[Federal Register: October 30, 2006 (Volume 71, Number 209)]
[Rules and Regulations]
[Page 63641-63664]
[DOCID:fr30oc06-24]

-----------------------------------------------------------------------

Part III

Environmental Protection Agency

-----------------------------------------------------------------------

40 CFR Parts 52 and 81

 Approval and Promulgation of Implementation Plans; Designation of
Areas for Air Quality Planning Purposes; State of California; PM-10;
Determination of Attainment for the San Joaquin Valley Nonattainment
Area; Determination Regarding Applicability of Certain Clean Air Act
Requirements; Final Rule

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R09-OAR-2006-0583, FRL-8234-1]

Approval and Promulgation of Implementation Plans; Designation of
Areas for Air Quality Planning Purposes; State of California; PM-10;
Determination of Attainment for the San Joaquin Valley Nonattainment
Area; Determination Regarding Applicability of Certain Clean Air Act
Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: EPA is finalizing its determination that the San Joaquin
Valley nonattainment area (SJV or the Valley) in California has
attained the National Ambient Air Quality Standards (NAAQS) for
particulate matter with an aerodynamic diameter less than or equal to a
nominal 10 micrometers (PM-10). This determination is based upon
monitored air quality data for the PM-10 NAAQS during the years 2003-
2005. The SJV continues to attain the PM-10 NAAQS in 2006 based on the
latest available quality assured data. EPA is also finalizing its
determination that, because the SJV has attained the PM-10 NAAQS,
certain Clean Air Act (CAA or the Act) requirements are not applicable
for as long as the SJV continues to attain the PM-10 NAAQS.

DATES: Effective Date: This rule is effective October 30, 2006.

ADDRESSES: You can inspect copies of the docket for this action at
EPA's Region IX office during normal business hours by appointment at
the following locations:
    Environmental Protection Agency, Region IX, 75 Hawthorne Street,
San Francisco, CA 94105-3901.
    Air and Radiation Docket and Information Center, U.S. Environmental
Protection Agency, Room B-102, 1301 Constitution Avenue, NW. (Mail Code
6102T), Washington, DC 20460.

FOR FURTHER INFORMATION CONTACT: Doris Lo, EPA Region IX, (415) 972-
3959<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and
``our'' refer to EPA.

Table of Contents

I. Summary of Proposed and Final Actions
II. Public Comments and EPA Responses
    A. Environmental Justice
    B. The Clean Data Policy
    C. New Particulate Matter (PM) NAAQS
    D. EPA Policy on Special Purpose Monitoring Data
    E. Adequacy of the SJV Monitoring Network
    F. Data Not Included in Determining Attainment
    1. Data From September 3, 2004 High Wind Event
    2. Data From BAM and TEOM Monitors
    G. Representativeness of Data
    H. Other Comments
III. Final Action
IV. Effective Date of This Final Action
V. Statutory and Executive Order Reviews

I. Summary of Proposed and Final Actions

    On July 19, 2006, EPA proposed to determine that the SJV has
attained the 24-hour and annual NAAQS for PM-10 (71 FR 40952).\1\ The
proposed determination was based upon monitored air quality data during
the years 2003-2005 which indicated that there were no violations
during that time. This data is summarized in table 1 in the proposed
rule. 71 FR at 40953-54. EPA also based its proposed determination on
monitored air quality data indicating the area continued to attain in
2006. EPA also proposed to determine that certain Clean Air Act (CAA or
the Act) requirements were not applicable for as long as the SJV
continued to attain the PM-10 NAAQS. Specifically, for the SJV, EPA
proposed to determine that the CAA section 172(c)(9) contingency
measure requirement for the area is suspended. For a more detailed
discussion of the related background for the SJV and of the proposal,
please refer to the proposed rule.
---------------------------------------------------------------------------

    \1\ On September 21, 2006, EPA signed a final rule revoking the
annualPM-10 standard. That revocation will be effective 60 days from
publication of the rule in the Federal Register. Since the
revocation will not be effective until after our attainment
determination for the SJV, we are taking final action determining
that the area has attained both the annual and 24-hour PM-10
standard.
---------------------------------------------------------------------------

    In this notice EPA is finalizing its determination that the SJV has
attained the NAAQS, based upon three years of complete, quality-assured
monitored air quality data for 2003-2005, and based upon its
determination that the area continues to attain the PM-10 NAAQS in 2006
based on quality assured data submitted to EPA's AQS Database through
July 31, 2006. See AQS Report AMP350 titled ``SJV PM-10 SLAMS Raw Data
Report January 2003-July 2006'' included in the docket for this notice.
In finalizing its determination, EPA has also reviewed preliminary
monitoring data for monitors in the SJV that has become available since
July 31, 2006.
    EPA learned recently of preliminary data indicating that
exceedances of the standard were monitored on September 22, 2006 at
State and Local Air Monitoring Station (SLAMS) monitors in Corcoran
(215 [mu]g/m3), Bakersfield-Golden State Hwy. (157 [mu]g/
m3), and Oildale (162 [mu]g/m3).\2\ The
California Air Resources Board (CARB) and the San Joaquin Valley Air
Pollution Control District (District) have informed EPA that, based on
preliminary analysis, they believe that these exceedances are due to
high wind and wildfire natural events. CARB notified EPA that it
intends to flag these data as caused by natural events and to request
that EPA concur with these flags. As such the data would not be
included for consideration in a determination of attainment for the
SJV, pursuant to EPA's Natural Events Policy.\3\ Because these data,
which were collected using manual reference method samplers, are
preliminary and have not been quality-assured, and because EPA believes
that they may qualify as caused by natural events, and thus be excluded
from consideration in an attainment determination, EPA is proceeding to
finalize its determination that the area is in attainment. If, after
the data is quality-assured, and after further evaluating CARB's
request with respect to these data, EPA determines that the data do not
qualify for exclusion under EPA's natural events policy, and EPA
further believes that if included that they would establish that the
area is in violation of the NAAQS, EPA will proceed with appropriate
rulemaking action to withdraw its determination of attainment.
---------------------------------------------------------------------------

    \2\ 24-hour PM-10 exceedances were also recorded on September
22, 2006 with the automated equivalent (Beta Attenuation Mass/
Tapered Element Oscillating Microbalance) PM-10 analyzers operated
at the Bakersfield-Golden and Corcoran sites, as well as the Beta
Attenuation Mass monitor at the Tracy site. See response to comment
15 below.
    \3\ EPA's NEP Memorandum from Mary D. Nichols, Assistant
Administrator for Air and Radiation to Regional Air Directors,
``Areas Affected by PM-10 Natural Events'', May 30, 1996.
---------------------------------------------------------------------------

    EPA is also finalizing its determination that, because the SJV has
attained the PM-10 NAAQS, certain requirements, and specifically the
contingency measure requirement of section 172(c)(9) of the Clean Air
Act, do not apply to the SJV area for so long as the area continues to
attain the NAAQS.

II. Public Comments and EPA Responses

    EPA received one comment letter in support of our proposal from the
District stating that the determination is a result of ``nearly two
decades of intense efforts to reduce emissions of PM-10 and its
precursors.'' The District also states that

``emissions of PM-10 and its precursors have decreased by about 24%
since 1990'' which is significant given the population growth. Finally
the District states that this determination ``does not in any way imply
or allow the District or CARB to relax air quality strategies'' and
will allow the District to better dedicate resources for upcoming plans
that will focus on PM-2.5 and ozone attainment.
    EPA received one adverse comment letter from Earthjustice,
representing Medical Advocates for Healthy Air, Sierra Club, Latino
Issues Forum, Steven and Michele Kirsch Foundation, the Center for
Biological Diversity, El Comite para el Bienestar de Earlimart/The
Committee for the Well Being of Earlimart, Fresno Metro Ministry and
the Coalition for Clean Air. EPA also received approximately 2000
adverse comment letters from individual citizens. Many of these
comments were form letters that contained identical comments. EPA
addresses all of the specific comments raised by Earthjustice in its
responses to comments numbers 1 to 24. EPA is responding to many of the
individual citizens' comments in responses to comments numbers 25 and
26 and in the context of the responses to Earthjustice, since they
raised many of the same issues.

A. Environmental Justice

    Comment 1: EPA received comments arguing that its process for
making this determination did not adequately consider EPA's
environmental justice mission: ``[t]o achieve equal environmental
protection so no segment of the population, regardless of race,
ethnicity, culture or income bears an undue burden of environmental
pollution and to ensure that the benefits of environmental protection
are shared by everyone.'' The principal environmental justice
commenter, Earthjustice, argues that most sources of PM-10 pollution in
the Valley are located in agricultural areas where population densities
are low, but percentages of minority and low-income residents are high.
The comment claims that EPA has not adequately investigated whether
such areas, particularly in the western part of the Valley, are in
attainment and is not adequately monitoring those areas. Without more
thorough investigation and monitoring of air quality in the western
part of the Valley, the comment concludes, EPA cannot ``carry out its
environmental justice mandate.''
    Response: EPA is committed to environmental justice, and a November
2005 memorandum by Administrator Johnson has reiterated EPA's ``ongoing
commitment to ensure environmental justice for all people, regardless
of race, color, national origin, or income.'' EPA believes that this
attainment determination is fully consistent with that commitment, and
ensures environmental protection for all residents of the Valley,
including residents of the western part of the Valley, and regardless
of race, color, national origin, or income.
    The gist of the environmental justice argument is that EPA has not
adequately investigated and analyzed air quality in minority and low-
income communities in the western part of the Valley. Although that is
framed as an environmental justice argument, it is really a challenge
to the adequacy of the legal basis for EPA's determination that the
entire Valley is in attainment. As explained more fully elsewhere, EPA
has an adequate factual and legal basis for that determination, and has
assessed air quality through monitored data that is representative of
all areas of the Valley, including the west side, minority and low
income communities addressed in the comment. Thus, the commenter is
mistaken in claiming that EPA failed to investigate those areas
adequately, or that such a purported failure prevented the Agency from
adequately implementing environmental justice.
    Similarly, EPA rejects claims that the monitoring conducted by the
State and District is deficient. As explained more fully elsewhere, the
District's monitoring network provides for adequate and accurate
assessments of air quality throughout the Valley, including minority
and low income communities in the western area.
    Comment 2: Commenters, principally Earthjustice, assert that low
income and minority populations were not provided an adequate
opportunity to comment on the rule. Earthjustice asserts that ``the
concerned people of the Valley'' sought an ``opportunity to be heard,''
and unsuccessfully requested that EPA hold a hearing. That comment also
points out that many west side residents ``do not speak English, do not
own computers, and do not have the time or expertise to draft public
comments.''
    Response: EPA believes that interested parties were given adequate
opportunities to comment on the proposed determination of attainment.
Section 553(c) of the Administrative Procedure Act (APA), which governs
informal rulemaking actions, such as determinations of attainment, does
not require EPA to provide for a hearing. Section 553 (c) states that:

    The agency shall give interested persons an opportunity to
participate in the rulemaking through submission of written data,
views, or arguments with or without opportunity for oral
presentation.

    EPA does not, as a matter of standard practice, conduct hearings on
determinations of attainment. EPA does not believe a hearing was needed
in this case, or would have been an appropriate use of the Agency's
limited resources. EPA also does not agree with the commenters'
implicit suggestion that, without a hearing, Valley residents had no
forum for expressing their concerns.
    EPA believes that the opportunity to provide written comments was
sufficient for providing input from the public. That gave interested
parties an opportunity to present data, views and arguments through
written comments. No showing has been made that the opportunity to
provide written comments precluded meaningful public participation. To
the contrary, EPA received comments that identified and expansively
discussed the concerns of minority and low income communities in the
Valley. Thus, EPA does not agree with the suggestion that Valley
residents, or anyone else, did not have adequate input into Agency
decision making.

B. The Clean Data Policy

    Comment 3: The commenter contends that EPA cannot use its Clean
Data Policy to exempt the District from subpart 4 requirements. The
commenter notes that EPA cites to two EPA memoranda incorporated into
EPA's Phase 2 8-hour ozone implementation rule, and relies on other
attainment findings and redesignations that interpret the Clean Data
Policy to justify waiving CAA requirements for PM-10 areas. The
commenter argues that EPA provides none of its own analysis for
proposing that the attainment determination will relieve the District
of the obligation to comply with CAA requirements for reasonably
available control measures (``RACM''), attainment demonstrations,
reasonable further progress (``RFP'') and contingency measures. The
commenter also alleges that EPA improperly expands the Clean Data
Policy by claiming that the District will no longer be subject to the
RACM requirements of the Act. The commenter further contends that even
if one were to accept EPA's argument, it would not apply to the SJV
because as a serious PM-10 nonattainment area the Valley is subject to
the BACM requirements of section 189(b)(1)(B). The commenter notes that
EPA's Addendum to the General Preamble makes clear that unlike RACM,
determinations of BACM

are not tied to what is necessary for attainment. The commenter points
out that the proposal correctly omits BACM from the list of CAA
requirements waived under the Clean Data Policy, but requests that the
final rule should be explicit that the BACM requirement is maintained.
    Response: As noted in the proposal, EPA has previously approved all
of the serious area PM-10 attainment plan requirements for the SJV
except for the contingency measure requirements of CAA section
172(c)(9). See 69 FR 30006 (May 26, 2004) approving the 2003 PM-10 Plan
for the SJV. In that action, EPA approved the RFP, attainment and RACM/
BACM demonstrations for the SJV. Thus the issue of whether these
requirements should be suspended is not before us, except insofar as
our reasoning for why the contingency measures requirement is suspended
rests on the rationale for suspending the attainment demonstration and
RFP requirements. Nevertheless, as explained below, EPA believes that
once the area attains the standards the RFP, attainment and RACM
demonstrations would not be needed even though they have already been
approved.
    That said, EPA is correct in applying the Clean Data Policy in its
determination of attainment in the SJV, and affirms the Agency's
interpretation of subparts 1 and 4 of part D of the CAA. As EPA noted
in its proposal, the Clean Data Policy has been applied in the context
of the 1-hour and 8-hour ozone standards as well as in a number of PM-
10 rulemakings. EPA's discussion of the application of the Clean Data
Policy is set forth at length in its proposed rulemaking on Weirton,
West Virginia 71 FR 27440, 27443-27445 (May 11, 2006), as well as in
the memoranda and rulemakings cited therein. As we explained in that
notice, the reasons for relieving an area that has attained the
relevant standard of certain part D, subpart 1 and 2 obligations, apply
equally as well to part D, subpart 4, which contains specific
attainment demonstration and RFP provisions for PM-10 nonattainment
areas.
    EPA's analysis of the Clean Data Policy as it applies to PM-10
areas was contained in the documents cited in the proposal. Contrary to
commenter's contention, the fact that EPA's analysis was provided in
prior memoranda and rulemakings does not detract from the fact that it
is EPA's own analysis. Indeed, EPA's consistency in the application of
its interpretation lends it added weight. We reiterate here that EPA's
analysis of its legal interpretation can be found in its ``Final Rule
to Implement the 8-hour Ozone National Ambient Air Quality Standard--
Phase 2'' (Phase 2 Final Rule) 70 FR 71612, 71645-71646 (November 29,
2005) and the rulemakings and memoranda cited therein, the May 10, 1995
memorandum from John S. Seitz, entitled ``Reasonable Further Progress,
Attainment Demonstration, and Related Requirements for Ozone
Nonattainment Areas Meeting the Ozone National Ambient Air Quality
Standard,'' the December 14, 2004 memorandum from Stephen D. Page,
entitled, ``Clean Data Policy for the Fine Particle National Ambient
Air Quality Standards,'' and rulemakings concerning the application of
the policy to PM--10 areas--71 FR 6352, 6354 (February 8, 2006); 71 FR
13021, 13024 (March 14, 2006); and 71 FR 27440, 27443-27444 (May 11,
2006).
    Furthermore, three U.S. Circuit Courts of Appeals have upheld EPA
rulemakings applying EPA's interpretation of subparts 1 and 2 with
respect to clean data for ozone. Sierra Club v. EPA, 99 F.3d 1551 (10th
Cir. 1996); Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004); Our
Children's Earth Foundation v. EPA, No. 04-73032 (9th Cir. June 28,
2005) (Memorandum Opinion). EPA has also set forth its legal rationale
for the Clean Data Policy in briefs filed in these cases, and hereby
incorporates those briefs insofar as relevant here. See Sierra Club v.
EPA, No. 95-9541 (10th Cir.), Sierra Club v. EPA, No. 03-2839, 03-3329
(7th Cir.), Our Children's Earth Foundation v. EPA, No. 04-73032 (9th
Cir.).\4\
---------------------------------------------------------------------------

    \4\ These briefs are in the docket for this rulemaking.
---------------------------------------------------------------------------

    As EPA noted in those memoranda and rulemakings, EPA believes it is
reasonable to interpret the provisions regarding attainment
demonstrations, reasonable further progress, RACM requirements,
contingency measures, and other related requirements as being suspended
and as not requiring further submissions to achieve attainment for so
long as the area is in fact attaining the standards. Under the policy,
EPA is not granting an exemption from any applicable requirements under
part D. Rather, EPA has interpreted these provisions as not requiring
submissions for so long as the area remains in attainment with the
standard. This is not a waiver of requirements that by their terms
apply; it is a determination that certain requirements are written so
as to be operative only if the area is not attaining the standards.
Thus, in making its determination of attainment, EPA is also concluding
that certain subpart 4 and subpart 1 requirements are no longer
applicable for so long as the area remains in attainment.
    With respect to the requirement for attainment demonstrations, EPA
believes that the statutory requirement for an attainment
demonstration--a SIP revision which identifies the level of future
reductions needed to achieve the NAAQS and any additional adopted
measures needed to achieve these reductions `` is written so as to be
inapplicable once the NAAQS is attained. Section 189(a)(1)(B) requires
that the plan provide for ``a demonstration (including air quality
modeling) that the [SIP] will provide for attainment by the applicable
attainment date. * * *'' Section 189(b)(1) further requires that
serious PM-10 nonattainment areas submit:

    (A) A demonstration (including air quality modeling)--
    (I) that the plan provides for attainment of the national
ambient air quality standard by the applicable attainment date, or
(ii ) for any area for which the State is seeking, pursuant to
section 188(e), an extension of the attainment date beyond the date
set forth in section 188(c), that attainment by that date would be
impracticable, and that the plan provides for attainment by the most
expeditious alternative date practicable.

    If an area is already monitoring attainment, EPA believes that
Congress intended no requirement for an area to make a further
submission containing additional measures to achieve attainment. Since
the SJV area is already in attainment, there is no need for it to
submit a plan demonstrating how the area will reach attainment had it
not already done so. This is consistent with the interpretation of the
section 172(c)(1) attainment demonstration requirement that EPA
provided in the General Preamble and the Page memorandum, and of the
section 182(b) and (c) requirements set forth in the Seitz memorandum.
As EPA stated in the General Preamble, no other measures to provide for
attainment would be needed by areas seeking redesignation to attainment
since ``attainment will have been reached.'' 57 FR at 13564.
    We note that the commenter offered no specific critique of EPA's
interpretation of the Clean Data Policy with regard to the attainment
demonstration requirement. In addition, EPA's conclusion is consistent
with the rule of statutory construction that statutes should be
construed to avoid absurd results and favor public convenience. Because
the SJV has already reached attainment based on existing measures, no
additional measures to demonstrate attainment are required. Thus, under
the language of section 172(c)(1), section 189(a)(1)(B) and section
189(b)(1), an attainment

demonstration would be the empty set. EPA therefore believes that, in
the context of evaluating whether the contingency measure requirement
is suspended, because the SJV area is attaining the standard, the
attainment demonstration requirement would also be suspended for so
long as the area remains in attainment, had it not already been
approved.
    As for the suspension of the RACM requirement, it does not have
significance in the context of the SJV, because, as the commenter
notes, BACM, which goes beyond RACM, has already been approved for the
SJV, and BACM would not be suspended by the determination of attainment
because as petitioner notes the BACM requirement is not tied to
attainment needs. Thus EPA need not further address whether the
requirement for RACM is suspended in accordance with the Clean Data
Policy.
    Comment 4: The commenter alleges that EPA relies heavily on the
proposed redesignation of Weirton, West Virginia, to provide the
analysis for waiving the RFP requirements for PM-10 areas. The
requirements for PM-10 areas are found in CAA section 189(c)(1). The
commenter argues that EPA's analysis ignores the plain language of the
CAA. The commenter claims that the decisions in Our Children's Earth
Foundation v. EPA, No. 04-73032 (9th Cir. June 28, 2005) (Memorandum
Opinion) and Sierra Club v. EPA, 99 F.3d 1551, 1555 (10th Cir. 1996)
upheld EPA's interpretation based on the Court's finding of ambiguity
in the statutory language in sections 172(c)(1), (2), and (9) and
section 182(b)(1)(A)(I). The commenter asserts that, unlike those
provisions, the language of section 189(c)(1) is perfectly clear. The
commenter contends that milestones are to be set to show reasonable
further progress and an area is required to submit revisions
demonstrating that it has achieved those milestones every three years
until the area is ``redesignated.'' The commenter concludes that there
is no ambiguity and that appeals to policy objections cannot rewrite
clear language into something ambiguous.
    The commenter adds that references in the Weirton notice to other
provisions in section 189 are unavailing. Section 189(c)(3) requires
areas that fail to achieve a milestone to submit revisions to assure
the next milestone will be met. The commenter asserts that this
obligation continues through the final milestone. Where there is ``no
next milestone'' the final revision must ensure that the area will
attain the NAAQS. The commenter states that nothing in these
requirements is internally inconsistent or prevents areas from
complying with the plain language of section 189(c)(2).
    The commenter contends that arguments that this amounts to
``overcontrol'' are without merit. The commenter argues that a key
distinction between a finding of attainment and redesignation is that a
redesignation requires EPA to find that ``the improvement in air
quality is due to permanent and enforceable reductions in emissions.''
CAA section 107(d)(3)(E)(iii). The commenter argues that since EPA is
not making such a finding, it is rational for Congress to have insisted
that an area continue to reduce emissions until that showing can be
made and the area can be redesignated.
    Response: EPA's interpretation does not ``waive'' requirements nor
does it ignore the plain language of the statute. With respect to RFP,
it has been EPA's longstanding interpretation that the general
provisions of part D, subpart 1 of the Act (sections 171 and 172) do
not require the submission of SIP revisions concerning RFP for areas
already attaining the ozone NAAQS. In the General Preamble, we stated:

    [R]equirements for RFP will not apply in evaluating a request
for redesignation to attainment, since, at a minimum, the air
quality data for the area must show that the area has already
attained. A showing that the State will make RFP toward attainment
will, therefore, have no meaning at that point.

57 FR at 13564. EPA believes that the same reasoning applies to the PM-
10 provisions of part D, subpart 4.
    Section 171(1) (section 7501 (1)) states that for purposes of part
D of title I, RFP ``means such annual incremental reductions in
emissions of the relevant air pollutant as are required by this part or
may reasonably be required by the Administrator for the purpose of
assuring attainment of the applicable national ambient air quality
standard by the applicable date.'' Thus, whether dealing with the
general RFP requirement of section 172(c)(2), the ozone-specific RFP
requirements of sections 182(b) and (c), or the specific RFP
requirements for PM-10 areas of part D, subpart 4, section 189(c)(1),
the stated purpose of RFP is to ensure progress towards attainment by
the applicable attainment date. Section 189(c)(1) states that:

    Plan revisions demonstrating attainment submitted to the
Administrator for approval under this subpart shall contain
quantitative milestones which are to be achieved every 3 years until
the area is redesignated to attainment and which demonstrates
reasonable further progress, as defined in section 7501a(1) of this
title, toward attainment by the applicable date.

Although this section states that revisions shall contain milestones to
be achieved ``until the area is redesignated to attainment,'' it
further specifies that these are milestones that ``demonstrate
reasonable further progress, as defined in section 7501(1) of this
title, toward attainment by the attainment date.'' They are also to be
included in ``plan revisions demonstrating attainment.'' Thus such
milestones have the purpose of showing reasonable further progress
``toward attainment by the applicable date,'' as defined in section
171. It is therefore clear from the language of the statute that once
the area has attained the standard, no further milestones are necessary
or meaningful. By definition, the ``reasonable further progress''
provision requires only such reductions in emissions as are necessary
to attain the NAAQS by the attainment date. This interpretation is
supported by language in section 189(c)(3), which mandates that a state
that fails to achieve a milestone must submit a plan that assures that
the state achieve the next milestone or attain the NAAQS if there is no
next milestone. Section 189(c)(3) assumes that the requirement to
submit and achieve milestones does not continue after attainment of the
NAAQS. Thus, once attainment has been reached, there are no further
milestones to be achieved, even though the area has not yet been
redesignated to attainment, for so long as the area remains in
attainment. The commenter is therefore incorrect in asserting that
section 189(c)(1) is ``perfectly clear'' in requiring additional RFP
milestones after attainment has been reached.
    In the General Preamble, we noted with respect to section 189(c)
that ``the purpose of the milestone requirement is to `provide for
emission reductions adequate to achieve the standards by the applicable
attainment date' (H.R. Rep. No. 490 101st Cong., 2d Sess. 267
(1990)).'' 57 FR 13539 (April 16, 1992). If an area has in fact
attained the standards, the stated purpose of the RFP requirement will
already have been fulfilled--the only milestones that are required are
those that demonstrate reasonable further progress toward attainment,
as defined by section 171. Thus we believe that it is a distinction
without a difference that section 189(c)(1) speaks of the RFP
requirement as one to be achieved until an area is ``redesignated to
attainment,'' as contrasted to section 172(c)(2), which is silent on
the period to which the requirement pertains, or the ozone
nonattainment area RFP requirements in

sections 182(b)(1) or 182(c)(2), which refer to the RFP requirements as
applying until the ``attainment date,'' since section 189(c)(1) makes
clear that the milestones that are to be achieved are those that
demonstrate RFP toward attainment by the applicable attainment date,
and since section 189(c)(1) defines RFP by reference to section 171(1)
of the Act. Reference to section 171(1) makes clear that, as with the
general RFP requirements in section 172(c)(2) and the ozone-specific
requirements of section 182(b)(1) and 182(c)(2), the PM-specific RFP
requirements may only be required ``for the purpose of ensuring
attainment of the applicable national ambient air quality standard by
the applicable date.'' 42 U.S.C. 7501(1). EPA interprets the RFP
requirements, in light of the language of section 189(c)(1) and the
definition of RFP in section 171(1) incorporated therein, to be a
requirement that no longer applies so long as the standard has been
attained.
    Similarly, the requirements of section 189(c)(2) with respect to
milestones no longer apply so long as an area has attained the
standard. Section 189(c)(2) provides in relevant part that:

    Not later than 90 days after the date on which a milestone
applicable to the area occurs, each State in which all or part of
such area is located shall submit to the Administrator a
demonstration * * * that the milestone has been met.

Where the area has attained the standard and there are no further
milestones, there is no further requirement to make a submission
showing that such milestones have been met. As noted above, this is
consistent with the position that EPA took with respect to the general
RFP requirement of section 172(c)(2) in the April 16, 1992 General
Preamble and also in the May 10, 1995 Seitz memorandum with respect to
the requirements of sections 182(b) and (c). In the May 10, 1995 Seitz
memorandum EPA also noted that section 182(g), the milestone
requirement of Subpart 2, which is analogous to provisions in section
189(c), is suspended upon a determination that an area has attained.
The memorandum, also citing additional provisions related to attainment
demonstration and RFP requirements, stated

    Inasmuch as each of these requirements is linked with the
attainment demonstration or RFP requirements of section 182(b)(1) or
182(c)(2), if an area is not subject to the requirement to submit
the underlying attainment demonstration or RFP plan, it need not
submit the related SIP submission either.

1995 Seitz memorandum at 5.
    That the requirements for redesignation of an area require EPA to
find that the improvement in air quality is due to permanent and
enforceable emission controls does not undermine EPA's interpretation
that when EPA determines an area is in attainment, the requirement for
further emission reductions beyond that necessary for attainment is
suspended for so long as the area remains in attainment. EPA does not
contend that a determination of attainment is equivalent to a
redesignation, which requires additional showings beyond the fact of
attainment before changing the designation of an area from
nonattainment to attainment. A determination of attainment merely
suspends certain requirements for so long as the area remains in
attainment. That permanent emission reductions are required for a
redesignation does not indicate that Congress intended an area to keep
reducing emissions beyond the attainment level until an area is
redesignated. There is no statutory support for the proposition that an
area must keep reducing emissions below the level needed for attainment
until that area is redesignated. EPA's construction of the statute
recognizes the public interest in reducing burdens on states and
sources within states associated with adopting and implementing
additional control measures that are no longer necessary to attain the
NAAQS. EPA has construed the statutory provisions as not requiring
certain additional emission reductions above and beyond what was needed
to attain the NAAQS.
    EPA again notes that it has already approved a demonstration of
reasonable further progress for the SJV. In the context of considering
whether a determination of attainment suspends the contingency measures
requirement of section 172(c)(9), however, EPA concludes that the RFP
requirements of sections 172(c)(2) and 189(c) would also be suspended
for so long as the SJV remains in attainment, had they not already been
approved.
    Comment 5: The commenter contends that contingency measures are
needed to ensure both reasonable further progress and attainment.
Waiver of the requirement for these measures in section 172(c))(9) was
premised on the argument that the RFP requirement of section 172(c)(2)
was tied to attainment and thus with an attainment finding there was no
longer a purpose for contingency measures. The commenter asserts that
because the RFP requirements of section 189(c)(2) cannot be waived for
PM-10 nonattainment areas, the contingency measure requirements of
section 172(c)(9) continue to have purpose. The commenter claims that
they are needed as interim, stop gap measures to protect public health
pending the SIP revisions required under section 189(c)(3). See 59 FR
42015.
    Response: CAA Section 172(c)(9) provides that SIPs in nonattainment
areas:

    Shall provide for the implementation of specific measures to be
undertaken if the area fails to make reasonable further progress, or
to attain the [NAAQS] by the attainment date applicable under this
part. Such measures shall be included in the plan revision as
contingency measures to take effect in any such case without further
action by the State [or EPA].

This requirement is referred to as ``the contingency measures''
requirement, and is inextricably tied to the attainment and reasonable
further progress requirements. Where sufficient progress has been made
based on existing controls so that an area has already achieved
attainment by the attainment date, it has no need to rely on
``contingency measures'' to come into attainment by the attainment
date, or to assure progress towards attainment.
    We have thus interpreted the contingency measures requirement of
sections 172(c)(9) (and 182(c))(9) in subpart 2 of part D) as no longer
applying when an area has attained the standard because those
``contingency measures are directed at ensuring RFP and attainment by
the applicable date.'' 57 FR at 13564; May 10, 1995 Seitz memo at 5-6.
As explained at length in the responses to comments above and in the
memoranda and rulemakings cited above, the requirements for RFP and
attainment demonstrations no longer apply once an area has attained the
standard. Thus it follows that the requirement for contingency measures
to be triggered in the event RFP or attainment is not reached is also
suspended for as long as the area attains the standard. As EPA stated
in its Addendum to the General Preamble for Serious PM-10 Areas,
``[s]ection 172(c)(9) requires that SIP's provide for the
implementation of specific measures to be undertaken if the
Administrator finds that the nonattainment area has failed to make RFP
toward attainment or to attain the primary NAAQS by the applicable
statutory deadline.'' 59 FR 42014-42015 (August 16, 1994). Where the
area has attained the standards, as EPA has shown in responses to
comments above, the attainment demonstration requirements and RFP
requirement under section 189(c)(1) and (2) are suspended, and thus the

contingency measure requirements of section 172(c)(9) are also
suspended.
    The commenter is incorrect in its assertion that the RFP provisions
under section 189 remain applicable despite a determination that the
area has attained the standards. As EPA has demonstrated in its
response to comment 4 above, once the area has attained the standards,
the RFP milestone requirements in section 189 are suspended for so long
as the area remains in attainment. Thus no contingency measures are
required to assure those requirements are met. Because EPA is
finalizing its determination that the SJV area has attained the
standards, it is also finalizing its determination that the requirement
for contingency measures under section 172(c)(9) is suspended for so
long as the area remains in attainment.

C. New Particulate Matter (PM) NAAQS

    Comment 6: The commenter argues that the most troubling
implications of EPA's proposed finding is EPA's proposal to revoke the
PM-10 standards altogether and eliminate monitors in areas that are
found to be in attainment. The commenter contends that the
reasonableness of EPA's Clean Data Policy is premised in part on the
assurance of the Clean Air Act that EPA will eventually demonstrate
that air quality has been permanently resolved due to the controls
being implemented and that contingency measures will be in place as
part of a plan to maintain clean air once an area has been redesignated
to attainment. The commenter argues that under EPA's then current
proposal for coarse PM, these assurances will be eliminated. The
commenter states that EPA proposes to revoke the PM-10 standard
``everywhere except in areas where there is at least one monitor that
is located in an urbanized area with a minimum population of 100,000
people and that violates the 24-hour PM-10 standard based on the most
recent three years of data.'' 71 FR at 2674. The commenter further
states that, with the proposed attainment finding, EPA is making the
determination that the PM-10 standard will be revoked in the Valley
without the Act's protections. The commenter is also concerned about
the potential for EPA to refuse to consider data collected by monitors
in rural areas. The commenter believes that EPA should provide an
explanation as to why its determination is reasonable when there will
be no safety net to recover from the decision if EPA is wrong.
    Response: The commenter's concerns are misplaced. First, EPA's
responses to comments above indicate that its decision is reasonable,
in accordance with its prior interpretations of the CAA, and in
accordance with the statute. EPA reiterates that a determination of
attainment results merely in a suspension of requirements for so long
as the area remains in attainment. If the area violates the standard,
then the requirements and protections of the Act again apply to ensure
that the area attains and makes reasonable further progress towards
attainment.
    Second, as noted above, on September 21, 2006, the EPA
Administrator signed a final rulemaking which, among other things,
revoked only the annual PM-10 standard, but left intact the 24-hour PM-
10 NAAQS. The EPA did not finalize its proposal to revoke the 24-hour
PM-10 NAAQS. The final rulemaking did not revoke any designations under
the 24-hour PM-10 standard, and all requirements for the 24-hour
standard and all designations under that standard remain in place.
Based on the most recent three years of data, all areas that monitored
nonattainment for the annual standard also monitored nonattainment for
the 24-hour standard. Thus the commenter is incorrect in contending
that the determination of attainment would relieve the SJV of the
protections of the PM-10 NAAQS. Should EPA determine that the SJV
violates the 24-hour PM-10 NAAQS, it would again become subject to any
requirements that had been suspended during its period of attainment.
In addition, the area would still retain the incentive to be
redesignated to attainment for the 24-hour `PM-10 NAAQS in order to be
relieved of nonattainment NSR offset requirements and to avoid further
attainment planning requirements should the area monitor a violation of
the standard in the future, and the provisions for a maintenance plan
pursuant to CAA sections 107(d)(3)(E) and 175A would still apply to any
redesignation request. Thus these assurances of and motivation for
continued attainment are not eliminated, and the ``safety net'' cited
by the commenter remains in place.
    The commenter also cites to a portion of the proposed rule on
Ambient Air Monitoring which discusses a five-part suitability test to
determine whether potential PM-10-2.5 monitoring sites were suitable
for comparison to the proposed NAAQs. 71 FR 2710, 2736 (January 17,
2006). In the final monitoring rule signed September 27, 2006 and
available at http://www.epa.gov/air/particles/actions.html, EPA is not

adopting the five-part suitability test or the proposed PM-10-2.5
monitoring network design. EPA had proposed the five-part suitability
test along with certain minimum monitoring requirements and monitor
placement criteria for the primary purpose of determining compliance
with the proposed PM-10-2.5 particulate NAAQS. EPA proposed as the
indicator for the NAAQS any ambient mix of PM-10-2.5 that is dominated
by resuspended dust from high-density traffic on paved roads and PM
generated by industrial sources and construction sources, but excluded
any ambient mix of PM-10-2.5 that is dominated by rural windblown dust
and soils and PM generated by agricultural and mining sources. The
proposed level for the PM-10-2.5 NAAQS was selected so as to be of
equal stringency to the 24 hour PM-10 NAAQS. However, in its recent
rule revising the NAAQS EPA stated that it is not adopting the proposed
PM-10-2.5 standard and instead, will be retaining the current 24 hour
PM-10 standard. Therefore, EPA also did not adopt the proposed PM-10-
2.5 monitoring network design, including the five-part suitability test
to which the commenter cites above. Thus the commenter's concerns about
this aspect of the rule have not been realized.

D. EPA Policy on Special Purpose Monitoring Data

    Comment 7: The commenter states that EPA's use of an August 22,
1997 memorandum from John Seitz on the use of special purpose
monitoring data is based on an illogical reading and is an insufficient
substitution for a reasoned determination. The commenter states that
nothing in the CAA provides for this intermediate step of an attainment
determination to be made independently of a redesignation under CAA
section 107(d)(3)(E). The commenter contends that to the extent such a
determination can be defended, it is subject to the rational basis
standard of the Administrative Procedures Act. The commenter cites
language from the 1997 Seitz memorandum that discusses the types of
data EPA must consider before redesignating an area from nonattainment
to attainment and concludes that the Agency cannot reasonably ignore
data that falls short of specific part 58 requirements without
explaining why those requirements undermine the validity of the data.
    Response: The commenter contends that an ``attainment determination
is a beast of EPA's own creation'' and that it must be defended on a
rational basis. In fact, attainment determinations have a basis in the
statute: see e.g., section

107(d)(3)(E)(i), as well as sections 179(c), 188(b)(2) and 181(b)(2),
but there is nothing that restricts EPA to making determinations of
attainment in the context solely of those provisions. Indeed, as noted
earlier, both the 9th and 10th U.S. Circuit Courts of Appeals have
upheld EPA's authority to make attainment determinations outside the
context of redesignation proceedings, and have also upheld EPA's
interpretation of the statutory consequences of such determinations.
Sierra Club v. EPA, 99 F.3d 1551 (10th Cir. 1996), Our Children's Earth
Foundation v. EPA, No. 04-73032 (9th Cir. June 28, 2005 (memorandum
opinion). Nothing in the Act compels EPA to wait until an area meets
all the requirements for redesignation before EPA makes a determination
that the area is in attainment with the standard with the effect that
the requirements for certain statutory provisions relating to
attainment are suspended by their own terms. Indeed, section 179(c) of
the Act requires EPA to make an attainment determination within six
months after an area's applicable attainment date whether or not EPA
has made a finding with respect to redesignation. EPA's interpretation
of the Act's provisions not to require, once attainment has been
reached, certain plan submissions whose purpose is to assure
attainment, is not at odds with the requirements for redesignation.
EPA's rationale for issuing attainment determinations is set forth at
length in the responses to comments on the Clean Data Policy, above. In
making determinations of attainment, which are subject to notice and
comment rulemaking, EPA is governed by the Clean Air Act and its
regulations.
    Similarly, in identifying the data that should be considered in
making a determination of attainment, EPA is subject to regulatory
provisions that set forth criteria defining what constitutes an
adequate monitoring schedule, methodology, and quality assurance for
data that will justify reliance upon it. 40 CFR 58.14 applies to
Special Purpose Monitors (SPMs), and requires that if intended to be
used for purposes of demonstrating attainment or nonattainment, they
must meet the requirements for State and Local Air Monitoring Stations
(SLAMS) set forth in 40 CFR 58.13 and 58.22 as well as in appendices A
and E of part 58. While EPA cited to the Seitz memorandum in its
proposal, EPA is not, as commenters contend, hiding behind a non-
binding policy memorandum. Rather, that memorandum cited to the
regulations applicable to data from special purpose monitors intended
for use in attainment determinations. These regulations are designed to
ensure that the data is accurate and reliable enough to be the basis
for a formal determination as to whether an area has attained the
relevant standard. The 1997 Seitz memorandum states that ``[the] Agency
policy on the use of special purpose monitoring data for any regulatory
purpose, with the exception of fine particulate matter data (PM-2.5) is
that all quality assured and valid data meeting 40 CFR part 58
requirements must be considered within the regulatory process.'' 1997
Seitz memorandum at 1. EPA's regulations under 40 CFR part 58 provide
for quality assurance and control requirements to ensure that
regulatory decisions are based on reliable and accurate information.
    Conversely, it follows that data that does not meet these quality
assurance criteria should not be considered, since basing regulatory
decisions on data that has not been shown to be reliable would not
further the public interest nor be consistent with EPA regulations on
special purpose monitors. See 40 CFR 58.14. As set forth below in other
responses to comments, EPA's decision to consider data from monitors
that meets quality assurance criteria and its concomitant decision to
exclude data that does not meet these criteria is based on its
regulations, has a rational basis, and is designed to result in
determinations that reflect accurate and reliable data.
    Here, the data from certain SPMs did not meet the quality assurance
requirements of part 58, and therefore were not included for
consideration in the determination of attainment. If in the future
additional data that has been quality assured demonstrate that the area
is in fact not attaining the standard, EPA will withdraw its
determination of attainment. Until that time, there is no compelling
reason for EPA not to proceed with an attainment finding based on all
quality assured data where such data demonstrates that the SJV has
attained the PM-10 standard.
    In EPA's Revisions to Ambient Air Monitoring Regulations, a final
rule signed on September 27, 2006, EPA issued revised regulations
concerning SPMs, and clarified that data from such monitors would not
be used for attainment/nonattainment determinations if the monitors had
not met the requirements of appendix A.
    Section 58.20(b) of the revised regulation provides in part:

    [a]ny SPM data collected by an air monitoring agency using a
Federal reference method(FRM), Federal equivalent method (FEM), or
approved regional method (ARM) must meet the requirements of section
58.11, section 58.12, and appendix A to this part or an approved
alternative to appendix A to this part * * *

    Section 58.20 (c) provides that:

    [a]ll data from an SPM using an FRM, FEM or ARM which has
operated for more than 24 months is eligible for comparison to the
relevant NAAQS, subject to the conditions of section 58.30, unless
the air monitoring agency demonstrates that the data came from a
particular period during which the requirements of appendix A or an
approved alternative, appendix C, or appendix E were not met in
practice.

Thus EPA's new monitoring regulations make plain that SPM data from a
period during which appendix A is not complied with are not eligible
for comparison to the NAAQS and EPA action in this case is consistent
with that requirement.

E. Adequacy of the SJV Monitoring Network

    One commenter and numerous individual citizens raised a number of
issues regarding the adequacy of the PM-10 monitoring network in the
SJV. In a final rule approving the serious area PM-10 attainment plan
for the SJV, EPA evaluated the adequacy of this network and concluded
that it meets all applicable statutory and regulatory requirements and
is adequate to support the technical evaluation of the PM-10
nonattainment problem in the plan. 69 FR 30006, 30032-30033. EPA
supported this conclusion in a technical support document accompanying
the final rule, ``Evaluation of the Adequacy of the Monitoring Network
for the San Joaquin Valley, California for the Annual and 24-Hour PM-10
Standards''; Bob Pallarino, EPA Region 9, Air Division; September 22,
2003 (2003 TSD). Nevertheless, EPA responds below to the specific
comments raised regarding the network in connection with its proposed
attainment determination for the SJV.
    Comment 8: The commenter states that CAA Section 110(a)(2)(B)
requires States to establish appropriate air monitoring networks and
that appendix D of 40 CFR part 58 identifies a minimum of six
objectives that a SLAMS network should be designed to meet, as well as
spatial representativeness criteria in developing the network. The
District fails to address all six criteria in its annual Monitoring
Network Reports (leaving out monitoring for regional pollutant
transport and for impacts on rural and remote places) and the existing
monitors represent only two of the six spatial

scales established in the regulations when three are required. Since
the District fails to meet these basic requirements, EPA should address
the adequacy of the monitoring network before making an attainment
determination, including whether system audits were conducted as
required by 40 CFR 58.2.5 (sic). EPA's only evaluation of the network
was in the 2003 TSD in which EPA identified several deficiencies in the
Valley's PM-10 monitoring network but signed off on the network in
spite of the deficiencies.
    Response: Pollutant monitoring networks are designed to serve a
number of purposes. While the primary purpose of a monitoring network
is to determine an area's attainment status with regard to the NAAQS,
there are a variety of other purposes networks serve, including
determining maximum concentration locations; determining the
effectiveness of air pollution control programs; evaluating the effects
of air pollution levels on public health; tracking the progress of
SIPs; providing dispersion modeling support; developing responsible,
cost-effective control strategies; reconciling emission inventories;
and developing air quality trends.\5\
---------------------------------------------------------------------------

    \5\ ``SLAMS/NAMS/PAMS Network Review Guidance'' EPA-454/R-98/
003, March 1998, section 1.0.
---------------------------------------------------------------------------

    The six monitoring objectives \6\ in EPA's regulations were
developed to assist in designing monitoring networks to meet these
various objectives. Clearly, monitoring to ``determine the welfare-
related impacts in more rural and remote areas (such as visibility
impairment and effects on vegetation)'' or monitoring to assess
regional transport of pollution are not directly related to determining
whether or not an area is in attainment of the NAAQS. These are
important objectives in terms of maximizing the utility of the
monitoring network. However, when determining whether the SJV is
attaining the PM-10 NAAQS, it is more important to demonstrate that the
PM-10 network has monitors sited to capture the maximum concentrations
expected to occur in the Valley and the representative concentrations
of PM-10 throughout the area that the population of the SJV are
breathing. As discussed in the 2003 TSD, the SJV PM-10 SLAMS network
meets the two primary and most important objectives by siting most of
its monitors to assess representative concentrations in areas of high
population and monitoring in the area where the maximum PM-10
concentrations are expected to occur. Thus the fact that the District
did not address the two objectives above is not a significant factor in
determining whether the SJV is in attainment of the PM-10 NAAQS.
---------------------------------------------------------------------------

    \6\ The six monitoring objectives as discussed in 40 CFR part
58, appendix D, section 1 are (1) to determine highest
concentrations expected to occur in the area covered by the network;
(2) to determine representative concentrations in areas of high
population density; (3) to determine the impact on ambient pollution
levels of significant sources or source categories; (4) to determine
general background concentrations; (5) to determine the extent of
regional transport among populated areas; and in support of the
secondary standards; and (6) to determine the welfare-related
impacts in more rural and remote areas (such as visibility
impairment and effects on vegetation).
---------------------------------------------------------------------------

    The commenter states that EPA regulations at 40 CFR part 58,
appendix D, require networks to use at least three spatial scales \7\
in establishing a monitoring network. However, the regulations do not
in fact require the use of any minimum number of spatial scales for PM-
10 SLAMS or National Air Monitoring Station (NAMS) \8\ networks.
Section 1 of appendix D discusses the relationship between monitoring
objectives and spatial scales of representativeness. As our regulations
state in this section, ``[p]roper siting of a monitoring station
requires precise specification of the monitoring objective which
usually includes a desired spatial scale of representativeness.''
---------------------------------------------------------------------------

    \7\ See 40 CFR part 58, appendix D, section 1, for a discussion
of spatial scales and their applicability in monitoring network
design.
    \8\ The NAMS area subset of the SLAMS ambient air quality
monitoring network.
---------------------------------------------------------------------------

    Table 1 of appendix D ``illustrates the four basic monitoring
objectives and the scales of representativeness that are generally most
appropriate for that objective.'' Emphasis added. Appendix D, section
1, table 1. It is clear from this language that EPA did not intend to
dictate specific spatial scales for each objective. However, it is
important to ensure that the spatial scale of the site is appropriate
for the monitoring objective that site is intended to meet. For
example, a site that is intended to represent typical population
exposure should be a neighborhood or urban scale site, not a microscale
site. While a microscale site can be used to monitor for highest
concentration, a middle or neighborhood scale site would also satisfy
this monitoring objective.\9\
---------------------------------------------------------------------------

    \9\ While Table 6 in 40 CFR part 58, appendix D, section 5 could
be interpreted to mean that three spatial scales are required for
PM-10 NAMS sites, EPA's purpose here was to summarize the spatial
scales which would be appropriate for NAMS sites, i.e. microscale,
middle scale, and neighborhood scale sites are appropriate scales
for PM-10 NAMS sites, but urban and regional scale sites are not.
This is because the objectives for NAMS sites are to monitor in
areas where the pollutant concentration and population exposure are
expected to be the highest. Furthermore, EPA's recently signed rule
revising the monitoring regulations at 40 CFR part 58, reiterates
EPA's intention that urban and regional scales are not appropriate
for PM-10 monitoring and the most important spatial scales for
monitoring PM-10 are the middle and neighborhood scales.
---------------------------------------------------------------------------

    With respect to the system audit programs described in 40 CFR part
58, appendix A, section 2.5, it is important to note that this type of
audit, commonly referred to as a technical system audit (TSA, is a
qualitative review of an agency's overall air monitoring operations
designed to determine whether what the monitoring organization says is
going to be performed in its quality management plan, quality assurance
project plan, and standard operating procedures are performed as
specified. A TSA is required to be ``on site'' in the sense of taking
place at the monitoring organization facilities, either at one or more
locations where monitoring activities are performed or where
monitoring-related documents and records are kept, but it need not
involve a visit to an actual monitoring site. When a discrepancy is
identified, EPA asks the monitoring organization to correct the
discrepancy and tracks the monitoring organization's efforts until the
correction is made. Significantly, EPA does not disqualify any data
already collected based on the results of a TSA, although the
monitoring organization in principle might do so itself. See ``Quality
Assurance Handbook for Air Pollutant Measurement Systems, Volume II,
Part 1, section 15 (EPA-454/R-98-004, August 1998) and ``EPA
Requirements for Quality Assurance Project Plans'' (EPA/240/B-01/003
March 2001) at B-4.
    In contrast, the measurement quality checks described in appendix
A, sections 3.1, 3.2, 3.3 and 3.4, are quality control checks in which
quantitative data generated by quality control samplers or independent
standards are compared against the routine monitors operated by the air
monitoring agency in order to evaluate instrument performance or
laboratory procedures. Id. at B-3. When determining whether data
generated by air quality monitors can be considered to be valid and
accurate for the purpose of determining whether an area has attained
the NAAQS, measurement quality checks are critical.
    As a mechanism for helping to ensure that data generated by air
quality monitors is valid and accurate and thus suitable for
determining whether an area has attained the NAAQS, it is the
measurement quality checks that are most important. These checks create
an incentive for continuous attention to

proper operation and maintenance of each monitor, can identify problems
with specific monitors so that the problems can be corrected, and
provide a basis for the monitoring organization to disqualify data
already collected if specific audit findings are found to be outside of
acceptable limits. EPA discusses these evaluations with respect to the
SJV monitoring network below in response to comment 13.
    EPA Regional Offices are required by appendix A to perform TSAs of
State reporting organizations once every three years. A reporting
organization, as defined in 40 CFR part 58, appendix A, section 3.0.2,
is a State, subordinate organization within a State, or other
organization that is responsible for a set of stations that monitors
the same pollutant and for which data quality assessments can be
pooled. States must define one or more reporting organizations for each
pollutant such that each monitoring station in the State SLAMS network
is included in one, and only one, reporting organization.
    California has designated four reporting organizations within the
State: CARB, the South Coast Air Quality Management District, the Bay
Area Air Quality Management District, and the San Diego Air Pollution
Control District. All other air quality districts in the State,
including the San Joaquin Valley Air Pollution Control District, are
included in the CARB reporting organization. CARB and the Districts in
its reporting organization represent one of the largest and most
experienced air quality reporting organizations in the nation.
    EPA has audited certain aspects of the CARB monitoring program
recently. EPA's Office of Air Quality Planning and Standards (OAQPS)
performed measurement quality checks and TSAs of the CARB PM
laboratories in October 2002 and March 2004. These evaluations and
audits confirmed that the laboratories used by CARB and the San Joaquin
Valley Air Pollution Control District for weighing PM filters were
operating consistently with appendix A requirements. No deficiencies
for the PM lab were noted. Overall good laboratory practices were
observed during this TSA. See Technical Memorandum on CARB Laboratory
Audit to Jim Homolya, EPA, OAQPS, from Michael S. Clark, National Air
and Radiation Environmental Laboratory, February 26, 2003 and Technical
Memorandum on CARB Laboratory Audit to Jim Homolya, EPA, OAQPS, from
Eric Boswell, National Air and Radiation Environmental Laboratory,
dated April 22, 2004. Moreover, CARB Quality Assurance Section also
conducts its own internal audits of the PM laboratory.
    In October 2004, EPA Region 9 performed a technical evaluation of
the CARB `Through-the-Probe' (TTP) audit program for gaseous pollutants
to establish system equivalence between the CARB and EPA TTP programs
and to independently review the CARB TTP program. See ``Review of
California Air Resources Board's `Through-the-Probe' Audit Program'',
October 6-7, 2004. The TTP audit is a procedure for performing
measurement quality checks of gaseous analyzers and is the primary tool
used by CARB to fulfill its audit responsibility for these types of
analyzers in 40 CFR part 58, appendix A, section 3.2. While EPA's audit
of the CARB TTP program focused on gaseous pollutant performance
audits, the audit served as an on-site TSA with respect to CARB's
corrective action procedures used by CARB following a performance audit
failure of a PM-10 monitor, as CARB's corrective action procedures are
common to all pollutants including PM-10. We have since evaluated the
CARB TTP program three additional times in June 2005, October 2005 and
April 2006. See memorandums to Catherine Brown, USEPA Region 9 from
Kevin Woodruff, ESAT TTP Task Manager, dated July 8, 2005, May 8, 2006,
and May 18, 2006.
    CARB has conducted its own TSA-like assessment of the District's
monitoring program. CARB's oversight includes routine annual
performance audits of PM-10 SLAMS monitors, verification that sites
meet EPA siting criteria and periodic assessments of the District's air
monitoring program. See the CARB's Annual Data Quality Reports and the
San Joaquin Valley Air Pollution Control District Program Review,
Report of Findings and Recommendations, by CARB Stationary Source
Division, October 2005. Audit information for individual monitoring
stations in the CARB reporting organization is available at the CARB
Web site http://www.arb.ca.gov/qaweb/. The Web site includes maps of

each site, site photographs, and a detailed survey of the physical
parameters and conditions at each site. These activities, while
performed by CARB, are very similar to the field operation portion of
EPA's TSAs.
    Region 9 continues to keep informed of CARB and its Districts'
monitoring program developments through our ability to review revisions
to quality assurance (QA) documents and the other information described
above on the CARB QA Web site. EPA believes that these activities as
well as the on-site activities described above, EPA's evaluation in the
2003 TSD, and the performance audits described below, can and should be
considered to substantially meet the requirements of appendix A and are
sufficient to ensure that the data produced by the PM-10 SLAMS network
operating in the SJV is adequate for EPA to base our finding of
attainment.
    Furthermore, the District and CARB annually certify that the data
in EPA's Air Quality System (AQS) database is correct and accurate. EPA
also annually reviews the precision and accuracy data (precision and
accuracy data are discussed in more detail in the response to comment
13 below) submitted along with the PM-10 concentration data by CARB and
the District.
    As stated above, in the 2003 TSD EPA determined that the PM-10
monitoring network for the SJV, which includes monitors operated by
both CARB and the District, meets all applicable statutory and
regulatory requirements. EPA Region 9 uses the following four criteria
to evaluate whether agencies operate approvable networks: (1) The SLAMS
network used EPA approved samplers to collect data, (2) the agency has
a quality assurance plan in place that meets EPA requirements, (3) the
agency operates the required number of monitoring sites designated as
NAMS, and (4) the monitoring network is designed in accordance with the
requirements of 40 CFR part 58, appendices D and E. These criteria are
based on requirements in 40 CFR part 58 and on EPA guidance
documents.\10\
---------------------------------------------------------------------------

    \10\ These guidance documents include ``PM-10 SIP Development
Guideline'', EPA-450/2-86-001, June 1987; ``Network Design and
Optimum Site Exposure Criteria for Particulate Matter'', EPA-450/4-
87-009/ May 1987; ``Guidance For Network Design and Optimum Site
Exposure For PM-2.5 and PM-10'', EPA-454/R-99-022, December 1997;
``SLAMS/NAMS/PAMS Network Review Guidance'', EPA-454/R-98-003, March
1998.
---------------------------------------------------------------------------

    The only deficiency in The District's PM-10 network that EPA has
identified relates to the number of sites designated as NAMS. In the
2003 TSD at 5, we stated:

    According to EPA regulations, the [District] should have a
minimum of 11 sites designated as NAMS sites, based on the average
PM-10 concentrations during the years 1999-2001 and the 2000 census
population data. * * * The number of monitoring sites in the [SJV]
designated as NAMS is less than that required in EPA regulations.
However * * * EPA has been de-emphasizing the difference between
NAMS and SLAMS sites. * * * EPA is planning to revise the
regulations at 40 CFR part 58, Appendix D, which discusses the NAMS
requirement, to eliminate the designation of sites as either NAMS or
SLAMS.

    In footnote 3 in the 2003 TSD, EPA explained that:

    EPA, in partnership with State and local air agencies, has been
developing a National Monitoring strategy which no longer makes a
distinction between NAMS and SLAMS sites. The strategy, once
codified in EPA regulations, will simply establish a certain minimum
number of monitoring sites in a metropolitan area, still based on
population and pollutant concentration severity. The current network
in the [SJV] will easily meet these minimum requirements.

    At the time we evaluated the SJV PM-10 monitoring network, we
believed, in light of the de-emphasis on the difference between NAMS
and SLAMS sites, that it would be unreasonable to find the network
inadequate because of this technical deficiency which EPA was planning
to eliminate. In fact, in our final Ambient Air Monitoring rule signed
on September 27, 2006 that amends 40 CFR part 58 we did eliminate the
NAMS designation requirement completely. Elimination of the NAMS
requirement does not affect the number of monitors operating in the PM-
10 network. Sites designated as NAMS simply convert to SLAMS sites.
Based on the above, we believe the data produced by the SLAMS network
is technically sound and can be used to determine the SJV's attainment
status. EPA wants to emphasize, however, that the action today is
simply an assessment of the data collected at the District's PM-10
monitoring stations from 2003-2005, and continuing into 2006. This
attainment determination does not preclude any future assessments of
the PM-10 monitoring network, addition of new monitoring sites, or shut
down of any existing sites.
    Comment 9: The commenter states that the monitoring network does
not meet the basic objectives laid out by federal regulation and leaves
vast portions of the Valley completely unmonitored. The commenter
asserts that EPA must address this deficiency before making an
attainment determination. The commenter states that the majority of the
PM-10 monitoring takes place along the Highway 99 corridor which
captures most of the SJV's major urban centers, but entirely overlooks
the eastern and western portions of the SJV. The western portion of the
SJV should be of particular concern to the District and EPA as it is an
area of widespread poverty and environmental injustice, as well as
being an area of intense agricultural activity.
    Response: We disagree with the commenter's contention that the
network fails to meet the basic monitoring objectives described in 40
CFR part 58, appendix D, section 1. EPA regulations do not prescribe
the size of an area's PM-10 monitoring network or the exact placement
of monitors. 40 CFR part 58, appendix D, section 1, ``SLAMS Monitoring
Objectives and Spatial Scales'' states:

    \It should be noted that this appendix contains no criteria for
determining the total number of stations in SLAMS networks * * *.
The optimum size of a particular SLAMS network involves trade offs
among data needs and available resources that EPA believes can best
be resolved during the network design process.\11\
---------------------------------------------------------------------------

    \11\ See also ``SLAMS/NAMS/PAMS Network Review Guidance'' EPA-
454/R-98/003, March 1998, section 2.1.2.

    It is unreasonable and cost prohibitive to require a monitoring
agency to operate a monitoring station in every location expected to
have high levels of a particular pollutant. The District operates SLAMS
in a variety of areas that represent typical emission scenarios in the
SJV including urban areas of dense population, industrial areas, and
rural areas dominated by agricultural emission sources. See 2003 TSD at
5.
    The monitoring network in the SJV has both neighborhood and middle
scale sites. As stated previously in this notice (see response to
comment 8 and footnote 7), these spatial scales are the most important
in monitoring for PM-10. Monitoring sites that are representative of
middle scale impacts cannot only represent the area immediately around
the monitoring site but also areas of similar emission characteristics.
Similarly, neighborhood scale sites can represent not only the
immediate neighborhood but also neighborhoods of similar types in the
city or area. Furthermore, neighborhood stations provide the most
relevant information about trends and compliance with standards because
they often represent conditions in areas where people commonly live and
work for periods comparable to those specified in the NAAQS. See 40 CFR
part 58, appendix D, sections <IP_ADDRESS> and <IP_ADDRESS>.
    Most of the monitors in the SJV network are neighborhood scale
sites with the objective of assessing population exposure. Since the
majority of the SJV's population resides in urbanized areas along the
Highway 99 corridor and since many of the emission sources are mobile
or traffic-related, we believe this is an appropriate focus of the
monitoring network. 2003 TSD at page 5.
    The District also monitors in locations in addition to the Highway
99 locations, e.g. Corcoran, Taft, and Hanford.\12\ Thus, the District
network does represent the source types that make up the majority of
emission sources in the western and eastern portions of the SJV. The
monitoring locations at Corcoran and Hanford are both rural locations
surrounded by agricultural sources of PM-10. Since it is not feasible
for the District to monitor in every rural location, these sites can be
viewed as representative of other unmonitored locations in the Valley.
---------------------------------------------------------------------------

    \12\ See ``State and Local Air Monitoring Network Report--2005''
San Joaquin Valley Unified Air Pollution Control District. Planning
Division, August 2005.
---------------------------------------------------------------------------

    Comment 10: The commenter points out that back in the 1990s, there
were at least four monitoring sites in what can be considered the rural
west side. These sites, located at Los Banos, Five Points, Kern
Wildlife Refuge, and Kettleman City, were all shut down in the mid-
1990s with little or no explanation, consultation with EPA or public
notification, as required by 40 CFR 58.26(e). These monitors were
mentioned in passing in the District's 1994 Air Monitoring Network
Report as ``not necessary'' and ``resource intensive'' and were to be
closed to ``redirect resources.'' The commenter notes that the Five
Points monitor monitored sizeable violations until 1993, the year it
disappeared from the District's network.
    Response: The public notification requirement in 40 CFR 58.26(e)
cited by the commenter was part of the monitoring regulation revisions
made to implement the PM-2.5 NAAQS (62 FR 38833 (July 18, 1997)) and
applies only to that pollutant:

    After 3 years following September 16, 1997 or once a monitoring
area has been determined to violate the NAAQS, then changes to an
MPA monitoring network affecting the valuating locations shall
require public review and notification.

``MPA'' stands for ``Monitoring Planning Area'' and ``means a
contiguous geographic area * * * having a common area that is used for
planning monitoring locations for PM 2.5'' Emphasis added. 40 CFR 58.1.
    Moreover, EPA generally defers to a State or local agency's
judgment in determining which SLAMS to operate in a network as long as
the overall monitoring objectives in our regulations are being met.
However, EPA would object if an agency discontinued a design value site
or a site with unique source characteristics that is violating the
NAAQS.
    In 1993-1994 the District and CARB operated 18 monitoring sites in
the

Valley. Three sites were shut down at the end of 1993: Los Banos, Kern
Wildlife Refuge, and Five Points. Los Banos and Kern Wildlife Refuge
were never in violation of the PM-10 NAAQS so the District's decision
to shut them down for any of the reasons cited by the commenter would
not have been questioned by EPA.
    The Kettleman City monitor continued to run until 1996. This
monitor did record 5 exceedances of the 24-hour PM-10 NAAQS during the
period 1990 to 1993 but was in attainment of the PM-10 NAAQS from 1994
to 1996 when it was discontinued.
    While Five Points was a violating monitor, it was not unique in
that there were other monitors in the Valley that operated in areas
subject to the same type of agricultural emission sources. In the year
that it was shut down there were significantly higher and more frequent
exceedances of the NAAQS at the Corcoran monitoring site. Consequently,
there was no restriction preventing the District from discontinuing it.
In addition, because this site was in a largely uninhabited area it was
not as useful as other sites in the network for assessing population
exposure to PM-10 air pollution.
    The Corcoran monitoring site has always been one of the highest-
reading sites \13\ in the District's PM-10 network and that site has
run continuously \14\ since the PM-10 NAAQS has been in existence. The
Corcoran site is very similar to the Five Points site in terms of the
surrounding land use (agricultural). During the period 1986 to 1993 the
Five Points site recorded six exceedances of the 24-hour NAAQS, and
only one year that exceeded the annual NAAQS (1988 with a 52 [mu]g/
m\3\). In comparison, during the same time period, Corcoran showed 21
observed exceedances of the 24-hour NAAQS and exceeded the annual NAAQS
every year during that time period (the maximum annual concentration
was 70.2 [mu]g/m\3\ in 1991). The Corcoran site also monitors in an
area where there is greater population, which makes it a more desirable
site.
---------------------------------------------------------------------------

    \13\ The Corcoran site has had multiple PM-10 monitoring
instruments in operation during its history, including three federal
reference method (FRM) high volume samplers, a beta attenuation mass
(BAM) analyzer, and a tapered element oscillating microbalance
(TEOM) analyzer. At present, the site operates three FRM high volume
samplers and a TEOM analyzer. The BAM and TEOM analyzers are not
FRMs but have been designated as federal equivalent method (FEM)
monitors by EPA. Two of the three FRM samplers have been designated
by the District as the primary, or SLAMS, samplers for the Corcoran
monitoring site. The third FRM is operated for quality control
purposes.
    FRMs are manual samplers that pull air through a filter for 24
hours (midnight to midnight). The filters are then weighed in a lab
and a PM concentration is calculated based on the mass increase of
the filter and the volume of air drawn through it. The two primary
FRMs operate on a staggered one in six day schedule such that a
sample is collected once every three days.
    \14\ The original Corcoran site was located on Van Dorsten
Avenue and ran from 1986 to 1998. The current Corcoran site at
Patterson Avenue began monitoring in 1997 and continues at this
time. The Patterson Avenue site is approximately 1.1 miles north of
the Van Dorsten Avenue site and has similar site characteristics.
---------------------------------------------------------------------------

    Comment 11: The commenter and other individual citizens state that
the unmonitored (since mid-1990s) west side of Highway 99 is a large
area of the SJV where monitoring is needed in order to understand the
impacts of PM-10 pollution on the rural communities affected by intense
agricultural operations and to fulfill federal monitoring objectives.
    Response: As stated previously, the District does monitor in areas
of intense agricultural activity that are similar to and thus
representative of conditions in other rural communities, including the
western portion of the District. There may be site-specific reasons to
monitor on the west side of the Valley for reasons beyond measuring
attainment of the NAAQS, e.g. reporting more specific air quality
information for people living and working in the western portion of the
Valley for other health-related purposes. However, EPA believes that
for the purposes of determining attainment, the current monitoring
network, since it meets the requirements and objectives of the federal
monitoring regulations, is representative of conditions throughout the
Valley and thus is adequate for making an attainment determination.
    Comment 12: The commenter asserts that while the District claims
that PM-10 levels in the SJV have greatly improved, these improvements
come from a monitoring network that has gotten significantly smaller.
In 1993, the commenter claims that there were 22 sites monitoring for
PM-10 across a wider swath of the SJV, while today there are only 15
sites concentrated along Highway 99. Given this narrow slice of the SJV
under surveillance, it is unreasonable for EPA to declare the area in
attainment of PM-10 without first making a meaningful evaluation of the
adequacy of the monitoring network.
    Response: As stated above, EPA evaluated the SJV PM-10 monitoring
network in 2003 and found it to be adequate under EPA regulations and
guidance. 2003 TSD. That said, the District's claim that PM-10 levels
in the Valley have improved is correct. The improvement in air quality
is clearly evident from an examination of the air quality data for the
last 19 years. The document ``United States Environmental Protection
Agency Quicklook Criteria Parameters'' dated October 5, 2006 provides a
summary of PM-10 data collected in the SJV since 1987.
    While the monitoring network has seen a reduction in the number of
sites over this time period, from a high of 23 monitoring sites in 1990
to the current 15 sites that have made up the District network since
1999, most monitoring networks evolve over time and vary in size. Most
of the sites shut down by the District during the past 19 years were in
attainment of the PM-10 NAAQS for the previous three years. Some
discontinued sites were replaced by new, nearby sites (Fresno, Drummond
replaced Fresno, Olive; Fresno, 1st Street replaced Fresno, Cal State;
Bakersfield, California Ave. replaced Bakersfield, Chester Street; Taft
College replaced Taft, 10th Street; Corcoran, Patterson replaced
Corcoran, Van Dorsten; Hanford, Irwin replaced Hanford, Lacey; Merced,
M Street replaced Merced, E Street; Modesto, 14th Street replaced
Modesto, City Center).\15\ Some sites were shut down and not replaced
(Fresno Five Points, Kern Wildlife Refuge, Kettleman City, Madera
Library, Madera Health Dept., Los Banos, Modesto I street, Crows
Landing). Generally these sites were in attainment of the PM-10
NAAQS.\16\ Other new sites were established where previously there were
no monitors. (Fresno, Clovis; Bakersfield, Golden State Hwy.; Stockton,
Wagner; Turlock). The following table summarizes the monitoring sites
in the Valley that have been operational over the past 19 years and
illustrates that the monitors in the current network are not less
representative of air quality throughout the SJV than the network that
existed in 1993.
---------------------------------------------------------------------------

    \15\ CARB recommends that Districts perform ``parallel
monitoring'' when proposing to relocate a monitoring site. While
parallel monitoring is not a required activity when relocating a
site, parallel monitoring data is often the best way to determine if
important monitoring objectives for the existing site will be
satisfactorily continued at the replacement site. See the document
``Site Relocation and Parallel Monitoring Guidelines'' June 1997,
California Air Monitoring and Technical Advisory Committee.
    \16\ Two sites shut down were in violation of the 24-hour PM-10
NAAQS. Fresno Five Points, which was discontinued in 1993, had
recorded a single exceedance of 190 [mu]g/m\3\ in 1993, but had no
exceedances in 1991 and 1992. Crows Landing in Stanislaus County,
which was discontinued in 1991, had a single exceedance in 1990 of
180 [mu]g/m\3\, but recorded no exceedances in 1989 or 1991.

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Year
        Site        ------------------------------------------------------------------------------------------------------------------------------------
                       87     88     89     90     91     92     93     94     95     96     97     98     99     00     01     02     03     04     05
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno Olive            X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno Drummond                       X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno 1st St                                X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno Cal State        X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno Five Points      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno Clovis                                       X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bakersfield Chester     X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bakersfield Golden                                                       X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bakersfield CA Ave                                                       X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Oildale                 X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Kern Wildlife                         X      X      X      X      X
 Refuge
--------------------------------------------------------------------------------------------------------------------------------------------------------
Taft 10th Street        X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Taft College                                 X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cocoran Van Dorsten     X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Corcoran Patterson                                                                     X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hanford Lacey           X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hanford Irwin                                                     X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Kettleman City          X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Madera Library          X             X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Madera Health Dept.                   X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Los Banos                      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Merced E Street                X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Merced M Street                                                                                X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stockton Hazelton       X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stockton Wagner                                                                        X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Modesto I Street                      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Modesto City Center     X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Modesto 14th Street                   X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Turlock                                                                  X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Crows Landing                  X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
Visalia                 X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X      X
--------------------------------------------------------------------------------------------------------------------------------------------------------
X indicates the site was operational in that year.
Source: EPA's AQS Database.

    Comment 13: The commenter states that, in addition to their failure
to demonstrate the adequacy of the network, EPA and the District have
also failed to provide records attesting to the proper functioning and
maintenance of the particular monitors used to determine attainment.
While EPA uses claims of improper maintenance to ignore data from
continuous monitors, it never establishes that the data it is
considering is in fact reliable and comes from a properly maintained
network. The commmenter further claims that the record before EPA fails
to demonstrate that the network complies with 40 CFR part 58 and
therefore EPA must collect additional information as required by
regulations and provide it to the public before it can cherry pick the
data to be used for the attainment determination.

    Response: Contrary to the commenter's contention, the FRM data on
which EPA is basing its attainment decision is reliable and from
instruments that are properly functioning and maintained in accordance
with 40 CFR 58 and its appendices. EPA's confidence in the data is
based on records submitted by the State that demonstrate that the
network operations which produced the data meet, or in some cases
exceed, the requirements in our regulations at 40 CFR part 58.
    EPA and its regulations provide for different types of requirements
to assure the quality of data, depending upon the types of equipment
used to measure PM-10. There are two categories of instruments that can
be used to measure PM-10 concentrations in the ambient air, manual
reference method samplers and automated equivalent method or continuous
analyzers.\17\
---------------------------------------------------------------------------

    \17\ All equipment designated by EPA as approved for NAAQS
comparisons can be found in the document ``List of Designated
Reference and Equivalent Methods'', USEPA, National Exposure
Research Laboratory, July 26, 2006 available at the Web site http://www.epa.gov/ttn/amtic/files/ambient/criteria/ref0706.pdf
.

---------------------------------------------------------------------------

    A manual reference method sampler provides a 24 hour average
concentration value for PM-10 in the ambient air. A manual reference
method sampler uses a filter medium through which ambient air is drawn
at a near constant flow rate for a period of 24 hours (midnight to
midnight). This flow rate through the filter is an important parameter
and must be recorded accurately. Monitoring the actual flow rate to
verify that the designed flow rate is being maintained during the 24-
hour period is important because the inlet of the sampler will ensure
the needed separation of particles 10 microns or less in diameter from
larger particles only if the proper flow rate is maintained. Also, the
flow rate measurement provides us with the total volume of air drawn
through the filter during the 24-hour period. The total volume of air
is needed to calculate the PM-10 concentration.
    The filters used in PM-10 manual reference method samplers are
weighed in a laboratory before they are installed in the sampler and
weighed again after air has been drawn through the sampler for 24
hours. The pre-sampled mass of the filter is subtracted from the post-
sampled mass and the result is the total mass of PM-10 collected. This
total mass is divided by the total volume of air to determine the 24
hour average PM-10 concentration. In the best case a manual sampler can
provide a 24 hour average concentration in about two days from the day
a sample was collected. In practice and depending on a number of
factors (e.g. how many filters the lab has to process, the distance
between the laboratory and the monitoring site, on what day of the week
a sample was taken) processing the filters in a laboratory and
calculating the concentration can take a few weeks, on average.
    Automated equivalent methods or continuous analyzers, such as Beta
Attenuation Mass (BAM) or Tapered Element Oscillating Microbalance
(TEOM) monitors, use one of two alternative measurement approaches
(beta ray attenuation or mass-dependent oscillation frequency) to avoid
the need to collect PM-10 on a filter medium that must subsequently be
weighed in a laboratory. Continuous analyzers report PM-10
concentrations over short intervals in near real time. The analyzers
can be (and typically are) configured to report the average 24 hour PM-
10 concentration just as a manual reference method does.
    As discussed elsewhere in this action, the SJV PM-10 SLAMS network
consists of 15 monitoring sites using manual reference method samplers.
These samplers operate on a once every six day schedule except for the
site at Corcoran, which operates once every three days because it has
two samplers operating on staggered once every six day schedules.
Corcoran's sampling frequency is twice that of other sites in the SJV
PM-10 SLAMS network because it is historically the highest reading PM-
10 site in the network.
    One of the goals in any data collection effort is to be able to
quantify measurement uncertainty. Measurement uncertainties are the
errors associated with the ambient air monitoring agency, including
errors associated with the field, preparation and laboratory
measurement phases. At each measurement phase, errors can occur, that
in most cases are additive. Air quality monitoring agencies aim to
control measurement uncertainty to an acceptable level through the use
of various quality control and evaluation techniques. Two of the
primary checks used to evaluate measurement uncertainty are precision
and accuracy checks. We will discuss each of these procedures below in
more detail. An important point to understand is that in addition to
allowing an evaluation of the uncertainty in the data that has been
collected, these checks can reveal equipment or procedural problems
that can be corrected. They can also lead a monitoring agency to
disqualify or withdraw data collected in a period before a check
revealed a problem, on the reasonable assumption that the data was
affected by the problem.
    EPA regulations at 40 CFR part 58, appendix A, section 3.0.1 states
that ``All ambient monitoring methods or analyzers used in SLAMS shall
be tested periodically, as described in this section, to quantitatively
assess the quality of the SLAMS data.'' Precision checks are a
measurement of mutual agreement among individual measurements of the
same property usually under prescribed similar conditions, expressed
generally in terms of standard deviation. There are different ways to
determine the precision of PM-10 monitoring networks depending on
whether the network utilizes manual reference methods or automated
equivalent methods. Precision checks of manual and automated methods
are addressed in 40 CFR part 58, Appendix A, sections 3.3 and 3.1,
respectively.
    The SJV PM-10 SLAMS network is a subset of the larger California
PM-10 SLAMS network.\18\ Section 3.3 of Appendix A discusses how to
establish the precision of a PM-10 network made up of manual method
samplers, which applies to the SJV PM-10 SLAMS network. The requirement
is to operate a certain number of collocated monitoring sites, i.e.,
duplicate samplers, depending on the total number of samplers in the
network: 1 collocated site for networks consisting of up to five sites,
2 collocated sites for networks consisting of 6 to 20 sites, and 3
collocated sites for networks of 20 or more sites. These collocated
samplers must run on the same days as the primary samplers and must be
run on at least a once every six days schedule.
---------------------------------------------------------------------------

    \18\ For the purposes of EPA quality assurance requirements, the
California PM-10 SLAMS network is defined as those PM-10 monitors
designated as SLAMS in the CARB document ``California State and
Local Air Monitoring Network Plan--2005'' Planning and Technical
Support Division, Air Quality Branch, October 2006 with the
exception of PM-10 SLAMS monitors operated by the South Coast AQMD,
the Bay Area AQMD, and the San Diego APCD.
---------------------------------------------------------------------------

    The California State PM-10 SLAMS network consists of 97 monitoring
sites and has five collocated sites located at Bakersfield, Visalia,
Taft, Corcoran, and Sacramento. The first four of these listed
collocated monitoring sites are located in the SJV. If the SJV PM-10
network was evaluated separately from the rest of the State network,
EPA regulations would only require two collocated precision sites. From
this perspective, there are twice the number of collocated precision
sites as required by EPA regulations. Each of these samplers will
produce a pair of concentrations on a

given sampling day.\19\ These concentrations must be greater than 20
[mu]g/m3 in order to be used in determining the precision of
the network. According to the CARB QA manual, if concentrations are
below 80 [mu]g/m3, the two paired values must be within 5
[mu]g/m3 of each other, or further investigation and
corrective action are required. If the concentrations are greater than
80 [mu]g/m3 they must be within 7 percent of
each other.\20\ These acceptance criteria are consistent with EPA
criteria in the guidance document ``Quality Assurance Handbook for Air
Pollution Measurement Systems, Volume II: Part 1, Ambient Air Quality
Monitoring Program Quality System Development'', (EPA-454/R-98-004,
August 1998).
---------------------------------------------------------------------------

    \19\ Because it operates on a one in three day sampling schedule
and is also a collocated precision site, the Corcoran monitoring
site has three manual reference method samplers in operation, two
that run concurrently and a third that runs on the staggered one in
six day schedule that enables the site to produce data every three
days.
    \20\ State of California Air Resources Board, Air Monitoring
Quality Assurance, Volume I, Quality Assurance Plan, Monitoring and
Laboratory Division, June 2005.
---------------------------------------------------------------------------

    EPA's QA guidance cited above provides a target for the system-wide
precision performance, taken across all pairs of collocated data. EPA
regulations at 40 CFR part 58, appendix A section 5.3 requires 95
percent upper and lower probability limits be used to evaluate the
collocated data. The target given in the guidance for the 95th
percentile upper and lower limits for reporting organizations is 15
percent. The annual precision summary statistics for the CARB PM-10
SLAMS network meet these requirements as shown in the AQS Report ``P/A
Reporting Organization Summary, AMP 240.''
    Establishing precision for automated equivalent method analyzers,
such as BAM or TEOM monitors, consists of performing a bi-weekly one
point precision check of an analyzer's operational flow rate. See 40
CFR part 58, appendix A, section 3.1. The check is made using a flow
rate transfer standard. The actual flow rate measured by the transfer
standard and the indicated flow rate of the analyzer (the flow rate as
measured by the analyzer's own flow rate meter) are reported to the AQS
database. In the case of the automated equivalent analyzers operated by
the District as special purpose monitors rather than as SLAMS monitors,
these precision checks were not made in accordance with Appendix A
section 3.1 and therefore EPA cannot have the same confidence in these
data as we have in the SLAMS data. Without performing the precision
checks, the District may have overlooked operational problems and
allowed them to affect the data from the special purpose monitors, and
without the precision check data we have no way to evaluate the
acceptability of the data.
    The other primary data quality control (QC) check for proper
operation and maintenance of a monitor is the accuracy check. As with
the precision checks, there are two different procedures for
determining the accuracy of PM-10 monitors depending on whether we are
checking a manual reference method or an automated equivalent
(continuous) analyzer. These two procedures are addressed in 40 CFR
part 58, Appendix A, sections 3.4 and 3.2 respectively.
    For the SJV PM-10 SLAMS network that used manual reference method
samplers, the procedures in section 3.4 are used to determine accuracy.
The procedure entails auditing the flow rate of each sampler annually
such that 25 percent of the network \21\ is audited each calendar
quarter. An independent auditor (i.e., not the person who regularly
operates the sampler) using dedicated equipment (i.e., not the flow
meter built into the sampler) audits the flow rate of the sampler and
reports the actual flow rate and the indicated (sampler) flow rate. Two
measurement quality parameters are calculated from these measurements:
The percent difference in the flow rate measurements by the sampler's
own flow rate meter and the auditor's dedicated flow rate meter, and
the percent difference between the actual flow rate created by the
sampler and the flow rate it was designed to have. Percent differences
beyond acceptance limits can cause an incorrect measurement of PM-10
concentrations. As the QA oversight agency, CARB's QA section performs
the accuracy audits of the SJV PM-10 SLAMS network. These accuracy
audits were performed by CARB as required by EPA regulations, and
showed that the monitors were operating within the accepted control
limits, i.e., the flow rates had not deviated enough from their design
flow rates to require any corrective action on the part of the CARB or
District monitoring staff. The results of the accuracy checks performed
by CARB were submitted to EPA and are shown in the AQS Report ``P/A
Reporting Organization Summary, AMP 240.'' The following table
summarizes the accuracy results for the individual audits of the PM-10
monitors in the SJV. The table shows the date of each audit (one per
year) the differences in the flow rate measurement by the sampler's own
flow rate meter (% Diff.) and the difference between the actual flow
rate created by the sampler and the flow rate it was designed to have
(% Diff. Design). This information shows that the monitors operated in
the SJV PM-10 SLAMS network are performing within the acceptance
criteria established by EPA in its QA guidance, which sets a target
confidence interval for the 95th percentile upper and lower limits
aggregated across the reporting organization of 20 percent, over a
three year period. The CARB PM-10 SLAMS network easily meets this
target based on the small differences shown in the table below. CARB's
performance of these audits at the required frequencies and subsequent
submittal of the results of the audits to EPA's AQS database meets the
requirements of 40 CFR part 58, appendix A, section 3.4.
---------------------------------------------------------------------------

    \21\ In this case, 25 percent of the network applies to the
California State PM-10 SLAMS network not the SJV PM-10 SLAMS
network.

----------------------------------------------------------------------------------------------------------------
                                                                                % Diff.
                                                              Audit date      Sampler ID     % Diff.     design
----------------------------------------------------------------------------------------------------------------
Bakersfield-Golden........................................        6/4/2003            4121        0.0       -6.8
                                                                 7/13/2004            2456        6.8       -4.3
                                                                 10/5/2005            4121        5.3       -5.7
Clovis....................................................       6/18/2003            7380       -2.2        0.7
                                                                 7/29/2004            4040       -2.9        3.0
                                                                 11/7/2005            4040        0.3       -0.5

Corcoran-Patterson........................................        2/4/2003            1885       -2.6        7.0
                                                                  2/4/2003            4645        2.0       -2.0
                                                                  2/4/2003            4120       -8.0        3.0
                                                                 3/11/2004            1885       -0.7        0.5
                                                                 3/11/2004            4645        1.3       -1.5
                                                                 3/11/2004            4120       -0.7        0.5
                                                                 1/26/2005            1885        0.0       -0.7
                                                                 1/26/2005            4645        0.3       -1.0
                                                                 1/26/2005            4120        0.0        0.0
Fresno--Drummond..........................................       2/19/2003            4069        1.8       -2.2
                                                                 2/25/2004            4069       -2.3       -0.7
                                                                  3/1/2005            4069        4.3       -1.0
Hanford...................................................        2/4/2003            3048       -8.7       -2.5
                                                                 3/10/2004            1884        2.5       -1.3
                                                                 1/25/2005            1884        0.0       -3.8
Merced-M St...............................................        3/4/2003            4756       -5.3        7.5
                                                                 2/26/2004            4756        2.8       -3.5
                                                                 1/25/2005            4756        6.8       -8.0
Stockton--Wagner--Holt....................................       6/18/2003            3519        0.0        0.5
                                                                12/16/2004            3519        0.3       -2.2
                                                                11/28/2005            3519        4.8       -7.0
Taft......................................................        2/3/2003            8008      -11.7        7.2
                                                                  2/3/2003            7787       -5.4        6.5
                                                                 3/15/2004            8008       -9.0       -2.2
                                                                 3/15/2004            7787       -4.3        9.5
                                                                 3/14/2005            8008        5.2       -4.0
                                                                 3/14/2005            7787        3.6       -2.5
Turlock...................................................       3/11/2003            4161       -1.0       -1.8
                                                                  3/2/2004            4161       -8.5        6.3
                                                                 2/24/2005            3519        0.0       -3.8
Bakersfield-CA............................................       3/11/2003        20018176       -0.2        2.0
                                                                 3/11/2003        20018177        0.0        2.2
                                                                 3/16/2004        20018176       -2.2        3.8
                                                                 3/16/2004        20018177       -2.2        3.8
                                                                  3/8/2005        20018176        0.3       -0.3
                                                                  3/8/2005        20018177        1.0       -0.7
Fresno-First..............................................       6/16/2003        20018504        1.0        2.5
                                                                 7/28/2004            7660       -1.7        4.3
                                                                 7/26/2005            7660        0.7        1.5
Modesto-14th St...........................................        3/3/2003        20003727       -1.3       -3.0
                                                                  3/3/2004        20003727       -2.0        2.5
                                                                 2/23/2005        20003727        0.5        0.0
Oildale...................................................       3/12/2003        20004244        1.8       -0.3
                                                                 3/17/2004        20004244       -1.0        2.8
                                                                 3/10/2005        20004244        1.0       -1.0
Stockton-Hazelton.........................................      11/19/2003        20004282        1.0        0.5
                                                                12/16/2004        20004282        0.5        0.0
                                                                 12/1/2005        20004282        0.8       -1.8
Visalia...................................................       6/12/2003            7471        0.0        1.3
                                                                 6/12/2003            7678        1.3        0.0
                                                                 7/27/2004            7471       -1.7        4.7
                                                                 7/27/2004            7678       -1.4        4.3
                                                                 7/28/2005            7471        0.5        2.2
                                                                 7/28/2005            7678        2.8        0.0
----------------------------------------------------------------------------------------------------------------

    The accuracy audit for the automated equivalent analyzer is similar
to that for manual reference methods. See 40 CFR part 58, appendix A,
section 3.2.2. Like the audit performed for the manual reference
methods the audit required for automated analyzers is a field audit.
However, as discussed in this notice, no accuracy audits of the
automated analyzers operated by the District were performed, and
therefore EPA cannot assess the accuracy of these monitors. Because the
flow-related components of the manual reference method samplers and of
the automated equivalent analyzers are different in design and
materials, the good performance of the manual samplers cannot be
extrapolated to the automated analyzers.
    Additionally, annual certifications of quality control standards
(e.g., a flow rate meter) are critical in order to insure that the
checks and measurements being made are traceable to National Institute
of Standards and Technology (NIST) standards. See 40 CFR part 58,
appendix A, section 2.3.3. This certification is achieved by
transferring the accuracy or authority of a primary standard to a
field-usable standard. Also, calibrations of the internal flow rate
meters of PM-10 samplers, which are generally performed annually or
after sampler repairs, also ensure that these meters are functioning
correctly. The following table lists the calibration dates of the
internal flow rate meters of the SLAMS monitors in the SJV network.
Calibrations of the flow rate meters are usually performed when a
sampler is first installed at a site or after repair. While EPA
regulations and guidance do

not specify a frequency for performing calibrations of flow rate
meters, performing them annually regardless of whether the instrument
required it demonstrates a good operation practice by the District and
CARB.

------------------------------------------------------------------------
                                             Sample ID       Cal. date
------------------------------------------------------------------------
Bakersfield-Golden......................            4121       2/27/2003
                                                    2456       5/25/2004
                                                    4121      12/15/2004
Clovis..................................            7380       3/13/2003
                                                    4040       7/27/2004
                                                    4040       10/6/2005
Corcoran-Patterson......................            1885      10/28/2002
                                                    4645       1/30/2003
                                                    4120      10/28/2002
                                                    1885      11/12/2003
                                                    4645       12/9/2003
                                                    4120       12/9/2003
                                                    1885       10/5/2004
                                                    4645        1/5/2005
                                                    4120        9/2/2004
Fresno-Drummond.........................            4069      11/12/2002
                                                    4069       2/24/2004
                                                    4069      12/21/2004
Hanford.................................            3048      10/14/2002
                                                    1884      10/15/2003
                                                    1884        8/4/2004
Merced-M St.............................            4756       10/9/2002
                                                    4756       2/10/2004
                                                    4756       12/9/2004
Stockton-Wagner--Holt...................            3519       2/20/2003
                                                    3519       9/10/2004
                                                    3519       7/20/2005
Taft....................................            8008      11/19/2002
                                                    7787      10/25/2002
                                                    8008       2/26/2004
                                                    7778       2/26/2004
                                                    8008       8/18/2004
                                                    7778       8/18/2004
Turlock.................................            4161       1/23/2003
                                                    4161       7/16/2003
                                                    3519       2/23/2005
Bakersfield--CA.........................        20018176        3/7/2002
                                                20018177        3/7/2002
                                                20018176        3/9/2004
                                                20018177        3/9/2004
                                                20018176        6/3/2004
                                                20018177       6/16/2004
Fresno--First...........................        20018504       6/13/2003
                                                    7660       1/21/2004
                                                    7660       2/28/2005
Modesto--14th St........................        20003727       1/17/2003
                                                20003727       2/10/2004
                                                20003727       2/11/2005
Oildale.................................        20004244       2/27/2003
                                                20004244        1/8/2004
                                                20004244       1/31/2005
Stockton--Hazelton......................        20004282      11/12/2003
                                                20004282       12/9/2004
                                                20004282       11/9/2005
Visalia.................................            7471       5/20/2003
                                                    7678       5/20/2003
                                                    7471       5/20/2003
                                                    7678       5/20/2003
                                                    7471      11/24/2004
                                                    7678      11/24/2004
------------------------------------------------------------------------

    As detailed above, CARB has certified and submitted quarterly \22\
to EPA's AQS database, all the supporting QA data for the SJV SLAMS PM-
10 network, including data collected by the collocated precision
network and all required audit data. This data shows that the operation
and maintenance of the SLAMS network met the requirements of sections
3.3 and 3.4 of Appendix A Part 58. By contrast the required number of
precision checks and independent flow rate audits were not performed on
the automated equivalent (BAM and TEOM) method monitors pursuant to
sections 3.1.2 and 3.2.2 nor was data on the precision checks that were
performed on the BAM monitors submitted to the AQS database as required
by 40 CFR part 58, appendix A, section 4.1.\23\ Thus EPA is not, as the
commenter contends, ``cherry picking'' data, but rather relying for its
determination on data that has met the requirements for reliability
under its regulations.
---------------------------------------------------------------------------

    \22\ EPA regulations require the submittal of precision and
accuracy data on a quarterly basis, as it does for the pollutant
concentration data. See 40 CFR 58.35 and 40 CFR part 58, appendix A,
section 4.1.
    \23\ The District did perform some precision checks of the BAM
monitor at Corcoran but these were considerably fewer than required
in EPA regulations. See response to comment 15. Section 3.1.2
requires the checks to be performed at a designated frequency and
the data submitted to the AQS database.
---------------------------------------------------------------------------

F. Data Not Included in Determining Attainment

1. Data From September 3, 2004 High Wind Event
    Comment 14: The commenter questions the validity of waiving the
September 3, 2004 exceedance as a Natural Events Action Plan (NEAP)
\24\ event and states that there is no technical basis for ignoring the
exceedance and that best available control measures (BACM) were not
being implemented for the largest sources of dust in the Valley on that
date. The commenter notes that removal of the flag puts the Valley
right at the limit of violations allowed under the NAAQS and should
make EPA wary to find the PM-10 problem solved in the Valley.
---------------------------------------------------------------------------

    \24\ See memorandum from Mary D. Nichols, Assistant
Administrator for Air and Radiation to Regional Air Directors,
``Areas Affected by PM-10 Natural Events,'' May 30, 1996.
---------------------------------------------------------------------------

    Response: The exceedance in question occurred at the Corcoran-
Patterson Avenue monitoring site. EPA notes in its proposed rule that