2024-27050. Air Plan Approval; Connecticut; Approval of State Implementation Plan Requirements for the 2008 Ozone Standard

Table 1—Summary of RFP Calculations for CT's Portion of the NY-NJ-CT Nonattainment Area

Description	VOC emissions (tons/summer day)	NO X emissions (tons/summer day)
RFP 2011 Baseline inventory	115.6	115.1
2020 target level of emissions	106.4	96.7
2020 projected, controlled emissions	83.9	60.4

RFP plans must include budgets, which identify the allowable on-road mobile emissions an area can produce and continue to demonstrate RFP. The State's RFP plan includes budgets for the Connecticut portion of the NY-NJ-CT nonattainment area for 2020. The budgets are discussed in detail in section III.B of this notice.

B. RFP Motor Vehicle Emissions Budgets/Transportation Conformity

Transportation conformity is required by section 176(c) of the CAA. Conformity to a SIP means conformity to an implementation plan's purpose of eliminating or reducing the severity and number of violations of the NAAQS and achieving expeditious attainment of the NAAQS, and that transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the NAAQS or any required interim emission reductions or other milestones in any area. (CAA 176(c)(1)(A) and (B)). The EPA's conformity rule at 40 CFR part 93, subpart A requires that transportation plans, transportation improvement programs, and projects conform to SIPs and establishes the criteria and procedures for determining whether or not they conform. To effectuate its purpose, the conformity rule requires a demonstration that emissions from the metropolitan planning organization's (MPO) Regional Transportation Plan (RTP) and the Transportation Improvement Program (TIP) are consistent with the budgets contained in the control strategy SIP revision or maintenance plan (40 CFR 93.101, 93.118, and 93.124). The term “Motor vehicle emissions budget” is defined in 40 CFR 93.101 as “that portion of the total allowable emissions defined in the submitted or approved control strategy . . . [SIP] or maintenance plan for a certain date for the purpose of meeting reasonable further progress milestones or demonstrating attainment or maintenance of the NAAQS, for any pollutant or its precursors, allocated to highway and transit vehicle use and emissions.”

The RFP plan submitted by Connecticut is a control strategy SIP, and it contains 2020 budgets for VOCs and NO_X for the Connecticut portion of the NY-NJ-CT nonattainment area. Table 2 contains these VOC and NO_X budgets, based on MOVES2014b, in units of tons per summer day:

Table 2—Motor Vehicle Emissions Budgets in the Connecticut RFP Plan

Area name	2020 Transportation conformity budgets (tons/day)
	VOC	NO X
NY-NJ-CT area (CT portion) Without Contingency Buffer	17.3	22.8
NY-NJ-CT area (CT portion) With Contingency Buffer	17.6	23.3

In this action, we are proposing approval of the 2020 budgets for VOC and NO_X for the Connecticut portion of the NY-NJ-CT nonattainment area shown in table 2 above. As part of this action, EPA is also initiating the adequacy process for these 2020 budgets providing opportunity for the public to review and comment. The criteria we use to determine whether a SIP's budgets are adequate for conformity purposes are outlined in 40 CFR 93.118(e)(4). We further described our process for determining the adequacy of submitted SIP budgets in 40 CFR 93.118(f). The public can comment on the adequacy of budgets, along with EPA's proposed approval of the budgets, during the comment period defined in the DATES section above.

C. Inspection and Maintenance (I/M) Program

The goal of I/M programs is to identify and repair high-emitting vehicles to improve air quality in areas that are not attaining the NAAQS.^[1]

Section 182(c)(3) of the CAA requires States with ozone nonattainment areas classified as Serious or above to implement an Enhanced I/M program to reduce VOC and NO_X emissions from in-use motor vehicles registered in urbanized portions of the nonattainment area. The Federal rules addressing I/M program requirements are provided at 40 CFR part 51, subpart S. Under these requirements, Serious ozone nonattainment areas in urbanized areas with 1980 Census-defined urbanized populations of 200,000 or more are required to adopt Enhanced I/M programs (40 CFR 51.350(a)(2)).

Similarly, pursuant to CAA section 182(b)(4), States with ozone nonattainment areas classified as Moderate are required to implement a Basic I/M program in certain applicable areas. To address this Basic I/M requirement for the Connecticut portion of the NY-NJ-CT 2008 ozone NAAQS Moderate nonattainment area, Connecticut submitted a SIP revision on August 8, 2017. Due to more stringent nonattainment classifications under previous NAAQS and Connecticut's inclusion as part of the Ozone Transport Region (OTR), Connecticut already had been implementing an Enhanced I/M program.^[2] On March 29, 2019, at 84 FR 11884, EPA approved Connecticut's ( print page 92083) certification that the State's vehicle emissions I/M program implemented via the regulation and statute mentioned above satisfied the CAA's requirement for Moderate ozone nonattainment areas and for States located within the Ozone Transport Region (OTR).

Connecticut's I/M certification submittal of June 23, 2022, being proposed for approval here, notes that although the OTR requirements of the CAA include a requirement that Enhanced I/M programs be implemented within metropolitan statistical areas with populations exceeding 100,000, the State implements Enhanced I/M statewide and thus the I/M program is SIP-strengthening and more stringent than required. Connecticut's Enhanced I/M program tests gasoline-fueled and diesel-fueled motor vehicles up to 10,000 pounds gross vehicle weight rating (GVWR), requires on-board diagnostic testing on Model Year (MY) 1996 and newer vehicles, and requires more comprehensive tailpipe testing on MY 1995 and older vehicles. The Enhanced I/M program also implements an emissions control device inspection through visual inspection for the presence of catalytic converter(s) and other major emissions control equipment. More details of the State's Enhanced I/M program may be found in section 6 of Connecticut's June 23, 2022, submittal. The State's submittal also attests that Connecticut's I/M program complies with all applicable CAA and I/M rule requirements for Enhanced I/M programs.

On November 17, 2022, Connecticut submitted supplemental documentation containing an I/M performance standard modeling analysis using EPA's latest mobile source emissions model at the time of the analysis (MOVES3). To demonstrate that the Connecticut Enhanced I/M program meets the Enhanced program performance standard described in 40 CFR 51.351, the Connecticut program must be modeled to show that, it achieves the same or lower emission rates of VOC and NO_X as the Federal model Enhanced program to within 0.02 grams per mile for the area's total vehicle miles travelled on a July weekday in the appropriate analysis year. Connecticut's supplemental demonstration shows that the State's I/M program meets the applicable Enhanced I/M performance standard requirements for the 2008 ozone NAAQS for the analysis years of 2020, 2023, and 2025.

Table 3 contains the results of the performance standard modeling, which illustrates that the Connecticut I/M program achieves the same or lower emission rates as the Federal model Enhanced program to within 0.02 grams per mile.

Table 3—I/M Performance Standard Evaluation Emission Rates

	CT's portion of the NY-NJ-CT nonattainment area
	Current Connecticut I/M program	Enhanced performance standard
I/M Performance Standard Evaluation Emission Rates (grams/mile)
2020 Summer
VOC	0.364	0.369
CO	3.772	4.333
NO X	0.267	0.265
2023 Summer
VOC	0.230	0.227
CO	3.143	3.615
NO X	0.279	0.278
2025 Summer
VOC	0.211	0.207
CO	2.783	3.203
NO X	0.238	0.236