone NAAQS in the 2016 Ventura County AQMP as meeting the requirements of CAA section 182(c)(2)(A) and 40 CFR 51.1108.

E. Rate of Progress Plan and Reasonable Further Progress Demonstration

1. Statutory and Regulatory Requirements

Requirements for RFP for ozone nonattainment areas are specified in CAA sections 172(c)(2), 182(b)(1), and 182(c)(2)(B). Under CAA section 171(1), RFP is defined as meaning such annual incremental reductions in emissions of the relevant air pollutant as are required under CAA part D (“Plan Requirements for Nonattainment Areas”) or may reasonably be required by the EPA for the purpose of ensuring attainment of the applicable NAAQS by the applicable date. CAA section 172(c)(2) generally requires that a nonattainment plan include provisions for RFP. CAA section 182(b)(1) specifically requires that ozone nonattainment areas that are classified as Moderate or above demonstrate a 15 percent reduction in VOC between the years of 1990 and 1996. The EPA has typically referred to section 182(b)(1) as the rate of progress (ROP) requirement. For ozone nonattainment areas classified as Serious or higher, section 182(c)(2)(B) requires reductions averaged over each consecutive 3-year period, beginning 6 years after the baseline year until the attainment date, of at least 3 percent of baseline emissions per year. The provisions in CAA section 182(c)(2)(B)(ii) allow an amount less than 3 percent of such baseline emissions each year if the state demonstrates to the EPA that the plan includes all measures that can feasibly be implemented in the area in light of technological achievability.

In the 2008 Ozone SRR, the EPA provides that areas classified Moderate or higher for the 2008 ozone NAAQS will have met the ROP requirements of CAA section 182(b)(1) if the area has a fully approved 15 percent ROP plan for the 1-hour or 1997 ozone NAAQS, provided that the boundaries of the ozone nonattainment areas are the same.^[86] For such areas, the EPA interprets the RFP requirements of CAA section 172(c)(2) to require areas classified as Moderate to provide a 15 percent emission reduction of ozone precursors within 6 years of the baseline year. Areas classified as Serious or higher must meet the RFP requirements of CAA section 182(c)(2)(B) by providing an 18 percent reduction of ozone precursors in the first 6-year period, and an average ozone precursor emission reduction of 3 percent per year for all remaining 3-year periods thereafter.^[87] To meet CAA sections 172(c)(2) and 182(c)(2)(B) RFP requirements, the state may substitute NO_X emissions reductions for VOC reductions.^[88]

Except as specifically provided in CAA section 182(b)(1)(C), emissions reductions from all SIP-approved, federally promulgated, or otherwise SIP-creditable measures that occur after the baseline year are creditable for purposes of demonstrating that the RFP targets are met. Because the EPA has determined that the passage of time has caused the effect of certain exclusions to be de minimis, the RFP demonstration is no longer required to calculate and specifically exclude reductions from measures related to motor vehicle exhaust or evaporative emissions promulgated by January 1, 1990; regulations concerning Reid vapor pressure promulgated by November 15, 1990; measures to correct previous RACT requirements; and, measures required to correct previous inspection and maintenance (I/M) programs.^[89]

The 2008 Ozone SRR requires the RFP baseline year to be the most recent calendar year for which a complete triennial inventory was required to be submitted to the EPA. For the purposes of developing RFP demonstrations for the 2008 ozone NAAQS, the applicable triennial inventory year is 2011. As discussed previously, the 2008 Ozone SRR provided states with the opportunity to use an alternative baseline year for RFP,^[90] but that provision of the 2008 Ozone SRR was vacated by the D.C. Circuit in the South Coast II decision.

2. Summary of the State's Submission

The 2016 Ventura County AQMP addresses both the ROP (VOC only) demonstration requirement and the RFP demonstration requirement. With respect to the former, the District cites the EPA's 1997 approval of the ROP demonstration for the 1-hour ozone NAAQS for Ventura County and concludes that, based on the 1997 approval, the ROP requirement has been met for Ventura County for the 2008 ozone NAAQS.^[91]

With respect to the RFP demonstration requirement, the 2016 Ventura County AQMP includes an RFP demonstration derived from a 2012 RFP baseline year.^[92] In response to the South Coast II decision, CARB developed the 2018 SIP Update, which includes a section that replaces the RFP portion of the 2016 Ventura County AQMP and includes emissions estimates for the RFP baseline year, subsequent milestone years, and the attainment year, and an updated RFP demonstration based on the 2011 RFP baseline year.^[93] To develop the 2011 RFP baseline inventory, CARB relied on actual emissions reported from industrial point sources for year 2011. For emissions from smaller stationary sources and area sources, CARB backcast emissions from 2012 to 2011 using the same growth and control factors as were used for the 2016 Ventura County AQMP. To develop the emissions inventories for the 2017 RFP milestone year and 2020 RFP milestone/attainment year, CARB also relied upon the same growth and control factors as the 2016 Ventura County AQMP.

Documentation for the Ventura County RFP baseline and milestone emissions inventories is found in the 2018 SIP Update on pages 15-18 and Appendix A on pages A-7 through A-10. For both sets of baseline emissions inventories (those in the 2016 Ventura County AQMP and those in the 2018 SIP Update), emissions estimates reflect District rules adopted through July 2015 and CARB rules adopted through November 2015. Unlike the emissions inventories for the attainment demonstration in the 2016 Ventura County AQMP, the RFP baseline and milestone emissions inventories only include emissions within the Ventura County ozone nonattainment area and do not include marine emissions (e.g., emissions from ocean-going vessels) beyond three nautical miles from the coastline. In contrast, the attainment demonstration inventories include emissions from marine vessels out to 100 nautical miles from the coastline.

Table 3 provides a summary of CARB's 2011 RFP baseline year, 2017 RFP milestone year, and 2020 RFP milestone/attainment year emissions estimates in tpd for VOC and NO_X.

Table 3—Ventura County 2011 Base Year, 2017 RFP Milestone Year and 2020 Attainment Year Emissions Inventories

[Summer planning inventory, tpd]

Category	2011		2017		2020
	VOC	NOX	VOC	NOX	VOC	NOX
Stationary	8.4	2.0	8.4	1.9	8.6	1.9
Area Sources	11.7	1.0	10.8	0.7	11.0	0.6
On-Road Mobile Sources	9.2	13.9	5.4	8.0	4.2	6.0
Other (Off-Road) Mobile Sources	8.7	9.2	7.2	7.9	6.6	7.3
Total (not including ERC balance)	38.1	26.0	31.7	18.5	30.4	15.8
ERC Balance					1.7	0.8
Total (including ERC balance)	38.1	26.0	31.7	18.5	32.1	16.6
Source: 2018 SIP Update, pp. 15-18 and Appendix A, pp. A-7—A-10. The sum of the emissions values may not equal the total shown due to rounding of the numbers.

In August 2019, CARB provided a technical clarification of the RFP demonstration in the 2018 SIP Update for Ventura County.^[94] Specifically, CARB revised the RFP demonstration in the 2018 SIP Update to include the safety margin included in the 2020 motor vehicle emissions budgets in the 2016 Ventura County AQMP. Table 4 presents the updated RFP demonstration for Ventura County for the 2008 ozone NAAQS as clarified by CARB in August 2019.

Table 4—RFP Demonstration for Ventura County for the 2008 Ozone NAAQS

[Summer planning inventory, tpd or percent]

	VOC
	2011	2017	2020
Baseline VOC a	38.1	31.7	32.1
2020 Transportation Conformity Rounding Margin b			0.7
Baseline VOC + Rounding Margin		31.7	32.8
Required change since 2011 (VOC or NOX), %		18%	27%
Target VOC level		31.2	27.8
Apparent shortfall (−)/surplus (+) in VOC		−0.5	−5.0
Apparent shortfall (−)/surplus (+) in VOC, %		−1.4%	−13.2%
VOC shortfall previously provided by NOX substitution, %		0.0%	1.4%
Actual VOC shortfall (−)/surplus (+), %		−1.4%	−11.7%

  TDESC>[summer planning inventory, tpd or percent]

	NOX
	2011	2017	2020
Baseline NOX a	26.0	18.5	16.6
2020 Transportation Conformity Rounding Margin b			0.9
Baseline NOX + Rounding Margin		18.5	17.5
Change in NOX since 2011		7.5	8.5
Change in NOX since 2011, %		28.8%	32.8%
NOX reductions used for VOC substitution through last milestone year, %		0%	1.4%
NOX reductions since 2011 available for VOC substitution in this milestone year, %		28.8%	31.4%
NOX reductions since 2011 used for VOC substitution in this milestone year, %		1.4%	11.7%
NOX reductions since 2011 surplus after meeting VOC substitution needs in this milestone year, %		27.4%	19.6%
Total shortfall for RFP		0%	0%
RFP met?		Yes	Yes
Source: Letter dated August 29, 2019, from Dr. Michael T. Benjamin, Chief, Air Quality Planning and Science Division, CARB, to Amy Zimpfer, Assistant Director, Air Division, EPA Region IX, Attachment A.
a 2020 projections include addition of ERC balance as of January 1, 2012.
b Transportation conformity rounding margin is referred to herein as a “safety margin.”

The revised RFP demonstration calculates future year VOC targets from the 2011 baseline, consistent with CAA 182(c)(2)(B)(i), which requires reductions of “at least 3 percent of baseline emissions each year;” and it substitutes NO_X reductions for VOC reductions beginning in milestone year 2017 to meet VOC emission targets.^[95] For Ventura County, CARB concludes that the revised RFP demonstration meets the applicable requirements for each milestone year as well as the attainment year.

3. The EPA's Review of the State's Submission

In 1997, the EPA approved a 15 percent ROP plan for the Ventura County ozone nonattainment area for the 1-hour ozone NAAQS, and the Ventura County nonattainment area for the 2008 ozone NAAQS is the same as the Ventura County nonattainment area for the 1-hour ozone NAAQS.^[96] As a result, we agree with the District that the District and CARB have met the ROP requirements of CAA section 182(b)(1) for Ventura County with respect to the 2008 ozone NAAQS.

With respect to the RFP demonstration requirement, based on our review of the emissions inventory documentation in the 2016 Ventura County Ozone SIP, we find that CARB and the District have used the most recent planning and activity assumptions, emissions models, and methodologies in developing the RFP baseline and milestone year emissions inventories. We have also reviewed the calculations in Table III-3 of the 2018 SIP Update, as clarified by CARB in August 2019, and find that CARB has used an appropriate calculation method to demonstrate RFP.^[97] For these reasons, we have determined that the 2016 Ventura County Ozone SIP, as clarified by CARB in August 2019, demonstrates RFP in the 2017 milestone year and the 2020 milestone/attainment year, consistent with applicable CAA requirements and EPA guidance. Therefore, we propose to approve the RFP demonstration for Ventura County for the 2008 ozone NAAQS under sections 172(c)(2) and 182(c)(2)(B) of the CAA and 40 CFR 51.1110(a)(2)(ii).

F. Contingency Measures

1. Statutory and Regulatory Requirements

Under the CAA, 8-hour ozone nonattainment areas classified under subpart 2 as Moderate or above must include in their SIPs contingency measures consistent with sections 172(c)(9) and 182(c)(9). Contingency measures are additional controls or measures to be implemented in the event the area fails to make reasonable further progress or to attain the NAAQS by the attainment date. The SIP should contain trigger mechanisms for the contingency measures, specify a schedule for implementation, and indicate that the measure will be implemented without significant further action by the state or the EPA.^[98]

Neither the CAA nor the EPA's implementing regulations establish a specific level of emissions reductions that implementation of contingency measures must achieve, but the EPA's 2008 Ozone SRR reiterates the EPA's policy that contingency measures should provide for emissions reductions approximately equivalent to one year's worth of progress, amounting to reductions of 3 percent of the RFP baseline emissions inventory for the nonattainment area.^[99]

It has been the EPA's longstanding interpretation of section 172(c)(9) that states may rely on federal measures (e.g., federal mobile source measures based on the incremental turnover of the motor vehicle fleet each year) and local measures already scheduled for implementation that provide emissions reductions in excess of those needed to provide for RFP or expeditious attainment. The key is that the statute requires that contingency measures provide for additional emissions reductions that are not relied on for RFP or attainment and that are not included in the RFP or attainment demonstrations. The purpose of contingency measures is to provide continued emissions reductions while the plan is being revised to meet the missed milestone or attainment date.

The EPA has approved numerous SIPs under this interpretation—i.e., SIPs that use as contingency measures one or more federal or local measures that are in place and provide reductions that are in excess of the reductions required by the attainment demonstration or RFP plan,^[100] and there is case law supporting the EPA's interpretation in this regard.^[101] However, in Bahr v. EPA, the Ninth Circuit rejected the EPA's interpretation of CAA section 172(c)(9) as allowing for early implementation of contingency measures.^[102] The Ninth Circuit concluded that contingency measures must take effect at the time the area fails to make RFP or attain by the applicable attainment date, not before.^[103] Thus, within the geographic jurisdiction of the Ninth Circuit, states cannot rely on early-implemented measures to comply with the contingency measure requirements under CAA section 172(c)(9) and 182(c)(9).^[104]

2. Summary of the State's Submission

The District and CARB had largely prepared the 2016 Ventura County Ozone SIP prior to the Bahr v. EPA decision, and thus, consistent with contingency measure elements of previous ozone plans, it relies solely upon surplus emissions reductions from already-implemented control measures to demonstrate compliance with the contingency measure requirements of CAA sections 172(c)(9) and 182(c)(9).^[105]

In the 2018 SIP Update, CARB revises the RFP demonstration for the 2008 ozone NAAQS for Ventura County and recalculates the extent of surplus emission reductions (i.e., surplus to meeting the RFP milestone requirement for a given milestone year) in the milestone years and estimates the incremental emissions reductions in the year following the attainment year. In light of the Bahr v. EPA decision, however, the 2018 SIP Update does not rely on the surplus or incremental emissions reductions to comply with the contingency measures requirements of sections 172(c)(9) and 182(c)(9) but, rather, to provide context in which to evaluate the adequacy of Bahr-compliant (i.e., to take effect if triggered) contingency measures for the 2008 ozone NAAQS.^[106]

To comply with CAA sections 172(c)(9) and 182(c)(9), as interpreted in the Bahr v. EPA decision, the state must develop, adopt, and submit a contingency measure to be triggered upon a failure to meet an RFP milestone or attain the NAAQS by the applicable attainment date regardless of the extent to which already-implemented measures would achieve surplus or incremental emissions reductions beyond those necessary for RFP or attainment of the NAAQS. Therefore, to fully address the contingency measure requirement for the 2008 ozone NAAQS in Ventura County, the District has committed to supplement the contingency measure element of the 2016 Ventura County Ozone SIP by developing, adopting and submitting a contingency measure to CARB in sufficient time to allow CARB to submit the contingency measure as a SIP revision to the EPA within 12 months of the EPA's conditional approval of the contingency measure element of the 2016 Ventura County Ozone SIP.^[107]

The District's specific commitment is to amend at least one of the following existing VCAPCD rules, through the required public review and subsequent VCAPCD board approval processes, to apply more stringent requirements upon a determination that the Ventura County nonattainment area failed to meet an RFP milestone or failed to attain the 2008 ozone NAAQS by the applicable attainment date.

• Amendments to Rule 74.26 (“Crude Oil Storage Tank Degassing Operations”) to add, if triggered by an RFP milestone failure or a failure to attain the 2008 ozone NAAQS, requirements for reducing VOC emissions from certain operations not covered by the existing rule, including cleaning, removing, repair and depressurizing of pipelines;
• Amendments to Rule 74.14 (“Polyester Resin Material Operations”) to add a non-monomer content VOC limit of no more than 5 percent by weight, if triggered; or
• Amendments to Rule 74.2 (“Architectural Coatings”) to lower the VOC limit for coating categories; delete the Specialty Primer, Sealer, and Undercoater categories and regulate them as just primers, sealers and undercoaters; add the specialty coating categories (Interior Stains, and Tile and Stone Sealers); and lower certain VOC content limits for colorants, once again, if triggered.

CARB attached the District's commitment to revise a rule to include contingency provisions to a letter committing CARB to adopt and submit the revised VCAPCD rule or rules to the EPA within one year of the effective date of the EPA's final conditional approval of the contingency measure element of the 2016 Ventura County Ozone SIP.^[108]

3. The EPA's Review of the State's Submission

Sections 172(c)(9) and 182(c)(9) require contingency measures to address potential failure to achieve RFP milestones or failure to attain the NAAQS by the applicable attainment date. For the purposes of evaluating the contingency measure element of the 2016 Ventura County Ozone SIP, we find it useful to distinguish between contingency measures to address potential failure to achieve RFP milestones (“RFP contingency measures”) and contingency measures to address potential failure to attain the NAAQS (“attainment contingency measures”).

With respect to the RFP contingency measure requirement, we have reviewed the surplus emissions estimates in each of the RFP milestone years, as shown in the 2018 SIP Update (and clarified in August 2019), and find that the calculations are correct. Therefore, we agree that the 2016 Ventura County Ozone SIP provides surplus emissions reductions well beyond those necessary to demonstrate RFP in the RFP milestone years. While such surplus emissions reductions in the RFP milestone years do not represent contingency measures themselves, we believe they are relevant in evaluating the adequacy of RFP contingency measures that are submitted (or will be submitted) to meet the requirements of sections 172(c)(9) and 182(c)(9).

In this case, the District and CARB have committed to develop, adopt, and submit a revised District rule or rules as a contingency measure within one year of the effective date of our final conditional approval action. The specific types of revisions the District has committed to make, such as adding new limits or other requirements, upon a failure to achieve a milestone or a failure to attain would comply with the requirements in CAA sections 172(c)(9) and 182(c)(9) because they would be undertaken if the area fails to attain and would take effect without significant further action by the State or the EPA.

Next, we considered the adequacy of the RFP contingency measure (once adopted and submitted) from the standpoint of the magnitude of emissions reductions the measure would provide (if triggered). Neither the CAA nor the EPA's implementing regulations for the ozone NAAQS establish a specific amount of emissions reductions that implementation of contingency measures must achieve, but we generally expect that contingency measures should provide for emissions reductions approximately equivalent to one year's worth of RFP, which, for ozone, amounts to reductions of 3 percent of the RFP baseline year emissions inventory for the nonattainment area. For the 2008 ozone NAAQS in Ventura County, one year's worth of RFP is approximately 1.1 tpd of VOC or 0.8 tpd of NO_X reductions.^[109]

The District did not quantify the potential additional emission reductions from its contingency measure commitment, but we believe that it is unlikely that the attainment contingency measure, once adopted and submitted, will achieve one year's worth of RFP (i.e., 1.1 tpd of VOC or 0.8 tpd of NO_X) given the types of rule revisions under consideration and the magnitude of emissions reductions constituting one year's worth of RFP. However, the 2018 SIP Update provides the larger SIP planning context in which to judge the adequacy of the to-be-submitted District contingency measure by calculating the surplus emissions reductions estimated to be achieved in the RFP milestone years and the year after the attainment year. More specifically, the 2018 SIP Update, as clarified by CARB in August 2019, identified surplus NO_X reductions in the various RFP milestone years. For Ventura County, the estimates of surplus NO_X reductions are 7.1 tpd in 2017 and 6.5 tpd in 2020 and are 8 or 9 times greater than one year's worth of progress (0.8 tpd of NO_X).^[110]

The surplus reflects already implemented regulations and is primarily the result of vehicle turnover, which refers to the ongoing replacement by individuals, companies, and government agencies of older, more polluting vehicles and engines with newer vehicles and engines. In light of the extent of surplus NO_X emissions reductions in the RFP milestone years, the emissions reductions from the District contingency measure would be sufficient to meet the contingency measure requirements of the CAA with respect to RFP milestones, even though the measure would likely achieve emissions reductions lower than the EPA normally recommends for reductions from such a measure.

For attainment contingency measure purposes, we view the emissions reductions from the contingency measure in the context of the expected reduction in emissions within Ventura County in the year following the attainment year relative to those occuring in the attainment year. Based on the emission inventories in Appendix A to the 2018 SIP Update, we note that overall county-wide emissions are expected to be approximately 0.9 tpd of NO_X lower in 2021 than in 2020. Thus, baseline measures are expected to provide for continued progress (i.e., incremental reduction in ozone precursors) greater than one year's worth of progress (i.e., 0.8 tpd of NO_X). In light of these incremental year-over-year NO_X emissions reductions, we find that the emissions reductions from the District contingency measure would also be sufficient to meet the attainment contingency measure requirement of the CAA, even though the measure would likely achieve emissions reductions lower than the EPA normally recommends for reductions from such a measure.

For these reasons, we propose to approve conditionally the contingency measure element of the 2016 Ventura County Ozone SIP, as supplemented by commitments from the District and CARB to adopt and submit an additional contingency measure, to meet the contingency measure requirements of CAA sections 172(c)(9) and 182(c)(9). Our proposed approval is conditional because it relies upon commitments to adopt and submit a specific enforceable contingency measure (i.e., a revised District rule or rules with contingent provisions). Conditional approvals are authorized under CAA section 110(k)(4).

G. Motor Vehicle Emissions Budgets for Transportation Conformity

1. Statutory and Regulatory Requirements

Section 176(c) of the CAA requires federal actions in nonattainment and maintenance areas to conform to the SIP's goals of eliminating or reducing the severity and number of violations of the NAAQS and achieving timely attainment of the standards. Conformity to the SIP's goals means that such actions will not: (1) Cause or contribute to violations of a NAAQS, (2) worsen the severity of an existing violation, or (3) delay timely attainment of any NAAQS or any interim milestone.

Actions involving Federal Highway Administration (FHWA) or Federal Transit Administration (FTA) funding or approval are subject to the EPA's transportation conformity rule, codified at 40 CFR part 93, subpart A. Under this rule, MPOs in nonattainment and maintenance areas coordinate with state and local air quality and transportation agencies, the EPA, the FHWA, and the FTA to demonstrate that an area's regional transportation plans and transportation improvement programs conform to the applicable SIP. This demonstration is typically done by showing that estimated emissions from existing and planned highway and transit systems are less than or equal to the motor vehicle emissions budgets (“budgets”) contained in all control strategy SIPs. Budgets are generally established for specific years and specific pollutants or precursors. Ozone plans should identify budgets for on-road emissions of ozone precursors (NO_X and VOC) in the area for each RFP milestone year and, if the plan demonstrates attainment, the attainment year.^[111]

For budgets to be approvable, they must meet, at a minimum, the EPA's adequacy criteria (40 CFR 93.118(e)(4)). To meet these requirements, the budgets must be consistent with the attainment and RFP requirements and reflect all of the motor vehicle control measures contained in the attainment and RFP demonstrations.^[112]

The EPA's process for determining adequacy of a budget consists of three basic steps: (1) Providing public notification of a SIP submission; (2) providing the public the opportunity to comment on the budget during a public comment period; and, (3) making a finding of adequacy or inadequacy.^[113]

2. Summary of the State's Submission

The 2016 Ventura County AQMP includes budgets for the 2018 RFP milestone year and the 2020 attainment year.^[114] The budgets for 2018 were derived from the 2012 RFP baseline year and the associated 2018 RFP milestone year. As such, the budgets are affected by the South Coast II decision vacating the alternative baseline year provision, and therefore, the EPA has not previously acted on the budgets. In the submittal letter for the 2016 Ventura County AQMP, CARB requested that the EPA limit the duration of our approval of the budgets in the 2016 Ventura County AQMP to last only until the effective date of future EPA adequacy findings for replacement budgets.^[115] In August 2019, CARB provided further explanation in connection with its request to limit the duration of the approval of the budgets in the 2016 Ventura County AQMP.^[116]

On December 5, 2018, CARB submitted the 2018 SIP Update, which revised the RFP demonstration consistent with the South Coast II decision (i.e., by using a 2011 RFP baseline year). The 2018 SIP Update does not identify new budgets for Ventura County for VOC and NO_X for the 2017 RFP milestone year because budgets for the 2017 milestone year would never be used for conformity determinations given that milestone/attainment budgets for the immediate near-term year of 2020 have also been submitted. Today, we are proposing action only on the 2020 RFP milestone/attainment budgets from the 2016 Ventura County AQMP.

The budgets in the 2016 Ventura County AQMP were derived from motor vehicle emissions estimates prepared using EMFAC2014,^[117] and the travel activity data provided by SCAG. The conformity budgets for NO_X and VOC in the 2016 Ventura County AQMP for Ventura County in 2020 are provided in Table 5 below. To develop the budgets, the District rounded up the motor vehicle emissions estimates for 2020 to the nearest ton. Thus, the motor vehicle emissions estimates for Ventura County for VOC and NO_X in 2020, i.e., 4.21 tpd and 6.01 tpd, respectively, were rounded up to become budgets for VOC and NO_X of 5 tpd and 7 tpd, respectively.

Table 5—Transportation Conformity Budgets for the 2008 Ozone NAAQS in Ventura County

[Summer planning inventory, tpd]

Budget year	VOC	NOX
2020	5	7
Source: 2016 Ventura County AQMP, Table 3-7, 52.

3. The EPA's Review of the State's Submission

As part of our review of the approvability of the budgets in the 2016 Ventura County AQMP, we have evaluated the budgets using our adequacy criteria in 40 CFR 93.118(e)(4) and (5). We will complete the adequacy review concurrent with our final action on the 2016 Ventura County AQMP. The EPA is not required under its transportation conformity rule to find budgets adequate prior to proposing approval of them.^[118] Today, the EPA is announcing that the adequacy process for these budgets begins, and the public has 30 days to comment on their adequacy, per the transportation conformity regulation at 40 CFR 93.118(f)(2)(i) and (ii).

As documented in a separate memorandum included in the docket for this rulemaking, we preliminarily conclude that the budgets in the 2016 Ventura County AQMP meet each adequacy criterion.^[119] While adequacy and approval are two separate actions, reviewing the budgets in terms of the adequacy criteria informs the EPA's decision to propose to approve the budgets. We have completed our detailed review of the 2016 Ventura County AQMP and are proposing herein to approve the attainment and RFP demonstrations. We have also reviewed the budgets in the 2016 Ventura County AQMP and found that they are consistent with the attainment and RFP demonstrations for which we are proposing approval, are based on control measures that have already been adopted and implemented, and meet all other applicable statutory and regulatory requirements including the adequacy criteria in 40 CFR 93.1118(e)(4) and (5). Therefore, we are proposing to approve the 2020 budgets in the 2016 Ventura County AQMP. At the point when we either finalize the adequacy process or approve the budgets for the 2008 ozone NAAQS in the 2016 Ventura County AQMP as proposed (whichever occurs first; note that they could also occur concurrently per 40 CFR 93.118(f)(2)(iii)), they will replace the budgets that we previously found adequate for use in transportation conformity determinations.^[120]

Under our transportation conformity rule, as a general matter, once budgets are approved, they cannot be superseded by revised budgets submitted for the same CAA purpose and the same year(s) addressed by the previously approved SIP until the EPA approves the revised budgets as a SIP revision. In other words, as a general matter, such approved budgets cannot be superseded by revised budgets found adequate, but rather only through approval of the revised budgets, unless the EPA specifies otherwise in its approval of a SIP by limiting the duration of the approval to last only until subsequently submitted budgets are found adequate.^[121]

In this instance, as noted above, in its submittal letter, CARB requested that we limit the duration of our approval of the budgets in the 2016 Ventura County AQMP only until the effective date of the EPA's adequacy finding for subsequently submitted budgets, and in August 2019, CARB provided further explanation for its request. Generally, we will consider a state's request to limit an approval of a budget only if the request includes the following elements: ^[122]

• An acknowledgement and explanation as to why the budgets under consideration have become outdated or deficient;
• A commitment to update the budgets as part of a comprehensive SIP update; and
• A request that the EPA limit the duration of its approval to the time when new budgets have been found to be adequate for transportation conformity purposes.

CARB's request includes an explanation for why the budgets have become, or will become, outdated or deficient. In short, CARB requested that we limit the duration of the approval of the budgets in light of the EPA's recent approval of EMFAC2017, an updated version of the model (EMFAC2014) used for the budgets in the 2016 Ventura County AQMP. EMFAC2017 updates vehicle mix and emissions data of the previously approved version of the model, EMFAC2014.

Preliminary calculations by CARB indicate that EMFAC2017-derived motor vehicle emissions estimates for Ventura County will exceed the corresponding EMFAC2014-derived budgets in the 2016 Ventura County AQMP. In light of the approval of EMFAC2017, CARB explains that the budgets from the 2016 Ventura County AQMP, for which we are proposing approval in today's action, will become outdated and will need to be revised using EMFAC2017. In addition, CARB states that, without the ability to replace the budgets using the budget adequacy process, the benefits of using the updated data may not be realized for a year or more after the updated SIP (with the EMFAC2017-derived budgets) is submitted, due to the length of the SIP approval process. We find that CARB's explanation for limiting the duration of the approval of the budgets is appropriate and provides us with a reasonable basis on which to limit the duration of the approval of the budgets.

We note that CARB has not committed to update the budgets as part of a comprehensive SIP update, but as a practical matter, CARB must submit a SIP revision that includes updated demonstrations as well as the updated budgets to meet the adequacy criteria in 40 CFR 93.118(e)(4); ^[123] and thus, we do not need a specific commitment for such a plan at this time. For the reasons provided above, and in light of CARB's explanation for why the budgets will become outdated and should be replaced upon an adequacy finding for updated budgets, we propose to limit the duration of our approval of the budgets in the 2016 Ventura County AQMP until we find revised budgets based on EMFAC2017 to be adequate.

H. General Conformity Budgets

1. Statutory and Regulatory Requirements

Section 176(c) of the CAA requires federal actions in nonattainment and maintenance areas to conform to the SIP's goals of eliminating or reducing the severity and number of violations of the NAAQS and achieving timely attainment of the standards. Conformity to the SIP's goals means that such actions will not: (1) Cause or contribute to violations of a NAAQS, (2) worsen the severity of an existing violation, or (3) delay timely attainment of any NAAQS or any interim milestone.

Section 176(c)(4) of the CAA establishes the framework for general conformity. The EPA first promulgated general conformity regulations in November 1993.^[124] On April 5, 2010, the EPA revised the general conformity regulations.^[125] The general conformity regulations ensure that federal actions not covered by the transportation conformity rule will not interfere with the SIP and encourage consultation between the federal agency and the state or local air pollution control agencies before or during the environmental review process, as well as public participation (e.g., notification of and access to federal agency conformity determinations and review of individual federal actions).

The general conformity regulations provide three phases: Applicability analysis, conformity determination, and review process. The applicability analysis phase under 40 CFR 93.153 is used to find if a federal action requires a conformity determination for a specific pollutant. If a conformity determination is needed, federal agencies can use one of several methods to show that the federal action conforms to the SIP. In an area without a SIP, a federal action may be shown to “conform” by demonstrating there will be no net increase in emissions in the nonattainment or maintenance area from the federal action. In an area with a SIP, conformity to the applicable SIP can be demonstrated in one of several ways. For actions where the direct and indirect emissions exceed the rates in 40 CFR 93.153(b), the federal action can include mitigation measures to offset the emission increases from the federal action or can show that the action will conform by meeting any of the following requirements:

• Showing that the net emission increases caused by an action are included in the SIP,
• documenting that the state agrees to include the emission increases in the SIP,
• offsetting the action's emissions in the same or nearby area of equal or greater classification, or
• providing an air quality modeling demonstration in some circumstances.^[126]

The general conformity regulations at 40 CFR 93.161 allow state and local air quality agencies working with federal agencies with large facilities (e.g., commercial airports, ports, and large military bases) that are subject to the general conformity regulations to develop and adopt an emissions budget for those facilities in order to facilitate future conformity determinations. Such a budget, referred to as a facility-wide emissions budget, may be used by federal agencies to demonstrate conformity as long as the total facility-wide budget level identified in the SIP is not exceeded.

According to 40 CFR 93.161, the state or local agency responsible for implementing and enforcing the SIP can develop and adopt an emissions budget to be used for demonstrating conformity under 40 CFR 93.158(a)(1). The requirements include the following: (1) The facility-wide budget must be for a set time period; (2) the budget must cover the pollutants or precursors of the pollutants for which the area is designated nonattainment or maintenance; (3) the budgets must be specific about what can be emitted on an annual or seasonal basis; (4) the emissions from the facility along with all other emissions in the area must not exceed the total SIP emissions budget for the nonattainment or maintenance area; (5) specific measures must be included to ensure compliance with the facility-wide budget, such as periodic reporting requirements or compliance demonstrations when the federal agency is taking an action that would otherwise require a conformity determination; (6) the budget must be submitted to the EPA as a SIP revision; and (7) the SIP revision must be approved by the EPA. Having or using a facility-wide emissions budget does not preclude a federal agency from demonstrating conformity in any other manner allowed by the conformity rule.

2. Summary of the State's Submission

The 2016 Ventura County AQMP establishes VOC and NO_X general conformity budgets for the Naval Base Ventura County (NBVC) for each year from 2017 through 2020 as shown in Table 6 below. The budgets are intended to reflect aircraft and missile operations associated with NBVC Point Mugu and ship operations at Port Hueneme occuring within the Ventura County ozone nonattainment area. The budgets include a 4 percent growth allowance to account for uncertainties in potential projects resulting from future actions and unknown projects. As shown in Table 6, the budgets for NBVC in the attainment year (2020) are 198.0 tpy of VOC and 475.9 tpy of NO_X, which is equivalent to 0.54 tpd of VOC and 1.30 tpd of NO_X on an annual average daily basis.

Table 6—NBVC General Conformity Budgets for the 2008 Ozone NAAQS in Ventura County

[summer planning inventory, tpy]

Budget year	VOC	NOX
2017	178.6	434.2
2018	184.8	447.6
2019	191.3	461.5
2020	198.0	475.9
Source: 2016 Ventura County Ozone AQMP, Table 4-9.

3. The EPA's Review of the State's Submission

We propose to approve the general conformity budgets in the 2016 Ventura County AQMP for NBVC shown in Table 6, as meeting the requirements of CAA section 176(c) and 40 CFR 93.161. We find that the general conformity budgets in the 2016 AQMP: are established for a set time period; cover both precursors of ozone; are precisely quantified in terms of tons per year; and, along with all other emissions in Ventura County, are consistent with the RFP and attainment demonstration for the 2008 ozone NAAQS.

If we finalize our approval of these budgets, NBVC can use these budgets to demonstrate that their projects conform to the SIP through a letter from the State and District confirming that the project emissions are accounted for in the SIP's general conformity budgets.

I. Other Clean Air Act Requirements Applicable to Serious Ozone Nonattainment Areas

In addition to the SIP requirements discussed in the previous sections, the CAA includes certain other SIP requirements applicable to Serious ozone nonattainment areas, such as Ventura County. We describe these provisions and their current status below.

1. Enhanced Vehicle Inspection and Maintenance Programs

Section 182(c)(3) of the CAA requires states with ozone nonattainment areas classified under subpart 2 as Serious or above to implement an enhanced motor vehicle I/M program in those areas. The requirements for those programs are provided in CAA section 182(c)(3) and 40 CFR part 51, subpart S.

Consistent with the 2008 Ozone SRR, no new I/M programs are currently required for nonattainment areas for the 2008 ozone NAAQS.^[127] The EPA previously approved California's I/M program in Ventura County as meeting the requirements of the CAA and applicable EPA regulations for enhanced I/M programs.^[128]

2. New Source Review Rules

Section 182(a)(2)(C) of the CAA requires states to develop SIP revisions containing permit programs for each of its ozone nonattainment areas. The SIP revisions are to include requirements for permits in accordance with CAA sections 172(c)(5) and 173 for the construction and operation of each new or modified major stationary source for VOC and NO_X anywhere in the nonattainment area. The 2008 Ozone SRR includes provisions and guidance for nonattainment NSR programs.^[129] Earlier this year, the EPA proposed to approve the nonattainment NSR SIP submitted for Ventura County for the 2008 ozone NAAQS. The nonattainment NSR SIP includes a certification letter documenting how the VCAPCD's SIP-approved nonattainment NSR program, established in VCAPCD Rules 26 through 26.11, meets the applicable NSR requirements for Ventura County for the 2008 ozone NAAQS.^[130] We expect to take final action on the nonattainment NSR SIP for Ventura County for the 2008 ozone NAAQS in the near future in a separate rulemaking.

3. Clean Fuels Fleet Program

Sections 182(c)(4)(A) and 246 of the CAA require California to submit to the EPA for approval measures to implement a Clean Fuels Fleet Program. Section 182(c)(4)(B) of the CAA allows states to opt-out of the federal clean-fuel vehicle fleet program by submitting a SIP revision consisting of a program or programs that will result in at least equivalent long-term reductions in ozone precursors and toxic air emissions.

In 1994, CARB submitted a SIP revision to the EPA to opt-out of the federal clean-fuel fleet program. The submittal included a demonstration that California's low-emissions vehicle program achieved emissions reductions at least as large as would be achieved by the federal program. The EPA approved the SIP revision to opt-out of the federal program on August 27, 1999.^[131] There have been no changes to the federal Clean Fuels Fleet program since the EPA approved the California SIP revision to opt-out of the federal program, and no corresponding changes to the SIP are required. Thus, we find that the California SIP revision to opt-out of the federal program, as approved in 1999, meets the requirements of CAA sections 182(c)(4)(A) and 246 for Ventura for the 2008 ozone NAAQS.

4. Gasoline Vapor Recovery

Section 182(b)(3) of the CAA requires states to submit a SIP revision by November 15, 1992, that requires owners or operators of gasoline dispensing systems to install and operate gasoline vehicle refueling vapor recovery (“Stage II”) systems in ozone nonattainment areas classified as Moderate and above. California's ozone nonattainment areas implemented Stage II vapor recovery well before the passage of the CAA Amendments of 1990.^[132]

Section 202(a)(6) of the CAA requires the EPA to promulgate standards requiring motor vehicles to be equipped with onboard refueling vapor recovery (ORVR) systems. The EPA promulgated the first set of ORVR system regulations in 1994 for phased implementation on vehicle manufacturers, and since the end of 2006, essentially all new gasoline-powered light- and medium-duty vehicles are ORVR-equipped.^[133] Section 202(a)(6) also authorizes the EPA to waive the SIP requirement under CAA section 182(b)(3) for installation of Stage II vapor recovery systems after such time as the EPA determines that ORVR systems are in widespread use throughout the motor vehicle fleet. Effective May 16, 2012, the EPA waived the requirement of CAA section 182(b)(3) for Stage II vapor recovery systems in ozone nonattainment areas regardless of classification.^[134] Thus, a SIP submittal meeting CAA section 182(b)(3) is not required for the 2008 ozone NAAQS.

While a SIP submittal meeting CAA section 182(b)(3) is not required for the 2008 ozone NAAQS, under California state law (i.e., Health and Safety Code section 41954), CARB is required to adopt procedures and performance standards for controlling gasoline emissions from gasoline marketing operations, including transfer and storage operations. State law also authorizes CARB, in cooperation with local air districts, to certify vapor recovery systems, to identify defective equipment and to develop test methods. CARB has adopted numerous revisions to its vapor recovery program regulations and continues to rely on its vapor recovery program to achieve emissions reductions in ozone nonattainment areas in California.

In Ventura County, the installation and operation of CARB-certified vapor recovery equipment is required and enforced through VCAPCD Rule 70 (“Storage And Transfer Of Gasoline”), which was most recently approved into the SIP on January 31, 2011.^[135]

5. Enhanced Ambient Air Monitoring

Section 182(c)(1) of the CAA requires that all ozone nonattainment areas classified as Serious or above implement measures to enhance and improve monitoring for ambient concentrations of ozone, NO_X, and VOC, and to improve monitoring of emissions of NO_X and VOC. The enhanced monitoring network for ozone is referred to as the photochemical assessment monitoring station (PAMS) network. The EPA promulgated final PAMS regulations on February 12, 1993.^[136]

On November 10, 1993, CARB submitted to the EPA a SIP revision addressing the PAMS network for six ozone nonattainment areas in California, including Ventura County, to meet the enhanced monitoring requirements of CAA section 182(c)(1) and the PAMS regulations. The EPA determined that the PAMS SIP revision met all applicable requirements for enhanced monitoring and approved the PAMS submittal into the California SIP.^[137]

Prior to 2006, the EPA's ambient air monitoring regulations in 40 CFR part 58 (“Ambient Air Quality Surveillance”) set forth specific SIP requirements (see former 40 CFR 52.20). In 2006, the EPA significantly revised and reorganized 40 CFR part 58.^[138] Under revised 40 CFR part 58, SIP revisions are no longer required; rather, compliance with EPA monitoring regulations is established through review of required annual monitoring network plans.^[139] The 2008 Ozone SRR made no changes to these requirements.^[140]

The 2016 Ventura County Ozone SIP does not specifically address the enhanced ambient air monitoring requirement in CAA section 182(c)(1). However, we note that CARB includes the ambient monitoring network within Ventura County in its annual monitoring network plan that is submitted to the EPA, and that we have approved the most recent annual monitoring network plan (“Annual Network Plan Covering Monitoring Operations in 25 California Air Districts (June 2018)” or “2018 ANP”) with respect to the Ventura County element.^[141] Based on our review and approval of the 2018 ANP with respect to Ventura County and our earlier approval of the PAMS SIP revision, we propose to find that CARB and VCAPCD meet the enhanced monitoring requirements under CAA section 182(c)(1) for Ventura County with respect to the 2008 ozone NAAQS.

IV. Proposed Action

For the reasons discussed in this notice, under CAA section 110(k)(3), the EPA is proposing to approve as a revision to the California SIP the following portions of the 2016 Ventura County Ozone SIP submitted by CARB on April 11, 2017 and December 5, 2018:

• Base year emissions inventory element in the 2016 Ventura County AQMP as meeting the requirements of CAA sections 172(c)(3) and 182(a)(1) and 40 CFR 51.1115 for the 2008 ozone NAAQS;
• Emissions statement element in the 2016 Ventura County AQMP as meeting the requirements of CAA section 182(a)(3)(B) and 40 CFR 51.1102 for the 2008 ozone NAAQS;
• RACM demonstration element in the 2016 Ventura County AQMP as meeting the requirements of CAA section 172(c)(1) and 40 CFR 51.1112(c) for the 2008 ozone NAAQS;
• Attainment demonstration element for the 2008 ozone NAAQS in the 2016 Ventura County AQMP as meeting the requirements of CAA section 182(c)(2)(A) and 40 CFR 51.1108;
• ROP demonstration element in the 2016 Ventura County AQMP as meeting the requirements of CAA 182(b)(1) and 40 CFR 51.1110(a)(2) for the 2008 ozone NAAQS;
• RFP demonstration element in the 2018 SIP Update, as clarified in August 2019,^[142] as meeting the requirements of CAA sections 172(c)(2) and 182(c)(2)(B), and 40 CFR 51.1110(a)(2)(ii) for the 2008 ozone NAAQS;

• Motor vehicle emissions budgets in the 2016 Ventura County AQMP for the RFP milestone/attainment year of 2020 (as shown in Table 5) because they are consistent with the RFP and attainment demonstrations for the 2008 ozone NAAQS proposed for approval herein and meet the other criteria in 40 CFR 93.118(e); and
• General conformity budgets of VOC and NO_X (as shown in Table 6) for Naval Base Ventura County, as meeting the requirements of CAA section 176(c) and 40 CFR 93.161.

We are also proposing to find that the:

• Enhanced vehicle inspection and maintenance program in Ventura County meets the requirements of CAA section 182(c)(3) and 40 CFR 51.1102 for the 2008 ozone NAAQS;
• California SIP revision to opt-out of the federal Clean Fuels Fleet Program meets the requirements of CAA sections 182(c)(4)(A) and 246 and 40 CFR 51.1102 for the 2008 ozone NAAQS with respect to Ventura County; and
• Enhanced monitoring in Ventura County meets the requirements of CAA section 182(c)(1) and 40 CFR 51.1102 for the 2008 ozone NAAQS.^[143]

With respect to the motor vehicle emissions budgets, we are proposing to limit the duration of the approval of the budgets to last only until the effective date of the EPA's adequacy finding for any subsequently submitted budgets. We are doing so at CARB's request and in light of the benefits of using EMFAC2017-derived budgets prior to our taking final action on the future SIP revision that includes the updated budgets.

In addition, we are proposing, under CAA section 110(k)(4), to approve conditionally the contingency measure element of the 2016 Ventura County Ozone SIP as meeting the requirements of CAA sections 172(c)(9) and 182(c)(9) for RFP and attainment contingency measures. Our proposed approval is based on commitments by the District and CARB to supplement the element through submission, as a SIP revision (within one year of the effective date of our final conditional approval action), of a revised District rule or rules that would add new limits or other requirements if an RFP milestone is not met or if Ventura County fails to attain the 2008 ozone NAAQS by the applicable attainment date.^[144]

The EPA is soliciting public comments on the issues discussed in this document. We will accept comments from the public on this proposal for the next 30 days and will consider comments before taking final action.

V. Statutory and Executive Order Reviews

Under the Clean Air Act, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. Accordingly, this proposed action merely proposes to approve, or conditionally approve, state plans as meeting federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

• Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
• Is not an Executive Order 13771 (82 FR 9339, February 2, 2017) regulatory action because SIP approvals are exempted under Executive Order 12866;
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
• Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
• Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act; and
• Does not provide the EPA with the discretionary authority to address disproportionate human health or environmental effects with practical, appropriate, and legally permissible methods under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where the EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the proposed rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects in 40 CFR Part 52

• Environmental protection
• Air pollution control
• Incorporation by reference
• Intergovernmental relations
• Nitrogen dioxide
• Ozone
• Reporting and recordkeeping requirements
• Volatile organic compounds

Authority: 42 U.S.C. 7401 et seq.

Dated: December 5, 2019.

Michael Stoker,

Regional Administrator, Region IX.

Footnotes

1.  The State of California refers to reactive organic gases (ROG) rather than VOC in some of its ozone-related SIP submissions. As a practical matter, ROG and VOC refer to the same set of chemical constituents, and for the sake of simplicity, we refer to this set of gases as VOC in this proposed rule.

2.  “Fact Sheet—2008 Final Revisions to the National Ambient Air Quality Standards for Ozone,” dated March 2008.

3.  44 FR 8202 (February 8, 1979).

4.  43 FR 8962, at 8972 (March 3, 1978). Ventura County lies within California's South Central Coast Air Basin, which includes the counties of Santa Barbara and San Luis Obispo in addition to Ventura County.

5.  Under California law, CARB is the state agency that is responsible for the adoption and submission to the EPA of California SIPs and SIP revisions, and it has broad authority to establish emissions standards and other requirements for mobile sources. Local and regional air pollution control districts in California are responsible for the regulation of stationary sources and are generally responsible for the development of regional air quality plans. In Ventura County, the Ventura County Air Pollution Control District develops and adopts air quality management plans to address CAA planning requirements applicable to that region. Such plans are then submitted to CARB for adoption and submittal to the EPA as revisions to the California SIP.

6.  56 FR 56694 (November 6, 1991). For the 1-hour ozone NAAQS, the Channel Islands of Ventura County are part of the unclassifiable/attainment area comprised by the Channel Islands portion of the South Central Coast Air Basin. See 56 FR 56694, at 56732 (November 6, 1991).

7.  74 FR 25153 (May 27, 2009).

8.  Under EPA regulations at 40 CFR 50.9 and appendix H, the 1-hour ozone NAAQS is attained at a site when the expected number of days per calendar year with maximum hourly average concentrations above 0.12 ppm is equal to or less than 1. The design value for 1-hour ozone is generally the fourth highest daily maximum 1-hour ozone concentration measured during a 3-year period at each site in the area, assuming 3 complete years of data. The highest design value among the various ozone monitoring sites represents the design value for the area. The data for Ventura County is from CARB, Aerometric Data Analysis System Air Quality Database, Ventura County Ozone Trends Summary Report, September 11, 2019.

9.  62 FR 38856 (July 18, 1997).

10.  69 FR 23857 at 23889 (April 30, 2004); 73 FR 29073 (May 20, 2008).

11.  77 FR 56775 (September 14, 2012).

12.  Under EPA regulations at 40 CFR 50.10 and appendix I, the 1997 ozone NAAQS is attained at a site when the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentration is less than or equal to 0.08 ppm. This 3-year average is referred to as the design value. When the design value is less than or equal to 0.084 ppm (based on the rounding convention in 40 CFR part 50, appendix I) at each monitoring site within the area, then the area is meeting the 1997 ozone NAAQS. The highest design value among the various ozone monitoring sites in the area represents the design value for the area. The data for Ventura County is from EPA, Design Value Report, dated July 3, 2019.

13.  73 FR 16436 (March 27, 2008). The EPA further tightened the 8-hour ozone NAAQS to 0.070 ppm in 2015, but this proposed action relates to the requirements for the 2008 ozone NAAQS. Information on the 2015 ozone NAAQS is available at 80 FR 65292 (October 26, 2015).

14.  77 FR 30088 (May 21, 2012).

15.  CAA section 181(a)(1), 40 CFR 51.1102 and 51.1103(a).

16.  The South Coast Air Basin includes Orange County, the southwestern two-thirds of Los Angeles County, southwestern San Bernardino County, and western Riverside County.

17.  80 FR 12264 (March 6, 2015).

18.  South Coast Air Quality Management District v. EPA, 882 F.3d 1138 (D.C. Cir. 2018) (“South Coast II”).

19.  The term “South Coast II” is used in reference to the 2018 court decision to distinguish it from a decision published in 2006 also referred to as “South Coast.” The earlier decision involved a challenge to the EPA's Phase 1 implementation rule for the 1997 ozone NAAQS. South Coast Air Quality Management Dist. v. EPA, 472 F.3d 882 (D.C. Cir. 2006).

20.  Letter dated April 11, 2017, from Richard W. Corey, Executive Officer, CARB, to Alexis Strauss, Acting Regional Administrator, EPA Region IX.

21.  The 2012 base year emissions inventory included in the 2016 Ventura County AQMP supersedes and replaces a previous submittal of the 2012 base year emissions inventory for Ventura County in the “8-Hour Ozone State Implementation Plan Emission Inventory Submittal” (the “Multi-Area Emission Inventory”). The Multi-Area Emission Inventory was submitted by CARB on July 17, 2014, and included 2012 base year emissions inventories for 16 nonattainment areas, including Ventura County. Relative to the corresponding inventory for Ventura County in the Multi-Area Emission Inventory, the 2012 base year emissions inventory in the 2016 Ventura County AQMP reflects updated stationary, area, and nonroad source calculations as well as an updated version of the EMFAC model for on-road motor vehicle estimates. In a letter dated November 15, 2019, CARB withdrew the earlier submitted 2012 base year emissions inventory for Ventura County in light of the updated inventory in the 2016 Ventura County AQMP. Letter dated November 15, 2019, from Richard W. Corey, Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region IX. In section III.A of this document, we are proposing approval of the superseding 2012 base year emissions inventory in the 2016 Ventura County AQMP.

22.  Letter dated August 29, 2019, from Dr. Michael T. Benjamin, Chief, Air Quality Planning and Science Division, CARB, to Amy Zimpfer, Assistant Director, Air Division, EPA Region IX, including attachments A and B.

23.  Letter dated December 5, 2018, from Richard Corey, Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region IX.

24.  Bahr v. EPA, 836 F.3d 1218 (9th Cir. 2016) (“Bahr v. EPA”). In Bahr v. EPA, the court rejected the EPA's longstanding interpretation of CAA section 172(c)(9) as allowing for early implementation of contingency measures. The court concluded that a contingency measure must take effect at the time the area fails to make RFP or attain by the applicable attainment date, not before.

25.  CARB withdrew the RFP demonstration from the 2016 Ventura County AQMP in light of the revised RFP demonstration for Ventura County in the 2018 SIP Update. Letter dated November 15, 2019, from Richard W. Corey, Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region IX. In section III.E of this document, we are proposing approval of the superseding RFP demonstration for Ventura County in the 2018 SIP Update.

26.  84 FR 11198 (March 25, 2019) (final approval of the San Joaquin Valley portion of the 2018 SIP Update) and 84 FR 52005 (October 1, 2019) (final approval of the South Coast portion of the 2018 SIP Update).

27.  Letter dated August 30, 2019, from Richard Corey, Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region IX.

28.  Letter dated August 16, 2019, from Michael Villegas, VCAPCD Air Pollution Control Officer, to Richard Corey, CARB Executive Officer, provided as enclosure to August 30, 2019 CARB letter.

29.  Notice of Public Meeting to Consider the 2016 Ozone SIP for Ventura County, signed by Richard Corey, Executive Officer, CARB, February 17, 2017.

30.  CARB Resolution 17-5.

31.  CARB “Public Comment Log,” dated March 30, 2017. See also, Transcript of the March 23, 2017 Meeting of the State of California Air Resources Board, 7-8.

32.  Notice of Public Meeting to Consider the 2018 Updates to the California State Implementation Plan signed by Richard Corey, Executive Officer, CARB, September 21, 2018.

33.  2008 Ozone SRR at 40 CFR 51.1115(a) and the Air Emissions Reporting Requirements at 40 CFR part 51, subpart A.

34.  “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” EPA-454/B-17-002, May 2017. At the time the 2016 Ventura County AQMP was developed, the following EPA emissions inventory guidance applied: “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” EPA-454-R-05-001, August 2005.

35.  40 CFR 51.1115(a) and (c), and 40 CFR 51.1100(bb) and (cc).

36.  80 FR 12264, at 12290 (March 6, 2015).

37.  The 2012 base year and future year baseline emissions inventories in the 2016 Ventura County AQMP exclude non-anthropogenic “natural sources” emissions such as biogenics, geogenics, and wildfires. However, emissions from such natural sources are included in the emissions inventories used for the attainment demonstration because they affect ozone formation.

38.  EMFAC is short for EMission FACtor.

39.  In December 2015, the EPA approved EMFAC2014 for SIP development and transportation conformity purposes in California. 80 FR 77337 (December 14, 2015). EMFAC2014 was the most recently approved version of the EMFAC model that was available at the time of preparation of the 2016 Ventura County AQMP. Recently, the EPA approved an updated version of the EMFAC model, EMFAC2017, for future SIP development and transportation purposes in California. 84 FR 41717 (August 15, 2019).

40.  See http://scagrtpscs.net/​Pages/​FINAL2016RTPSCS.aspx.

41.  2016 Ventura County AQMP, 22.

42.  2016 Ventura County AQMP, Appendix A, tables A-4 and A-6.

43.  40 CFR 51.165(a)(3)(ii)(C)(1).

44.  See 2018 SIP Update, Section III (“SIP Elements for Ventura County”), 15-20; and Appendix A, pp. A-7—A-10.

45.  The list of rules in Table 1 of our September 11, 2019 memorandum includes all the District rules for which specific future year emissions reductions are assumed as shown in Table 3-1 of the 2016 Ventura County AQMP.

46.  See 81 FR 39424 (June 16, 2016), 82 FR 14446 (March 21, 2017), and 83 FR 23232 (May 18, 2018).

47.  40 CFR 51.1102.

48.  See 80 FR 12264, at 12291 (March 6, 2015).

49.  2016 Ventura County AQMP, 16-18.

50.  District Rule 24 refers to “reactive organic compounds,” another term for “volatile organic compounds.”

51.  65 FR 76567 (December 7, 2000).

52.  2016 Ventura County AQMP, 17.

53.  40 CFR 51.1112(c).

54.  See General Preamble, 57 FR 13498 at 13560 (April 16, 1992) and memorandum dated November 30, 1999, from John S. Seitz, Director, EPA Office of Air Quality Planning and Standards (OAQPS), to Regional Air Division Directors, titled “Guidance on the Reasonably Available Control Measures (RACM) Requirement and Attainment Demonstration Submissions for Ozone Nonattainment Areas.”

55.  Id. See also 44 FR 20372 (April 4, 1979), and memorandum dated December 14, 2000, from John S. Seitz, Director, EPA OAQPS, to Regional Air Division Directors (Regions I, II, III, V and VI), titled “Additional Submission on RACM from States with Severe 1-hour Ozone Nonattainment Area SIPs.”

56.  For ozone nonattainment areas classified as Moderate or above, CAA section 182(b)(2) also requires implementation of reasonably available control technology (RACT) for all major sources of VOC and for each VOC source category for which the EPA has issued a control techniques guideline. CAA section 182(f) requires that RACT under section 182(b)(2) also apply to major stationary sources of NO_X. In Serious areas, a major source is a stationary source that emits or has the potential to emit at least 50 tpy of VOC or NO_X (see CAA section 182(c) and (f)). Under the 2008 Ozone SRR, states were required to submit SIP revisions meeting the RACT requirements of CAA sections 182(b)(2) and 182(f) no later than 24 months after the effective date of designation for the 2008 Ozone NAAQS and to implement the required RACT measures as expeditiously as practicable but no later than January 1 of the 5th year after the effective date of designation (see 40 CFR 51.1112(a)). California submitted the CAA section 182 RACT SIP for Ventura County on July 18, 2014, and the EPA fully approved this submission at 80 FR 2016 (January 15, 2015).

57.  Memorandum dated September 11, 2019, from John J. Kelly, Air Planning Office, EPA Region 9 to “Approval of Air Quality Implementation Plans; California; Ventura County; 8-Hour Ozone Nonattainment Area Requirements; Docket ID EPA-R09-OAR-2018-0146,” subject: District Rules Assumed for Purposes of Developing Baseline Emissions Projections.

58.  80 FR 2016, January 15, 2015.

59.  The five District rules include Rule 74.2 (“Architectural Coatings”), Rule 74.19.1 (“Screen Printing Operations”), Rule 74.21 (“Semiconductor Manufacturing”); Rule 74.22 (“Natural Gas-Fired, Central Fan-Type Furnaces”), and Rule 74.34 (“NO_X Reductions from Miscellaneous Sources”).

60.  The four source categories include composting and organic material conversion operations, vacuum truck operations, emissions of oxides of nitrogen from commercial food ovens, and food products manufacturing and processing operations.

61.  See 2016 Ventura County AQMP, Appendix F, page F-1.

62.  See 2016 Ventura County AQMP, Appendix F, page F-3.

63.  See 2016 Ventura County AQMP, Appendix C (“Key ARB Mobile Source Regulations and Programs”) and Appendix D (“Air Resources Board Control Measures, 1985-2016”).

64.  See, e.g., the EPA's approval of standards and other requirements to control emissions from in-use heavy-duty diesel-powered trucks, at 77 FR 20308 (April 4, 2012), revisions to the California on-road reformulated gasoline and diesel fuel regulations at 75 FR 26653 (May 12, 2010), and revisions to the California motor vehicle inspection and maintenance program at 75 FR 38023 (July 1, 2010).

65.  See 2016 Ventura County AQMP, Appendix G, page G-5.

66.  We find that the District's identification of a 2-tpd threshold for the minimum reduction necessary to advance attainment of the 2008 ozone NAAQS in Ventura County by one year to be reasonable. The nonattainment area relies on both VOC and NO_X controls, and the potential emissions reductions of NO_X and VOC (considered together) from potential RACM (stationary source, TCM, and mobile) would not achieve the necessary emissions reductions to advance attainment by one year, and therefore, such additional measures are not required to meet the RACM requirement.

67.  78 FR 34178, at 34184 (June 6, 2013) (proposed rule for implementing the 2008 ozone NAAQS).

68.  80 FR 12264, at 12268 (March 6, 2015).

69.  Modeling Guidance, December 2014 Draft, EPA OAQPS; available at https://www.epa.gov/​scram/​state-implementation-plan-sip-attainment-demonstration-guidance. The 2014 modeling guidance updates, but is largely consistent with, the earlier “Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for the 8-Hour Ozone and PM_2.5 NAAQS and Regional Haze,” EPA-454/B-07-002, April 2007. Additional EPA modeling guidance can be found in 40 CFR 51 Appendix W, “Guideline on Air Quality Models,” 82 FR 5182 (January 17, 2017); available at https://www.epa.gov/​scram/​clean-air-act-permit-modeling-guidance.

70.  Modeling Guidance at section 2.7.1.

71.  Ibid.

72.  See also CAA section 110(a)(2)(A).

73.  40 CFR 51.1108(d).

74.  40 CFR 51.1100(h).

75.  SCAQMD, 2016 South Coast AQMP (March 2017), Appendix V (“Modeling and Attainment Demonstration”), Chapter 3 (“Meteorological Modeling and Sensitivity Analyses”), Attachment 1 (“WRF Model Performance Time Series”).

76.  The Modeling Guidance recommends that RRFs be applied to the average of three three-year design values centered on the base year, in this case the design values for 2010-2012, 2011-2013, and 2012-2014. This amounts to a 5-year weighted average of individual year 4th-high concentrations, centered on the base year of 2012, and so is referred to as a weighted design value.

77.  2016 Ventura County AQMP, Appendix I, Table I-2 (“Base Year and Future Year Ozone Design Values”).

78.  2016 Ventura County AQMP, Appendix K, page K-2.

79.  2016 Ventura County AQMP, Appendix J (“Ventura County Unmonitored Area Analysis”), prepared by the SCAQMD.

80.  Modeling Guidance, section 4.7.

81.  2016 Ventura County AQMP, Appendix J, Figure J-3 (“2020 Predicted 8-hr Ozone Design Values”).

82.  See 2016 Ventura County AQMP, Appendix A, Table A-5 (“District Rules Included in the SIP Inventory”).

83.  Modeling Guidance, 30.

84.  Only stations with more than 74.5% (the EPA's data completeness requirement) of the hourly measurements during each month of the ozone season were included in the analysis.

85.  Modeling Guidance, 101.

86.  70 FR 12264, at 12271 (March 6, 2015).

87.  Id.

88.  40 CFR 51.1110(a)(2)(i)(C) and 40 CFR 51.1110(a)(2)(ii)(B); and 70 FR 12264, at 12271 (March 6, 2015).

89.  40 CFR 51.1110(a)(7).

90.  40 CFR 51.1110(b).

91.  See 2016 Ventura County AQMP, 89, and 62 FR 1150 (January 8, 1997).

92.  See 2016 Ventura County AQMP, chapter 6 (“Reasonable Further Progress”).

93.  2018 SIP Update, RFP demonstration, chapter III (“SIP Elements for Ventura County”), section III-B (“Reasonable Further Progress”).

94.  Letter dated August 29, 2019, from Dr. Michael T. Benjamin, Chief, Air Quality Planning and Science Division, CARB, to Amy Zimpfer, Assistant Director, Air Division, EPA Region IX.

95.  NO_X substitution is permitted under EPA regulations. See 40 CFR 51.1110(a)(2)(i)(C) and 40 CFR 51.1110(a)(2)(ii)(B); and 70 FR 12264, at 12271 (March 6, 2015).

96.  62 FR 1150, at 1183 (January 8, 1997).

97.  We note a minor discrepancy between the safety margins included in the revised RFP demonstration for the 2020 attainment year and the safety margins included in the motor vehicle emissions budgets for 2020 in the 2016 Ventura County AQMP. The safety margins for the RFP demonstration, as shown in Table 4 of this document, are 0.7 tpd for VOC and 0.9 tpd for NO_X. The safety margins for the motor vehicle emissions budgets in the 2016 Ventura County AQMP are 0.79 tpd for VOC (0.8 tpd, if rounded to one significant figure) and 0.99 tpd (1.0 tpd, if rounded). Given the substantial extent to which the 2016 Ventura County Ozone SIP provides emissions reductions in excess of the RFP milestones, this minor discrepancy does not change our proposed finding that the 2016 Ventura County Ozone SIP meets the RFP demonstration requirement for the 2008 ozone NAAQS.

98.  70 FR 71612 (November 29, 2005). See also 2008 Ozone SRR, 80 FR 12264, at 12285 (March 6, 2015).

99.  80 FR 12264, at 12285 (March 6, 2015).

100.  See, e.g., 62 FR 15844 (April 3, 1997) (direct final rule approving an Indiana ozone SIP revision); 62 FR 66279 (December 18, 1997) (final rule approving an Illinois ozone SIP revision); 66 FR 30811 (June 8, 2001) (direct final rule approving a Rhode Island ozone SIP revision); 66 FR 586 (January 3, 2001) (final rule approving District of Columbia, Maryland, and Virginia ozone SIP revisions); and 66 FR 634 (January 3, 2001) (final rule approving a Connecticut ozone SIP revision).

101.  See, e.g., LEAN v. EPA, 382 F.3d 575 (5th Cir. 2004) (upholding contingency measures that were previously required and implemented where they were in excess of the attainment demonstration and RFP SIP).

102.  Bahr v. EPA, 836 F.3d 1218, at 1235-1237 (9th Cir. 2016).

103.  Id. at 1235-1237.

104.  The Bahr v. EPA decision involved a challenge to an EPA approval of contingency measures under the general nonattainment area plan provisions for contingency measures in CAA section 172(c)(9), but, given the similarity between the statutory language in section 172(c)(9) and the ozone-specific contingency measure provision in section 182(c)(9), we find that the decision affects how both sections of the Act must be interpreted.

105.  2016 Ventura County AQMP, chapter 7 (“Contingency Measures”), 91 and 92.

106.  2018 SIP Update, chapter III (“SIP Elements for Ventura County”), 18-20.

107.  Letter dated August 16, 2019, from Michael Villegas, Air Pollution Control Officer, VCAPCD, to Richard Corey, Executive Officer, CARB.

108.  Letter dated August 30, 2019, from Richard W. Corey, Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region IX.

109.  One year's worth of RFP for Ventura County corresponds to 3 percent of the RFP baseline year inventories for VOC (38.1 tpd) and NO_X (26.0 tpd).

110.  For the 2017 and 2020 RFP milestone years, surplus NO_X reductions correspond to 27.4 percent and 24.9 percent, respectively, of the 26.0 tpd 2011 RFP milestone inventory. See Table 4 in section III.E of this document.

111.  40 CFR 93.102(b)(2)(i).

112.  40 CFR 93.118(e)(4)(iii), (iv) and (v). For more information on the transportation conformity requirements and applicable policies on budgets, please visit our transportation conformity website at: http://www.epa.gov/​otaq/​stateresources/​transconf/​index.htm.

113.  40 CFR 93.118(f)(2).

114.  When the 2016 Ventura County AQMP was developed, 2012 was used as the RFP baseline year, and 2020 was not considered an RFP milestone year because it was not one of the years that follow in the three-year cycle after the initial six-year period after the RFP baseline year. However, in the wake of the South Coast II decision, 2011 became the required RFP baseline year and year 2020 became an RFP milestone year because it is three years after the initial six-year period from the 2011 RFP baseline year. Thus, the 2020 budgets from the 2016 Ventura County AQMP now serve as both the RFP milestone and attainment budgets.

115.  Letter dated April 11, 2017, from Richard Corey, Executive Officer, CARB, to Alexis Strauss, Acting Regional Administrator, EPA Region IX, transmitting the 2016 Ventura County AQMP.

116.  Letter dated August 29, 2019, from Dr. Michael T. Benjamin, Chief, Air Quality Planning and Science Division, CARB, to Amy Zimpfer, Assistant Director, Air Division, EPA Region IX.

117.  As previously noted, EMFAC2014 is CARB's model for estimating emissions from on-road vehicles operating in California. See 80 FR 77337 (December 14, 2015). We have recently announced the availability of an updated version of EMFAC, referred to as EMFAC2017. See 84 FR 41717 (August 15, 2019). For the 2016 Ventura County Ozone SIP, EMFAC2014 was the appropriate model to use for SIP development purposes at the time it was prepared.

118.  Under the transportation conformity regulations, the EPA may review the adequacy of submitted motor vehicle emission budgets simultaneously with the EPA's approval or disapproval of the submitted implementation plan. 40 CFR 93.118(f)(2).

119.  Memorandum dated September 5, 2019, from John J. Kelly, Air Planning Office, EPA Region 9, to docket for this proposed rulemaking, titled “Adequacy Documentation for Plan Motor Vehicle Emission Budgets in 2016 Ventura County Ozone Plan.”

120.  In May 2008, we found adequate the 2009 budgets from the Ventura County 2008 8-hour Ozone Early Progress Plan (February 2008). 73 FR 24595 (May 5, 2008). The 2009 budgets are 13 tpd for VOC and 19 tpd for NO_X.

121.  40 CFR 93.118(e)(1).

122.  67 FR 69139 (November 15, 2002) (final action limiting our prior approval of budgets in certain California SIPs).

123.  Under 40 CFR 93.118(e)(4), the EPA will not find a budget in a submitted SIP to be adequate unless, among other criteria, the budgets, when considered together with all other emissions sources, are consistent with applicable requirements for RFP and attainment. 40 CFR 93.118(e)(4)(iv).

124.  40 CFR part 51, subpart W, and 40 CFR part 93, subpart B.

125.  75 FR 17254.

126.  40 CFR 93.158; and VCAPCD Rule 220 (“General Conformity”), approved at 64 FR 19916 (April 23, 1999).

127.  2008 Ozone SRR, 80 FR 12264, at 12283 (March 6, 2015).

128.  75 FR 38023 (July 1, 2010).

129.  80 FR 12264 (March 6, 2015).

130.  84 FR 20604 (May 10, 2019); reproposed at 84 FR 43738 (August 22, 2019).

131.  64 FR 46849 (August 27, 1999).

132.  General Preamble, 57 FR 13498 at 13514 (April 16, 1992).

133.  77 FR 28772, at 28774 (May 16, 2012).

134.  See 40 CFR 51.126(b).

135.  76 FR 5277 (January 31, 2011). See also, 69 FR 29451 (May 24, 2004) (The EPA's approval of an earlier version of VCAPCD Rule 70 as meeting the requirements of CAA section 182(b)(3)).

136.  58 FR 8452 (February 12, 1993).

137.  82 FR 45191 (September 28, 2017).

138.  71 FR 61236 (October 17, 2006).

139.  40 CFR 58.2(b) now provides that, “The requirements pertaining to provisions for an air quality surveillance system in the SIP are contained in this part.”

140.  The 2008 ozone SRR addresses PAMS-related requirements at 80 FR 12264, at 12291 (March 6, 2015).

141.  Letter dated November 26, 2018, from Gwen Yoshimura, Manager, Air Quality Analysis Office, EPA Region IX, to Ravi Ramalingam, Chief, Consumer Products and Air Quality Assessment Branch, Air Quality Planning and Science Division, CARB.

142.  Letter dated August 29, 2019, from Dr. Michael T. Benjamin, Chief, Air Quality Planning and Science Division, CARB, to Amy Zimpfer, Assistant Director, Air Division, EPA Region IX.

143.  Regarding other applicable requirements for the 2008 ozone NAAQS in Ventura County, the EPA has previously approved SIP revisions that address the nonattainment area requirements for implementation of RACT for Ventura County for the 2008 ozone NAAQS. See 80 FR 2016 (January 15, 2015) (approval of Ventura County RACT SIP). With respect to the Nonattainment NSR SIP for Ventura County for the 2008 ozone NAAQS, the EPA proposed approval at 84 FR 20604 (May 10, 2019) and is expected to take final action in the near future.

144.  Letter dated August 16, 2019, from Michael Villegas, Air Pollution Control Officer, VCAPCD, to Richard Corey, Executive Officer, CARB; and letter dated August 30, 2019, from Richard W. Corey, Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region IX.