[Federal Register Volume 61, Number 241 (Friday, December 13, 1996)]
[Proposed Rules]
[Pages 65780-65872]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-31437]
[[Page 65779]]
_______________________________________________________________________
Part VI
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 53 and 58
Proposed Requirements for Designation of Reference and Equivalent
Methods for PM2.5 and Ambient Air Quality Surveillance for
Particulate Matter; Proposed Rule
Federal Register / Vol. 61, No. 241 / Friday, December 13, 1996 /
Proposed Rules
[[Page 65780]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 53 and 58
RIN 2060-AH09
[AD-FRL-5659-2]
Proposed Requirements for Designation of Reference and Equivalent
Methods for PM2.5 and Ambient Air Quality Surveillance for
Particulate Matter
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The EPA proposes to revise 40 CFR part 58 to establish ambient
air quality monitoring requirements for PM2.5 (particles with an
aerodynamic diameter less than or equal to a nominal 2.5 micrometers)
as measured by a new reference method being proposed in Appendix L to
40 CFR part 50 or by an equivalent method designated in accordance with
requirements being proposed in 40 CFR part 53. In addition, this
document also proposes certain revisions to existing ambient air
quality monitoring requirements for PM10 (particles with an
aerodynamic diameter less than or equal to a nominal 10 micrometers).
The changes proposed in this document address among other things,
network design and siting, quality assurance and quality control, and
monitoring methodology. The document also indicates EPA's intent to
explore opportunities to coordinate and integrate the existing
visibility monitoring requirements with the ambient air quality
monitoring requirements for particulate matter being proposed today to
accommodate a better regional haze program and to reduce burdens and
achieve multiple monitoring objectives.
DATES: Comments must be submitted on or before February 18, 1997.
ADDRESSES: Comments should be submitted (in duplicate, if possible) to:
Air Docket (LE-131), U.S. Environmental Protection Agency, Attn. Docket
No. A-96-51, 401 M Street, SW, Washington, DC 20460. The docket may be
inspected between 8:00 a.m. and 5:30 p.m. on weekdays. A reasonable fee
may be charged for copying.
Public hearing: The EPA will announce in a separate Federal
Register document the date, time, and address of the public hearing on
this proposed decision.
FOR FURTHER INFORMATION CONTACT: Mr. Neil Frank (MD-14), Monitoring and
Quality Assurance Group, Emissions, Monitoring, and Analysis Division,
U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina 27711, telephone (919) 541-5560.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Authority
II. Introduction
III. Discussion of Proposed Revisions to Part 53
A. Designation of Reference and Equivalent Methods
B. Quality Assurance
IV. Discussion of Proposed Revisions to Part 58
A. Section 58.1 Definitions
B. Section 58.13 Operating schedule
C. Section 58.14 Special purpose monitors
D. Section 58.15 PM2.5 NAAQS eligible monitors
E. Section 58.20 Air quality surveillance: plan content
F. Section 58.23 Monitoring network completion
G. Section 58.25 System modification
H. Section 58.26 Annual SLAMS summary report
I. Section 58.30 NAMS network establishment
J. Section 58.31 NAMS network description
K. Section 58.34 NAMS network completion
L. Section 58.35 NAMS data submittal
M. Appendix A--Quality Assurance Requirements for State and
Local Air Monitoring Stations (SLAMS)
N. Appendix B--Quality Assurance Requirements for Prevention of
Significant Deterioration (PSD) Air Monitoring
O. Appendix C--Ambient Air Quality Monitoring Methodology
P. Appendix D--Network Design for State and Local Air Monitoring
Stations (SLAMS), National Air Monitoring Stations (NAMS), and
Photochemical Assessment Monitoring Stations (PAMS)
Q. Appendix E--Probe and Monitoring Path Siting Criteria for
Ambient Air Quality Monitoring
R. Cost Estimates for New PM Networks
S. Reference
V. Administrative Requirements
A. Regulatory Impact Analysis
B. Reporting and Record keeping Requirements
C. Impact on Small Entities
D. Unfunded Mandates Reform Act of 1995
I. Authority
Sections 110, 301(a), and 319 of the Clean Air Act as amended 42
U.S.C. 7410, 7601(a), 7619.
II. Introduction
A. Proposed Revision to the Particulate Matter NAAQS
Elsewhere in today's Federal Register, EPA announced proposed
revisions to the national ambient air quality standards for particulate
matter. In that notice, EPA proposes to amend the current suite of
PM10 standards by adding new PM2.5 standards and by revising
the form of the current 24-hour PM10 standard. Specifically, the
EPA proposes to add two new primary PM2.5 standards set at 15
g/m3, annual mean, and 50 g/m3, 24-hour
average. The proposed new annual PM2.5 standard would be met when
the 3-year average of the annual arithmetic mean PM2.5
concentrations, spatially averaged across an area, is less than or
equal to 15 g/m3. The proposed new 24-hour PM2.5
standard would be met when the 3-year average of the 98th percentile of
24-hour PM2.5 concentrations at each monitor within an area is
less than or equal to 50.
The EPA also proposes to retain the current annual PM10
standard at the level of 50 g/m3, which would be met when
the 3-year average of the annual arithmetic PM10 concentrations at
each monitor within an area is less than or equal to 50 g/
m3. Further, EPA proposes to retain the current 24-hour PM10
standard at the level of 150 g/m3, but to revise the form
such that the standard would be met when the 3-year average of the 98th
percentile of the monitored concentrations at the highest monitor in an
area is less than or equal to 150 g/m3.
In the part 50 notice, EPA also proposed to revise the current
secondary standards by making them identical to the suite of proposed
primary standards. The suite of PM2.5 and PM10 standards, in
conjunction with the establishment of a regional haze program under
section 169A of the Clean Air Act (Act), are intended to protect
against PM-related welfare effects including soiling and materials
damage and visibility impairment.
As discussed in the part 50 notice, the proposed new PM2.5
standards are intended to protect against exposures to fine particulate
pollution, while the new PM10 standards are intended to protect
against coarse fraction particles as measured by PM10.
For PM2.5, the annual standard is intended to protect against
both long- and short-term exposures to fine particle pollution. Under
this approach, the PM2.5 24-hour standard would serve as a ``back
stop'' to provide additional protection against days with high
PM2.5 concentrations, localized ``hot spots,'' and risks arising
from seasonal emissions that would not be well controlled by a national
annual standard.
In specifying that the calculation of the annual arithmetic mean
for an area (for purposes of comparison to level of PM2.5 annual
standard) should be
[[Page 65781]]
accomplished by averaging the annual arithmetic means derived from
multiple, population-oriented monitoring sites, EPA took into account
several factors. As discussed in the part 50 notice, many of the
community-based epidemiologic studies examined in this review used
spatial averages, when multiple monitoring sites were available, to
characterize area-wide PM exposure levels and associated public health
risk. Even in those studies that used only one monitoring location, the
selected site was chosen to represent community-wide exposures, not the
highest value likely to be experienced within the community. Because
the annual PM2.5 standard would be intended to reduce aggregate
population risk from both long- and short-term exposures by lowering
the broad distribution of PM concentrations across the community, an
annual standard based on spatially averaged concentrations from several
population-oriented monitoring sites would better reflect areawide PM
exposure levels and associated health risks than would a standard based
on concentrations from a single monitor with the highest measured
values in the area. The spatial average approach is not appropriate for
PM10 because the spatial distribution of coarse particles is
different and tends to be more localized in its behavior.
Finally, under the policy approach presented in the part 50 notice,
the 24-hour PM2.5 standard would be intended to supplement a
spatially-averaged annual PM2.5 standard by providing protection
against peak 24-hour concentrations arising from situations that would
not be well-controlled by an annual standard. Accordingly, the 24-hour
PM2.5 standard would be based on the single population-oriented
monitoring site within a monitoring planning area with the highest
measured values.
In EPA's judgment, an annual PM2.5 standard expressed as a
spatial average, established in conjunction with a 24-hour standard
based on the monitoring site with the highest measured values, would
provide the most appropriate target for reducing area-wide population
exposure to fine particle pollution and would be most consistent with
the underlying epidemiologic data base. On the other hand, EPA is
mindful that adoption of spatial averaging for a PM2.5 standard
would add a degree of complexity to the monitoring siting requirements
and to the specification of those areas across which spatial averaging
should be permitted. This approach may also require larger monitoring
networks in some areas. By proposing a spatial averaging approach, the
part 50 notice recognizes that some monitoring planning areas may have
to be subdivided into smaller subareas to reflect gradients in particle
levels (e.g., upwind suburban sites, central city sites, downwind
sites) as well as topographical barriers or other factors that may
result in a monitoring planning area having several distinct air
quality regimes.
Recognizing the complexities that spatial averaging may introduce
into risk management programs and that unforeseen issues may arise from
public comment on the requirements presented in this notice, the part
50 notice also requests comment on the alternative of basing the
PM2.5 annual standard on the population-oriented monitoring site
within the monitoring planning area with the highest 3-year average
annual mean. The part 50 notice indicates, based on comments received,
that EPA may choose either of these two approaches for specifying the
form of the annual PM2.5 standard at the time of promulgation of
any revisions to the PM standards.
In the part 50 notice, EPA also solicits comments on alternative
levels of both annual and 24-hour PM2.5 primary standards and on
revoking the current 24-hour primary PM10 standard.
B. Air Quality Monitoring Requirements
Section 110(a)(2)(C) of the Act requires ambient air quality
monitoring for purposes of the State implementation plans (SIP's) and
for reporting data quality to EPA. Uniform criteria to be followed when
measuring air quality and provisions for daily air pollution index
reporting are required by section 319 of the Act. To satisfy these
requirements, on May 10, 1979 (44 FR 27558), EPA established 40 CFR
part 58 which provided detailed requirements for air quality
monitoring, data reporting, and surveillance for all of the pollutants
for which national ambient air quality standards have been established
(criteria pollutants). Provisions were promulgated subsequently for
particulate matter (PM10) on July 1, 1987 (52 FR 24740).
The intent of the air quality surveillance requirement being
proposed today is to establish a revised particulate matter monitoring
network that would produce air quality data for the purpose of
comparison to the proposed primary and secondary PM NAAQS and to
facilitate implementation of a possible new regional haze program. In
developing a new particulate matter monitoring network and associated
requirements, consideration has been given to the indicators, forms,
and levels of the proposed primary and secondary PM NAAQS. As a result,
nationwide monitoring would be performed for two indicators of PM:
PM2.5 and PM10. To be reflective of the basis for and the
specification of the forms of the proposed new annual and 24-hour
primary and secondary PM2.5 NAAQS, new monitoring network design
and siting requirements are being proposed. For purposes of comparison
to the proposed PM2.5 annual standard, such sites would be
population-oriented and be representative of community-wide exposure
levels. The siting criteria for monitors to be used for comparison to
the proposed 24-hour PM2.5 standard would also be population-
oriented but reflective of the highest measured values within the
community. To ensure PM data of the highest possible quality, new
requirements for quality assurance and designation of new PM2.5
reference or equivalent samplers are also described.
With respect to NAAQS comparisons and visibility protection in more
rural areas, the new network design and siting requirements would
encourage the placement of PM2.5 monitors outside population
centers with two purposes in mind: (1) To provide air quality data
necessary to facilitate implementation of the proposed NAAQS, and (2)
augmentation of the existing visibility fine particle monitoring
network. The coordination of these two monitoring objectives would
facilitate implementation of a regional haze program and lead to an
integrated monitoring program for fine particles.
The network design and siting requirements for the annual and 24-
hour PM10 NAAQS would continue to emphasize identification of
locations at maximum concentrations. The PM10 network itself,
however, would be revised because the proposed PM2.5 standards
would likely be the controlling standards in most situations.
The new network for PM10 would be derived from the existing
network of State and Local Air Monitoring Stations (SLAMS), National
Air Monitoring Stations (NAMS), and other monitors generically
classified as Special Purpose Monitors (SPM's) which include industrial
and special study monitors. Population-oriented NAMS will generally be
maintained, other key sampling locations in existing nonattainment
areas, and in areas whose concentrations are near the levels of the
proposed PM10 NAAQS will be continued. Currently approved
reference or equivalent PM10 samplers could continue to be
utilized. The revised network would ensure that analysis of national
trends in PM10 can
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be continued, that air surveillance in areas with established PM
emission control programs can be maintained, and that the PM10
NAAQS will not be jeopardized by additional growth in PM10
emissions. PM10 sites should be collocated with new PM2.5
sites at key population-oriented monitoring stations so that better
definition of fine and coarse contributions to PM10 can be
determined to provide a better understanding of exposure, emission
controls, and atmospheric processes. PM10 sites not needed for
trends or for monitoring in areas with relatively high PM10
concentrations would likely be discontinued in a longer-term PM10
network. The sampling frequency at all PM10 sites would be reduced
to a minimum of once in 6 days, which would be sufficient to make
comparisons with proposed PM10 standards. The combination of fewer
PM10 sites and the reduction in required sampling frequency would
save significant resources that could be redirected to PM2.5
monitoring.
The new network for PM2.5 would consist of a ``core'' network
of population-oriented SLAMS monitors, ``core'' regional background and
regional transport SLAMS, a NAMS subset for long-term monitoring, other
SLAMS monitors, and supplementary network of SPM's. The core
population-oriented sites would be reflective of community-wide
exposure and would be required in all of the largest metropolitan areas
and must sample everyday. Frequent measurements are important to
understand episodic behavior of PM2.5, and to establish effective
emission control strategies to assure protection of the NAAQS. Many of
the new PM2.5 sites are expected to be located at existing
PM10 sites, and would be collocated with some PAMS sites.
Consistency with the proposed new PM2.5 NAAQS necessitates the
adoption of new concepts for identification and establishment of
monitoring stations for the PM2.5 ambient air monitoring network
as well as use of the data in relation to the proposed PM2.5
NAAQS. These concepts include: (1) The addition of specially coded
sites whose data would be used to compare to the levels of the annual
and 24-hour PM2.5 NAAQS, and (2) the inclusion of monitoring
planning areas and spatial averaging zones (SAZ) to correspond to the
population-oriented, spatial averaging approach. These concepts and
associated requirements are discussed in sections 58.15 and sections
2.8.1-2.8.3 of Appendix D below.
Although the major emphasis of the new PM networks is compliance
monitoring in support of the NAAQS, the network is also intended to
assist in reporting of data to the general public, especially during
air pollution episodes and to assist in the SIP planning process. To
these ends, additional monitoring and analysis requirements are
proposed concerning the location of nephelometers (or other continuous
particulate matter measuring devices) at some core monitoring sites and
the archiving of filters for possible subsequent analysis for subsets
of the PM2.5 SLAMS sites. Moreover, collection of meteorological
data at core SLAMS sites (including background and regional transport
sites) are suggested. The additional requirements should help to
further characterize the composition and trends in PM2.5 and
better understand the sources and processes leading to elevated
PM2.5 concentrations. Because these proposed revisions do not
specifically require the chemical analysis of collected PM2.5 or
PM10 filters, the Administrator would welcome comments on this
issue. In particular, comments are solicited on the need for
alternative PM2.5 monitoring methodologies and additional
monitoring requirements which might accompany the part 51
implementation rules to identify the causes of detected PM2.5
NAAQS violations and to assist in the development of PM2.5
emission control strategies.
While the proposed siting criteria and network designs are
appropriate for both the proposed revisions to the primary and
secondary NAAQS as a whole, additional consideration must be given to
air quality surveillance in more rural/remote areas to characterize
fine particle levels in order to protect against broader regional scale
visibility impairment. To achieve the appropriate level of air quality
surveillance in such areas, EPA believes it is important to coordinate
and integrate the background and transport monitoring sites specified
in this notice with the existing Interagency Monitoring of Protected
Visual Environments (IMPROVE) monitors that are in place in a number of
locations around the country to characterize fine particle levels and
visibility in mandatory Federal Class I areas (e.g., certain national
parks and wilderness areas). The need for coordination and integration
of visibility-oriented monitoring sites will increase when EPA proposes
rules under section 169A of the Act to supplement the secondary NAAQS
in addressing regional haze. More detailed guidance on monitoring and
assessment requirements will be provided when those rules are proposed.
This will include details on topics such as monitor placement,
monitoring methodology, duration of sampling and frequency of sampling.
It is anticipated, however, that the existing IMPROVE network, together
with sites established under this proposal, would be an integral part
of the network for determining reasonable progress under a regional
haze program.
In the meantime, EPA recommends that States, in conjunction with
EPA and Federal land managers, explore opportunities for expanding and
managing PM2.5 and visibility monitoring networks in most
efficient and effective ways to meet the collective goals of these
programs. To facilitate this, EPA has proposed changes in Appendix C
below, to allow use of existing or new IMPROVE monitoring sites to meet
the requirements for a transport and/or background site for the
proposed PM2.5 standards. States should consider the feasibility
of siting new transport/background and/or visibility monitoring
locations at or near mandatory Federal Class I areas currently without
an IMPROVE site so that such sites could provide data to characterize
both fine particle levels and visibility in or near Class I areas. It
is EPA's intent that monitoring conducted for purposes of the PM
primary and secondary NAAQS (including background and transport sites),
and for visibility protection be undertaken as one coordinated national
PM monitoring program, rather than as a number of independent networks.
It is recognized by EPA as well as many outside groups including
the Clean Air Act Advisory Committee's Subcommittee on Ozone,
Particulate Matter, Regional Haze Implementation Programs and the
National Research Council in its 1993 report ``Protecting Visibility in
National Parks and Wilderness Areas'' that chemical speciation of PM
data would permit development of more effective control strategies to
better target those sources of emissions that are causing or
contributing to elevated levels of PM2.5 and PM10. Speciation
of PM2.5 data can also be used to develop reliable estimates of
seasonal and annual average visibility conditions.
Because of the costs associated with conducting filter analysis on
a routine basis, this proposal only requires filters to be archived so
they are available for analysis on an as needed basis. The EPA requests
comment, however, on the extent to which chemical speciation should be
conducted. This would include: (1) Whether specific monitoring sites
should be designated for such analyses; (2) the criteria to be
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used to select sites for speciated sampling and analysis; (3) the
extent and frequency to which speciation should be required by EPA for
at least some monitoring stations and (4) the need for monitoring
methodologies not described in this proposal which may be needed to
facilitate compositional analysis. The EPA recognizes that there is a
need for speciation and other specialized monitoring efforts which are
not specifically required by this proposed rule. Accordingly, EPA will
give these PM monitoring efforts high priority in its section 105
grants program. The Administrator solicits comment on the appropriate
portion of the nation's monitoring resources which should be dedicated
to speciation and collection of special study data relative to the
siting and collection of mass measurements for purposes of comparisons
to the NAAQS and visibility assessments at permanent and temporary
monitoring stations. The estimated cost for the new PM monitoring
program is discussed further in Section IV. R.
Finally, in anticipation of a new regional haze program and
associated additional monitoring requirements, EPA also requests
comment on ways that the future PM and IMPROVE networks can be
coordinated to conserve resources and serve the goals of both the PM
and regional haze implementation program.
This proposed rulemaking is taken in conjunction with the proposed
revisions to the PM NAAQS published elsewhere in today's Federal
Register and pertains to changes in the ambient air monitoring
requirements for particulate matter contained primarily in 40 CFR part
58. A new Federal Reference Method for PM2.5, and changes to the
definition of PM10 measurements are proposed in a new Appendix L
and revisions to Appendix J respectively in 40 CR part 50. The
effective date of these proposed monitoring regulations would be 6
months after the actual promulgation date. The EPA is soliciting
comment on all aspects of all of the proposed rules.
III. Proposed Revisions to Part 53
A. Designation of Reference Methods for PM2.5
The specifications for reference methods for PM2.5 are
described in Appendix L to part 50, proposed elsewhere in this issue of
the Federal Register. The performance-based specifications for the
operational aspects of a reference method sampler allow various sampler
manufacturers to design and fabricate different samplers that would
meet the specifications. Accordingly, multiple PM2.5 reference
methods are expected to become available from several manufacturers, as
is the case for reference methods for PM10 and most gaseous
criteria pollutants. Similarly, each reference method for PM2.5,
based on a particular sampler, would be formally designated as such by
the EPA under new provisions added to part 53.
These new provisions, primarily contained in a new subpart E, would
require that the applicant submit information and documentation to
demonstrate that a candidate reference method sampler meets the design
specifications set forth in Appendix L of part 50. The provisions would
also require that the applicant carry out specific tests to demonstrate
that the sampler meets all performance specifications. The nature of
these tests and the requirement that they be carried out by the
applicant rather than the EPA is consistent with the current
requirements in part 53 for designating reference methods for other
criteria pollutants.
Since the critical inlet and particle size separation components of
the sampler are specified by design, no wind tunnel or aerodynamic
performance tests of these components would be required. But
documentation would be required to demonstrate that samplers to be sold
as reference methods would be manufactured under an effective quality
control system, such as required in an International Organization for
Standardization (ISO) 1 9001-certified facility, or a quality
control system otherwise certified to meet similar requirements.
Specific tests would be required to verify that the critical PM2.5
impact or jet diameter was within the design specifications, and that
the surface finish of surfaces required to anodized meets the surface
finish specifications. Also, a checklist certifying that reference
method samplers are or will be manufactured under an acceptable quality
assurance system would have to be completed by an ISO-certified or
equivalent auditor and submitted initially and annually.
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\1\ The ISO certification ensures compliance to international
manufacturing standards from the design and engineering
specifications. An ISO certification, or its equivalence for the
manufacturing of the reference samplers is consistent with National
Technology Transfer and Advancement Act Section 12(d), 15 U.S.C.
Section 272 (1996).
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The performance tests for reference method samplers would focus on
testing of the sampler's operational performance parameters, the
accuracy of its measurement systems, its field precision, and various
other sampler control functions. A comprehensive test procedure is
proposed for testing a representative candidate sampler for correct
flow rate, flow rate regulation, flow rate measurement accuracy,
ambient air temperature and barometric pressure measurement accuracy,
filter temperature control and measurement accuracy, and sampling time
accuracy. This test procedure would require a temperature-controlled
environmental test chamber, a technique to simulate reduced barometric
pressure, and facilities to generate simulated solar radiation. Other
specific tests are proposed to test the sampler's post-sampling filter
temperature control, leak check procedure, flow rate cut off function,
and field operational precision. It should be noted that work to test
the feasibility of these proposed test procedures has not been
completed at this time; therefore, some technical changes to the
proposed test procedures may be necessary following the results of that
work.
B. Designation of Equivalent Methods for PM2.5
In keeping with the EPA's largely performance-based approach for
specification of measurement methods for environmental pollutants,
provision is also proposed for designating equivalent methods for
PM2.5. These provisions are contained in proposed additions to
subparts A and C and proposed new subparts E and F of part 53. To
minimize the number and extent of performance tests to which candidate
equivalent methods would be subjected, three classes of equivalent
method are proposed to be defined.
The first class (Class I) would include PM2.5 methods based on
samplers that are very similar to a reference method sampler as
specified in appendix L to part 50. Class I would primarily include
methods based on samplers whose primary difference from reference
method samplers is one or more modifications necessary to provide
capability for collection of several sequential samples automatically
without intermediate operator service. Samplers capable of collecting
multiple sequential samples are important because the sampling
schedules proposed in Sec. 58.13 of part 58 call for daily sampling for
certain SLAMS. With such a requirement, there is an expected need for
samplers that will permit the collection of the required daily samples
without the need for an operator to visit the site on a daily basis or
for installing multiple samplers at the site. (Since the samplers would
need to sample from midnight to midnight, a minimum of two single day
samplers would be
[[Page 65784]]
required for full daily sampling; however, as a practical matter,
additional single day samplers would generally be needed at a daily
monitoring site to cover weekends, holidays, and personnel and
scheduling logistics.) A sampler capable of automatically collecting
five sequential samples would permit twice-weekly servicing of a
monitoring site (assuming sample filters can be retrieved and reloaded
on the inactive channels without affecting the actively sampling
channel).
Since the design of sequential samplers is not specified
explicitly, sampler manufacturers would be able to design and develop
their own techniques to provide for this capability. Where the
sequential sample technique consists of relatively minor or simple
modifications of the reference method sampler, the sampler would be
classified as a Class I candidate equivalent method. (Sequential
samplers would also be possible as Class II or III equivalent methods.)
Class I equivalent method sequential samplers would have to be
tested to make sure that the modifications required to provide for
sequential sampling do not significantly compromise sampler
performance. However, because of their similarity to the reference
method sampler, the only additional test requirement for most Class I
candidate equivalent methods--in addition to the tests and performance
requirements applicable to reference method samplers--would be a test
for possible loss of PM in any new or modified components in the
sampler inlet upstream of the sample filter. This additional test for
Class I samplers is set forth in the proposed new Subpart E, along with
the tests for reference method samplers.
Class II equivalent methods would include all other PM2.5
methods that are based on a 24-hour integrated filter sample which is
subjected to subsequent moisture equilibration and gravimetric mass
analysis, but with an associated sampler having substantial deviations
from the design or performance specifications for reference method
samplers. These samplers may have a different inlet, a different
particle size separator, a different volumetric flow rate, a different
filter or filter face velocity, or other significant differences. More
extensive performance testing would be required for designation of
Class II candidate equivalent methods, with various tests required
depending on the nature and extent of the differences between the
candidate sampler and specified reference method samplers. These tests
include a full wind tunnel evaluation, a wind tunnel inlet aspiration
test, a static fractionator test, a fractionator loading test, and a
volatility test. The tests and their specific applicability to various
types of candidate Class II equivalent method samplers are set forth in
proposed new subpart F.
Finally, Class III equivalent methods would include any candidate
PM2.5 methods that could not qualify as Class I or Class II. This
class would include any filter-based integrated sampling method having
other than a 24-hour PM2.5 sample collection interval followed by
moisture equilibration and gravimetric mass. More importantly, class
III would also include filter-based continuous or semi-continuous
methods, such as beta attenuation instruments, harmonic oscillating
element instruments, and other complete in situ monitor types, as well
as non-filter-based methods such as nephelometry or other optical
instruments.
The testing requirements for designation of Class III candidate
methods would be the most stringent, since quantitative comparability
to the reference method would have to be shown under various potential
particle size distributions and aerosol composition. However, because
of the variety of measurement principles and types of methods possible
for Class III candidate equivalent methods, the test requirements would
have to be individually selected or specifically designed or adapted
for each such type of method. Therefore, the EPA believes that it is
not practical to attempt to develop and explicitly describe the test
procedures and performance requirements for all of these potential
Class III methods a priori. Rather, it is proposed that the test
procedures and performance requirements applicable to specific Class
III candidate methods would be determined by the EPA on a case-by-case
basis upon request, in connection with each proposed or anticipated
application for a Class III equivalent method determination. In this
regard, the EPA is interested in receiving comments pertinent to the
nature and extent of tests that would be appropriate and effectual in
determining the performance of various types of Class III candidate
equivalent methods relative to the performance of reference methods for
PM2.5.
All classes of candidate equivalent methods would have to be field-
tested to determine their comparability to measurements obtained with
collocated reference methods. For Classes I and II, these collocated
field test requirements are specified explicitly in Subpart C, which is
proposed to be revised to include the specific requirements for
PM2.5 candidate equivalent methods. The proposed requirements for
PM2.5 methods are generally patterned after the existing
requirements for PM10 candidate methods.
However, because of the need for greater measurement precision for
PM2.5, the comparability specifications, summarized in Table C-4,
are somewhat more stringent than those previously established for
PM10. Also, for Class II candidate equivalent methods--where two
different test sites are required--more definitive specifications are
proposed for the tests sites in terms of the PM2.5 to PM10
measurement ratio for the test samples. This is necessary because
experience with PM10 measurements has indicated that PM
measurements made with dissimilar samplers are often considerably
affected by differences in the ``character'' of the PM at different
monitoring sites, as represented by differences in particle size
distribution, composition, density, humidity, and other factors. For
purposes of the comparability test, the character of the PM at each
test site is represented by the measured PM2.5 to PM10 ratio,
which must be greater than 0.75 for one site and less than 0.40 at the
other site. (More definitive tests of PM character at the test site are
deemed too difficult or costly to carry out for purposes of the
comparability test.) Insuring comparability to reference method
measurements at sites having profoundly different character of PM is
critically important for Class II (and Class III) candidate equivalent
methods. Note, however, that the PM2.5 to PM10 ratio
requirement does not apply to testing of Class I candidate methods,
where only one test site is required.
C. Quality Assurance
Accurate measurement of ambient particulate matter concentrations
is severely hampered by the impracticality of providing PM
concentration standards for field (or even laboratory) testing of
ambient samplers or monitors. Therefore, it is necessary to rely on a
specific, well-defined reference method, uniformity of reference method
devices and procedures, and continual assessment of bias and operating
precision. For the purposes of this regulation, PM2.5
concentration measurements would be referenced to measurements made
with a reference method sampler in accordance with the reference method
as specified in Appendix L of part 50 of this chapter. Monitoring for
PM2.5 requires greater attention to achieving data of high
quality, with minimal imprecision and
[[Page 65785]]
relative error. These higher quality monitoring data are essential to
reduce the chance that PM2.5 measurements would potentially cause
unjustified health risk to the population, when measurements
underestimate true concentrations, or unnecessary control requirements,
when measurements overestimate the true concentrations.
To meet a data quality objective of 15% precision for
ambient PM2.5 attainment measurements, enhanced quality assurance
would be required in all areas relating to sampler performance
including sampler manufacturing and sampler operation. This is
especially important because a reference method sampler is proposed to
be used to audit other field monitors, as described later.
Designated reference and equivalent method samplers and monitors
would be required to be manufactured in a manufacturing facility that
is either (1) an ISO 9001-registered manufacturing facility, with
registration maintained continuously, or (2) a facility that can be
demonstrated, on the basis of information submitted to the EPA, to be
operated according to an EPA-approved and periodically audited quality
system which meets, to the extent appropriate, the same general
requirements as for an ISO-registered facility. (This requirement is
referred to in this document as an ISO-registered facility, regardless
of the procedure taken for EPA approval.)
In addition to the ISO registration (or equivalent) requirement, a
quality assurance manufacturing checklist would have to be submitted
annually attesting that the appropriate quality assurance procedures
are routinely implemented in the manufacturing of samplers sold as
reference or equivalent method samplers. This check list would have to
be signed by an ISO-certified auditor or by an auditor who, based on
information submitted to the EPA, meets the same general requirements
as provided for ISO-certified auditors. (Similarly, an auditor approved
by EPA through either mechanism is referred to in this document as an
ISO-certified auditor.) This requirement allows for the demonstration
of consistency in production and sustained uniformity in design and
operation. Further, all testing related to an application for a
reference or equivalent method determination under part 53 would have
to be carried out in accordance with ISO 9001 and ANSI/ASQC E4
standards.
It is believed that these requirements are necessary to insure that
all samplers or analyzers sold as reference or equivalent methods are
manufactured to the high standard required to achieve the needed data
quality. These procedures are in keeping with the developing
international standards for manufacturing in this and other industries.
However, comments on the appropriateness and impact of these proposed
requirements are solicited. While these requirements are currently
proposed to apply only to the manufacture of PM2.5 monitors,
extending these requirements to the manufacture of PM10 monitors
and possibly other types of SLAMS monitors will likely be considered at
a later time.
A new operational requirement would also have to be met by each
PM2.5 sampler or monitor to retain its designation as a reference
or equivalent method. Each user agency operating a SLAMS site would be
required to obtain at least 6 collocated measurements (audits) per year
with a reference method ``audit'' sampler for each routinely operating
PM2.5 monitor. The data obtained from these collocated audits
would be used to determine a national network integrated operating
precision and relative accuracy performance indicator for each
designated method. A PM2.5 monitoring method that fails to meet
the specified limits for this performance indicator would be subject to
possible cancellation of its reference or equivalent method designation
under the provisions of Sec. 53.11. For more information on this
provision, see section 6 of proposed revisions to Appendix A of part 58
and its associated preamble, set forth elsewhere in this Federal
Register.
D. Other Changes
A number of other relatively minor technical changes are proposed
to Appendix A, some of which affect designation of reference or
equivalent methods for other criteria pollutants as well as for
PM2.5. These changes include new definitions and clarifications of
existing definitions in Sec. 53.1; clarifications of the reference and
equivalent method designation requirements for methods for all
pollutants, including the new classes of equivalent methods for
PM2.5 and a new table summarizing all the designation
requirements; and updating of the name of the EPA laboratory to which
applications are to be sent. Additional changes include proposed
clarifications of the content of information required in submitted
applications regarding the candidate method test data, manufacturing
quality assurance system, and product warranty, and the content
required in the operation or instruction manual associated with a
candidate method sampler or analyzer.
Also, because of the increasing complexity of anticipated candidate
methods for all criteria pollutants, an increase in the EPA's time
limit for processing applications for reference and equivalent methods,
from 75 to 120 days, is proposed. Finally, it is proposed (under
Sec. 53.4) that applicants for a PM2.5 reference or equivalent
method determination be required to provide a sampler or analyzer that
is representative of the one associated with the candidate method for
inspection and possible testing by the EPA in connection with
processing of the application.
IV. Discussion of Proposed Revisions to Part 58
A. Section 58.1--Definitions
The revisions proposed today would revise the definition of the
term traceable and add definitions of the terms Consolidated
Metropolitan Statistical Area (CMSA), core SLAMS, equivalent methods,
Metropolitan Statistical Area (MSA), monitoring planning area (MPA),
monitoring plan, PM2.5, Primary Metropolitan Statistical Area
(PMSA), population-oriented, reference method, SAZ (SAZ), SPM fine
monitors, and Annual State Monitoring Report.
B. Section 58.13--Operating Schedule
1. PM10 Sampling. The current operating schedule for PM10
is based primarily on an analysis of the ratio of measured PM10
concentrations to the controlling PM10 standard. Depending upon
the ratio, the sampling frequency is either every day, every other day,
or every sixth day. The proposed operating schedule would reduce the
sampling frequency at all PM10 sites to once every sixth day.
The Administrator has proposed a new 24-hr PM10 standard based
on the 98th percentile which offers a more stable statistical form. She
has also solicited comment on the need to retain any 24-hour PM10
standard. Unlike the current 24-hr PM10 standard, the proposed
standard, if adopted, would not place emphasis on the most extreme 24-
hr concentrations, especially in areas influenced by fugitive dust.
Furthermore, more emphasis for control requirements is anticipated to
be placed on annual average concentrations and fewer nonattainment
areas (i.e. violation areas) are expected to be based on peak daily
concentrations. Consequently, 1 in 6 day sampling should be sufficient
to support the new PM10 NAAQS and a less dense monitoring network
would also be needed. Comments are solicited on the appropriate
sampling schedules
[[Page 65786]]
for PM10 sites if the 24-hour NAAQS for PM10 is retained.
2. PM2.5 Sampling. Core PM2.5 SLAMS (including NAMS and
Core SLAMS collocated at PAMS sites) would be required to sample every
day, unless an exception is approved by EPA during established seasons
of low PM pollution during which time a minimum of once in 6 days
sampling would be permitted. Non-core SLAMS sites would generally be
required to sample a minimum of once every sixth day, although episodic
or seasonal sampling could also be possible (e.g., in areas where
significant violations of the 24-hour NAAQS are expected or at sites
heavily influenced by regional transport or episodic conditions).
Special purpose monitors, however, may sample on any sampling schedule.
There is currently very little PM2.5 measurement data. New
networks must be established as expeditiously as possible to help
characterize the nature and extent of PM2.5 ambient air quality
nationwide. Daily sampling for PM2.5 is especially important
during the first few years of the new PM2.5 monitoring program to
allow for the collection of complete sets of data in order to help with
identifying temporal patterns and to understand the episodic behavior
of fine particles.
Although daily sampling with manual methods is labor intensive due
to site visits and filter equilibration and weighing, semi-automatic
sequential samplers are anticipated to be approvable as class I
equivalent samplers (under the provisions of Part 53) which will
simplify the data collection process. The EPA solicits comments on the
need to extend the start date for a requirement to perform everyday
sampling until the time when Class I equivalent samplers have been
approved by the Agency.
In addition, alternative PM2.5 operating schedules which
combine intermittent sampling with the use of acceptable continuous
fine particle samplers are approvable at some core sites. This
alternative is intended to give the States additional flexibility in
designing their PM2.5 monitoring networks and to permit data from
continuous instruments to be telemetered. This would facilitate public
reporting of fine particle concentrations, allow air pollution alerts
to be issued and episodic controls to be implemented (as currently done
in woodburning areas for PM10). Furthermore, this would permit
monitoring agencies to take advantage of new and improved monitoring
technologies that should become available during the first few years
following the promulgation. As proposed, applicability of the
alternative depends on population size of the monitoring area and
PM2.5 air quality status.
After the initial 3 years of PM2.5 data collection and after
characterization of PM2.5 levels, determination of violation areas
and development of State Implementation Plans), reductions in the
frequency of PM2.5 sampling may be appropriate. The EPA welcomes
comments on the need for continued long-term monitoring with reference
or equivalent samplers on an every day schedule at some or all
monitoring stations and on the appropriateness of the criteria for
allowing alternative schedules.
C. Section 58.14--Special Purpose Monitors
Special purpose monitoring is needed to help identify potential
problems, to help define boundaries of problem areas, to better define
temporal (e.g., diurnal) patterns, to determine the spatial scale of
high concentration areas, and to help characterize the chemical
composition of PM (using alternative samplers and supplemental
analyzers), especially on high concentration days or during special
studies. Special purpose monitors are an important part of the overall
PM monitoring program, and sufficient EPA and State resources must be
allocated for their use.
Today's revisions propose that special purpose PM2.5 and
PM10 monitors may sample with any measurement method on any
sampling schedule. However, the data from SPM's would not be used for
attainment/nonattainment designations if the monitoring method is not a
reference or equivalent method or does not meet the requirements of
Section 2.4 of Appendix C of Part 58. Moreover, in order to encourage
the deployment of SPM's, today's revisions propose that nonattainment
designations will not be based on data produced at an SPM site with any
monitoring method for a period of 3 years following the promulgation
date of the NAAQS.
The rationale for this concept is based on the need for to
encourage building from ``ground zero'' a monitoring infrastructure.
Such an infrastructure is needed because of the complexity of the
PM2.5 problem and the relative paucity of PM2.5 data to
determine where problem areas lie, and the lack of information about
sources and formation of aerosols in particular areas. The requirements
for the NAMS, minimum core SLAMS, and minimum additional SLAMS sites,
described in this notice, are designed to provide much of the
information needed to merely define the location of problem areas.
There is a need, however, to look beyond this minimal network to
create an ``optimal'' network that would gather air quality data over a
wider geographic area. The optimal network would consist of SLAMS
monitors in addition to the required minimums and also SPM's. There are
several reasons for a moratorium on regulatory use of data from the
during the first 3 years following promulgation of the NAAQS:
(1) SPM data have historically supplemented the SLAMS network to
provide the States with a flexible monitoring program. Although the SPM
monitoring does not have to use reference or equivalent monitors, the
States tend to use these monitors for data collection. And although SPM
data are not required to be submitted to EPA, the States tend to enter
all such data into the AIRS data base. Because of the paucity of
PM2.5 data, we want to encourage both the collection--with
reference or equivalent monitors--and the reporting of as much new
PM2.5 data as possible. This includes SPM data.
(2) There is a general reluctance among State and local governments
and businesses to monitor ambient air quality beyond those minimum
requirements contained in regulations promulgated by the Environmental
Protection Agency (EPA) in the Code of Federal Regulations at Part 58.
The reluctance is based in part on the fact that areas have
historically been designated to nonattainment where monitoring shows
violations of the NAAQS and then classified according to the
seriousness of the air pollution problem. Currently, such a
nonattainment designation and classification automatically trigger the
State implementation attainment planning and demonstration
requirements, potential stationary and mobile source emission controls,
nonattainment new source review for sources wanting to locate or expand
in the new nonattainment area, and possibly additional requirements
relating to nonattainment of the NAAQS. Thus, to many affected parties,
the current regulatory system results in a disincentive for detecting
violations.
(3) The EPA is evaluating a concept involving the identification of
areas that have measured or modeled violations and subsequent
identification of other areas whose emissions contribute to those
violations. The new required PM2.5 monitoring network, however,
may be insufficient to determine all such violation areas and
contributing areas, and therefore additional monitors may be desirable.
Ambient air
[[Page 65787]]
monitoring will play an important and expanded role in defining
violating and contributing areas; with a moratorium on the regulatory
use of SPM data, States and businesses would have an additional
incentive to monitor for data to more accurately determine the extent
of these areas.
(4) During the initial stages of development of a new PM2.5
network, there is a greater need for experimental sampling--to move
samplers around, to sample for short periods of time, and to utilize
different methods. Incomplete data sets may not be fully representative
of local air quality. For these and other similar reasons, there is a
need for a pilot network that would not be subjected to the same rules
as the full SLAMS network.
(5) Finally, collecting data at a number of sites beyond either the
minimum or optimal number proposed in these regulations would support
modeling studies to better define pollution problems, identification of
potential pollution problems for enhanced air management programs, the
design and implementation of episodic control plans to encourage quick
response actions for voluntary emission reduction measures to lower
pollution and thereby possibly avoiding nonattainment or ``bump-ups'',
and to measure progress toward attainment by relating air quality to
population.
The system of SPM's would at first not be part of the full required
or even the ``optimal'' network. To provide the best kind of
information, EPA believes that properly sited Federal Reference or
Equivalent Methods be used for these SPM efforts in order to collect
technically credible data. The EPA also believes that data from those
efforts be reported to AIRS so that they are generally available to the
public at large and to those who need them for understanding the nature
of the problem and for developing solutions and control strategies.
In proposing a 3-year moratorium on the regulatory use of SPM data,
EPA is trying to establish an incentive for States to engage in this
additional SPM monitoring using properly sited Federal Reference or
Equivalent Monitors. The data from these SPM's would supplement the
data collected by SLAMS sites. Although the SPM data would be exempt
from regulatory use during the 3-year moratorium, they would
nevertheless be evaluated by the State during its annual SLAMS network
review. A notice of NAAQS violations resulting from PM SPM``s should be
reported to EPA, such high concentrations should be evaluated by the
State in the design of its overall SLAMS network and considered by EPA
in its review and approval of the State''s monitoring plan. Therefore,
during the first 3 years, the SPM data would still play an important
role in the regulatory process. After the proposed 3-year exemption
period, SPM locations should be considered as potential SLAMS in the
State's development and subsequent EPA reviewal process of their
monitoring plan network, if the sites record high concentrations which
indicate potential violations of the PM NAAQS (for either PM10 or
PM2.5) and have been operating for at least 6 months.
The EPA could have taken a different approach to this problem and
not propose a moratorium on the regulatory use of data from the SPM
sites. States would still be able to deploy SPM monitors in ways to
avoid legal consequences if an exceedance of the NAAQS were found. For
instance, any State may use non-reference or non-equivalent methods,
which do not meet EPA specifications. Any State could site monitors so
that they do not meet EPA siting criteria. Such monitoring would avoid
the above-described legal entanglements associated with any NAAQS
exceedances, because the data collected would not, under current EPA
regulations, be valid for use in comparison to the NAAQS. Moreover, any
State could simply not submit the SPM data to EPA.
The approach described in the above paragraph, however, does have
major disadvantages. For instance, an approach that uses unacceptable
monitors or siting would result in data that--even if close to being
representative of the area or what a properly sited acceptable monitor
would measure, would still be clouded with questions regarding its
accuracy or precision, which would limit their value in the kinds of
analyses mentioned above. In the case of data simply not submitted to
EPA, data would not be available to either other States that would be
working on development of a solution to the PM-fine problem, or, more
important, to the public at large so that they could be aware if there
really are problems detected by the monitor.
In light of these concerns, EPA's proposal is an attempt to take a
more straightforward approach, which will encourage collection of
additional data that is technically credible and publicly available,
and therefore address the Act's mandate for EPA to take the lead in
this matter, as found in section 103(c).
D. Section 58.15--PM2.5 NAAQS Eligible Monitors
This new section is proposed to define the PM2.5 monitors
eligible for use in determining compliance with the PM2.5 annual
and 24-hour NAAQS. The EPA proposes that States identify on EPA's AIRS
monitoring site file, all PM2.5 sites eligible for both annual
NAAQS comparisons and 24-hour comparisons and those only eligible for
24-hour (daily) comparisons. The former sites are intended to be
population oriented spatial averaging sites and the latter are intended
to represent population-oriented ``hot spot'' locations. The reasons
for the different types of monitors are discussed in the preamble to 40
CFR part 50.
E. Section 58.20--Air Quality Surveillance: Plan Content
The revisions proposed today would require States to submit a PM
monitoring plan to the Regional Administrator within 6 months of the
effective date promulgation. The monitoring plan would describe the PM
monitoring strategy based on the use of SLAMS (including NAMS and PAMS)
and SPM's for PM10 and PM2.5; describe the phase-in of
PM2.5 monitors and changes in the existing PM10 monitoring
program; describe monitoring objectives and scales of
representativeness to facilitate subsequent interpretation of data;
define sampling schedules; denote sites intended for comparison to the
PM NAAQS; and define the monitoring planning areas (MPA's) and SAZ's
(SAZ's) within the State. It should also reference the revised quality
assurance plan which is required by Appendix A to Part 58. In regard to
the use of air quality data for making comparisons to the NAAQS and
other SIP related purposes, the monitoring plan shall also describe the
SPM's whose data the State intends to use for SIP purposes. The
monitoring plan must also provide for an annual review for termination,
relocations, or establishment of new SLAMS or core SLAMS.
F. Section 58.23--Monitoring Network Completion
Under the revisions proposed today, the PM networks would be
expected to be completed within 3 years of the effective date of
promulgation. While new PM2.5 networks are developed, existing
PM10 networks should be considered for reductions consistent with
the goals stated in the background section earlier. For PM2.5, a
3-year phase-in would be used. The proposed schedule for deployment of
new required PM2.5 monitors is described
[[Page 65788]]
here. During the first year, a minimum of one monitoring planning area
per State would be required to have core PM2.5 SLAMS. This area
would be selected by the State according to the likelihood of observing
high PM2.5 concentrations and according to the size of the
affected population. In addition, one PM2.5 site would be
collocated at one site in each of the PAMS areas. During the second
year, all other core population-oriented PM2.5 SLAMS, and all core
background and transport sites, must be fully operational. During the
third year, any additional required PM2.5 (non-core) SLAMS must be
fully deployed and all NAMS sites must be selected from core SLAMS and
proposed to EPA for approval.
G. Section 58.25--System Modification
No changes to the regulatory language are proposed to Sec. 58.25;
however, under the revisions proposed today, the annual system
modifications review must include changes to PM2.5 site
designations (e.g., NAAQS comparison sites), the number or boundaries
of monitoring planning areas and/or SAZ's.
H. Section 58.26--Annual State Monitoring Report
Under the current regulations, States are required to submit an
annual SLAMS data summary report. Under today's proposed revisions,
this report shall be expanded to include additional information. First,
the new State Monitoring report shall describe the proposed changes to
the State's Monitoring Plan, as defined in Sec. 58.20. It shall include
a new brief narrative report to describe the findings of the annual
SLAMS network review, reflecting within year and proposed changes to
the State air quality surveillance system, and to provide information
on PM SPM's and other PM sites described in the monitoring plan
regardless of whether data from the stations are submitted to EPA
(including number of monitoring stations; general locations; monitoring
objective; scale of measurement; and appropriate concentration
statistics to characterize PM air quality such as number of
measurements, averaging time, and maximum, minimum, and average
concentration). The latter is needed for EPA to ensure that a proper
mix of permanent and temporary monitoring locations are used, that
populated areas throughout the nation are monitored, and to provide
needed flexibility in the State monitoring program. The content of this
brief report shall be in accordance with EPA guidance, and will be
available at the time of promulgation of the final Part 58 rule.
Next, States would be required to describe the proposed changes to
existing PM networks. Proposed changes to the existing networks may
include modifications to the number, size, or boundaries of Monitoring
Planning Areas or SAZ's, number and location of PM SLAMS; number or
location of core PM2.5 SLAMS; alternative sampling frequencies
proposed for PM2.5 SLAMS (including core PM2.5 SLAMS and
PM2.5 NAMS); core PM2.5 SLAMS to be designated PM2.5
NAMS; and PM SLAMS to be designated PM NAMS. SLAMS with NAAQS
violations should be considered to become new or replacement core
sites, and SPM's with NAAQS violations could become part of the SLAMS
network. The proposed changes should be developed in close consultation
with the appropriate EPA Regional Office and submitted to the
appropriate Regional Office for approval. The portion of the plan
pertaining to NAMS would be submitted to the Administrator (through the
appropriate Regional Office).
Finally, as a continuation of current regulations, the States shall
be required to submit the Annual SLAMS summary report and to certify to
the Administrator that the SLAMS data submitted are accurate and in
conformance with applicable Part 58 requirements. Under the revisions
proposed today, States would also be required to submit annual
summaries of SPM data to the Regional Administrator for sites included
in their Monitoring Plan and to certify that such data are similarly
accurate and likewise in conformance with applicable Part 58
requirements or other requirements approved by the Regional
Administrator, if these data are intended to be used for SIP purposes.
During the first 3 years following promulgation, the monitoring
plan and any modifications of it must be submitted to EPA by July 1
(starting on the year following promulgation) or by alternate annual
date to be negotiated between the State and Regional Administrator,
with review and approval/disapproval by the Regional Administrator
within 45 days. After the initial 3-year period or once a SAZ has been
determined to be violating any PM2.5 NAAQS, then changes to a
monitoring planning area will require public review and notification to
ensure that the appropriate monitoring locations and site types are
included. Specific comment on or suggestions for alternate procedures
that are not unduly time consuming or burdensome to allow public review
and comment on changes in MPA's, SAZ's, or other elements of a
monitoring plan developed by a State or local air pollution control
agency are especially welcome.
I. Section 58.30--NAMS Network Establishment
The revision proposed today would designate 6 months after the
effective date of promulgation as the date by which the NAMS network
portion (to be derived from core PM2.5 SLAMS) of each State's
SLAMS network must be fully described and documented in a submittal to
the Administrator (through the appropriate EPA Regional Office). At
this time, a State's NAMS PM10 network must be reaffirmed if no
changes are made to the existing network and if changed must also be
fully described and documented in a submittal to the Administrator
(through the appropriate EPA Regional Office).
J. Section 58.31--NAMS Network Description
Today's proposed revision would require that the NAMS network
description also include for PM2.5 the monitoring planning area,
SAZ, and the site code designation to identify which site will be used
to determine violation of the appropriate NAAQS (annual or 24-hour).
K. Section 58.34--NAMS Network Completion
The revision proposed today would designate 3 years after the
effective date of promulgation as the date by which the State must have
all PM2.5 NAMS in operation, and 1 year after the effective date
of promulgation as the date by which the State must have made all
changes to the existing PM10 NAMS.
L. Section 58.35--NAMS Data Submittal
This section defines the data submittal requirements for NAMS and
SLAMS. Consistent with current requirements, only the total mass
derived from PM10 and PM2.5 SLAMS would be required to be
submitted to EPA. However, EPA encourages reporting all data from
monitors proposed in the State monitoring plan. These optional data
would include data from SPM's and compositional data from all monitors.
M. Appendix A--Quality Assurance Requirements for SLAMS
Meeting the more stringent data quality objectives for ambient
PM2.5 monitoring will require considerably enhanced quality
assurance in the areas of sampler operation, filter handling, data
quality assessment, and other
[[Page 65789]]
operator-related aspects of the PM2.5 measurement process.
Most operational quality control aspects are specified in Appendix
A in general terms. For PM2.5, however, explicit, more stringent,
requirements are proposed for sample filter treatment--including the
moisture equilibration protocol, weighing procedures, temperature
limits for collected samples, and time limits for prompt analysis of
samples. These requirements, which are specified in the reference
method set forth in proposed new Appendix L to part 50, will help to
control measurement precision. Additional or supplemental detailed
quality assurance procedures and guidance for all operator-related
aspects of the PM2.5 monitoring process will be developed and
published as a new Section 2.12 of the EPA's, Quality Assurance
Handbook for Air Pollution Measurement Systems series to assist
monitoring personnel in maintaining high standards of data quality.
Procedures for continually assessing the operational quality of the
SLAMS monitoring data are specified explicitly in Appendix A of part
58. Perhaps the most significant new data quality assessment
requirement proposed for PM2.5 monitoring is the requirement that
each routinely operating PM2.5 ``compliance'' monitor must be
``audited'' at least 6 times per year. A compliance monitor is a
monitor at a site which is included in the PM monitoring plan and whose
data is intended for comparison to the NAAQS as described in Appendix
D. This is the first time a requirement has been proposed to assess the
relative accuracy of the mass concentration measured by a SLAMS PM
monitor.
Each of these 6 ``audits'' would be performed by the monitoring
agency and would consist of concurrent operation of a collocated
reference method audit sampler along with the routinely operated
compliance sampler or monitor. The data from these collocated audits
would be pooled by the EPA to assess the performance of PM2.5
monitoring methods on a national basis and for each reporting
organization. These data would also be used in a screening test of the
performance of individual monitors at each monitoring location. Six has
been determined to be the minimum number of audit data points needed to
yield a reasonable assessment of individual monitor operational
performance on an annual basis. This number is analagous to the data
requirements for the precision and accuracy assessments for PM10,
PM2.5 and other pollutants described in Section 5.
The integrated operating precision and relative accuracy, evaluated
annually, would have to meet a limit of 15 percent. A
monitoring method that fails this requirement nationally would be
placed in a probationary status pending resolution of the inadequate
performance or possible cancellation of its reference or equivalent
method designation under the provisions of Sec. 53.11 of part 53 of
this chapter. While this action would not result in immediate
cancellation of the designation, it would require the method applicant
(e.g., the manufacturer) to correct the method performance problems or
to submit alternative evidence or arguments (possibly in collaboration
with other affected entities) that the method's designation should not
be canceled.
Reporting organizations whose monitoring data failed to meet this
requirement (or are significantly worse than the national norm) would
be notified that its quality assurance plan or procedures need
improvement. Similarly, monitoring data from individual sites that fail
the screening test would require remedial action or replacement of the
monitoring method. Note, however, that failure of either of these tests
or the national test would not automatically cause the associated
monitoring data to be invalid.
Comments are solicited on these method operating performance audits
and particularly on the potential use of the audit data by EPA to: (1)
Determine a national network operating precision and accuracy
performance indicator for each type of designated method, (2) determine
the operational performance of methods used by reporting organizations
relative to the national norm, and (3) consider cancellation of the
reference or equivalent method designation of methods failing to meet
the 15 percent operational performance specification.
Other data assessment requirements proposed in Appendix A for
PM2.5 monitoring networks are patterned after the current
requirements for PM10 networks and are intended to supplement the
audit procedure. PM2.5 network monitors would be subject to
precision and accuracy assessments for both manual and automated
methods, using procedures similar or identical to the current
procedures required for PM10 monitoring networks. Results of these
field tests performed by the monitoring agencies (along with the
results of the field audits) would be sent to the EPA, which then would
carry out the specified calculations. These calculated statistics would
become part of the annual assessment of the quality of the monitoring
data.
For automated methods, the additional assessment of the precision
would consist of a one-point precision check performed at least once
every 2 weeks on each automated analyzer used to measure PM2.5.
This precision check would be made by checking the operational flow
rate of the analyzer. A standard precision flow rate check procedure
similar to that currently used for PM10 network assessments is
proposed. Also proposed is an alternative procedure where, under
certain specific conditions, it would be permissible to obtain the
precision check flow rate data from the analyzer's internal flow meter
without the use of an external flow rate transfer standard. (This
alternative procedure would also be made applicable to PM10
methods.)
The additional accuracy assessment procedure proposed for
PM2.5 automated methods is also similar to that used for PM10
networks, although each PM2.5 analyzer would have to be audited
quarterly rather than annually, as is the current requirement for
PM10 analyzers. The assessment would be performed on the
analyzer's operational flow rate using a flow rate transfer standard,
with the accuracy calculated from the percent difference between the
actual flow rate and the corresponding flow rate indicated by the
analyzer.
For manual methods, an additional precision assessment would be
calculated from the data collected from collocated samplers, as is
currently required for manual PM10 methods. The number of
collocated samplers within each PM2.5 network is proposed to be
based upon the total number of samplers within the reporting
organization's network. For 1 to 10 total sites, 1 site would be
selected for collocation; for 11 to 20 total sites, 2 sites would be
selected for collocation; and if a reporting organization has over 20
total sites, then 3 sites would be selected for collocation. As for
PM10, one sampler of the collocated pair would be designated as
the primary sampler whose samples would be used to report air quality
for the site, and the other would be designated as the duplicate
sampler. The percent differences in measured concentration between the
two collocated samplers would be used to calculate this additional
network precision.
The accuracy of the flow rate system of manual methods for
PM2.5 would be determined, as for automated methods, by auditing
each sampler each calendar quarter. Using a flow rate transfer
standard, each sampler would be audited at its normal operating flow
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rate. The percent differences between these flow rates would be used to
calculate an additional indicator of accuracy.
Although the new quality assurance requirements for PM2.5
would result in an increase in the quality of the PM monitoring data,
the additional QA/QC checks would entail additional cost to the
monitoring agency. Some of the new QA/QC assessment requirements may
somewhat overlap the similar information provided by other checks, such
as the periodic flow rate checks and the use of collocated samplers in
monitoring networks. Consequently, the EPA solicits comments on the
need to maintain all of these QA requirements and also on the adequacy
of the proposed QA data assessments to ensure the defined quality for
PM2.5 measurements.
Table A-1, which summarizes the minimum data quality assessment
requirements, would be updated to include the new requirements for
PM2.5 methods, and other minor, mostly editorial changes are
proposed to Appendix A to update and clarify the language and specific
requirements.
A change to section 2.5 of Appendix A is also being proposed to
provide for technical system audits to be performed by EPA at least
every three years rather than every year. This change to a less
frequent system audit schedule recognizes the fact that for many well
established agencies, an extensive system audit and rigorous inspection
may not be necessary every year. The determination of the extent and
frequency of system audits at an even lower frequency than the proposed
three year interval is being left to the discretion of the appropriate
Regional Office, based on an evaluation of the Agency's data quality
measures. This change would afford both the EPA and the air monitoring
agencies flexibility to manage their air monitoring resources to better
address the most critical data quality issues.
N. Appendix C--Monitoring Methodology
Section 2.2 of Appendix C is proposed to be amended to allow the
use of PM10 monitors as surrogates for PM2.5 monitors for
purposes of demonstrating compliance with the NAAQS. However, following
the measurement of a PM10 concentration higher than the 24-hour
PM2.5 standard or an annual average concentration higher than the
annual average PM2.5 standard, the PM10 monitor would have to
be replaced with a PM2.5 monitor. In addition, for NAMS that are
converted to PM2.5 monitoring from PM10 monitoring, the
PM10 monitoring must continue concurrently with the PM10
monitoring for 1 year following the beginning of the PM