Document ID: EPA-HQ-OAR-2006-0735-6592
Agency: epa
Document Type: Rule
Title: Revisions to Lead Ambient Air Monitoring Requirements
Posted Date: 2010-12-27T05:00Z

[Federal Register Volume 75, Number 247 (Monday, December 27, 2010)]
[Rules and Regulations]
[Pages 81126-81138]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-32153]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 58

[EPA-HQ-OAR-2006-0735; FRL-9241-8]
RIN 2060-AP77

Revisions to Lead Ambient Air Monitoring Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The EPA issued a final rule on November 12, 2008, (effective 
date January 12, 2009) that revised the primary and secondary National 
Ambient Air Quality Standards (NAAQS) for lead and associated 
monitoring requirements. On December 30, 2009, EPA proposed revisions 
to the lead monitoring requirements. This action promulgates revisions 
to the monitoring requirements pertaining to where State and local 
monitoring agencies (``monitoring agencies'') would be required to 
conduct lead monitoring.

DATES: This final rule is effective on January 26, 2011.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OAR-2006-0735. All documents in the docket are listed on the 
http://www.regulations.gov Web site. Although listed in the index, some 
information is not publicly available, e.g., Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the Internet and will be publicly available only in hard 
copy form. Publicly available docket materials are available either 
electronically through http://www.regulations.gov or in hard copy at 
the Revisions to Lead Ambient Air Monitoring Requirements Docket, 
Docket ID No. EPA-OAR-2006-0735, EPA Docket Center, EPA/DC, EPA West, 
Room 3334, 1301 Constitution Ave., NW., Washington, DC. This Docket 
Facility is open from 8:30 a.m. to 4:30 p.m. Monday through Friday 
excluding legal holidays. The docket telephone number is (202) 566-
1742. 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 (202) 566-1744.

FOR FURTHER INFORMATION CONTACT: Mr. Kevin Cavender, Air Quality 
Assessment Division, Office of Air Quality Planning and Standards 
(C304-06), Environmental Protection Agency, Research Triangle Park, 
North Carolina 27711; telephone number (919) 541-2364; fax number (919) 
541-1903; e-mail address: cavender.kevin@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Does this action apply to me?
II. Where can I obtain a copy of this action?
III. Background
IV. Source-Oriented Monitoring Requirements
    A. What We Proposed for Source-Oriented Monitoring
    B. Comments Received on Source-Oriented Monitoring
    C. Final Decision on Source-Oriented Monitoring
V. Monitoring at Airport Facilities
    A. What We Proposed for Airport Monitoring
    B. Comments Received on Monitoring at Airports
    C. Final Decision on Airport Monitoring
VI. Non-Source-Oriented Monitoring Requirements
    A. What We Proposed for Non-Source-Oriented Monitoring
    B. Comments on Non-Source-Oriented Monitoring
    C. Final Decision on Non-Source-Oriented Monitoring
VII. Monitor Deployment Schedule
    A. What We Proposed for Monitor Deployment Schedule
    B. Comments on Monitor Deployment Schedule
    C. Final Decision on Monitoring Deployment Schedule
VIII. References
IX. Judicial Review
X. 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

[[Page 81127]]

    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
    K. Congressional Review Act

I. Does this action apply to me?

    This action applies to State, territorial, and local air quality 
management programs that are responsible for ambient air monitoring 
under 40 CFR part 58. This action may also affect tribes that conduct 
ambient air monitoring similar to that conducted by States and that 
wish EPA to use their monitoring data in the same manner as State 
monitoring data.
    Categories and entities potentially regulated by this action 
include:

------------------------------------------------------------------------
                                                              NAICS code
                          Category                                \a\
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State/territorial/local/tribal government...................     924110
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\a\ North American Industry Classification System.

II. Where can I obtain a copy of this action?

    In addition to being available in the docket, an electronic copy of 
this rule will also be available on the Worldwide Web through the 
Technology Transfer Network (TTN). Following the Administrator's 
signature, a copy of the final 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 
exchange in various areas of air pollution control.

III. Background

    The EPA issued a final rule on November 12, 2008, that revised the 
NAAQS for lead and associated ambient air lead monitoring requirements 
(73 FR 66964, codified at 40 CFR part 58). As part of the lead 
monitoring requirements, monitoring agencies are required to monitor 
ambient air near lead sources which are expected to or have been shown 
to have a potential to contribute to a 3-month average lead 
concentration in ambient air in excess of the level of the NAAQS. At a 
minimum, the 2008 rule required monitoring agencies to monitor near 
lead sources that emit 1.0 ton per year (tpy) or more. However, the 
2008 rule allows this requirement to be waived by the EPA Regional 
Administrator if the monitoring agency can demonstrate that the source 
will not contribute to a 3-month average lead concentration in ambient 
air in excess of 50 percent of the level of the NAAQS (based on 
historical monitoring data, modeling, or other means).
    Monitoring agencies were also required by the 2008 rule to conduct 
lead monitoring in large urban areas (identified as Core Based 
Statistical Areas, or CBSA, as defined by the Office of Management and 
Budget (OMB)) with a population of 500,000 people or more. The 
locations for these monitoring sites are intended to measure 
neighborhood-scale lead concentrations in urban areas impacted by 
resuspended dust from roadways, closed industrial sources which 
previously were significant sources of lead, hazardous waste sites, 
construction and demolition projects, or other fugitive dust sources of 
lead.
    Following promulgation of the revised lead NAAQS and monitoring 
requirements, the Natural Resources Defense Council (NRDC), the 
Missouri Coalition for the Environment Foundation, Physicians for 
Social Responsibility, and Coalition to End Childhood Lead Poisoning 
(``the Petitioners'') petitioned (NRDC, 2009) EPA to reconsider the 
lead emission rate at which monitoring is required (the ``emission 
threshold,'' set at 1.0 tpy by the 2008 rule).\1\ On July 22, 2009, EPA 
granted the petition to reconsider aspects of the monitoring 
requirements (Jackson, 2009). In response to the petition, EPA reviewed 
and reconsidered the monitoring requirements and on December 30, 2009, 
EPA proposed revisions to the requirements for both source-oriented and 
non-source-oriented monitoring for lead (74 FR 69050). We proposed to 
lower the emission threshold at which monitoring would be required (or 
a waiver granted) to 0.50 tpy, to require lead monitoring at NCore 
sites, and remove the existing CBSA-based non-source-oriented 
monitoring requirement. The comment period ended February 16, 2010. 
This action promulgates changes to the lead monitoring requirements 
reflecting our consideration of the comments received on the proposed 
revisions.
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    \1\ The Petitioners also filed a legal challenge to the 
monitoring provisions of the final lead NAAQS rule. See Missouri 
Coalition for the Environment, et al. v. EPA, (DC Cir. No. 09-1009). 
That litigation has been held in abeyance pending completion of 
EPA's reconsideration.
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IV. Source-Oriented Monitoring Requirements

    We are finalizing revisions to the source-oriented monitoring 
requirements. Specifically, we are lowering the emission threshold from 
1.0 tpy to 0.50 tpy for industrial sources of lead (e.g., lead smelters 
and foundries). However, as discussed more thoroughly in Section V, we 
are maintaining the emission threshold for airports at 1.0 tpy, and 
implementing an airport monitoring study to determine the need for 
monitoring of airports which emit less than 1.0 tpy of lead. The 
following paragraphs discuss what we proposed, the comments we 
received, and our rationale for our final decisions regarding the 
emission thresholds in response to the petition for reconsideration.

A. What We Proposed for Source-Oriented Monitoring

    An emission threshold is used to identify lead emission sources 
which should be monitored because their emissions may cause or 
contribute to ambient lead concentrations that exceed the lead NAAQS. 
Monitoring agencies are required to conduct source-oriented lead 
monitoring (unless a waiver is granted as allowed by 40 CFR part 58 
Appendix D, paragraph 4.5(a)(ii)) to measure the maximum lead 
concentration in ambient air resulting from each lead source which 
emits lead at a rate equal to or more than the emission threshold. The 
emission threshold for the revised NAAQS was first set at 1.0 tpy as 
part of the October 2008 lead NAAQS revisions (73 FR 66964, codified at 
40 CFR part 58). On December 30, 2009, we proposed to lower the 
emission threshold from 1.0 tpy to 0.50 tpy (74 FR 69050).
    We based our proposed revision on a review of the analyses 
conducted to identify an appropriate emission threshold at the time of 
final NAAQS revision. The analyses and our review are documented in the 
preamble to the proposed monitoring revisions (74 FR 69052). 
Specifically, we re-evaluated one of the analyses that EPA believed 
provided the best information on the potential impact of lead sources 
on ambient lead concentrations. This analysis used source-monitor pairs 
to estimate the lowest emission rate at which an industrial facility 
could exceed the lead NAAQS (Cavender 2008). In this analysis, source-
oriented lead monitors within one mile of a lead source (identified 
from the 2002 National Emissions Inventory (NEI)) were identified. This 
group of sites was then narrowed down to sites near facilities emitting 
1 tpy or more of lead into the ambient air, and then to sites which 
were only impacted by one lead emitting facility. Also, in cases where 
more than one monitor was identified within one mile of the same 
facility

[[Page 81128]]

emitting 1 tpy or more of lead annually, EPA only used the monitor 
measuring the maximum lead concentration in the analysis. In this 
manner, EPA identified seven monitor-facility pairs meeting the 
emissions and distance criteria. Using data in the Air Quality System 
(AQS) database (http://www.epa.gov/ttn/airs/airsaqs/) for the years 
2001-2003, EPA developed an estimate of the maximum 3-month average 
lead concentration for each monitoring site.\2\ Next, EPA calculated a 
ratio of the maximum 3-month average concentration to the facility 
annual emissions (as identified in the 2002 NEI) to provide an estimate 
of the impact from the facility in units of micrograms per meter cubed 
([micro]g/m \3\) per tpy. Dividing the level of the lead NAAQS (0.15 
[micro]g/m \3\) by this ratio provides an estimate of the annual 
emissions level for the facility which would result in ambient lead 
concentrations just meeting the lead NAAQS, referred to here as a 
``site-specific emission threshold'' (see Table 1).
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    \2\ The estimate of the maximum 3-month average lead 
concentration for this analysis was completed prior to promulgation 
of the final data handling rules contained in 40 CFR Part 50 
Appendix R. As such, minor differences in the estimated maximum 3-
month average lead concentration appear in the estimates presented 
below for the same time period.

                    Table 1--Data Used To Estimate Facility Impacts Based on Monitoring Data
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                                                    Maximum 3-
                                                   month average     NEI 2002                      Site-specific
                   AQS site ID                         lead          facility     Ratio  ([mu]g/     emission
                                                   concentration   emission rate    m \3\-tpy)       threshold
                                                   ([mu]g/m \3\)       (tpy)                           (tpy)
----------------------------------------------------------------------------------------------------------------
011090003.......................................             1.2             4.5            0.27            0.56
171190010.......................................            0.33             1.3            0.25            0.59
290990013.......................................             1.8            58.8            0.03            4.90
340231003.......................................            0.23             1.7            0.14            1.11
420110717.......................................            0.24             4.8            0.05            3.00
471870100.......................................            0.93             2.6            0.36            0.42
480850009.......................................            0.75             3.2            0.23            0.64
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    This analysis shows that four of these seven lead sources support 
an emission threshold less than the emission threshold of 1.0 tpy set 
by the final rule on the revised lead NAAQS.
    As part of the reconsideration, EPA evaluated the stability and 
sensitivity of the above analysis. To evaluate the stability of the 
site-specific emission threshold calculation, EPA performed the same 
analysis for these same seven facilities based on the emission 
estimates from the 2002 and 2005 NEI (Table 2) and estimated design 
values (i.e., 3-month rolling average Pb concentration as determined by 
40 CFR part 50 Appendix R) over the periods 2001-2003 and 2004-2006 
(Table 3). Table 4 summarizes the site-specific emission thresholds 
calculated for these periods.

                                         Table 2--NEI Emission Estimates
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                                                                                          2002 NEI     2005 NEI
                                                                                          facility     facility
          AQS site ID                    NEI facility ID              Facility name       emission     emission
                                                                                         rate (tpy)   rate (tpy)
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011090003......................  NEI18383.......................  Sanders Lead Co.....          4.5         4.44
171190010......................  NEI55848.......................  National Steel Corp--         1.3         0.90
                                                                   Granite City Div.
290990013......................  NEI34412.......................  Doe Run Company,             58.8        28.09
                                                                   Herculaneum Smelter.
340231003......................  NEINJ16031.....................  Johnson Controls              1.7         1.34
                                                                   Battery Group Inc.
420110717......................  NEI117.........................  East Penn Mfg.......          4.8         1.88
471870100......................  NEI715.........................  Metalico-College              2.6         2.55
                                                                   Grove, Inc.
480850009......................  NEI6493........................  GNB Metals Div......          3.2         3.18
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       Table 3--Estimated Design Values Based on Alternative Years
------------------------------------------------------------------------
                                                 2001-2003    2004-2006
                                                   design       design
                  AQS site ID                      value        value
                                                  ([mu]g/m     ([mu]g/m
                                                    \3\)         \3\)
------------------------------------------------------------------------
011090003.....................................          1.2         1.16
171190010.....................................         0.33         0.43
290990013.....................................          1.8         1.44
340231003.....................................         0.23         0.32
420110717.....................................         0.24         0.20
471870100.....................................         0.93        --\4\
480850009.....................................         0.75         0.77
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      Table 4--Estimated Site-Specific Emission Thresholds Based on
                            Alternative Years
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                                                 Site-specific emission
                                                        threshold
                  AQS site ID                  -------------------------
                                                    2002         2005
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011090003.....................................         0.56         0.57
171190010.....................................         0.59         0.32
290990013.....................................         4.90         2.93
340231003.....................................         1.11         0.63
420110717.....................................         3.00         1.41
471870100.....................................         0.42        --\4\
480850009.....................................         0.64         0.62
Minimum.......................................         0.42         0.32
Median........................................         0.64         0.62
Maximum.......................................         4.90         2.93
------------------------------------------------------------------------

    Table 4 shows that, in most cases, the calculated emission 
threshold remained

[[Page 81129]]

fairly constant for a given facility over time, in general, varying by 
a factor of 2 or less. Site-specific emission thresholds varied from 
0.32 tpy to 4.9 tpy with a median of 0.63 tpy.
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    \3\ EPA notes that, for facilities where emissions have 
dramatically decreased in recent years, re-entrained lead from 
historical deposits may influence the emission threshold calculation 
to a greater extent than for facilities where lead emissions have 
remained constant.
    \4\ Monitoring data at this site did not meet the minimum 
completeness requirements of 40 CFR part 50 Appendix R for this time 
period. No design value or site-specific emission factor was 
calculated for this time period.
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    EPA noted that these metrics may be exaggerated by outliers due to 
the limited number of facilities being evaluated. As such, EPA looked 
at how these metrics changed when the extreme sites (i.e., the highest 
and lowest emitting sources) were removed. Excluding site 290990013 
resulted in a lowering of the upper range to 3 tpy and the median to 
0.62 tpy but did not affect the minimum (0.32 tpy). Excluding site 
171190010 increased the minimum to 0.42 and the median to 0.64 tpy but 
did not affect the maximum.
    In our discussion of the review, we noted that four of the seven 
lead sources used to determine an emission threshold support an 
emission threshold less than 1.0 tpy. Based on our review, we concluded 
that lead sources emitting less than 1.0 tpy of lead could cause or 
contribute to an exceedence of the lead NAAQS, and, as such, we 
proposed to lower the emission threshold to 0.50 tpy for all sources of 
lead. We requested comment on setting the emission threshold at a level 
above or below 0.50 tpy.

B. Comments Received on Source-Oriented Monitoring

    We received 616 comments on our proposal to lower the emission 
threshold for all lead sources to 0.50 tpy. Of these comments, 601 were 
in favor of the proposed change to the emission threshold, four 
commenters supported maintaining the current 1.0 tpy emission 
threshold, and three commenters suggested emission thresholds below 
0.50 tpy. The following paragraphs summarize the significant comments 
received and our responses to these comments.
    The NRDC, on behalf of 20 additional organizations and two 
individuals,\5\ supported our proposed revision of the emission 
threshold to 0.50 tpy, stating, ``The latest and best available 
scientific evidence supports the adoption of a near-source monitoring 
threshold of 0.50 tons per year of lead to protect public health with 
an adequate margin of safety. The available evidence demonstrates that 
facilities emitting 0.5 tons per year of lead or more have the 
potential to contribute to a violation of the NAAQS.'' NRDC also 
states, ``monitoring downwind of facilities that emit between 0.5 and 1 
tons per year of lead is necessary to provide sufficient information 
about airborne lead levels near these facilities in order to adequately 
enforce the NAAQS and to protect health with an adequate margin of 
safety.''
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    \5\ NRDC's comments were submitted on behalf of the National 
Resources Defense Council, the Missouri Coalition for the 
Environment, Physicians for Social Responsibility, the Coalition to 
End Childhood Lead Poisoning, American Bottom Conservancy, American 
Lung Association, Center on Race, Poverty & the Environment, 
Citizens Against Ruining the Environment, Clean Air Council, East 
Michigan Environmental Action Council, Learning Disabilities 
Association of America, New York City Environmental Justice 
Alliance, The Point, Public Interest Law Center of Philadelphia's 
Public Health and Environmental Justice Project, Respiratory Health 
Association of Metropolitan Chicago, Science and Environmental 
Health Network, Trust for Lead Poisoning Prevention, UPROSE, Utah 
Physicians for a Healthy Environment, Leslie and Jack Warden, WEACT 
for Environmental Justice and the Wasatch Clean Air Coalition.
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    The National Association of Clean Air Agencies (NACAA) agreed there 
is evidence that high levels of lead exposure can occur near sources 
(other than airports) emitting 0.50 tpy of lead and supported the 
proposal to lower the source-oriented emissions threshold to 0.50 tpy, 
stating that lowering the threshold will help regulatory agencies 
gather the data necessary for fully implementing the lead NAAQS. 
Northeast States for Coordinated Air Use Management (NESCAUM) agreed 
with the proposal to change the emission threshold from 1.0 to 0.50 tpy 
at lead sources (other than airports). Other monitoring agencies that 
supported the change to an emission threshold of 0.50 tpy for 
industrial sources include the states of Maine, Illinois, and 
Wisconsin. In addition, several hundred comments supporting the change 
to a 0.50 tpy emission threshold were received from individuals as part 
of two mass comment campaigns.
    The Doe Run Company offered two comments regarding the analysis 
used to identify the emission threshold. In its first comment, Doe Run 
questioned the use of the median of the site-specific emission 
thresholds rather than the arithmetic average of the individual site-
specific emission thresholds. In response, we chose to use the median 
rather than the arithmetic average because the median is more 
representative of the central tendency of the site-specific emission 
thresholds. Outliers (values much higher or lower than the rest of the 
data set) can dramatically impact the arithmetic average, whereas the 
median is less affected by outliers. As can be seen in Table 1 above, 
the site-specific emission threshold calculated for site 290990013 is 
much higher than the rest of the site-specific emission thresholds, 
appears to be an outlier, and, as such, skews the average to a level 
much higher than the median (i.e., central tendency) of the data. As 
can be seen, five of the seven site-specific emission threshold 
estimates (71 percent) are less than the average. Since the emission 
threshold is intended to represent an estimate of the lowest lead 
emission rate that under reasonable worst-case conditions (e.g., 
meteorological and emission release conditions that lead to poor 
dispersion and high lead concentrations) could result in lead 
concentrations exceeding the NAAQS (Cavender, 2008), setting the 
emission threshold at a level that is higher than the site-specific 
emission thresholds for 71 percent of the sites evaluated is 
inappropriate. As such, we believe it is appropriate to use the median 
of this data set rather than the arithmetic mean to determine the 
emission threshold.
    Doe Run also questioned why we limited the sites selected for the 
analysis to sources that were estimated to emit 1 tpy or more of lead. 
In response, we elected to only evaluate monitor-source pairs where the 
source was estimated to emit 1 tpy or more to better focus the analysis 
on those monitor-source pairs where the lead source was the primary 
contributor to the ambient lead concentrations. Based on our earlier 
review of the existing ambient lead measurements, we determined that 
even in areas where there is no current industrial source of lead, 
ambient lead concentrations were typically in the range of 0.02 to 0.03 
[mu]g/m\3\ (USEPA, 2007). This ``urban background'' level of lead can 
impact the calculated site-specific emission thresholds, and has a 
higher impact as the source emissions (and consequently ambient lead 
concentrations) decrease. Therefore, we elected to limit our analysis 
to monitor-source pairs where the source was estimated to emit 1 tpy or 
more to minimize the impact on the emission threshold calculation from 
the ambient lead concentration impacts that were not due to the 
source's lead emissions. As can be seen in Table 1 above, the lead 
concentrations around the source-monitor pairs used were considerably 
higher than background, ranging from 0.23 to 1.8 [mu]g/m\3\ on a 3-
month rolling average, and as such, by limiting the analysis to sources 
with emissions greater than 1 tpy, background Pb concentrations had a 
small impact on the emission threshold calculation.

C. Final Decision on Source-Oriented Monitoring

    Our review of the emission threshold analyses reflects a greater 
certainty that an emission source (other than airports which is 
discussed separately below) emitting 0.50 tpy or greater may cause

[[Page 81130]]

ambient lead concentrations to approach or exceed the lead NAAQS. We 
believe it is necessary to lower the emission threshold for industrial 
sources to 0.50 tpy to better identify areas where the lead NAAQS may 
be exceeded. Therefore, we are revising the emission threshold for 
industrial sources to 0.50 tpy. Based on the 2005 NEI, 96 industrial 
facilities are estimated to emit 0.50 tpy or more.\6\ Monitoring 
agencies will be required to install and operate lead monitors at these 
sources, demonstrate actual emissions are less than 0.50 tpy based on 
the more current emissions or improved emission estimates, or request a 
waiver if they can demonstrate that the impact for the source will not 
contribute to ambient lead concentrations in excess of 50 percent of 
the lead NAAQS (as allowed for under 40 CFR part 58 appendix D, 
paragraph 4.5(a)(ii)).
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    \6\ Note the 2008 NEI will be available before monitoring 
agencies will be required to develop their revised lead monitoring 
plans.
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V. Monitoring at Airport Facilities

    We are maintaining a lead emission threshold for airports of 1.0 
tpy, and are requiring a monitoring study at 15 airports with lead 
emission inventories of 0.50 to 1.0 tpy that we have identified as 
having characteristics that may cause or contribute to ambient lead 
concentrations that approach or exceed the lead NAAQS. This section 
summarizes what we proposed, the comments we received and our response 
to these comments, and our final decision and rationale.

A. What We Proposed for Airport Monitoring

    We proposed to lower the emission threshold for airport monitoring 
from 1.0 tpy to 0.50 tpy. We explained that we had limited information 
on the ambient lead impact from airports. We identified one study 
conducted near the Santa Monica airport which measured a maximum 3-
month average lead concentration of 0.1 [mu]g/m\3\ near the runway 
blast fence (Cavender, 2009a). Based on the 2002 lead emission estimate 
for the Santa Monica airport of 0.4 tpy (USEPA, 2008), an estimated 
site-specific emission threshold of 0.6 tpy was calculated using the 
same procedures used to estimate a site-specific emission threshold for 
industrial sources [i.e., 0.15 [mu]g/m\3\/(0.1 [mu]g/m\3\/0.4 tpy) = 
0.6 tpy]. We noted that this site-specific emission threshold (0.6 tpy) 
falls within the lower end of the range of specific emission thresholds 
calculated for industrial sources above (0.32 to 4.9 tpy) and did not 
support the case for different treatment of airports. As such, we 
proposed to require monitoring at airports that had an estimated 
emission rate of 0.50 or more tpy (or request a monitoring waiver as 
allowed under 40 CFR part 58, Appendix D, paragraph 4.5(a)(ii)).
    We also requested information on additional data that could be used 
in setting a different emission threshold for airports, and comments on 
whether we should consider other factors or criteria that might be 
useful in determining whether a different approach is appropriate for 
identifying those airports that have the potential to cause or 
contribute to ambient lead concentrations approaching or exceeding the 
lead NAAQS. We provided one example of an alternative where we could 
require monitoring at airports that EPA determines have the potential 
to cause or contribute to increased ambient lead concentrations 
approaching or exceeding the NAAQS based on criteria including the 
estimated lead emissions and other factors such as the number of 
runways where piston-engine aircraft operate.

B. Comments Received on Monitoring at Airports

    We received 16 comments on our proposal to lower the emission 
threshold for airport monitoring to 0.50 tpy. Of these, two commenters 
(on behalf of 21 organizations and three individuals) supported the 
proposed lowering of the emission threshold, and nine did not support 
the change. Five additional commenters provided input and advice for 
improving the emission inventories for airports. The following 
paragraphs summarize the significant comments received and our 
responses to these comments.
    NRDC, on behalf of itself, 20 additional organizations and two 
individuals, supported the change to a 0.50 tpy emission threshold for 
airports, stating that the available evidence supports a 0.50 tpy 
monitoring threshold for airports. NRDC also stated that because 
piston-engine powered aircraft continue to be a significant presence at 
general aviation airports, these airports continue to be a source of 
lead emissions with the potential to result in lead concentrations in 
exceedence of the NAAQS, and that there is no evidence to support a 
departure from the monitoring threshold for industrial sources.
    Based on the limited available ambient lead concentration data near 
airports, we agree that lead emissions from some airports have the 
potential to cause or contribute to exceedances of the lead NAAQS, and 
that lead monitoring of airports is necessary to ensure compliance with 
the lead NAAQS. To identify airports that have the greatest potential 
to cause or contribute to increased ambient lead concentrations 
approaching or violating the NAAQS, we are applying a 0.50 tpy emission 
threshold and additional criteria as described further below in the 
discussion of the airport monitoring study.
    A number of States and State organizations commented against the 
use of a 0.50 tpy emission threshold for airports. NACAA urged EPA to 
develop an airport monitoring study of general aviation airports 
emitting more than 1.0 tpy of lead prior to the deployment of a full 
airport monitoring program. NACAA claimed that a study is necessary in 
order to determine sound sampling siting criteria and to evaluate 
whether the 0.50 tpy threshold should be applicable to airports. 
NESCAUM commented that a 0.50 tpy threshold is not appropriate for 
NAAQS monitoring purposes at general aviation airports, arguing that 
the airport study cited in the Federal Register (74 FR 69054) does not 
support the need for lowering the monitoring threshold for general 
aviation airports. NESCAUM claims the study indicates that neither the 
Santa Monica nor the Van Nuys airports showed lead concentrations 
higher than the Los Angeles basin average of 0.018 [mu]g/m\3\ at sites 
beyond the airport property. NESCAUM recommended that the monitoring 
threshold for general aviation airport lead monitoring remain at 1.0 
tpy. NESCAUM noted that based on the draft 2008 NEI, a 1.0 tpy 
threshold would require monitoring at the eight largest general 
aviation airports. NESCAUM suggests that EPA reassess the need for 
additional lead monitoring at smaller general aviation airports in a 
future rulemaking based on information gathered from monitoring of the 
airports that emit 1.0 tpy or more. The State of New York also 
commented that the emission threshold for airports should remain at 1.0 
tpy and that the data obtained from these airports should be used to 
assess the need for additional monitoring at airports. Other States, 
including Florida, Michigan, and North Carolina, suggested that an 
airport monitoring study should be conducted to gain information on the 
potential for airports to exceed the lead NAAQS.
    In response, we agree that there is limited information available 
on which to evaluate the potential for lead emissions from piston-
engine aircraft operations at airports to exceed or contribute to 
exceedances of the lead NAAQS. However, we believe that lead

[[Page 81131]]

emissions from piston-engine aircraft operations at airports may cause 
ambient lead concentrations to exceed the lead NAAQS at some airports 
based on the limited data available on ambient lead concentrations at 
and near airports. We also agree with the commenters that an airport 
monitoring study would provide useful information that could be used to 
determine whether a revision to the 1.0 tpy threshold for monitoring of 
airports would be appropriate.
    A number of States asserted that monitoring should not be required 
at airports because States do not have the authority to require 
controls on aircraft emissions that are not identical to EPA's 
standards, and regulatory authority to reduce or eliminate lead 
emissions from piston-engine aircraft resides with the Federal 
Government. We understand States are preempted by Clean Air Act (CAA) 
section 233 from adopting or attempting to enforce any standard for 
aircraft or aircraft engine emissions that is not identical to an EPA 
standard. However, that does not negate the responsibility to monitor 
sources of criteria pollutants to identify whether exceedences of the 
NAAQS are occurring.
    EPA has made some designations under the 2008 Lead NAAQS and 
anticipates making the remaining initial designations under that 
standard by October 2011. EPA does not anticipate that the additional 
monitors required under this rule would be installed and operating in 
time to provide data for consideration when EPA completes the remaining 
initial designations under the 2008 Lead NAAQS. If EPA receives 
monitoring data exceeding the NAAQS after the date of initial 
designations, EPA may determine whether to undertake a redesignation to 
nonattainment, issue a ``SIP Call'' under section 110(k)(5), or take 
other discretionary steps to ensure that an area attains and maintains 
the NAAQS. EPA recognizes that, if ambient air near an airport was 
found to be exceeding the standard, and EPA were to take such 
discretionary action, there would be limits under federal law as to the 
measures a state could propose to adopt in a state implementation plan. 
EPA may take such limits into consideration in determining what steps 
to take following an exceedance of the standard.
    Separate from this Pb monitoring rule, EPA is responding to a 
petition submitted by Friends of the Earth (FOE) requesting that EPA 
determine whether Pb emissions from aircraft cause or contribute to air 
pollution that may reasonably be anticipated to endanger public health 
or welfare. As part of this work, EPA published in April 2010 an 
Advance Notice of Proposed Rulemaking (ANPR) on Lead Emissions from 
Piston-Engine Aircraft Using Leaded Aviation Gasoline. In this action 
we described and requested comment on the data available for evaluating 
lead emissions, ambient concentrations and potential exposure to lead 
from the use of leaded aviation gasoline (avgas) in piston-engine 
powered aircraft. This ANPR also described considerations regarding 
emission engine standards and requested comment on approaches for 
transitioning the piston-engine fleet to unleaded avgas. The EPA and 
FAA are working with industry to evaluate alternatives to leaded avgas. 
As part of this assessment, EPA and FAA are also considering safety, 
fuel supply, and economic impact issues including effects on small 
business.

C. Final Decision on Airport Monitoring

    We are maintaining the previously promulgated 1.0 tpy monitoring 
threshold for airports, rather than promulgating the proposed lowering 
of the threshold to 0.50 tpy, and are requiring lead monitoring for a 
minimum of one year at 15 additional airports that we have identified 
as having characteristics that could lead to ambient lead 
concentrations approaching or exceeding the lead NAAQS. We are also 
revising the provision regarding the Regional Administrator's (RA) 
authority (40 CFR part 58, Appendix D, paragraph 4.5(c)), which allows 
the RA to require additional lead monitoring at locations where the RA 
suspects the lead NAAQS may be exceeded, to clarify that this RA 
authority also applies to airports. The following paragraphs provide 
our rationale for this approach to monitoring of ambient lead 
concentrations at airports.
    As stated above and in the proposal to this rulemaking, we believe 
that lead emissions may approach or exceed the lead NAAQS at some 
airports based on the limited data available on ambient lead 
concentrations at airports. As such, we believe monitoring of airports 
is necessary. However, in light of the limited available data, and in 
consideration of the comments we have received, we believe that 
monitoring at airports with certain characteristics (as discussed 
below) is appropriate to identify airports with the potential for the 
highest ambient lead concentrations that could approach or exceed the 
lead NAAQS.
    We agree with the comments that a monitoring study should be 
conducted to determine whether a revision to the 1.0 tpy threshold for 
monitoring airports would be appropriate. We do not agree with the 
comments that suggested the study should be limited to airports that 
emit 1.0 tpy or more, as airports emitting 1.0 tpy or more of lead 
often have much larger footprints and multiple runways (characteristics 
that we believe will result in lower ambient lead concentration impacts 
per ton of lead emitted) than many of the airports in the 0.50 tpy to 
1.0 tpy emissions range. These differences would make the information 
gathered at 1.0 tpy airports less applicable to smaller airports. 
Consequently, we are requiring monitoring agencies to conduct 
monitoring at 15 selected airports where the most recent year of 
activity data indicates lead emissions are above 0.50 tpy, but below 
1.0 tpy, for a minimum of one year as part of a monitoring study 
(Hoyer, 2010).\7\ Details of the monitoring study are provided below. 
Table 5 lists the 15 selected airports for this monitoring study.
---------------------------------------------------------------------------

    \7\ Airports selected for the monitoring study must conduct 
ambient lead monitoring for the 12-month period of the study. Unlike 
other source-oriented lead monitors, the waiver provision will not 
apply to the short-term monitors in the airport monitoring study.

             Table 5--Airports Selected for Monitoring Study
------------------------------------------------------------------------
              Airport                       County             State
------------------------------------------------------------------------
Merrill Field.....................  Anchorage............  AK
Pryor Field Regional..............  Limestone............  AL
Palo Alto Airport of Santa Clara    Santa Clara..........  CA
 County.
McClellan-Palomar.................  San Diego............  CA
Reid-Hillview.....................  Santa Clara..........  CA
Gillespie Field...................  San Diego............  CA
San Carlos........................  San Mateo............  CA

[[Page 81132]]

 
Nantucket Memorial................  Nantucket............  MA
Oakland County International......  Oakland..............  MI
Republic..........................  Suffolk..............  NY
Brookhaven........................  Suffolk..............  NY
Stinson Municipal.................  Bexar................  TX
Northwest Regional................  Denton...............  TX
Harvey Field......................  Snohomish............  WA
Auburn Municipal..................  King.................  WA
------------------------------------------------------------------------

    These airports were selected because they have characteristics that 
we believe will result in lead concentrations higher than those at 
other airports with estimated emission rates between 0.50 tpy and 1.0 
tpy. Specifically, in addition to having emissions greater than or 
equal to 0.50 tpy and less than 1.0 tpy (based on current emission 
inventories), these airports have ambient air within 150 meters of the 
location of maximum emissions (e.g., the end of a runway or run-up 
location), and an airport configuration and meteorological scenario 
that leads to a greater frequency of operations from one runway. These 
characteristics were selected because we expect that, collectively, 
they allow us to identify airports with the highest potential to have 
ambient lead concentrations approaching or exceeding the lead NAAQS. A 
cutoff of 0.50 tpy was selected because it was the proposed emission 
threshold, and the higher the emission rate, the higher the ambient 
impact if all other factors are equal. We selected a maximum distance 
to ambient air from the location of maximum emissions of 150 meters 
because the available information indicates that ambient lead 
concentrations drop off quickly with distance, and it is less likely 
that an exceedence of the lead NAAQS will occur at greater distances. 
Finally, airport configuration and meteorology were evaluated because 
the lead impacts will be highest if the take-offs (and therefore lead 
emissions) are conducted at one or two runways. We evaluated every 
airport in the draft 2008 NEI based on these three characteristics and 
identified the 15 airports listed in Table 5 as those airports most 
likely to have the highest ambient lead impacts that could lead to 
ambient lead concentrations in excess of the lead NAAQS.
    As part of the airport monitoring study, monitoring agencies will 
be required to conduct lead monitoring for a period of 12 consecutive 
months. Monitors will be sited at the location of estimated maximum 
lead concentration in ambient air, taking into account logistical 
considerations and the potential for population exposure. To ensure 
that the results of the study will be directly comparable to the lead 
NAAQS, monitoring agencies will be required to monitor using either 
Federal Reference Method (FRM) or Federal Equivalent Method (FEM) Pb-
TSP samplers, and will not be allowed to use Pb-PM10 
samplers for the study. Any monitoring location that measures a rolling 
3-month average that exceeds 50 percent of the NAAQS as determined 
according to 40 CFR part 50, Appendix R during the monitoring study 
will become a required monitor according to 40 CFR part 58 paragraph 
4.5(c). Data collected during the monitoring study will be reported to 
the AQS according to 40 CFR 58.16.
    Data from this monitoring study will be used to assess the need for 
additional lead monitoring at airports. Under EPA's previously 
established monitoring network requirements, required source-oriented 
monitors that read above 50 percent of the NAAQS (0.075 [mu]g/m\3\ on a 
rolling 3-month average) may not be taken down or stop operating (40 
CFR part 58 Appendix D, paragraph 4.5(a)(ii)). The purpose of that 
provision is to ensure monitoring of an area where ambient 
concentrations could be of concern. EPA continues to believe that this 
rationale is also applicable to monitors at airports; therefore, 40 CFR 
part 58 Appendix D, paragraph 4.5(a)(ii) will apply to the results of 
airport monitors that show concentrations higher than 50 percent of the 
NAAQS. Such monitors will remain in operation, affected States will 
include them in annual monitoring network plans, and the monitors will 
become a part of the State and local monitoring network.
    If after a review of the data from the monitoring study we have 
information that indicates additional airports may have the potential 
to cause or contribute to ambient lead concentrations that exceed the 
lead NAAQS, we will consider use of the RA authority to require 
monitoring at additional airports where appropriate. Finally, data from 
this study will be used in future lead NAAQS reviews when considering 
requirements for monitoring at airports.

VI. Non-Source-Oriented Monitoring Requirements

    We are revising the non-source-oriented lead monitoring 
requirements. We are requiring lead monitoring at NCore sites in CBSA 
with a population greater than 500,000 people in lieu of the 
requirement for non-source-oriented monitoring in each CBSA with a 
population of 500,000 people or more. This section summarizes what we 
proposed, the comments we received and our response to these comments, 
and our final decision and rationale for the revisions to the non-
source-oriented monitoring requirement.

A. What We Proposed for Non-Source Oriented Monitoring

    We proposed to replace the existing requirement to have one non-
source-oriented monitor in each CBSA with a population greater than 
500,000 people with the requirement to monitor lead at NCore sites. We 
indicated that the existing requirement was intended to monitor non-
inventoried lead sources such as closed industrial sources, hazardous 
waste sites, and construction and demolition projects. We noted that 
non-inventoried sources would be better addressed under the existing 
source-oriented monitoring requirements, and that the existing RA 
authority could be used to require source-oriented monitoring at 
locations where it was suspected that a non-inventoried source was 
likely to cause an exceedence of the lead NAAQS.
    We discussed the original objectives for non-source-oriented 
monitors (i.e., measuring typical neighborhood-scale lead 
concentrations in urban areas so we can better understand the risk 
posed by lead to the general population and provide information that 
could assist with the determination of nonattainment boundaries) and 
that non-source-oriented sites are important to support the development 
of long-term

[[Page 81133]]

trends at typical concentrations sites. We noted that these objectives 
match those of the multi-pollutant NCore network required under section 
3 of Appendix D to 40 CFR part 58. We also noted that many NCore sites 
will have the low-volume PM10 sampler appropriate for 
conducting Pb-PM10 monitoring, reducing the cost and time 
necessary to implement the non-source-oriented monitoring requirements. 
Due to the many advantages of including lead monitoring at NCore sites 
rather than having separate non-source-oriented monitoring 
requirements, we proposed to revise the existing non-source-oriented 
monitoring requirements (paragraph 4.5(b) of Appendix D to 40 CFR part 
58) to require lead monitoring at all NCore sites in place of the 
current CBSA population-based requirements. Finally, we requested 
comments on whether lead monitoring should be required at all NCore 
sites or only NCore sites in large urban areas (e.g., in CBSA with a 
population greater than 500,000 people).

B. Comments on Non-Source-Oriented Monitoring

    We received 13 comments on our proposal to require lead monitoring 
at NCore sites instead of the existing requirement to have one non-
source-oriented monitor in each CBSA with a population greater than 
500,000 people. Of these, three supported the proposed change to 
require lead monitoring at all NCore sites, six supported changing the 
requirement to require lead monitoring at only urban NCore sites, and 
no comments supported maintaining the existing non-source-oriented 
monitoring requirement. In addition, two commenters requested we 
provide guidance on when the RA authority should be used to require 
monitoring at non-inventoried lead sources. The following paragraphs 
summarize the significant comments received and our responses to these 
comments.
    In their comments, NACAA supported the proposal to conduct non-
source-oriented lead monitoring using the NCore network but recommended 
that EPA require monitoring only at NCore sites located in larger urban 
areas (i.e., CBSA with a population greater than 500,000). NACAA 
indicated that doing so would allow States to use their limited 
resources to focus non-source-oriented monitoring and control 
strategies in the most sensitive areas. NESCAUM commented that the 
proposed inclusion of the rural NCore sites is inconsistent with the 
monitoring goal and would be a waste of State resources. New York 
commented that in many CBSA, the tentatively approved NCore monitoring 
location is probably well suited for non-source-oriented monitoring 
objectives, but that there is no need to monitor lead at the rural 
NCore sites. North Carolina commented that using the NCore sites 
provides efficient use of EPA and State resources and provides data on 
background levels of lead most cost-effectively. Wisconsin supported 
population-oriented sites located at urban NCore locations and 
questioned monitoring at rural NCore sites where concentrations likely 
will be extremely low.
    In their comments, NRDC supported the inclusion of lead at all 
NCore sites stating that it will provide valuable data on multi-
pollutant exposures in cities and towns across the county. However, 
they added that inclusion of lead at NCore sites does not sufficiently 
address all of the original objectives of the non-source-oriented 
monitoring, and that the RA authority is not adequate to ensure that 
non-inventoried sources that have the potential to exceed the NAAQS 
will be monitored without additional guidance to the States. They 
suggested that the source-oriented monitoring requirement should be 
revised to provide additional guidance to States on monitoring non-
inventoried sources that have the potential to exceed the NAAQS. We 
agree that additional guidance is needed on identifying locations that 
have the potential to exceed the lead NAAQS due to re-suspension of 
deposited lead and, as discussed below, are clarifying the language for 
the RA authority provision to include requiring monitoring of re-
entrained dust sources as well as other sources of lead.
    Several commenters suggested we provide for the use of alternative 
sites such as National Air Toxic Trends Sites (NATTS) where measuring 
lead at NCore is either impractical or the alternative site would 
provide more useful information on urban lead concentrations. We note 
that lead measurements taken at NATTS sites would satisfy the 
objectives for non-source-oriented monitoring. Furthermore, we proposed 
to require lead non-source-oriented monitoring at NCore in part due to 
expected efficiencies (i.e., use of the same equipment needed for 
PM10-2.5 mass measurements). We believe that the requested 
flexibility is appropriate for situations where non-NCore sites such as 
NATTS sites can meet the non-source-oriented monitoring objectives at a 
lower cost to monitoring agencies.\8\
---------------------------------------------------------------------------

    \8\ Note that some NATTS sites do not use FRM/FEM methods. If a 
NATTS site is to be used to meet the non-source-oriented monitoring 
requirement, the monitoring agency would be required to switch to an 
FRM/FEM method.
---------------------------------------------------------------------------

    Two commenters noted that the non-source-oriented lead monitoring 
sites will be the only lead monitoring site in many primary quality 
assurance organizations (PQAO). The collocation requirement in Appendix 
A to 40 CFR part 58, paragraph 3.3.4.3, would require these PQAO to 
collocate a second lead monitor at each of the non-source-oriented lead 
monitoring sites, nearly doubling the cost of non-source-oriented lead 
monitoring in these CBSA. Both commenters questioned the need for such 
extensive collocation when lead concentrations are expected to be well 
below the lead NAAQS at the non-source-oriented lead monitoring sites. 
We agree with the commenters that, as currently written, the 
collocation requirement would lead to an unnecessarily high level of 
collocation at the non-source-oriented monitoring sites. We have 
modified the quality assurance requirements to allow the 15 percent 
collocation requirement to be based on the entire NCore network rather 
than on a per PQAO basis which is consistent with the 
PM10-2.5 collocation requirement for NCore sites.

C. Final Decision on Non-Source-Oriented Monitoring

    We are adding the requirement for lead monitoring to the list of 
pollutants to be monitored for NCore sites in CBSA with a population of 
500,000 people or more and revoking the existing requirement for non-
source-oriented monitoring (40 CFR part 58, Appendix D, paragraph 
4.5(b)). Also, we are revoking the existing requirement to conduct lead 
monitoring at 10 NCore sites because it is redundant to the new non-
source-monitoring requirement being promulgated today (40 CFR part 58, 
Appendix D, paragraph 3(c)). This change will improve our ability to 
track changes in typical urban lead concentrations and provide useful 
information on typical urban lead exposures. In addition, we are 
revising the RA authority (40 CFR part 58, Appendix D, paragraph 
4.5(c)) provision to clarify that the RA may require monitoring of re-
entrained lead dust sources which are expected to cause or contribute 
to ambient lead concentrations that may approach or exceed the lead 
NAAQS. Finally, we are revising the 15 percent collocation requirement 
for non-source-oriented lead monitors to be based on the entire NCore 
network rather than based on each PQAO.

[[Page 81134]]

VII. Monitor Deployment Schedule

    We are requiring that monitoring agencies install and begin 
operation of source-oriented monitors near lead sources emitting 0.50 
tpy or more but less than 1.0 tpy, and at the 15 airports identified 
for the airport monitoring study by December 27, 2011. We are requiring 
monitoring agencies to install and begin operation of non-source-
oriented monitors at NCore sites (or approved alternative sites) in 
CBSA with a population of 500,000 people or more by December 27, 2011. 
We are also requiring that monitoring agencies update their annual 
monitoring network plans by July 1, 2011, to incorporate plans for all 
required source-oriented (including airports) and non-source-oriented 
lead monitors. This section summarizes what we proposed, the comments 
we received and our response to these comments, and our final decision 
and rationale for the final monitoring deployment schedule.

A. What We Proposed for Monitor Deployment Schedule

    We proposed that monitoring agencies would have six months from the 
effective date of the final rule to update their annual monitoring 
network plans. The update would incorporate plans for source-oriented 
monitors near lead sources emitting 0.50 tpy or more, but less than 1.0 
tpy. We also proposed to allow one year from the date of the final rule 
for monitoring agencies to install and begin operation of source-
oriented monitors near lead sources emitting 0.50 tpy or more, but less 
than 1.0 tpy. We also requested comment on staggering the monitor 
deployment over two years. Note, we did not propose changes to the 
existing schedules for updating plans (July 1, 2009) and beginning 
operation (January 1, 2010) of source-oriented monitors near lead 
sources emitting 1.0 tpy or more.
    We proposed to require monitoring agencies to commence lead 
sampling at NCore sites when NCore sites are to become operational no 
later than January 1, 2011. Monitoring agencies must have installed and 
begun operation of required NCore sites and monitors (other than lead) 
by January 1, 2011. Many NCore sites will have the necessary 
PM10 sampler needed to conduct Pb-PM10 sampling 
due to the existing requirement to conduct PM10-2.5 
sampling. As such, we proposed to require monitoring agencies to 
commence lead sampling at NCore sites when NCore sites are to become 
operational no later than January 1, 2011.

B. Comments on Monitor Deployment Schedule

    We received several comments on the proposed monitoring deployment 
schedule. Seven commenters supported allowing for a longer deployment 
period. NACAA recommended that States' new source-oriented monitoring 
be deployed over a two year period which would give State and local 
agencies adequate time to adjust their resources and ensure that new 
monitors are properly sited and supported. Iowa commented that any new 
source-oriented monitors required under the provisions of this rule 
should be installed over a two year period, with the first tier of 
source-oriented monitors operational by January 2012, and the second 
tier of monitors by January 2013. Iowa states that this would allow 
States adequate time to refine emissions estimates by use of stack 
tests, to model the refined estimates, and to attempt to locate 
monitoring sites in the ``hot spots'' indentified by the modeling. 
Other monitoring agencies requesting a deployment period longer than 
one year include Texas, New York, Illinois, and Arkansas.
    We recognize the difficulty monitoring agencies will have in 
deploying the newly required monitors. However, as is discussed below, 
we believe it is feasible for monitoring agencies to deploy the 
monitors necessary to comply with this final rule within one year. We 
note that the estimated number of new sites that States will need to 
site and install (or receive waivers for) in this final rule is 111,\9\ 
which is 50 less than the number estimated based on the proposed rule. 
Following the 2008 revision, monitoring agencies were able to install 
approximately 100 new lead sites, and were granted waivers for an 
additional 35 sites. Based on the success and the experience gained 
from the deployment of the monitors to address the 2008 revision, we 
believe requiring up to 111 new sites to be sited and installed within 
one year will not create an excessive burden on monitoring agencies.
---------------------------------------------------------------------------

    \9\ The total number of newly required lead sites is 174. 
However, this number includes 63 NCore sites which have already been 
sited and installed due to the existing requirements for installing 
and operating NCore sites.
---------------------------------------------------------------------------

    One commenter requested that we synchronize the dates of the 
required revision to the lead monitoring plan with the date for the 
existing annual monitoring plan requirement. We recognize the 
efficiency of having the same dates for the revision to the lead 
monitoring plan and required annual monitoring plan. We also note that 
due to the timing of this final rule, the proposed deadline of 6-months 
following the final rule (June 27, 2011) is close to the deadline for 
the required 2011 annual monitoring network plans (July 1, 2011). We 
agree that it is appropriate to use the same date for the two plans due 
to the proximity of the two dates.
    Several commenters noted a discrepancy in the required dates in the 
preamble to the proposed rule and the proposed regulatory language. We 
note that the proposed regulatory language published in the Federal 
Register inadvertently indicated dates for the required plan and 
installation and operation of new monitors based on the date of the 
proposed rule. The preamble correctly indicated that the proposed dates 
would be based on the date the final rule was published.

C. Final Decision on Monitoring Deployment Schedule

    We are requiring that monitoring agencies install and begin 
operation of source-oriented monitors near lead sources emitting 0.50 
tpy or more but less than 1.0 tpy and at the 15 airports identified for 
the airport monitoring study by December 27, 2011, one year from the 
date of publication of this final rule. We estimate that monitoring 
agencies will be required to site and install up to 111 new source-
oriented monitors \10\ based on the final monitoring requirements. This 
number is slightly higher than the 100 monitors that have already been 
installed near sources emitting 1.0 tpy or more. We believe monitoring 
agencies can install the newly required source-oriented-monitoring 
sites within one year of the publication of this final rule especially 
in light of the experience and success achieved by monitoring agencies 
in complying with the previous source-oriented-monitoring requirement.
---------------------------------------------------------------------------

    \10\ The total number of new source oriented sites installed 
will likely be less as this estimate does not account for waivers.
---------------------------------------------------------------------------

    We are requiring monitoring agencies to install and begin operation 
of non-source-oriented monitors at NCore sites in CBSA with a 
population of 500,000 people or more by December 27, 2011. To allow 
monitoring agencies sufficient time to plan for and install any 
necessary equipment, we are allowing monitoring agencies a reasonable 
time, 1 year, from the time of publication of this final rule to comply 
with the non-source-oriented monitoring requirements.
    We are also requiring that monitoring agencies update their annual 
monitoring

[[Page 81135]]

network plans by July 1, 2011, to incorporate plans for all required 
source-oriented (including airports) and non-source-oriented lead 
monitoring. This date is the same as the existing requirement for 
States to submit their 2011 annual monitoring plan as required by 40 
CFR Part 58.10(a)(i).

VIII. References

Cavender, K. (2008). Development of Final Source-oriented Monitoring 
Emission Threshold. Memorandum to the Lead NAAQS Review Docket. EPA-
HQ-OAR-2006-0735. Available online at: http://www.epa.gov/ttnnaaqs/standards/lead/data/20081015Cavender.pdf.
Cavender, K. (2009). Summary of Discussion of Lead Monitoring Near 
Airports at Spring 2009 NACAA Monitoring Subcommittee Meeting. 
Memorandum to the Lead NAAQS Review Docket. EPA-HQ-OAR-2006-0735.
Hoyer, M. (2010). Selection of Airports for Airport Monitoring 
Study. Memorandum to the Lead NAAQS Review Docket. EPA-HQ-OAR-2006-
0735.
Jackson, L. (2009). Letter to petitioners. EPA-HQ-OAR-2006-0735. 
Available online at: http://www.epa.gov/air/lead/pdfs/OAR.09.000.7687.pdf.
NRDC, et al. (2009). Petition to Reconsider. EPA-HQ-OAR-2006-0735. 
Available online at: http://www.epa.gov/air/lead/pdfs/0122009petitionReconsideration.pdf.
U.S. Environmental Protection Agency. (2007) Policy Assessment of 
Scientific and Technical Information: Final Staff Paper. Available 
online at:  http://www.epa.gov/ttnnaaqs/standards/pb/data/20071101_pb_staff.pdf.
U.S. Environmental Protection Agency. (2008) Lead Emissions from the 
Use of Leaded Aviation Gasoline in the United States. EPA420-R-08-
020. Available online at: http://www.epa.gov/ttn/chief/net/tsd_avgas_lead_inventory_2002.pdf.
White, J. (2010). Environmental Justice Analysis for Revisions to 
Lead Monitoring Requirements. Memorandum to the Lead NAAQS Review 
Docket. EPA-HQ-OAR-2006-0735.

IX. Judicial Review

    Under section 307(b)(1) of the CAA, judicial review of this final 
rule is available by filing a petition for review in the U.S. Court of 
Appeals for the District of Columbia Circuit by February 25, 2011. 
Moreover, under section 307(b)(2) of the CAA, the requirements 
established by this action may not be challenged separately in any 
civil or criminal proceedings brought by EPA to enforce these 
requirements.

X. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is a ``significant regulatory action'' because it was deemed to 
``raise novel legal or policy issues.'' Accordingly, EPA submitted this 
action to the Office of Management and Budget (OMB) for review under 
Executive Order 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 rule will be 
submitted for approval to the OMB under the Paperwork Reduction Act, 44 
U.S.C. 3501 et seq. The information collection requirements are not 
enforceable until OMB approves them.
    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 ecosystem impacts, to develop 
emissions control strategies, and to measure progress for the air 
pollution program. The final amendments revise the technical 
requirements for lead monitoring sites, require the siting and 
operation of additional lead ambient air monitors, and the reporting of 
the collected ambient lead monitoring data to EPA's AQS database. We 
have estimated the burden based on the final monitoring requirements of 
this rule. Based on these requirements, the annual average reporting 
burden for the collection under 40 CFR part 58 (averaged over the first 
3 years of this Information Collection Request(ICR)) for 100 
respondents is estimated to increase by a total of 1,726 labor hours 
per year with an increase of $119,172 per year. Burden is defined at 5 
CFR 1320.3(b).
    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. When this ICR is 
approved by OMB, the Agency will publish a technical amendment to 40 
CFR part 9 in the Federal Register to display the OMB control number 
for the approved information collection requirements contained in this 
final rule.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act 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 impacts of this rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administration (SBA) regulations at 13 CFR 
121.21; (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 final rule on small 
entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This final 
rule will not impose any requirements on small entities. Rather, this 
rule establishes monitoring requirements for State and local (where 
applicable) monitoring agencies.

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. 
The amendments to 40 CFR part 58 are estimated to increase the ambient 
air monitoring costs by 22,376 labor hours per year with an increase of 
$1,910,059 per year from present levels. Thus, this rule is not subject 
to the requirements of sections 202 or 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. Small governments 
that may be affected by the amendments are already meeting similar 
requirements under the existing rules, and the costs of changing the 
network design requirements would be borne, in part, by the federal 
government through State assistance grants.

E. Executive Order 13132: Federalism

    This final rule does not have federalism implications. 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. The rule does not alter the 
relationship between the federal government and the States

[[Page 81136]]

regarding the establishment and implementation of air quality 
improvement programs as codified in the CAA. Thus, Executive Order 
13132 does not apply to this 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 solicited comment 
on the 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 adopt or implement any NAAQS. Thus, Executive 
Order 13175 does not apply to this action.

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

    EPA interprets Executive Order 13045 (62 F.R. 19885, April 23, 
1997) as applying only to those regulatory actions that concern health 
or safety risks, such that the analysis required under section 5-501 of 
the Executive Order has the potential to influence the regulation. This 
action is not subject to Executive Order 13045 because it does not 
establish an environmental standard intended to mitigate health or 
safety risks.

H. Executive Order 13211: Actions Concerning Regulations That 
significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy 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. This rule would result in an 
insignificant increase in power consumption associated with the 
additional power required to run 111 additional lead monitors 
nationwide.

I. National Technology Transfer and 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 action does not involve technical standards. Therefore, EPA 
did not consider the use of any voluntary consensus standards.

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.
    This proposed action revises the ambient monitoring requirements 
for measuring airborne lead. As such, the rule does not establish an 
environmental standard. Instead, by lowering the emissions threshold 
from 1.0 tons per year (tpy) to 0.5 tpy used to determine if an air 
quality monitor for lead should be placed near an industrial facility, 
this rule requires assessment of compliance at smaller emissions 
sources, and therefore effectively strengthens the lead monitoring 
requirements and, in turn, may increase the public health protection 
provided by the NAAQS itself. The rule maintains a 1.0 tpy emissions 
threshold for airports and implements an airport monitoring study to 
determine the need for monitoring of airports which emit less than 1.0 
tpy of lead. The rule also replaces the existing non-source-oriented 
monitoring requirement for lead monitoring in large urban areas with a 
requirement that lead be added to the list of pollutants to be 
monitored at NCore sites in CBSA with a population of 500,000 people or 
more. These rule amendments are designed to improve the lead monitoring 
network's capability to better assess compliance with the revised NAAQS 
(73 FR 66964, codified at 40 CFR part 58).
    Pursuant to E.O. 12898 EPA has undertaken to determine the 
aggregate demographic makeup of the communities potentially affected by 
this proposed rule revision. The EPA focused its analysis on 111 
industrial sources of lead (e.g., lead smelters, and foundries) 
impacted by the lowering of the emissions threshold from 1.0 tpy to 0.5 
tpy. The analytical approach, which assumed ``proximity-to-a-source'' 
as a surrogate for determining a population's potential exposure to 
lead emissions from these sources, evaluated several socio-demographic 
parameters and compared them against the respective national averages 
for the same parameters.
    The socio-demographic parameters used in the analysis included 
estimates of the percentage of the population near the sources that 
were White, Minority (i.e., all Non-White), African American, Native 
American, Other/Multiracial, and Hispanic. The study also evaluated the 
percentages of the same populations less than or equal to 18 years of 
age; greater than or equal to 65 years of age; and the total below 
poverty line.
    The analysis determined the composition of those census blocks that 
lay within a circular distance of one mile (or approximately 1.6 
kilometers) of affected sources with respect to the selected socio-
demographic parameters. The study area radius (i.e., 1 mile) was used 
because available data generally indicate that lead emissions from such 
sources are rapidly deposited and ambient lead concentrations decline 
quickly with distance from the emission source.
    The analysis indicated that the aggregate population living within 
a one-mile area around these sources tends to have lower proportions of 
Whites and higher proportions of African-Americans, Hispanics, and 
``Other and Multi-racial'' populations than their respective national 
averages. The Minority (i.e., total Non-White) population in these 
areas is greater than the national average (i.e., 29% versus 25% 
respectively). The Tribal population percentages are similar for both 
those living within the study area and the national average (i.e., both 
< 1%). The percentage of the population of those living below the 
poverty line within the area of study is higher than the national 
average (i.e., 17% versus 13% respectively). However, the percentage of 
the population less than or equal to 18 years of age and the percentage 
age 65 or older are similar for those within the area of study and the 
national average.
    Based on the fact that this proposed rule does not allow emission 
increases, but promulgates revisions to existing monitoring 
requirements that lower the threshold at which monitoring by state and 
local monitoring agencies would be

[[Page 81137]]

required, the EPA has determined that the proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority, low-income, or Tribal populations. Furthermore, to 
the extent that any minority, low-income, or Tribal subpopulation is 
disproportionately impacted by current lead emissions as a result of 
the proximity to lead emissions sources, that group also stands to 
benefit from the improvement in compliance with the lead NAAQS which 
will result from this rule and thereby potentially experience 
associated increases in environmental and health benefits.
    This proposed change is a ``notice and comment rulemaking'' and 
public involvement is encouraged. All monitoring changes at the local 
level will be documented in each state's monitoring plan and are 
available for public review and comment. In addition, EPA defines 
``Environmental Justice'' to include meaningful involvement of all 
people regardless of race, color, national origin, or income with 
respect to the development, implementation, and enforcement of 
environmental laws, regulations, and policies. To promote meaningful 
involvement, EPA has developed a communication and outreach strategy to 
ensure that interested communities have access to this proposed rule, 
are aware of its content, and have an opportunity to comment during the 
comment period. During the comment period, EPA will publicize the 
rulemaking via EJ newsletters, Tribal newsletters, EJ listservs, and 
the internet, including the Office of Policy (OP) Rulemaking Gateway 
Web site (http://yosemite.epa.gov/opei/RuleGate.nsf/). EPA will also 
provide general rulemaking fact sheets (e.g., why is this important for 
my community) for EJ community groups and conduct conference calls with 
interested communities.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). This rule will be effective January 26, 2011.

List of Subjects in 40 CFR Part 58

    Air pollution control, Ambient air monitoring, Environmental 
protection, Intergovernmental relations, Reporting and recordkeeping 
requirements.

    Dated: December 14, 2010.
Lisa P. Jackson,
Administrator.

0
For the reasons stated in the preamble, title 40, chapter I, part 58 of 
the Code of Federal Regulations is amended as follows:

PART 58--[AMENDED]

0
1. The authority citation for part 58 is revised to read as follows:

    Authority:  42 U.S.C. 7403, 7405, 7410, 7414, 7601, 7611, 7614, 
and 7619.

Subpart B--[Amended]

0
2. Section 58.10 is amended by revising paragraph (a)(4) to read as 
follows:

Sec.  58.10  Annual monitoring network plan and periodic network 
assessment.

    (a) * * *
    (4) A plan for establishing source-oriented Pb monitoring sites in 
accordance with the requirements of appendix D to this part for Pb 
sources emitting 1.0 tpy or greater shall be submitted to the EPA 
Regional Administrator no later than July 1, 2009, as part of the 
annual network plan required in paragraph (a)(1) of this section. The 
plan shall provide for the required source-oriented Pb monitoring sites 
for Pb sources emitting 1.0 tpy or greater to be operational by January 
1, 2010. A plan for establishing source-oriented Pb monitoring sites in 
accordance with the requirements of appendix D to this part for Pb 
sources emitting equal to or greater than 0.50 tpy but less than 1.0 
tpy shall be submitted to the EPA Regional Administrator no later than 
July 1, 2011. The plan shall provide for the required source-oriented 
Pb monitoring sites for Pb sources emitting equal to or greater than 
0.50 tpy but less than 1.0 tpy to be operational by December 27, 2011.
* * * * *

0
3. Section 58.13 is amended by revising paragraph (a) to read as 
follows:

Sec.  58.13  Monitoring network completion.

    (a) The network of NCore multipollutant sites must be physically 
established no later than January 1, 2011, and at that time, operating 
under all of the requirements of this part, including the requirements 
of appendices A, C, D, E, and G to this part. NCore sites required to 
conduct Pb monitoring as required under 40 CFR part 58 appendix D 
paragraph 3(b), or approved alternative non-source-oriented Pb 
monitoring sites, shall begin Pb monitoring in accordance with all of 
the requirements of this part, including the requirements of appendices 
A, C, D, E, and G to this part no later than December 27, 2011.
* * * * *

0
4. Appendix A to Part 58 is amended by revising paragraph 3.3.4.3 to 
read as follows:

Appendix A to Part 58--Quality Assurance for SLAMS, SPMs, and PSD Air 
Monitoring

* * * * *
    3.3.4.3 Collocated Sampling. PQAO that have a combination of 
source and non-source-oriented sites (unless the only non-source-
oriented site is an NCore site) will follow the procedures described 
in sections 3.3.1 of this appendix with the exception that the first 
collocated Pb site selected must be the site measuring the highest 
Pb concentrations in the network. If the site is impractical, 
alternative sites, approved by the EPA Regional Administrator, may 
be selected. If additional collocated sites are necessary, 
collocated sites may be chosen that reflect average ambient air Pb 
concentrations in the network. The collocated sampling requirements 
for PQAO that only have Pb monitoring at a non-source-oriented NCore 
site for sampling required under 40 CFR 58, Appendix D, paragraph 
4.5(b) shall be implemented as described in section 3.2.6 of this 
appendix with the exception that the collocated monitor will be the 
same method designation as the primary monitor.
* * * * *

0
5. Appendix D to Part 58 is amended as follows:
0
a. By revising paragraph 3.(b) introductory text,
0
b. By removing and reserving paragraph 3.(c),
0
c. By revising paragraph 4.5.(a),
0
d. By revising paragraph 4.5.(b), and
0
e. By revising paragraph 4.5.(c).

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

* * * * *
    3. * * *
    (b) The NCore sites must measure, at a minimum, PM2.5 
particle mass using continuous and integrated/filter-based samplers, 
speciated PM2.5, PM10-2.5 particle mass, 
speciated PM10-2.5, O3, SO2, CO, 
NO/NOy, wind speed, wind direction, relative humidity, 
and ambient temperature. NCore sites in CBSA with a population of 
500,000 people (as determined in the latest Census)

[[Page 81138]]

or greater shall also measure Pb either as Pb-TSP or Pb-
PM10. The EPA Regional Administrator may approve an 
alternative location for the Pb measurement where the alternative 
location would be more appropriate for logistical reasons and the 
measurement would provide data on typical Pb concentrations in the 
CBSA.
* * * * *
    (c) [Reserved.]
* * * * *
    4.5 * * * (a) State and, where appropriate, local agencies are 
required to conduct ambient air Pb monitoring near Pb sources which 
are expected to or have been shown to contribute to a maximum Pb 
concentration in ambient air in excess of the NAAQS, taking into 
account the logistics and potential for population exposure. At a 
minimum, there must be one source-oriented SLAMS site located to 
measure the maximum Pb concentration in ambient air resulting from 
each non-airport Pb source which emits 0.50 or more tons per year 
and from each airport which emits 1.0 or more tons per year based on 
either the most recent National Emission Inventory (http://www.epa.gov/ttn/chief/eiinformation.html) or other scientifically 
justifiable methods and data (such as improved emissions factors or 
site-specific data) taking into account logistics and the potential 
for population exposure.
    (i) One monitor may be used to meet the requirement in paragraph 
4.5(a) for all sources involved when the location of the maximum Pb 
concentration due to one Pb source is expected to also be impacted 
by Pb emissions from a nearby source (or multiple sources). This 
monitor must be sited, taking into account logistics and the 
potential for population exposure, where the Pb concentration from 
all sources combined is expected to be at its maximum.
    (ii) The Regional Administrator may waive the requirement in 
paragraph 4.5(a) for monitoring near Pb sources if the State or, 
where appropriate, local agency can demonstrate the Pb source will 
not contribute to a maximum Pb concentration in ambient air in 
excess of 50 percent of the NAAQS (based on historical monitoring 
data, modeling, or other means). The waiver must be renewed once 
every 5 years as part of the network assessment required under Sec.  
58.10(d).
    (iii) State and, where appropriate, local agencies are required 
to conduct ambient air Pb monitoring near each of the airports 
listed in Table D-3A for a period of 12 consecutive months 
commencing no later than December 27, 2011. Monitors shall be sited 
to measure the maximum Pb concentration in ambient air, taking into 
account logistics and the potential for population exposure, and 
shall use an approved Pb-TSP Federal Reference Method or Federal 
Equivalent Method. Any monitor that exceeds 50 percent of the Pb 
NAAQS on a rolling 3-month average (as determined according to 40 
CFR part 50, Appendix R) shall become a required monitor under 
paragraph 4.5(c) of this Appendix, and shall continue to monitor for 
Pb unless a waiver is granted allowing it to stop operating as 
allowed by the provisions in paragraph 4.5(a)(ii) of this appendix. 
Data collected shall be submitted to the Air Quality System database 
according to the requirements of 40 CFR part 58.16.

              Table D-3A Airports To Be Monitored for Lead
------------------------------------------------------------------------
              Airport                       County             State
------------------------------------------------------------------------
Merrill Field.....................  Anchorage............  AK
Pryor Field Regional..............  Limestone............  AL
Palo Alto Airport of Santa Clara    Santa Clara..........  CA
 County.
McClellan-Palomar.................  San Diego............  CA
Reid-Hillview.....................  Santa Clara..........  CA
Gillespie Field...................  San Diego............  CA
San Carlos........................  San Mateo............  CA
Nantucket Memorial................  Nantucket............  MA
Oakland County International......  Oakland..............  MI
Republic..........................  Suffolk..............  NY
Brookhaven........................  Suffolk..............  NY
Stinson Municipal.................  Bexar................  TX
Northwest Regional................  Denton...............  TX
Harvey Field......................  Snohomish............  WA
Auburn Municipal..................  King.................  WA
------------------------------------------------------------------------

     (b) State and, where appropriate, local agencies are required 
to conduct non-source-oriented Pb monitoring at each NCore site 
required under paragraph 3 of this appendix in a CBSA with a 
population of 500,000 or more.
    (c) The EPA Regional Administrator may require additional 
monitoring beyond the minimum monitoring requirements contained in 
paragraphs 4.5(a) and 4.5(b) where the likelihood of Pb air quality 
violations is significant or where the emissions density, 
topography, or population locations are complex and varied. EPA 
Regional Administrators may require additional monitoring at 
locations including, but not limited to, those near existing 
additional industrial sources of Pb, recently closed industrial 
sources of Pb, airports where piston-engine aircraft emit Pb, and 
other sources of re-entrained Pb dust.
* * * * *
[FR Doc. 2010-32153 Filed 12-23-10; 8:45 am]
BILLING CODE 6560-50-P