[Federal Register: July 16, 2009 (Volume 74, Number 135)]
[Proposed Rules]
[Page 34525-34539]
[DOCID:fr16jy09-13]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 58

[EPA-HQ-OAR-2008-0338; FRL-8930-7]
RIN 2060-AP15

Ambient Ozone Monitoring Regulations: Revisions to Network Design
Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing to revise the monitoring network design
requirements for ozone to assist in implementing changes to the primary
and secondary National Ambient Air Quality Standards (NAAQS) for ozone
that were promulgated on March 27, 2008. EPA is proposing to modify
minimum monitoring requirements in urban areas, add new minimum
monitoring requirements in non-urban areas, and extend the length of
the required ozone monitoring season in some States.

DATES: Comments must be received on or before September 14, 2009.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2008-0338, by one of the following methods:
     http://www.regulations.gov: Follow the on-line
instructions for submitting comments.
     E-mail: Comments may be sent by electronic mail (e-mail)
to<EMAIL_ADDRESS>Attention Docket ID No. EPA-HQ-OAR-2008-
0338.
     Fax: Fax your comments to<PHONE_NUMBER>, Attention Docket
ID No. EPA-HQ-OAR-2008-0338.
     Mail: Send your comments to Air and Radiation Docket and
Information Center, Environmental Protection Agency, Mailcode 2822T,
1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention Docket ID
No. EPA-HQ-OAR-2008-0338. Please include a total of two copies. In
addition, please mail a copy of your comments on the information
collection provisions to the Office of Information and Regulatory
Affairs, Office of Management and Budget (OMB), Attn: Desk Officer for
EPA, 725 17th St., NW., Washington, DC 20503.
     Hand Delivery: Deliver your comments to EPA Docket Center,
1301 Constitution Ave., NW., Room 3334, Washington, DC 20460. Such
deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2008-0338. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://
www.regulations.gov or e-mail. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through http://www.regulations.gov your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be

able to consider your comment. Electronic files should avoid the use of
special characters, any form of encryption, and be free of any defects
or viruses. For additional information about EPA's public docket, visit
the EPA Docket Center homepage at http://www.epa.gov/epahome/
dockets.htm.
    Docket: All documents in the docket are listed in the http://
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Ambient Ozone
Monitoring Regulations: Revisions to Network Design Requirements
Docket, EPA/DC, EPA West Building, Room 3334, 1301 Constitution Ave.,
NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to
4:30 p.m. Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is<PHONE_NUMBER>, and the
telephone number for the Ambient Ozone Monitoring Regulations:
Revisions to Network Design Requirements Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: For technical questions, please
contact Mr. Lewis Weinstock, U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, Air Quality Assessment
Division, Ambient Air Monitoring Group (C304-06), Research Triangle
Park, North Carolina 27711; telephone number:<PHONE_NUMBER>; fax
number:<PHONE_NUMBER>; e-mail address<EMAIL_ADDRESS>For
general questions, please contact Ms. Lula Melton, U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards, Air
Quality Assessment Division (C304-02), Research Triangle Park, North
Carolina 27711; telephone number:<PHONE_NUMBER>; fax number: (919)
541-4511; e-mail address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. General Information

A. Does This Action Apply to Me?

    Categories and entities potentially regulated by this action
include:

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           Category            NAICS \a\  Examples of regulated entities
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Federal government...........     924110  Federal agencies that conduct
                                           ambient air monitoring
                                           similar to that conducted by
                                           States under 40 CFR part 58
                                           and that wish EPA to use
                                           their monitoring data in the
                                           same manner as State data.
State/local/tribal government     924110  State, territorial, and local
                                           air quality management
                                           programs that are responsible
                                           for ambient air monitoring
                                           under 40 CFR part 58. The
                                           proposal may also affect
                                           tribes that conduct ambient
                                           air monitoring similar to
                                           that conducted by States and
                                           that desire that EPA use
                                           their monitoring data in the
                                           same manner as State
                                           monitoring data.
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\a\ North American Industry Classification System.

B. What Should I Consider as I Prepare My Comments for EPA?

    Do not submit information containing CBI to EPA through http://
www.regulations.gov or e-mail. Send or deliver information identified
as CBI only to the following address: Roberto Morales, OAQPS Document
Control Officer (C404-02), U.S. EPA, Office of Air Quality Planning and
Standards, Research Triangle Park, North Carolina 27711, Attention
Docket ID No. EPA-HQ-OAR-2008-0338. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information in a disk or
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as
CBI, and then identify electronically within the disk or CD ROM the
specific information that is claimed as CBI. In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.

C. Where Can I Get a Copy of This Document and Other Related
Information?

    In addition to being available in the docket, an electronic copy of
this proposed rule is also available on the Worldwide Web (WWW) through
the Technology Transfer Network (TTN). Following the Administrator's
signature, a copy of this proposed rule will be placed on the TTN's
policy and guidance page for newly proposed or promulgated rules at
http://www.epa.gov/ttn/oarpg. The TTN provides information and
technology exchanges in various areas of air pollution control.

D. How Is This Document Organized?

    The information presented in this preamble is organized as follows:

I. General Information
    A. Does This Action Apply to Me?
    B. What Should I Consider as I Prepare My Comments for EPA?
    C. Where Can I Get a Copy of This Document and Other Related
Information?
    D. How is This Document Organized?
II. Summary of Proposed Ozone Network Design Requirements and
Rationale
    A. What Are the Proposed Revisions to Urban Network Design
Requirements?
    B. What Are the Proposed Revisions to Non-Urban Network Design
Requirements?
    C. What Are the Proposed Revisions to the Length of the Required
O3 Monitoring Season?
III. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations

II. Summary of Proposed Ozone Network Design Requirements and Rationale

A. What Are the Proposed Revisions to Urban Network Design
Requirements?

    Presently, States (including the District of Columbia, Puerto Rico,
and the Virgin Islands) and local air quality management agencies when
so delegated by the State are required to operate minimum numbers of
EPA-approved ozone (O3) monitors based on the population of
each of their Metropolitan Statistical Area (MSA) and the most recently
measured O3 levels for each area. These requirements are
contained in 40 CFR part 58 Appendix

D, SLAMS Minimum O3 Monitoring Requirements, Table D-2.
These requirements were last revised on October 17, 2006, as part of a
comprehensive review of ambient monitoring requirements for all
criteria pollutants. (See 71 FR 61318 for the specific Table D-2
referenced above.)
    Currently, the minimum number of O3 monitors required in
an MSA ranges from zero (for an area with a population of at least
50,000 and under 350,000 and no recent history of an O3
design value greater than 85 percent of the level of the NAAQS) to four
(for an area with a population greater than 10 million and an
O3 design value greater than 85 percent of the level of the
NAAQS). Because these requirements apply at the MSA level, large urban
areas consisting of multiple MSAs can be required to have more than
four monitors.
    Currently, there are 369 MSAs in the U.S. subject to minimum
O3 monitoring requirements.\1\ Of these MSAs, 251 are
required to have one or more monitors based on their 2005 population
estimates \2\ and 2005 to 2007 O3 design values compared to
the revised O3 NAAQS, and the other 118 MSAs are not
required to have monitors. The specific size range of MSAs that are not
required to have monitors have urban area populations between 50,000
and less than 350,000, and have O3 design values less than
85 percent of the level of the NAAQS. Some of the MSAs do not have
current design values due to the lack of monitors. Also note that
monitoring requirements do not apply to Micropolitan Statistical
Areas.\3\
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    \1\ MSA must contain an urbanized area of 50,000 or more
population.
    \2\ http://www.census.gov/population/www/estimates/metropop/
2005/cbsa-01-fmt.xls.
    \3\ Micropolitan Statistical Areas must have at least one urban
cluster of at least 10,000 but less than 50,000 population.
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    In the 251 MSAs with one or more required O3 monitors, a
total of 392 monitors are required to meet the minimum requirements
listed in Table D-2. In actuality, 992 monitors were in operation
during 2005 to 2007 representing these MSAs.\4\ This monitor count
exceeds the minimum requirements based on Table D-2, indicating the
typical practice of operating more than the minimum required number of
monitors to support the basic monitoring objectives described in part
58, Appendix D. In addition, State and local agencies operated 55
monitors during 2005 to 2007 in MSAs that were not required to have
monitors.\5\
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    \4\ Of these 992 monitors, 873 monitors provided complete data
for calculation of design values.
    \5\ Of these 55 monitors, 20 monitors provided complete data for
calculation of design values.
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    We note that many of the O3 monitors that are operated
in excess of minimum requirements are necessary to characterize the
O3 concentrations that occur in metropolitan areas and in
downwind areas that are potentially impacted by transport from MSAs. As
noted in Appendix D (see 71 FR 61318), O3 minimum monitoring
requirements do not account for the full breadth of additional factors
that would be considered in designing a complete O3
monitoring program for an area. Some of these additional factors
include geographic size, population density, complexity of terrain and
meteorology, adjacent O3 monitoring programs, air pollution
transport from neighboring areas, and measured air quality in
comparison to all forms of the O3 NAAQS (i.e., 8-hour and 1-
hour forms). States and EPA Regional Administrators work together to
design and/or maintain the most appropriate O3 network to
service the variety of data needs in an area. The results of these
negotiations are documented in annual monitoring network plans that are
made available for public inspection and then approved by the EPA
Regional Administrator, and the O3 monitoring requirements
in approved plans become the basis for State O3 monitoring
requirements for the one-year period following plan approval.
    Because existing minimum monitoring requirements include a factor
based on the comparison of an area's design value to the O3
NAAQS (see 71 FR 61318), the recent revisions to the O3
NAAQS (see 73 FR 16436) may already necessitate that some States make
changes to their O3 monitoring network independent of the
proposed changes described below. The requirements listed in Table D-2
of 40 CFR part 58 Appendix D are based on how close measured ambient
concentrations are to the level of the O3 NAAQS, with a
design value threshold at 85 percent of the NAAQS. For an MSA of a
given population size, there are a greater number of required monitors
when the design value is greater than or equal to 85 percent of the
O3 NAAQS than when the design value is less than 85 percent
of the O3 NAAQS. With the recent decision to revise the 8-
hour primary and secondary standards from a level of 0.08 ppm to a
level of 0.075 ppm, the 8-hour O3 design value that will
trigger increased minimum monitoring requirements for an MSA decreased
from 0.068 ppm to 0.064 ppm. Therefore, MSAs with 8-hour design values
between 0.064 ppm and 0.067 ppm are now required to increase the number
of monitors operating to meet minimum requirements based on existing
monitoring requirements.\6\ A total of 15 MSAs have O3
design values between 0.064 ppm and 0.067 ppm based on 2005 to 2007
design values. Of those 15 MSAs, 13 MSAs are already meeting
requirements based on the operation of additional monitors by the
affected States. Thus, current data indicate that only two areas may
need additional monitors \7\ on the grounds that their design values
are now greater than or equal to 85 percent of the revised NAAQS.
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    \6\ States should document the required changes to O3
networks in their annual monitoring network plans that are required
by 40 CFR part 58.10. Such plans are due by July 1 of each year and
required to be made available for public inspection prior to
submission to EPA Regional Offices for review and approval.
    \7\ Based on 2005 to 2007 O3 design values and 2005
Census Bureau population estimates, these MSAs are Port St. Lucie-
Fort Pierce, Florida, and Salem, Oregon.
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    There are 105 MSAs with populations between 50,000 and less than
350,000 that are presently without any O3 monitors
supporting design value calculations for either 2004 to 2006 or 2005 to
2007.\8\ These unmonitored MSAs have a total population of
approximately 18 million people and include areas in 37 States and
Puerto Rico. The existing regulations do not require these MSAs to
begin monitoring for O3. Comments that were received from
State air monitoring agencies and from multi-State air planning
organizations in response to the O3 NAAQS proposal expressed
concern that these requirements ignore the needs that States and
localities have for additional monitors to measure O3 levels
in a variety of locations, particularly in areas with populations under
350,000. The commenters stated that unless this deficiency is
corrected, the health benefits of EPA's O3 NAAQS revision
would likely be limited to those living in MSAs having populations of
more than 350,000. Other commenters noted the difficulty in defining
the boundaries of new attainment/nonattainment areas without additional
monitoring in the MSAs below 350,000 population.\9\
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    \8\ Approximately 18 of these MSAs have operating O3
monitors but incomplete data for the purposes of calculating design
values for the 2004 to 2006 and 2005 to 2007 time periods.
    \9\ See the O3 NAAQS Response to Comments document in
docket EPA-HQ-OAR-2005-0172, document number 7185, available online
at http://www.regulations.gov/fdmspublic/component/
main?main=DocketDetail&d=EPA-HQ-OAR-2005-0172.

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    EPA notes that States already have the discretion to add
O3 monitors in these locations and in any currently
unmonitored areas where applicable siting criteria can be satisfied,
although they are not currently required to do so in the unmonitored
MSAs below 350,000 population based on existing O3 minimum
monitoring requirements.
    EPA has conducted a review of 8-hour design values obtained from
existing monitors that are in proximity to these unmonitored MSAs of
population below 350,000. Based on 2005 to 2007 data reported to the
Air Quality System (AQS), approximately 25 percent of these unmonitored
MSAs (26 of 105 areas) had an O3 monitor within 20
kilometers (approximately 12 miles) that violated the revised NAAQS.
Approximately 42 percent (44 of 105 areas) of the unmonitored MSAs had
a violating O3 monitor within 50 kilometers (approximately
31 miles). The close proximity of violating O3 monitors to
unmonitored MSAs indicates a reasonable likelihood that monitors placed
in many of these unmonitored areas would have recorded violating
concentrations over the same time period. When these unmonitored MSAs
are evaluated in comparison to the locations of non-violating
O3 monitors that measured a level of greater than or equal
to 85 percent of the revised NAAQS, approximately 34 percent (36 of 105
areas) were within 20 kilometers of such a monitor and 63 percent (66
of 105 areas) were within 50 kilometers. Concentrations of greater than
or equal to 85 percent of the NAAQS to 100 percent of the NAAQS level
obtained from many of the monitors in close proximity to these
unmonitored MSAs indicates a reasonable likelihood that monitors placed
in the unmonitored MSAs would have measured similar concentrations at
levels over the same time period. This suggests the need for
O3 monitoring in these unmonitored MSAs of between 50,000
and 350,000 population to ensure that potential NAAQS violations are
measured.
    Based on these analyses, EPA believes it is important to monitor
O3 concentrations in the smaller MSAs with populations
between 50,000 and less than 350,000 in light of the revised level of
the standards. While it was less likely that violating concentrations
of the former 0.08 parts per million (ppm \10\) primary standard were
being missed due to the lack of a monitoring requirement in these MSAs,
the likelihood of missing violating concentrations of the 0.075 ppm
primary standard is greater, and the public comments in regard to the
potential need to revise applicable O3 monitoring
regulations have merit.
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    \10\ Due to the data handling regulations associated with the
1997 O3 NAAQS level, an 8-hour design value of 0.085 ppm
was required to exceed the level of the NAAQS.
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    Accordingly, EPA is proposing to modify the minimum O3
monitoring requirements to require one monitor to be placed in MSAs of
populations ranging from 50,000 to less than 350,000 in situations
where there is no current monitor and no history of O3
monitoring within the previous 5 years indicating a design value of
less than 85 percent of the revised NAAQS. We propose to modify Table
D-2 of 40 CFR part 58 Appendix D by moving the current footnote 4 from
the right column of the table to the middle column of the table. By
doing so, we propose to require greater numbers of O3
monitors for MSAs that do not have design values compared with the
requirements that were promulgated in the October 17, 2006 revisions to
ambient monitoring regulations (see 71 FR 61318). Functionally, this
modification should mainly impact MSAs in the population range between
50,000 and 350,000 since virtually all MSAs of population 350,000 or
greater currently have at least two O3 monitors in
operation.\11\
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    \11\ Three MSAs with a population of at least 350,000 appear to
have no design values for either the 2004-2006 or 2005-2007 periods.
These MSAs include Anchorage, Alaska; Kileen-Temple-Fort Hood,
Texas; and San Juan-Caguas-Guaymabo, Puerto Rico. The Alaska and
Texas MSAs reached the 350,000 level based on the difference in the
2005 population estimate compared with the 2000 decennial census
figure and would therefore be subject to minimum requirements of two
monitors in each of these MSAs.
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    EPA solicits comment on whether the proposed 5-year historical data
period is appropriate for demonstrating that O3 design
values in a currently unmonitored MSA of population ranging from 50,000
to less than 350,000 have been less than 85 percent of the revised
NAAQS, or whether the time period for allowing the use of historical
data should be longer or shorter than 5 years.
    States may wish to relocate an existing O3 monitor to
the unmonitored MSA to meet the proposed requirements. Opportunities
for relocation may exist in areas where the current number of
O3 monitors in another MSA in the same State exceeds minimum
requirements and the relocation of one or more of the non-required
monitors meets one or more of the conditions described in 40 CFR part
58.14(c). States may also relocate a non-required O3 monitor
from a location outside of an MSA to an unmonitored MSA that is subject
to the proposed requirements. Relocations of monitors to meet the
proposed requirements would be subject to EPA Regional Administrator
approval, based on a review of State-supplied information such as the
ambient data trend from the monitor being proposed for relocation, the
potential impact on data stakeholders with the monitor discontinuance,
and the ability of other nearby O3 monitors to characterize
the O3 conditions in the area from which the monitor is
being proposed to be removed.
    While States will be required to add some new monitors or relocate
existing monitors to meet the proposed requirements, EPA notes that
many of these unmonitored MSAs already have existing O3
monitors in close proximity to their geographic boundaries. Based on
the siting characteristics and data record from the existing
O3 monitors near the unmonitored MSAs, it is plausible that
some of these monitors may adequately represent O3
concentrations in the unmonitored areas based on analyses of ambient
concentrations, O3 precursor emissions, meteorology,
photochemical modeling, and/or topography. Analyses based on these
factors or other available information could be used to support case-
by-case waivers from the requirement for monitoring within some of
these unmonitored MSAs, as described below, thereby mitigating the
expense and logistical hurdles involved with establishing new
O3 monitors or relocating non-required existing monitors
from other areas.
    In some cases where an existing monitor is located close to an
unmonitored MSA that would be required to site a new monitor based on
the proposed rule modification, the affected State may propose and EPA
Regional Administrators may consider approving a waiver of monitoring
requirements for the unmonitored MSA. When seeking such a waiver, the
State must provide relevant information including the siting
characteristics and data record from the existing O3
monitors near the unmonitored MSA, or other information sources that
the Regional Administrator must consider in evaluating the estimation
of current and future O3 levels in the unmonitored MSAs. The
Regional Administrator may approve such requests under the waiver
authority provided in paragraph 4.1.1(c) of 40 CFR part 58, Appendix D
of the proposed regulatory text. Any deviations based on the Regional
Administrator's waiver of requirements

must be described in the annual monitoring network plan.
    Such waiver requests must be accompanied by a letter documenting
the State's commitment to propose a nonattainment designation for the
unmonitored MSA based on violating readings from the nearby monitor(s)
and a commitment to modify a State Implementation Plan (SIP) to provide
for a specific, reproducible approach to representing the O3
concentration of the unmonitored MSA in the absence of the actual
monitoring data that would have been supplied by the required monitor.
We request comment on the practicality of allowing States to enter into
agreements with EPA Regional Administrators to use nearby O3
monitors to represent the conditions within unmonitored MSAs, the
specific commitments that must be included in these agreements and/or
submitted plans, and the implementation challenges that may arise
during the O3 designation process if the EPA Regional
Administrator approves of such arrangements.
    In all cases described above, proposed changes to O3
networks in response to the proposed new requirement would have to be
documented in the annual monitoring network plans that are required by
40 CFR part 58.10 and are subject to approval by the EPA Regional
Administrator.
    Based on the proposed requirements described above, EPA estimates
that approximately 109 new O3 monitors would be required in
the national O3 network if the proposed urban requirement
was satisfied solely with new monitors installed in the unmonitored
MSAs. In actuality, we expect the net addition of new monitors to the
national O3 network to be less than 109 monitors due to the
mitigating factors that have been previously described. These factors
include the presence of existing monitors that could satisfy the
proposed requirement in these unmonitored MSAs with improved data
completeness, the proposed flexibility for States to relocate non-
required O3 monitors to the unmonitored MSAs, and the
possibility of States proposing that existing monitors in close
proximity to the unmonitored MSAs be used to represent O3
concentrations within the unmonitored MSAs.
    It has been EPA's recent practice to allow at least a one-year
period for States to install new monitors when monitoring requirements
are revised through rulemaking (see 71 FR 61241). Consistent with this
practice and based on the projected schedule of completing a final
O3 monitoring rulemaking in early 2010, EPA proposes that
new O3 monitors be required to be installed and operating by
the first day of the required O3 monitoring season that is
effective in 2012 as described in Table D-3 of Appendix D to part 58
(see Section II.C of this proposal for the proposed changes to the
required O3 monitoring seasons). For some States, new
monitors would be required to be installed and operating as early as
January 1, 2012, while other States would have later deadlines based on
their respective O3 monitoring seasons.
    States would be required to identify how their monitoring networks
would be modified to meet the proposed new O3 requirements
in the annual monitoring network plan due on July 1, 2011.
    EPA also recognizes the logistical difficulty in siting new
O3 monitors or in relocating existing O3 monitors
that have been approved for discontinuation and subsequent relocation
to meet the proposed requirements. Accordingly, we solicit comment on
the proposed requirement for having new monitors operating in 2012,
specifically whether States might need additional time to site all the
new monitors (e.g., a staggered 2-year deployment schedule accomplished
in 2012 and 2013) versus the single-year deadline described above. We
note that the deployment schedule would be applicable to the proposed
urban monitoring requirements as well as the proposed non-urban
monitoring requirements described in the following section.

B. What Are the Proposed Revisions to Non-Urban Network Design
Requirements?

    The newly established secondary standard was put into place
specifically to provide protection to sensitive vegetation in less
urbanized areas, in particular those Class I Wilderness Areas set aside
by Congress to be protected so as to conserve the scenic value and the
natural vegetation and wildlife within such areas, and to leave them
unimpaired for the enjoyment of future generations. The secondary
O3 NAAQS also considered the benefits that would be provided
to the public welfare from increased protection of sensitive vegetation
in other Federal, State, Tribal and/or public interest lands that have
been set aside for a similar purpose. These areas are characterized by
the presence of O3-sensitive species of native vegetation
that have been shown to be subject to O3-induced visible
foliar injury, impaired growth, and/or other adverse impacts to a
degree that could be considered adverse.
    Currently, existing O3 monitoring requirements and
current State monitoring practices are primarily oriented towards
protecting against human health effects and therefore towards reporting
compliance with the primary NAAQS. This accounts for the current focus
of the monitoring requirements on urban areas, where large populations
reside, in which significant emissions of O3-forming
precursors are found, and where O3 concentrations of concern
have been historically measured. EPA believes that the previously
described proposed changes to urban monitoring requirements will be
adequate for determining compliance with the secondary NAAQS in MSAs,
noting that the assessment of welfare effects has not been a
traditional objective of urban-based O3 monitoring networks.
    It is now known, however, that O3 concentrations of
concern for vegetation can also occur in areas far downwind of urban
areas. In addition, the new more stringent level of the primary and
secondary NAAQS make it likely that O3 levels of concern for
both plants and people will be found outside of urban areas. Thus, EPA
believes that there is merit in proposing additional limited monitoring
requirements in non-urban areas to address both secondary and primary
standard needs.
    Although there are currently no EPA requirements for O3
monitoring other than in or adjacent to MSAs\12\, there are at present
about 200 State-operated O3 monitors in counties that are
not part of MSAs, and these monitors can be categorized in several
ways. States commonly locate O3 monitors both upwind and
downwind of major urban areas to evaluate the spatial gradient or
extent of transported O3 pollution and the lag time
typically associated with photochemical production. In some cases,
these O3 monitors are located in non-urban or rural areas
within MSAs or physically outside the MSA boundary if the expected
location of maximum downwind O3 concentration is outside the
MSA. These monitors are counted toward meeting the minimum urban
O3 monitoring requirements listed in Table D-2 of Appendix D
since they provide information about the air quality status of an urban
MSA.
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    \12\ States affected by Photochemical Assessment Monitoring
Stations (PAMS) requirements may be required to establish
O3 monitors outside of MSAs to characterize upwind or
downwind concentrations. See 40 CFR part 58 Appendix D, section 5.
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    States may also operate monitors in non-urban or rural areas to
meet other objectives such as the support of research programs
including studies of

atmospheric chemistry and ecosystem impacts, and these monitors are not
typically counted toward meeting minimum monitoring requirements
applicable to urban areas. States often categorize these non-required
monitors as special purpose monitors (SPMs). This provides inherent
flexibility because States are allowed to discontinue operation of SPMs
without EPA Regional Administrator approval, subject to the conditions
of 40 CFR 58.20. Furthermore, SPMs can be operated for a period of up
to 24 months without being considered in NAAQS compliance
determinations.
    As part of the Clean Air Status and Trends Network (CASTNET), the
EPA operates 57 O3 monitors, and the National Park Service
(NPS) operates 23 monitors across the eastern and western U.S. The NPS
also operates additional O3 monitors independent of CASTNET
stations. CASTNET O3 monitors operate year-round and are
primarily located in rural areas; siting criteria require distances of
at least 40 kilometers from cities of greater than 50,000 population as
well as other separation requirements from air pollution sources.\13\
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    \13\ http://www.epa.gov/castnet/library/qapp_v4/QAPP_v4_
Main_Body.pdf, page 105.
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    Taking into account both State and EPA/NPS-operated non-urban
O3 monitors, an analysis of the distribution of these
monitors indicates a relatively uniform spatial density in the eastern
one-third of the U.S. and in California, with significant gaps in
coverage elsewhere across the country. Virtually all States east of the
Mississippi River have at least two to four non-urban O3
monitors, while many large mid-western and western States have one or
no non-urban monitors.\14\
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    \14\ Based on an AQS retrieval of O3 monitors
reporting any data in 2007, regardless of data completeness
requirements, the following States had one or zero non-urban
O3 monitors: Georgia, Idaho, Louisiana, Nebraska, Nevada,
Montana, and Oregon. If data completeness is taken into
consideration, a total of 13 States had zero non-urban O3
monitors that could provide a design value for either 2004-2006 or
2005-2007.
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    Comments that were received from State monitoring agencies, State
organizations, and private individuals in response to the O3
NAAQS proposal noted the voluntary nature of most rural O3
monitoring and the resulting relative lack of rural O3
monitors in some areas. These commenters stated that EPA should
consider adding monitoring requirements to support the secondary NAAQS
by requiring O3 monitors in locations that contain
O3-sensitive plants or ecosystems. These commenters also
noted that the placement of current O3 monitors may not be
appropriate for evaluating issues such as vegetation exposure since
many of these monitors were likely located to meet other objectives.
    As explained in the following paragraphs, EPA agrees with the
public input received on this issue and believes that several important
objectives would be served by having additional non-urban monitoring
requirements. These objectives include: (1) Provide better
characterization of O3 exposures to O3-sensitive
vegetation and ecosystems in rural/remote areas to ensure that
potential secondary NAAQS violations are measured. This objective would
also serve the purpose of providing more consistent support for studies
examining the impact of elevated O3 levels in wilderness
areas, locations with O3-sensitive natural vegetation, and
in areas such as National Parks; (2) assessment of population exposure
due to elevated ambient O3 levels in smaller communities
located outside of the larger urban MSAs covered by the monitoring
requirements described in Section II.A; and (3) the assessment of the
location and severity of maximum O3 concentrations that
occur in non-urban areas and may be attributable to upwind urban
sources. Each of these three objectives is described below.
    With regard to the first objective, there is evidence that ambient
concentrations of O3 in rural and other non-urban areas may
be adversely affecting sensitive natural vegetation. As noted
previously by the public commenters, this objective addresses the
uncertainties that remain about the impact that O3
concentrations have on sensitive natural vegetation, ecosystems, and
wilderness areas. Additional monitors in National Parks and as well as
State and/or tribal areas set aside to provide similar public welfare
benefits would support evaluation of the revised secondary NAAQS as
well as future reviews of the secondary O3 NAAQS by
providing a more robust data set with which to assess actual vegetation
exposure in rural areas, and thereby reducing the need for
interpolations of rural air quality.
    With regard to the second objective as noted earlier in Section
II.A, O3 monitoring requirements do not currently apply to
Micropolitan Statistical Areas, defined as areas having at least one
urban cluster of at least 10,000 but less than a population of 50,000.
The lack of such monitoring requirements for smaller communities has
historically been based on the concept that the concentrations of
O3 in these non-urban areas would not be high enough
relative to the NAAQS to justify the imposition of national monitoring
requirements in less populated areas. However, in light of the revised
level of the O3 NAAQS, it is far more likely that these
smaller communities could be exposed to elevated concentrations that
approach or exceed the NAAQS due to the transport of O3 from
upwind areas and/or the formation of O3 due to precursor
emissions from industrial sources outside of urban areas. We note that
there are 582 Micropolitan Statistical Areas in the U.S. with a total
population of just under 2 million people based on the 2005 census
estimate. Although States are not required to monitor in these areas,
over 90 monitors providing 2005 to 2007 O3 design values
were operated. Of these 90 monitors, 45 monitors recorded design values
exceeding the level of the revised NAAQS. A total of 86 of these 90
monitors recorded design values greater than or equal to 85 percent of
the revised NAAQS. These data from monitors located in Micropolitan
Statistical Areas clearly indicate the potential for violations of the
NAAQS in some smaller communities located outside the boundaries of
MSAs that currently have minimum monitoring requirements.
    The third objective is the assessment of the location and severity
of maximum O3 concentrations that occur outside of urban
areas. Although the location of maximum non-urban O3
concentrations could occur within the boundary of a Micropolitan
Statistical Area or sensitive ecosystem, it is also possible that such
concentrations could occur in an unpopulated and unmonitored area.
Without specific information about the location and distribution of
such potentially violating maximum O3 concentration areas,
it would be difficult to ensure that all parts of a State meet the
revised NAAQS and that all necessary emission control strategies have
been accounted for in SIPs. We believe that the identification of such
non-urban maximum concentration areas would support objectives
including: (1) The understanding of the role of upwind urban-generated
O3 transport and impact in locations between MSAs, (2) the
verification of photochemical models at various time-scales (i.e.,
diurnal fluctuations, seasonal patterns) used for assessing the
effectiveness of control measures as well as real-time models
supporting O3 forecasts, and (3) the understanding of the
role of O3 precursor emissions from industrial sources and
development in more remote areas in the potential creation of high-
O3 areas in lightly

inhabited areas that historically have been unmonitored.
    Given the three objectives described above, EPA believes that there
is strong justification for proposing additional limited monitoring
requirements in non-urban areas to evaluate compliance with both the
secondary and primary NAAQS. EPA proposes to modify 40 CFR part 58
Appendix D by adding the requirement (in proposed rule section 4.1.2)
that each State operate non-urban O3 monitors in addition to
the current and proposed urban O3 monitoring requirements
detailed in Table D-2 and described in section II.A of this preamble.
The first required non-urban monitor is proposed to be located in areas
such as some Federal, State, or Tribal lands, including wilderness
areas that have O3-sensitive natural vegetation and/or
ecosystems; lands with other ownership may also be appropriate. The
second required non-urban monitor is proposed to be required to be
placed in a Micropolitan Statistical Area expected to have
O3 design value concentrations of at least 85 percent of the
NAAQS.\15\ The third required non-urban monitor is proposed to be in
the area of expected maximum O3 concentration outside of any
MSA, potentially including the far-downwind transport zones of
currently well-monitored urban areas.
---------------------------------------------------------------------------

    \15\ Monitors installed to meet the Micropolitan Statistical
Area requirement could be discontinued, with Regional Administrator
approval, after demonstrating an O3 design value of less
than 85 percent of the NAAQS.
---------------------------------------------------------------------------

    EPA proposes to require that States will propose new non-urban
O3 monitoring sites to meet each of the distinct monitoring
objectives, and that the resulting expanded network will provide the
foundation for an improved level of characterization of O3
concentrations outside of urban areas in support of the secondary and
primary NAAQS. In some cases, States may wish to operate additional
non-urban monitors beyond the proposed minimum requirements where, for
example, there are multiple sensitive ecosystems or wilderness areas
impacted by O3, multiple Micropolitan Statistical Areas
exposed to high levels of O3, or in States with multiple
isolated locations of similarly high projected O3
concentrations.
    EPA solicits comment on the proposed non-urban O3
monitoring requirements including the total number of required monitors
per State, the appropriateness of the distinct non-urban objectives,
the ability of such an expanded network to improve characterization of
O3 concentrations in support of the revised secondary and
primary NAAQS, and the capability of the proposed network to support
other objectives such as model validation.
    States will likely need to perform additional analyses to help
determine the appropriate locations for non-urban monitors meeting the
proposed requirements. States are encouraged to confer with partners
familiar with the patterns of vegetation damage and distribution of
O3 sensitive species in their areas, such as Federal Land
Managers, State, local, or Tribal ecosystem assessment experts, or
academic researchers who have established experience in the field.\16\
Resources and analyses such as the availability of photochemical
modeling, spatial interpolation of ambient data from existing
O3 monitors, or other quantitative assessment tools are
useful to determine the areas where there are projected maximum non-
urban O3 concentrations, and where these regions with
elevated O3 (typically greater than or equal to 85 percent
of the revised NAAQS) might overlap locations with O3-
sensitive ecosystems and other important wilderness areas and
Micropolitan Statistical Areas. The availability of regional
photochemical modeling based on updated emissions inventories is a very
useful tool to inform proposed non-urban and/or rural O3
monitoring locations in areas, such as the western U.S., where national
assessments have not fully accounted for recent changes in emissions
from industrial activities. EPA plans to update the current
O3 network design guidance document \17\ in time to support
the siting of new urban and non-urban O3 monitors that are
required by the final monitoring rule.
---------------------------------------------------------------------------

    \16\ An example of available resources is posted by the National
Park Service at http://www.nature.nps.gov/air/Pubs/pdf/flag/
NPSO3sensppFLAG06.pdf.
    \17\ Guideline on Ozone Monitoring Site Selection, EPA-454/R-98-
002, August 1998, http://www.epa.gov/ttn/amtic/files/ambient/
criteria/reldocs/r-98-002.pdf.
---------------------------------------------------------------------------

    Monitors counted toward satisfying these proposed non-urban
requirements would have to be operated in compliance with all
requirements of 40 CFR part 58 and Appendices A, C, D, and E. EPA
recognizes that a different set of monitor placement criteria from the
current Appendix E requirements might be appropriate for locating non-
urban O3 monitors compared with urban O3
monitors. For example, in less populated areas, States may wish to
establish different setback requirements from roadways, minimum
distances from urban areas or significant pollution sources, or
consider a different set of vertical probe height requirements. EPA is
not proposing specific changes to the monitoring regulations to support
non-urban O3 monitoring other than the changes already noted
to Appendix D. EPA encourages States to consider guidelines such as the
previously noted siting guidelines used for the CASTNET network. We
solicit comment on the need and substance of alternative non-urban
O3 siting requirements and what changes would be appropriate
for sites that will support the previously stated non-urban monitoring
objectives.
    EPA also acknowledges that there may be a logistical challenge in
operating monitors that are more physically remote than the monitors
that States have typically run to satisfy urban monitoring
requirements. The operation of such monitors could, in some cases,
create additional challenges for monitoring agencies. EPA solicits
comment on any changes to the monitoring requirements that apply
specifically to non-urban monitors that might be appropriate to
mitigate any increased challenges potentially associated with their
operation.
    As noted earlier in section II.A, States may wish to relocate
existing O3 monitors to appropriate non-urban locations to
meet the proposed requirements. Relocations of State and local air
monitoring station (SLAMS) monitors must meet the applicable monitoring
requirements and would be subject to EPA Regional Administrator
approval. States may also propose that existing non-required
O3 monitors or those O3 monitors at existing
candidate or approved rural national core (NCore) stations be counted
toward meeting the proposed requirements if these monitors are located
in areas that satisfy the proposed non-urban monitoring objectives.
    EPA expects that some States may be interested in the possibility
of existing CASTNET or NPS O3 monitors, or monitors operated
by some other organization, being counted towards meeting the proposed
non-urban minimum monitoring requirements. In these cases, EPA would
require States to enter into agreements with the operators \18\ of the
candidate sites to insure that the sites are operated according to all
40 CFR part 58 monitoring regulations that apply to monitors
categorized as SLAMS while also maintaining the monitoring requirements
of the existing program. Candidate O3 sites (e.g., CASTNET
or NPS) utilized for meeting minimum monitoring requirements would be

required to be included in a State's annual monitoring network plan and
would be subject to EPA Regional Administrator review and approval as
with all other SLAMS monitors. Of the currently operating CASTNET
O3 monitors, the 23 NPS-operated monitors are meeting
applicable quality assurance requirements and currently reporting data
to AQS. The remaining CASTNET monitors are in the process of being
upgraded to meet the quality assurance requirements of 40 CFR part 58
and all sites are expected to be upgraded and reporting to AQS by the
latter part of 2009.
---------------------------------------------------------------------------

    \18\ CASTNET O3 monitors are operated by the Clean
Air Markets Division of EPA's Office of Atmospheric Programs (OAP).
Some CASTNET sites are operated by the National Park Service in a
cooperative agreement with OAP.
---------------------------------------------------------------------------

    In certain cases, it may be difficult to identify suitable areas to
meet each of the proposed non-urban monitoring objectives. For example,
in a small relatively urbanized State, it may be difficult to
distinguish between monitoring requirements for a Micropolitan
Statistical Area versus a rural area impacted by maximum O3
concentrations. In a remote or isolated area without significant local
pollution sources or likelihood of being impacted by transport of
O3 precursors from another area (e.g., Guam or American
Samoa), it may be unwarranted to require the placement of additional
non-urban monitors. States with historically lower ambient
O3 levels may not have Micropolitan Statistical Areas likely
to experience O3 concentrations of at least 85 percent of
the NAAQS. It is also plausible that a State may not have ecosystems
characterized by O3-sensitive natural vegetation that have
been designated for providing specific public welfare amenities or
benefits. States might expect in some cases that the establishment of
multiple non-urban O3 monitors to meet one or two of the
proposed non-urban monitoring objectives (e.g., three monitors located
in areas with sensitive ecosystems), would be more important than
allocating an additional monitor to meet each of the three distinct
monitoring objectives. In addition, one monitor could conceivably serve
multiple purposes so that fewer than three monitors would be needed to
meet these objectives.
    In situations like those described above, States may choose to seek
from the EPA Regional Administrator a deviation from such requirements
that either modify or waive these requirements, consistent with the
authority to approve deviations from non-urban O3 minimum
monitoring requirements stated in the proposed regulatory language in
paragraph 4.1.2(e) of 40 CFR part 58, Appendix D. When seeking approval
of such deviations, the State must provide relevant information
specific to the basis for which the waiver is sought. Any deviations
based on the Regional Administrator's waiver of requirements must be
described in the annual monitoring network plan.
    Based on the proposed requirements described above, EPA estimates
that approximately 159 new non-urban O3 monitors would be
required in the national O3 network if the proposed non-
urban requirements were satisfied solely with new monitors. In
actuality, we expect the net addition of less than 159 additional
monitors to the national O3 network due to the mitigating
factors that have been previously described. These factors include the
presence of existing non-urban monitors that are satisfactorily located
to meet one or more of the proposed monitoring objectives, the proposed
flexibility for States to relocate existing non-required O3
monitors to non-urban areas, the option of States proposing that some
existing CASTNET or NPS monitors be counted towards meeting the
proposed non-urban requirements, and the possibility of States
obtaining Regional Administrator waivers of certain non-urban minimum
requirements based on the situations described above.
    EPA solicits comment on the appropriateness of these proposed
minimum non-urban monitoring requirements, including the distinct
monitoring objectives, the required number of monitors, the criteria
for placement, and the need to allow EPA Regional Administrators
discretion to waive or modify siting criteria or minimum requirements.

C. What Are the Proposed Revisions to the Length of the Required
O3 Monitoring Season?

    Unlike the ambient monitoring requirements for other criteria
pollutants that mandate year-round monitoring, O3 monitoring
is currently only required during the seasons of the year that are
conducive to O3 formation. These seasons vary in length from
place to place as the conditions that determine the likely
O3 formation (i.e., seasonally-dependent factors such as
ambient temperature, strength of solar insolation, and length of day)
differ by location.\19\ In some locations, conditions conducive to
O3 formation are limited to a few summer months of the year.
For example, in States with colder climates such as Montana and South
Dakota, the currently required O3 monitoring season has a
length of 4 months. However, in other States with warmer climates such
as California, Nevada, and Arizona, the currently required
O3 monitoring season for most sites continues all 12 months
of the year.\20\
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    \19\ See 40 CFR Part 58 Appendix D, section 2.5 for a table of
required O3 seasons.
    \20\ Certain States, such as California and Arizona, have been
approved for shorter seasons for a subset of O3 sites,
based on Regional Administrator review and approval (see 71 FR 61319
for the waiver authority).
---------------------------------------------------------------------------

    With the recent revision of the primary and secondary NAAQS to a
more stringent level, the issue arises of whether in some areas the
required O3 monitoring season should be made longer.
Lengthening the season in certain States may be appropriate as ambient
O3 concentrations could approach or exceed the level of the
revised standard more frequently and during more months of the year
than before. As noted later in this section, a related issue is the
status of any currently effective Regional Administrator-granted waiver
approvals to O3 monitoring seasons, and the impact of
proposed changes to monitoring requirements on such waiver approvals.
    EPA has done an analysis to address the issue of whether extensions
of currently required monitoring seasons are appropriate in light of
the revised NAAQS.\21\ In the analysis, we determined the number of
exceedences of the revised NAAQS (i.e., daily maximum 8-hour
O3 averages above 0.075 ppm) in the months falling outside
the currently required local O3 monitoring season using
monitors in areas that collected O3 data year-round in 2004-
2006.\22\ Additionally, we examined occurrences of daily maximum 8-hour
O3 averages of at least 0.060 ppm. This threshold represents
80 percent of the 0.075 ppm NAAQS level and provides an indicator of
ambient conditions that may be conducive to the formation of
O3 concentrations that approach or exceed the revised
NAAQS.\23\
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    \21\ Camalier, L. and Weinstock, L. (2008) Documentation of
O3 Monitoring Season Analysis for the Proposed
O3 Monitoring Rule, available in docket.
    \22\ Approximately 530 O3 monitors are currently
operated year-round, representing 45 percent of the total
O3 monitoring network. They include monitors that are
mandated to operate year-round due to the required O3
season and other monitors that are voluntarily operated year-round
by States and other organizations including EPA-operated monitors at
CASTNET sites.
    \23\ We note that an 8-hour concentration of 0.060 ppm also
corresponds to the threshold defining the revised Air Quality Index
(AQI) breakpoint between the Good and Moderate indicator level (see
73 FR 16484).
---------------------------------------------------------------------------

    While proposals for revising each State's required monitoring
season have been based on observed data in and surrounding the State,
statistically predicted exceedences were used to

validate conclusions for each State. For States where year-round data
were not available, EPA developed and employed a regression model to
predict the frequency of exceedences in areas during unmonitored
months. The model was fit separately for each major urban area and uses
the relationship between daily maximum 8-hour O3
concentrations and certain meteorological variables, including
temperature and relative humidity, to predict exceedences of a
particular O3 level.\24\
---------------------------------------------------------------------------

    \24\ See: Camalier, L., Cox, B., and Dolwick, P., 2007. The
effects of meteorology on O3 in urban areas and their use
in assessing O3 trends. Atmospheric Environment 41, 7127-
7137.
---------------------------------------------------------------------------

    In reviewing the year-round or close to year-round O3
data between 2004 and 2006, EPA's analysis found observed exceedences
of the revised O3 NAAQS in eight States during months
outside of the current required monitoring season. The eight States are
Maine, Massachusetts, New Hampshire, New Jersey, New York, South
Carolina, Vermont, and Wyoming. With the exception of Wyoming, the
exceedances occurred in a very limited manner and timeframe, just
before the beginning of these States' required O3 monitoring
season (beginning in these States on April 1). Every exceedance in the
aforementioned States was found to occur either on March 30 or March
31. In Wyoming, the frequency of O3 exceedances before the
beginning of the required O3 season was higher, with
multiple occurrences noted at several sites up to 2 months before the
April 1 startup of required O3 monitoring.\25\
---------------------------------------------------------------------------

    \25\ Additional information on this O3 situation is
available on the Wyoming DEQ Web site: http://deq.State.wy.us/aqd/
Monitoring%20Data.asp.
---------------------------------------------------------------------------

    The frequency of observed occurrences of maximum 8-hour average
O3 readings of at least 0.060 ppm was quite high across the
country in months outside of the current required monitoring season. A
total of 32 States experienced such occurrences; 22 States had such
readings only before the required monitoring season; 9 States had such
levels both before and after the required monitoring season; and 1
State had such levels only after the required monitoring season. In a
number of cases, the frequency of such ambient concentrations was high,
with some States experiencing between 31 to 46 out-of-season days
during 2004 to 2006 at a high percentage of all operating year-round
O3 monitors.\26\
---------------------------------------------------------------------------

    \26\ Florida, South Carolina, South Dakota, Utah, and Wyoming.
---------------------------------------------------------------------------

    EPA believes that these occurrences of O3 levels greater
than the 0.075 ppm NAAQS and as well as greater than or equal to a
threshold level of 0.060 ppm in months that are not within the
currently required O3 monitoring season support the proposed
lengthening of the O3 monitoring season requirements. We
note that basing O3 monitoring season requirements on the
goal of ensuring monitoring when ambient O3 levels reach 80
percent of the NAAQS supports established monitoring network objectives
described in Appendix D of part 58, including the requirement to
provide air pollution data to the general public in a timely manner
\27\ and to support comparisons of an area's air pollution levels
against the NAAQS.
---------------------------------------------------------------------------

    \27\ Public reporting requirements are detailed in 40 CFR part
58 Appendix G, Uniform Air Quality Index (AQI) and Daily Reporting.
Appendix G describes the requirements for the AQI and notes that it
conveys health implications of air quality and that the reports may
contain appropriate health and cautionary statements. CAA section
319(a) provides EPA with a general authority to ``promulgate
regulations establishing an air quality monitoring system'' that
uses ``uniform air quality monitoring criteria and measures such air
quality according to a uniform air quality index.''
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    We note that the operation of O3 monitors during periods
of time when ambient levels reach at least 80 percent of the NAAQS
ensures that persons unusually sensitive to O3 are alerted
to potential NAAQS exceedances. The majority of O3 monitors
in the U.S. report to AIRNOW, as well as to State-operated web sites
and automated phone reporting systems. These programs support many
objectives including real-time air quality reporting to the public,
O3 forecasting programs, and the verification of real-time
air quality forecast models.
    In conclusion, EPA believes that the stated approach of ensuring
that O3 monitors are operating during all periods likely to
involve NAAQS exceedances supports the proposed lengthening of required
O3 monitoring seasons as described in detail below.
    We note that basing these proposed revisions, in part, on
occurrences of O3 levels representing at least 80 percent of
revised NAAQS represents a modification of previous guidance.\28\ In
the past, monitoring season requirements were based solely on
O3 NAAQS exceedences, although previous guidance did utilize
the number of days in each month in which at least one 8-hour average
O3 concentration exceeded 0.080 ppm, a value slightly lower
than the value of 0.084 ppm used for nonattainment determinations. This
use of 0.080 ppm rather than 0.08(4) ppm as articulated in the previous
NAAQS for O3 resulted in a more conservative benchmark that
required monitoring in months that, given reasonable measurement
uncertainty, had the potential to violate the previous NAAQS.
---------------------------------------------------------------------------

    \28\ Guideline for Selecting and Modifying the Ozone Season
Based on an 8-Hour Ozone Standard, EPA-454/R-98-001, June 1998,
http://www.epa.gov/ttn/amtic/files/ambient/criteria/reldocs/
ozsea8hr.pdf.
---------------------------------------------------------------------------

    The specific proposed changes to the required State O3
monitoring seasons are detailed in the proposed changes to Table D-3 of
40 CFR part 58 Appendix D (O3 Monitoring Season by State).
These changes entail a proposed decrease of one month for Minnesota, an
increase of 1 month (19 States), 2 months (6 States), 4 months (3
States), and 5 months (Wyoming). O3 season requirements are
currently split by Air Quality Control Region in Louisiana and Texas.
Included in the above State-by-State accounting is the proposal to
lengthen the required season in the northern part of Louisiana by 1
month (southern Louisiana O3 monitors would remain on a
required year-round schedule) and the proposal for the required season
in Texas to become year-round for the entire State. Proposed
modifications to the current requirements were based on the previously
described technical analysis. In several States with limited available
data, proposed changes were made using supporting information from the
surrounding States; these changes were all minor, involving the
addition of a maximum of 1 month to the current required season.\29\
---------------------------------------------------------------------------

    \29\ Delaware, Iowa, North Dakota, and Wisconsin.
---------------------------------------------------------------------------

    EPA solicits comment on the proposed changes to the required
O3 monitoring seasons. We note that EPA Regional
Administrators have previously approved deviations from the required
O3 monitoring seasons in direct final rulemakings, the
process required before the latest monitoring rule revisions.\30\
Deviations from the required O3 monitoring seasons are
currently permitted by paragraph 4.1(i) of 40 CFR part 58 Appendix D
(see 71 FR 61319) as revised in the October 17, 2006 revisions to the
ambient monitoring regulations without rulemaking. EPA is retaining the
rule language permitting such deviations from the required
O3 monitoring seasons in proposed paragraph 4.1.1(j) of 40
CFR part 58, Appendix D. The proposed changes to O3
monitoring season requirements, if finalized, will render moot previous
Regional Administrator-granted waiver approvals. Post-final rule
requests submitted along with relevant supporting information by States
for monitoring season waivers from the revised requirements will be
reviewed

by Regional Administrators using, at a minimum, the same criteria
discussed in this proposal, i.e., the frequency of out-of-season
O3 NAAQS exceedances as well as occurrences of the Moderate
AQI. Any deviations based on the Regional Administrator's waiver of
requirements must be described in the annual monitoring network plan
and updated in the AQS.
---------------------------------------------------------------------------

    \30\ See 64 FR 3028, 67 FR 57332, 69 FR 52836
---------------------------------------------------------------------------

    Current regulations permit O3 monitors located at NCore
multi-pollutant stations to be counted toward meeting minimum network
monitoring requirements (see 71 FR 61318). The NCore network
requirements were promulgated in the October 17, 2006 revisions to
ambient monitoring regulations in order to build a long-term,
nationwide network that supports multiple objectives including air
quality trends analyses, model evaluation, ecosystem studies, and
assessment of transport between urban and rural areas. In the 2006
rulemaking, EPA did not propose a different O3 monitoring
season for NCore stations.
    NCore stations are required to operate a full suite of gaseous and
particulate matter monitors as well as basic meteorology to support
these objectives. Given the potential value of NCore data to support
year-round scientific studies, EPA believes that it is appropriate to
require that O3 monitors at NCore stations be operated on a
year-round basis. Accordingly, EPA proposes that the required
monitoring season for NCore stations be January through December
regardless of the length of the required O3 monitoring
season for the remainder of the SLAMS monitors within a State. EPA
solicits comment on this proposed requirement.
    As mentioned in Section II.A of this preamble, EPA is proposing to
require that additional urban and non-urban O3 monitors
needed to meet the revised minimum network requirements be documented
in the annual monitoring network plan, due by July 1, 2011, and that
the monitors be operational by January 1, 2012. For existing
O3 monitors, we believe that a shorter timeline is
reasonable for States to adjust their monitoring programs to reflect
the proposed O3 monitoring season changes. Therefore, EPA is
proposing that the revised O3 monitoring seasons become
effective on January 1, 2011. We encourage monitoring agencies to
voluntarily adopt the new O3 monitoring seasons, where
appropriate, during 2010. We invite comment on this proposed schedule,
including whether it is reasonable for States to adopt the revised
O3 monitoring season 1 year prior to the deadline for
installing and operating newly required O3 monitors based on
the proposed requirements.
    EPA notes that in the proposed regulatory language for 40 CFR part
58 Appendix D, we are reprinting a number of existing paragraphs
without change, including paragraphs 4.1.1(d), 4.1.1(e), 4.1.1(f),
4.1.1(g), and 4.1.1(h). We are doing so solely for the readers'
convenience in order that the proposed revisions to section 4 of
Appendix D appear in a single context. EPA is not re-proposing,
reconsidering, or otherwise reopening any of these reprinted
provisions. We will regard any comments as to these provisions as
outside the scope of this proposal.

III. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993),
this action is a ``significant regulatory action'' because it may raise
novel legal or policy issues arising out of legal mandates, the
President's priorities, or the principles set forth in the EO.
Accordingly, EPA submitted this action to the Office of Management and
Budget (OMB) for review under EO 12866, and any changes made in
response to OMB recommendations have been documented in the docket for
this action.

B. Paperwork Reduction Act

    The information collection requirements in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The
Information Collection Request (ICR) document prepared by EPA has been
assigned EPA ICR No. 2313.01.
    The information collected and reported under 40 CFR part 58 is
needed to determine compliance with the NAAQS, to characterize air
quality and associated health and ecosystems impacts, to develop
emission control strategies, and to measure progress for the air
pollution program. We are proposing to modify minimum monitoring
requirements in urban areas, add new minimum monitoring requirements in
non-urban areas, and to extend the length of the required O3
monitoring season in some States. We are proposing that new
O3 monitors be required to be established and operating by
January 1, 2012. In addition, we are proposing that the revised
O3 monitoring seasons become effective on January 1, 2011.
    Based on these assumptions, the annual average reporting burden for
the collection under 40 CFR part 58 (averaged over the first 3 years of
this ICR) for 145 respondents is estimated to be a total of 72,393
labor hours per year with a total of $6,320,187 per year. Burden is
defined at 5 CFR 1320.3(b). State, local, and tribal entities are
eligible for State assistance grants provided by the Federal government
under the CAA which can be used for monitors and related activities.
    An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy
of the provided burden estimates, and any suggested methods for
minimizing respondent burden, EPA has established a public docket for
this rule, which includes this ICR, under Docket ID number EPA-HQ-OAR-
2008-0338. Submit any comments related to the ICR to EPA and OMB. See
ADDRESSES section at the beginning of this notice for where to submit
comments to EPA. Send comments to OMB at the Office of Information and
Regulatory Affairs, Office of Management and Budget, 725 17th Street,
NW., Washington, DC 20503, Attention: Desk Office for EPA. Since OMB is
required to make a decision concerning the ICR between 30 and 60 days
after July 16, 2009, a comment to OMB is best assured of having its
full effect if OMB receives it by August 17, 2009. The final rule will
respond to any OMB or public comments on the information collection
requirements contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an Agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impact of this rule on small
entities, small entity is defined as: (1) A small business as defined
by the Small Business Administration's (SBA) regulations at 13 CFR
121.201; (2) a small governmental jurisdiction that is a government of
a city, county, town, school district or

special district with a population of less than 50,000; and (3) a small
organization that is any not-for-profit enterprise which is
independently owned and operated and is not dominant in its field.
    After considering the economic impacts of this proposed rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. This
proposed rule will not impose any requirements on small entities. The
proposed amendments to 40 CFR part 58 would affect State and larger
local agencies. Monitoring regulations have typically not applied to
government jurisdictions of less than 50,000 people. We continue to be
interested in the potential impacts of the proposed rule on small
entities and welcome comments on issues related to such impacts.

D. Unfunded Mandates Reform Act

    This rule does not contain a Federal mandate that may result in
expenditures of $100 million or more for State, local, and tribal
governments, in the aggregate, or the private sector in any one year.
We estimate the cost to State, local, and tribal governments to be
approximately $6 million. Therefore, the costs of this proposed rule is
much less than $100 million, and we conclude that this rule is not
subject to the requirements of sections 202 and 205 of UMRA.
    This rule is also not subject to the requirements of section 203 of
UMRA because it contains no regulatory requirements that might
significantly or uniquely affect small governments.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have Federalism implications.''
``Policies that have Federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
    This proposed rule does not have Federalism implications. EPA
estimates the total cost of the proposed rule to be approximately $6
million. Therefore, it will not have substantial direct effects on the
States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government, as specified in Executive Order 13132.
Thus, Executive Order 13132 does not apply to this rule.
    EPA recognizes that States will have a substantial interest in this
proposed rule and any corresponding revisions to associated air quality
surveillance requirements in 40 CFR part 58. Accordingly, EPA did
consult with the Monitoring Steering Committee of the National
Association of Clean Air Agencies during the preparation of this
proposed rule. In the spirit of Executive Order 13132, and consistent
with EPA policy to promote communications between EPA and State and
local governments, EPA specifically solicits comment on this proposed
rule from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This action does not have tribal implications, as specified in
Executive Order 13175 (65 FR 67249, November 9, 2000). It does not have
a substantial direct effect on one or more Indian Tribes, since Tribes
are not obligated to conduct ambient monitoring for ozone or to adopt
the ambient monitoring requirements of 40 CFR part 58. Thus, Executive
Order 13175 does not apply to this action.
    EPA specifically solicits additional comment on this proposed
action from tribal officials.

G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks

    EPA interprets EO 13045 (62 FR 19885, April 23, 1997) as applying
to those regulatory actions that concern health or safety risks, such
that the analysis required under section 5-501 of the Order has the
potential to influence the regulation. This action is not subject to EO
13045 because it is based solely on technology performance.

H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

    This action is not a ``significant regulatory action'' as defined
in Executive Order 13211 (66 FR 28355 (May 22, 2001)) because it is not
likely to have a significant adverse effect on the supply,
distribution, or use of energy. No significant change in the use of
energy is expected because the total number of additional monitors
would be relatively small.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law 104-113, 12(d)(15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards in its regulatory
activities unless to do so would be inconsistent with applicable law or
otherwise impractical. Voluntary consensus standards are technical
standards (e.g., materials specifications, test methods, sampling
procedures, and business practices) that are developed or adopted by
voluntary consensus standards bodies. NTTAA directs EPA to provide
Congress, through OMB, explanations when the Agency decides not to use
available and applicable voluntary consensus standards.
    This proposed rulemaking involves environmental monitoring and
measurement. Consistent with the Agency's Performance Based Measurement
System (PBMS), EPA proposed not to require the use of specific,
prescribed analytical methods. Rather, the Agency plans to allow the
use of any method that meets the prescribed performance criteria.
Ambient air concentrations of ozone are currently measured by the
Federal reference method (FRM) in 40 CFR part 50, Appendix D
(Measurement Principle and Calibration Procedure for the Measurement of
Ozone in the Atmosphere) or by Federal equivalent methods (FEM) that
meet the requirements of 40 CFR part 53. Procedures are available in
part 53 that allow for the approval of an FEM for ozone that is similar
to the FRM. Any method that meets the performance criteria for a
candidate equivalent method may be approved for use as an FEM. This
approach is consistent with EPA's PBMS. The PBMS approach is intended
to be more flexible and cost-effective for the regulated community; it
is also intended to encourage innovation in analytical technology and
improved data quality. The EPA is not precluding the use of any method,
whether it constitutes a voluntary consensus standard or not, as long
as it meets the specified performance criteria.
    EPA welcomes comments on this aspect of the proposed rulemaking and
specifically invites the public to identify potentially-applicable
voluntary consensus standards and to explain why such standards should
be used in this regulation.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629 (Feb. 16, 1994)) establishes
Federal executive policy on environmental justice. Its main provision
directs Federal agencies, to the greatest extent practicable and
permitted by law, to make environmental justice part of their mission
by identifying and addressing, as appropriate, disproportionately high
and adverse human health or environmental effects of their programs,
policies, and activities on minority populations and low-income
populations in the United States.
    EPA has determined that this proposed rule will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it does not
affect the level of protection provided to human health or the
environment. This proposed rule amendment does not relax the control
measures on sources regulated by the rule and therefore will not cause
emissions increases nor decrease environmental protection from these
sources.

List of Subjects in 40 CFR Part 58

    Environmental protection, Administrative practice and procedure,
Air pollution control, Intergovernmental relations, Reporting and
recordkeeping requirements.

    Dated: July 8, 2009.
Lisa P. Jackson,
Administrator.
    For the reasons stated in the preamble, title 40, chapter I, of the
Code of Federal Regulations is proposed to be amended as follows:

PART 58--[AMENDED]

    1. The authority citation for part 58 continues to read as follows:

    Authority:  42 U.S.C. 7403, 7410, 7601(a), 7611, and 7619.

Subpart B--[Amended]

    2. Section 58.10 is amended by adding paragraph (a)(5) to read as
follows:

Sec.  58.10  Annual monitoring network plan and periodic assessment.

    (a) * * *
    (5) A plan for establishing O3 monitoring sites in
accordance with the requirements of appendix D to this part shall be
submitted to the EPA Regional Administrator by July 1, 2011. The plan
shall provide for the required O3 sites to be operational by
January 1, 2012 or the first day of the applicable required
O3 monitoring season that is effective in 2012 as listed in
Table D-3 of appendix D of this part, whichever date is later.
* * * * *
    3. Appendix D to Part 58 is amended by revising section 4.1 to read
as follows:

Appendix D to Part 58--Network Design Criteria for Ambient Air Quality
Monitoring:

* * * * *
    4. * * *
    4.1 Ozone (O3) Design Criteria. State, and where
appropriate, local agencies must operate O3 sites to
appropriately characterize urban areas as well as a limited number
of non-urban areas for each State.
    4.1.1 Urban Requirements. (a) The minimum monitoring
requirements for characterizing O3 across an urban area
depend upon area size (in terms of population and geographic
characteristics) and typical peak concentrations (expressed in
percentages below, or near the O3 NAAQS). Specific SLAMS
O3 site minimum requirements are included in Table D-2 of
this appendix. The NCore sites are expected to complement the
O3 data collection that takes place at SLAMS sites with
one or more pollutant measurements, and both types of sites can be
used to meet the network minimum requirements. The total number of
O3 sites needed to support the basic monitoring
objectives of public data reporting, air quality mapping,
compliance, and understanding O3-related atmospheric
processes will include more sites than these minimum numbers
required in Table D-2 of this appendix. The EPA Regional
Administrator and the responsible State or local air monitoring
agency must work together to design and/or maintain the most
appropriate O3 network to service the variety of data
needs in an area.

     Table D-2 of Appendix D to Part 58--SLAMS Minimum O3 Monitoring
                              Requirements
------------------------------------------------------------------------
                                      Most recent 3-     Most recent 3-
                                    year design value  year design value
        MSA population 1 2            concentrations     concentrations
                                     >=85% of any O3     <85% of any O3
                                        NAAQS 3 4           NAAQS 3
------------------------------------------------------------------------
>10 million.......................                  4                  2
4-10 million......................                  3                  1
350,000-<4 million................                  2                  1
50,000-<350,000 \5\...............                  1                  0
------------------------------------------------------------------------
\1\ Minimum monitoring requirements apply to the Metropolitan
  Statistical Area (MSA).
\2\ Population based on latest available census figures.
\3\ The ozone (O3) National Ambient Air Quality Standards (NAAQS) levels
  and forms are defined in 40 CFR part 50.
\4\ These minimum monitoring requirements apply in the absence of a
  design value.
\5\ Metropolitan Statistical Areas (MSA) must contain an urbanized area
  of 50,000 or more population.

    (b) Within an O3 network, at least one O3
site for each MSA, or CSA if multiple MSAs are involved, must be
designed to record the maximum concentration for that particular
metropolitan area. More than one maximum concentration site may be
necessary in some areas. Table D-2 of this appendix does not account
for the full breadth of additional factors that would be considered
in designing a complete O3 monitoring program for an
urban area. Some of these additional factors include geographic
size, population density, complexity of terrain and meteorology,
adjacent O3 monitoring programs, air pollution transport
from neighboring areas, and measured air quality in comparison to
all forms of the O3 NAAQS (i.e., 8-hour and 1-hour
forms). Networks must be designed to account for all of these area
characteristics. Network designs must be re-examined in periodic
network assessments that document the particular factors used in
determining the size of the required O3 monitoring
network.
    (c) Deviations from the above urban O3 requirements
are allowed if approved by the EPA Regional Administrator. States
may propose and EPA Regional Administrators may consider approving a
waiver of monitoring requirements for unmonitored MSAs with
populations between 50,000 and less than 350,000 based on the
presence of nearby existing monitors. When seeking such a waiver,
the State must provide relevant information including the siting
characteristics and data record from the existing O3
monitors near the unmonitored MSA, or other information sources that
the Regional Administrator must consider in evaluating the
estimation of current and future O3 levels in the
unmonitored MSAs. Such waiver requests must be accompanied by a
letter documenting the State's

commitment to propose a nonattainment designation for the
unmonitored MSA based on violating readings from the nearby
monitor(s) and a commitment to modify a State Implementation Plan
(SIP) to provide for a specific, reproducible approach to
representing the O3 concentration of the unmonitored MSA
in the absence of the actual monitoring data that would have been
supplied by the required monitor. Any deviations based on the
Regional Administrator's waiver of requirements must be described in
the annual monitoring network plan.
    (d) The appropriate spatial scales for O3 sites are
neighborhood, urban, and regional. Since O3 requires
appreciable formation time, the mixing of reactants and products
occurs over large volumes of air, and this reduces the importance of
monitoring small scale spatial variability.
    (1) Neighborhood scale--Measurements in this category represent
conditions throughout some reasonably homogeneous urban sub-region,
with dimensions of a few kilometers. Homogeneity refers to pollutant
concentrations. Neighborhood scale data will provide valuable
information for developing, testing, and revising concepts and
models that describe urban/regional concentration patterns. These
data will be useful to the understanding and definition of processes
that take periods of hours to occur and hence involve considerable
mixing and transport. Under stagnation conditions, a site located in
the neighborhood scale may also experience peak concentration levels
within a metropolitan area.
    (2) Urban scale--Measurement in this scale will be used to
estimate concentrations over large portions of an urban area with
dimensions of several kilometers to 50 or more kilometers. Such
measurements will be used for determining trends, and designing
area-wide control strategies. The urban scale sites would also be
used to measure high concentrations downwind of the area having the
highest precursor emissions.
    (3) Regional scale--This scale of measurement will be used to
typify concentrations over large portions of a metropolitan area and
even larger areas with dimensions of as much as hundreds of
kilometers. Such measurements will be useful for assessing the
O3 that is transported to and from a metropolitan area,
as well as background concentrations. In some situations,
particularly when considering very large metropolitan areas with
complex source mixtures, regional scale sites can be the maximum
concentration location.
    (e) EPA's technical guidance documents on O3
monitoring network design should be consulted to evaluate the
adequacy of each existing O3 monitor, to relocate an
existing site, or to locate any new O3 sites.
    (f) For locating a neighborhood scale site to measure typical
city concentrations, a reasonably homogeneous geographical area near
the center of the region should be selected which is also removed
from the influence of major NOX sources. For an urban
scale site to measure the high concentration areas, the emission
inventories should be used to define the extent of the area of
important nonmethane hydrocarbons and NOX emissions. The
meteorological conditions that occur during periods of maximum
photochemical activity should be determined. These periods can be
identified by examining the meteorological conditions that occur on
the highest O3 air quality days. Trajectory analyses, an
evaluation of wind and emission patterns on high O3 days,
can also be useful in evaluating an O3 monitoring
network. In areas without any previous O3 air quality
measurements, meteorological and O3 precursor emissions
information would be useful.
    (g) Once the meteorological and air quality data are reviewed,
the prospective maximum concentration monitor site should be
selected in a direction from the city that is most likely to observe
the highest O3 concentrations, more specifically,
downwind during periods of photochemical activity. In many cases,
these maximum concentration O3 sites will be located 10
to 30 miles or more downwind from the urban area where maximum
O3 precursor emissions originate. The downwind direction
and appropriate distance should be determined from historical
meteorological data collected on days which show the potential for
producing high O3 levels. Monitoring agencies are to
consult with their EPA Regional Office when considering siting a
maximum O3 concentration site.
    (h) In locating a neighborhood scale site which is to measure
high concentrations, the same procedures used for the urban scale
are followed except that the site should be located closer to the
areas bordering on the center city or slightly further downwind in
an area of high density population.
    (i) For regional scale background monitoring sites and non-urban
monitoring sites, similar meteorological analysis as for the maximum
concentration sites may also inform the decisions for locating
regional scale sites. Regional scale sites may be located to provide
data on O3 transport between cities, as background sites,
or for other data collection purposes. Consideration of both area
characteristics, such as meteorology, and the data collection for
both urban and non-urban objectives, such as transport, must be
jointly considered for a regional scale site to be useful.
    (j) Since O3 levels decrease significantly in the
colder parts of the year in many areas, O3 is required to
be monitored at SLAMS monitoring sites only during the ``ozone
season'' as designated in the AQS files on a State-by-State basis
and described below in Table D-3 of this appendix. Deviations from
the O3 monitoring season must be approved by the EPA
Regional Administrator. Requests for monitoring season waivers must
be accompanied by relevant supporting information. These requests
will be reviewed by Regional Administrators using, at a minimum, the
frequency of out-of-season O3 NAAQS exceedances as well
as occurrences of the Moderate air quality index level. Any
deviations based on the Regional Administrator's waiver of
requirements must be described in the annual monitoring network plan
and updated in AQS. Changes to the O3 monitoring season
requirements in Table D-3 moot any previously approved Regional
Administrator waivers for affected States. O3 monitors at
NCore stations are required to be operated on a year-round basis,
i.e., January to December. Information on how to analyze
O3 data to support a change to the O3 season
in support of the 8-hour standard for a specific State can be found
in reference 8 to this appendix.

Table D-3 to Appendix D of Part 58--Ozone Monitoring Season by State \1\
------------------------------------------------------------------------
              State                   Begin month          End month
------------------------------------------------------------------------
Alabama.........................  March.............  October.
Alaska..........................  April.............  October.
Arizona.........................  January...........  December.
Arkansas........................  March.............  November.
California......................  January...........  December.
Colorado........................  March.............  September.
Connecticut.....................  March.............  October.
Delaware........................  March.............  October.
District of Columbia............  March.............  October.
Florida.........................  January...........  December.
Georgia.........................  February..........  October.
Hawaii..........................  January...........  December.
Idaho...........................  April.............  September.
Illinois........................  April.............  October.
Indiana.........................  March.............  October.
Iowa............................  April.............  October.
Kansas..........................  April.............  October.
Kentucky........................  March.............  October.

Louisiana AQCR 019,022..........  March.............  November.
Louisiana AQCR 106..............  January...........  December.
Maine...........................  April.............  September.
Maryland........................  March.............  October.
Massachusetts...................  March.............  September.
Michigan........................  April.............  September.
Minnesota.......................  April.............  September.
Mississippi.....................  January...........  December.
Missouri........................  March.............  October.
Montana.........................  May...............  September.
Nebraska........................  April.............  October.
Nevada..........................  January...........  December.
New Hampshire...................  March.............  September.
New Jersey......................  March.............  October.
New Mexico......................  January...........  December.
New York........................  March.............  October.
North Carolina..................  March.............  October.
North Dakota....................  April.............  September.
Ohio............................  April.............  October.
Oklahoma........................  March.............  November.
Oregon..........................  May...............  September.
Pennsylvania....................  March.............  October.
Puerto Rico.....................  January...........  December.
Rhode Island....................  April.............  September.
South Carolina..................  February..........  October.
South Dakota....................  April.............  September.
Tennessee.......................  February..........  October.
Texas...........................  January...........  December.
Utah............................  April.............  October.
Vermont.........................  March.............  September.
Virginia........................  March.............  October.
Washington......................  March.............  September.
West Virginia...................  April.............  October.
Wisconsin.......................  April.............  October.
Wyoming.........................  January...........  December.
American Samoa..................  January...........  December.
Guam............................  January...........  December.
Virgin Islands..................  January...........  December.
------------------------------------------------------------------------
\1\ The required O3 monitoring season for NCore stations is January
  through December.

    4.1.2 Non-urban Requirements. (a) Each State shall install and
operate at least three O3 sites to monitor concentrations in
non-urban areas. Three non-urban sites cannot fully characterize
O3 levels across most States; however, in many cases these
sites can provide important representative characterization of
O3 not addressed by O3 sites in or immediately
downwind of urban areas. The total number of non-urban O3
sites necessary for any one State may be more than are required in this
section, especially for those States that have multiple ecosystems or
wilderness areas with O3-sensitive natural vegetation and/or
significantly large distances between multiple Micropolitan Statistical
Areas. These non-urban O3 monitoring sites are in addition
to the required sites used to satisfy requirements listed in Table D-2
of this appendix and their operation will be determined through
negotiations between the EPA Regional Administrator and the responsible
State or local air monitoring agency. Non-urban O3 sites
must be operated during the O3 season as designated in Table
D-3 of this appendix unless deviations have been approved by the EPA
Regional Administrator.
    (b) For sites chosen to meet non-urban monitoring requirements,
each of the following objectives must be met.
    (1) To provide characterization of O3 exposures to
O3-sensitive vegetation and important ecosystems, at least
one monitoring site is to be located in an area such as those set aside
to conserve the scenic value and the natural vegetation and wildlife
within such areas. These areas may include Federal, State, or Tribal
and/or public interest lands that are subject to elevated O3
concentrations compared with the rest of the State and are
characterized by areas of O3-sensitive natural vegetation
species subject to visible foliar injury, seedling and biomass loss,
and other adverse impacts to a degree that could be considered adverse.
    (2) To provide O3 characterization of less-populated
areas, at least one monitoring site is to be located to represent a
Micropolitan Statistical Area expected to have a maximum O3
design value concentration of at least 85 percent of the NAAQS.
Micropolitan Statistical Areas have at least one urban cluster of at
least 10,000 but less than 50,000 population. Monitors meeting this
requirement can be discontinued, with Regional Administrator approval,
after demonstrating a design value of less than 85 percent of the
NAAQS.
    (3) To provide O3 characterization in non-urban areas
impacted by transport, at least one monitoring site is to be located in
the area of expected maximum O3 concentration outside of
currently monitored MSAs, Micropolitan Statistical Areas, and sensitive
ecosystems. This type of site could potentially include upwind
transport areas or rural locations that are farther downwind from
existing maximum concentration O3 sites intended to
represent an urban area.
    (c) States are encouraged to utilize resources and analyses such as

photochemical modeling, spatial interpolation of ambient data from
existing O3 monitors, or other quantitative assessment tools
to determine the areas where there are projected maximum non-urban
O3 concentrations, and where these regions with elevated
O3 might overlap O3-sensitive ecosystems, and
other important wilderness areas and Micropolitan Statistical Areas.
Federal Land Managers, State, local, or Tribal ecosystem assessment
experts, or academic researchers who are familiar with the patterns of
vegetation damage and distribution of O3 sensitive species
in their areas should also be consulted. A State may propose
establishing or moving a site as part of their annual monitoring
network plan due each year as provided in Sec.  58.10; however, such
quantitative assessments to determine the required non-urban
O3 monitors shall be updated as part of the assessment of
their air quality surveillance system due to the EPA Regional
Administrator every 5 years as required by Sec.  58.10.
    (d) In some cases, non-urban O3 monitors may already be
operating by monitoring organizations (e.g., the National Park Service)
other than the responsible State or local agency. State or local
agencies may utilize such O3 monitors for one or more of the
required non-urban monitors under the following provisions:
    (1) The O3 monitor in use by another monitoring
organization meets the quality assurance, method requirements, and
probe and siting criteria as provided for in Appendices A, C, and E of
this part, including any applicable approved waivers according to the
conditions of each applicable appendix.
    (2) The O3 monitor is included in the applicable State
or local agency annual monitoring network plan as provided for Sec.
58.10.
    (3) Data are included in the Annual Air Monitoring Data
Certification as provided for in Sec.  58.15.
    (4) Data are submitted according to the requirements of Sec.
58.16.
    (5) Data are made available to the State or local agency in a
timely manner for reports of the air quality index according to the
requirements of Sec.  58.50 and to support other real-time data
objectives such as national air quality mapping or forecasting.
    (6) If for any reason the O3 monitor is shut down, the
applicable State or local agency must address how it proposes to meet
the loss of data in the next required annual monitoring network plan as
provided for in Sec.  58.10.
    (e) States may choose to seek from the EPA Regional Administrator a
deviation from non-urban requirements that either modify or waive these
requirements, for example, in a small, relatively urbanized State, in
situations where a State believes that one of the required non-urban
monitors can meet more than one objective, or where a State can
demonstrate that no Micropolitan Statistical Area will experience
design value concentrations of at least 85 percent of the NAAQS. When
seeking approval of such deviations, the State must provide relevant
information specific to the basis for which the waiver is sought. Any
deviations based on the Regional Administrator's waiver of requirements
must be described in the annual monitoring network plan.
* * * * *
[FR Doc. E9-16802 Filed 7-15-09; 8:45 am]

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