6560-50-P 

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 58

[EPA–HQ–OAR–2006–0735; FRL-] 

RIN 2060-AP77 

Revisions to Lead Ambient Air Monitoring Requirements 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Final rule. 

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 [Insert date 30 

days after publication in the Federal Register]. 

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 www.regulations.gov web site. 

Although listed in the index, some information is not 

publicly available, e.g., Confidential Business Information 
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(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 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; email 

address: cavender.kevin@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 
Page 3 of 67

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 

 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 
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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: 

Category NAICS codea

State/territorial/local/tribal government 924110 

aNorth 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 
Page 5 of 67

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 
Page 6 of 67

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 sourceoriented 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 

 

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, (D.C. Cir. No. 09-1009). That 

litigation has been held in abeyance pending completion of EPA's 

reconsideration. 
Page 7 of 67

16, 2010. This action promulgates changes to the lead 

monitoring requirements reflecting our consideration of the 

comments received on the proposed revisions. 

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 
Page 8 of 67

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. 
Page 9 of 67

Also, in cases where more than one monitor was identified 

within one mile of the same facility 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 (μg/m3) per tpy. Dividing the level of the lead NAAQS 

(0.15 μg/m3) 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). 

Table 1. Data Used to Estimate Facility Impacts Based on 

Monitoring Data 

 

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. 
Page 10 of 67

AQS Site 

Id 

Maximum 3-

Month Average 

lead 

Concentration 

(μg/m3) 

NEI 2002 

Facility 

Emission 

Rate 

(tpy) 

Ratio 

(μg/m3-

tpy) 

SiteSpecific 

Emission 

Threshold 

(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 

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 

 2002 NEI 2005 NEI 
Page 11 of 67

AQS Site Id

NEI 

Facility 

ID 

Facility Name

Facility 

Emission 

Rate 

(tpy) 

Facility 

Emission 

Rate 

(tpy) 

011090003 NEI18383 Sanders Lead 

Co 

4.5 4.44 

171190010 NEI55848 National 

Steel Corp - 

Granite City 

Div 

1.3 0.90 

290990013 NEI34412 Doe Run 

Company, 

Herculaneum 

Smelter 

58.8 28.09 

340231003 NEINJ1603

1 

Johnson 

Controls 

Battery Group 

Inc 

1.7 1.34 

420110717 NEI117 East Penn Mfg 4.8 1.88 

471870100 NEI715 MetalicoCollege 

Grove, Inc. 

2.6 2.55 

480850009 NEI6493 GNB Metals 

Div 

3.2 3.18 

Table 3. Estimated Design Values Based on Alternative Years 

AQS Site 

Id 

2001-2003 

Design Value 

(μg/m3) 

2004-2006 

Design Value 

(μg/m3) 

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 

Table 4. Estimated Site-Specific Emission Thresholds Based 

on Alternative Years 

AQS Site 

Id 

Site-Specific 

Emission Threshold 

2002 2005 

011090003 0.56 0.57 

171190010 0.59 0.32 
Page 12 of 67

290990013 4.90 2.933 

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 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. 

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. 

 

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.
Page 13 of 67

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 individuals5, supported our proposed revision of the 

 

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 
Page 14 of 67

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.” 

 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 sourceoriented 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. 

 

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. 
Page 15 of 67

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 sitespecific emission threshold calculated for site 290990013 

is much higher than the rest of the site-specific emission 
Page 16 of 67

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
Page 17 of 67

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 μg/m3 (USEPA, 2007). This “urban 

background” level of lead can impact the calculated sitespecific 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 μg/m3 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 ambient lead concentrations to 
Page 18 of 67

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 more6. 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)). 

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 

 

6 Note the 2008 NEI will be available before monitoring agencies will 

be required to develop their revised lead monitoring plans. 
Page 19 of 67

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 μg/m3 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 μg/m3 /(0.1 μg/m3 / 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)). 
Page 20 of 67

 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 
Page 21 of 67

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. 
Page 22 of 67

 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 μg/m3 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 
Page 23 of 67

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 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.
Page 24 of 67

 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 
Page 25 of 67

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 
Page 26 of 67

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.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 (note, however, that EPA does not currently 

regulate lead emissions from aircraft). We understand 

States are preempted by Clean Air Act (CAA) section 233 

from adopting or attempting to enforce any standard for 

aircraft 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. The data 

collected at airports will assist the States and EPA in 

ensuring that the lead NAAQS are attained and maintained. 

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 
Page 27 of 67

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 
Page 28 of 67

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. 

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 

 

7 Airports selected for the monitoring study must conduct ambient lead 

monitoring for the 12-month period of the study. Unlike other sourceoriented lead monitors, the waiver provision will not apply to the 

short-term monitors in the airport monitoring study. 
Page 29 of 67

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 

 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 
Page 30 of 67

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
Page 31 of 67

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 exceeds 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 part 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 μg/m3 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, 
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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. 
Page 33 of 67

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 noninventoried 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-sourceoriented monitors (i.e., measuring typical neighborhoodscale 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 nonsource-oriented sites are important to support the 

development of long-term trends at typical concentrations 

sites. We noted that these objectives match those of the 

multi-pollutant NCore network required under section 3 of 
Page 34 of 67

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-sourceoriented 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 nonsource-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 populationbased 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 
Page 35 of 67

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 noninventoried 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-
Page 36 of 67

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-sourceoriented 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 noninventoried 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 reentrained 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 
Page 37 of 67

(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-sourceoriented 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

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-sourceoriented lead monitoring in these CBSA. Both commenters 

questioned the need for such extensive collocation when 

 

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. 
Page 38 of 67

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 
Page 39 of 67

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.

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 [insert date 12 months after date of 

publication in the Federal Register]. We are requiring 

monitoring agencies to install and begin operation of nonsource-oriented monitors at NCore sites (or approved 

alternative sites) in CBSA with a population of 500,000 

people or more by [insert date 12 months after date of 

publication in the Federal Register]. 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 nonsource-oriented lead monitors. This section summarizes 
Page 40 of 67

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 
Page 41 of 67

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. 
Page 42 of 67

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 1119, 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. 

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 

 

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. 
Page 43 of 67

the timing of this final rule, the proposed deadline of 6-

months following the final rule ([insert date 6 months 

after date of publication in the Federal Register]) 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 [insert date 12 months after date of publication 

in the Federal Register], one year from the date of 

publication of this final rule. We estimate that 
Page 44 of 67

monitoring agencies will be required to site and install up 

to 111 new source-oriented monitors10 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-orientedmonitoring 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. 

 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 [insert date 12 months after date of publication in the 

Federal Register]. 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 network plans by July 1, 2011, to 

incorporate plans for all required source-oriented 

(including airports) and non-source-oriented lead 

 

10 The total number of new source oriented sites installed will likely 

be less as this estimate does not account for waivers. 
Page 45 of 67

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). 

VII. 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/200810

15Cavender.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-OAR2006-0735. Available online at: 

http://www.epa.gov/air/lead/pdfs/OAR.09.000.7687.pdf

NRDC, et al. (2009). Petition to Reconsider. EPA-HQ-OAR2006-0735. Available online at: 
Page 46 of 67

http://www.epa.gov/air/lead/pdfs/0122009petitionRecons

ideration.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_invent

ory_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 [Insert date 60 days from date of 
Page 47 of 67

publication in the Federal Register]. 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 
Page 48 of 67

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
Page 49 of 67

 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 
Page 50 of 67

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 
Page 51 of 67

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 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 
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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 No. 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 
Page 53 of 67

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 LowIncome 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. 
Page 54 of 67

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 try 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 
Page 55 of 67

lowering the emissions threshold from 1.0 tpy to 0.5 tpy. 

The analytical approach, which assumed “proximity-to-asource” 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 NonWhite), 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. 
Page 56 of 67

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 required, the EPA has determined that the proposed 

rule will not have disproportionately high and adverse 

human health or environmental effects on minority, lowincome, or Tribal populations. Furthermore, to the extent 
Page 57 of 67

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 

polices. 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 
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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 [insert date 30 days after 

publication in the Federal Register]. 
Page 59 of 67

Revisions to Lead Ambient Air Monitoring Requirements

List of Subjects in 40 CFR Part 58 

Air pollution control, Environmental protection, 

Intergovernmental relations, Reporting and recordkeeping 

requirements, Ambient air monitoring. 

______________________ 

Dated: 

______________________ 

Lisa P. Jackson, 

Administrator. 
Page 60 of 67

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] 

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] 

2. Section 58.10 is amended by revising paragraph (a)(4) to 

read as follows: 

§ 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 
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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 [insert date 12 months after 

date of publication in the Federal Register]. 

* * * * * 

3. Section 58.13, is amended by revising paragraph (a) to read 

as follows: 

§ 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 [insert 
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date 12 months after date of publication in the Federal

Register]. 

* * * * * 

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. 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 nonsource-oriented NCore site for sampling required under 40 CFR 
Page 63 of 67

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. 

* * * * * 

5. Appendix D to Part 58 is amended as follows: 

 a. By revising paragraph 3.(b) introductory text,

 b. By removing and reserving paragraph 3.(c), 

 c. By revising paragraph 4.5.(a), 

 d. By revising paragraph 4.5.(b), and 

 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) or greater shall also measure Pb either as Pb-TSP or PbPM10. The EPA Regional Administrator may approve an alternative 
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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 sourceoriented 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 
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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 §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 [insert date 12 months after 

date of publication in the Federal Register]. 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 
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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 

County 

Santa Clara CA 

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 
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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. 

* * * * *