Vol. 81 Monday, 

No. 59 March 28, 2016 

Part II 

Environmental Protection Agency 

40 CFR Part 58 

Revisions to Ambient Monitoring Quality Assurance and Other 

Requirements; Final Rule 


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17248 Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 58 

[EPA–HQ–OAR–2013–0619; FRL–9942–91– 

OAR] 

RIN 2060–AS00 

Revisions to Ambient Monitoring 

Quality Assurance and Other 

Requirements 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: This action promulgates 

revisions to ambient air monitoring 

requirements for criteria pollutants. 

These revisions include adding and 

harmonizing definitions; clarifying 

annual monitoring network plan public 

notice requirements; revising network 

design requirements; system 

modifications and operating schedules; 

clarifying data certification, data 

submittal and archiving procedures; 

reorganizing and clarifying quality 

assurance requirements; and revising 

certain network design criteria for nonsource oriented lead monitoring. These 

revisions also address other issues in 

the Ambient Air Quality Surveillance 

Requirements, to help reduce the 

compliance burden of monitoring 

agencies operating ambient monitoring 

networks. 

DATES: This final rule is effective on 

April 27, 2016. 

ADDRESSES: The EPA has established a 

docket for this action under Docket ID 

No. EPA–HQ–OAR–2013–0619. 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 Docket ID No. EPA–HQ–OAR– 

2013–0619, EPA Docket Center, EPA 

WJC West Building, Room 3334, 1301 

Constitution Ave. NW., Washington, 

DC. The 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. 

Lewis Weinstock, Air Quality 

Assessment Division, Office of Air 

Quality Planning and Standards, U.S. 

Environmental Protection Agency, Mail 

code C304–06, Research Triangle Park, 

NC 27711; telephone: (919) 541–3661; 

fax: (919) 541–1903; email: 

weinstock.lewis@epa.gov. 

SUPPLEMENTARY INFORMATION: 

A. 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. Categories and entities 

potentially regulated by this action 

include: 

Category NAICSa code 

State/territorial/local/tribal 

government ....................... 924110 

a North American Industry Classification 

System. 

B. Where can I get a copy of this 

document? 

In addition to being available in the 

docket, an electronic copy of this action 

will also be available on the Worldwide 

Web (WWW) through the Technology 

Transfer Network (TTN). Following 

signature, a copy of this action will be 

posted at the TTN’s Ambient 

Monitoring Technology Information 

Center at the following address: https:// 

www3.epa.gov/ttnamti1/monregs.html. 

The TTN provides information and 

technology exchange in various areas of 

air pollution control. 

C. Judicial Review 

This rule is nationally applicable and, 

furthermore, the Administrator finds 

that it is of nationwide scope and effect. 

Under section 307(b)(1) of the Clean Air 

Act (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 May 

27, 2016. 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 the 

EPA to enforce these requirements. 

Table of Contents 

The following topics are discussed in this 

preamble: 

I. Background 

II. Amendments to the Ambient Monitoring 

Requirements 

A. General Information 

B. Definitions 

C. Annual Monitoring Network Plan and 

Periodic Network Assessment 

D. Network Technical Requirements 

E. Operating Schedules 

F. System Modification 

G. Annual Air Monitoring Data 

Certification 

H. Data Submittal and Archiving 

Requirements 

I. Network Design Criteria (Appendix D) 

III. Amendments to Quality Assurance 

Requirements 

A. Quality Assurance Requirements for 

Monitors Used in Evaluations for 

National Ambient Air Quality 

Standards—Appendix A 

1. General Information 

2. Quality System Requirements 

3. Measurement Quality Checks for Gases 

4. Measurement Quality Checks for 

Particulate Monitors 

5. Calculations for Data Quality 

Assessment 

B. Quality Assurance Requirements for 

Monitors Used in Evaluations of 

Prevention of Significant Deterioration 

Projects—Appendix B 

1. General Information 

2. Quality System Requirements 

3. Measurement Quality Checks for Gases 

4. Measurement Quality Checks for 

Particulate Monitors 

5. Calculations for Data Quality 

Assessment 

IV. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

B. Paperwork Reduction Act (PRA) 

C. Regulatory Flexibility Act (RFA) 

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 

and Safety Risks 

H. Executive Order 13211: Actions 

Concerning Regulations 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. Background 

On September 11, 2014, the EPA 

proposed revisions to its ambient air 

monitoring requirements for criteria 

pollutants to provide clarifications to 

existing requirements and to reduce the 

compliance burden of monitoring 

agencies operating ambient monitoring 

networks (79 FR 54356). The proposal 

focused on ambient monitoring 

requirements that are found in 40 CFR 

part 58 and the associated appendices 

(A, D, and new Appendix B), including 

issues such as operating schedules, the 


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1Links to the NAAQS final rules are available at: 

https://www3.epa.gov/ttn/naaqs/criteria.html. 

2The AQS is the EPA’s repository of ambient air 

quality data. The AQS stores data from over 10,000 

monitors, 5,000 of which are currently active. State, 

local and tribal agencies collect the data and submit 

it to the AQS on a periodic basis. See https://

www.epa.gov/aqs/aqs-obtaining-aqs-data for 

additional information. 

3https://aqs.epa.gov/aqsweb/codes/data/

CertifyingAgenciesByMonitor.html. 

development of annual monitoring 

network plans, data reporting and 

certification requirements, and the 

operation of the required quality 

assurance (QA) program. These 

revisions were proposed to maintain the 

robust nature of the ambient monitoring 

networks while identifying efficiencies 

and flexibilities that would help ensure 

the successful operation of the national 

monitoring system. 

The EPA last completed a 

comprehensive revision of its ambient 

air monitoring regulations in a final rule 

published on October 17, 2006 (71 FR 

61236). Minor revisions were completed 

in a direct final rule published on June 

12, 2007 (72 FR 32193). Periodic 

pollutant-specific monitoring updates 

have occurred in conjunction with 

revisions to the National Ambient Air 

Quality Standards (NAAQS). In such 

cases, the monitoring revisions were 

typically finalized as part of the NAAQS 

final rules.1

II. Amendments to the Ambient 

Monitoring Requirements 

A. General Information 

This section describes revisions to the 

EPA’s ambient air monitoring 

requirements found in 40 CFR part 58— 

Ambient Air Quality Surveillance: 

Subpart A—General Provisions, Subpart 

B—Monitoring Network, and Appendix 

D—Network Design Criteria for Ambient 

Air Quality Monitoring. 

The EPA received public comments 

on its September 2014 proposal from 31 

respondents including 15 state agencies, 

12 local agencies, two 

multijurisdictional organizations (MJO), 

one consulting firm, and one 

environmental organization whose 

comments represented two 

organizations. Due to the relatively large 

number of individual revisions 

contained in the proposal, commenters 

typically focused their attention on 

particular items of interest while 

occasionally providing a more general, 

overarching statement of support for the 

remaining provisions. In some cases, 

commenters remained silent on other 

provisions of the proposal and the level 

of support for those provisions cannot 

be ascertained. In the following 

sections, the specific comments will be 

noted as they pertain to each particular 

proposed revision. This preamble will 

summarize the affected regulation, 

proposed changes, public comments 

that were received, the EPA’s analysis of 

those comments where applicable, and 

EPA’s final decision concerning the 

revisions. A detailed description of 

changes to Quality Assurance 

Requirements is contained in section III 

of the preamble. 

B. Definitions 

The presence of a definitions section 

in the regulation ensures a consistent 

interpretation of technical terminology 

across the various parts of the CFR that 

pertain to ambient air monitoring, as 

well as in supporting guidance 

documents, databases, and outreach 

materials that support the monitoring 

community. 

The EPA proposed to add and revise 

several terms to ensure consistent 

interpretation within the monitoring 

regulations and to harmonize usage of 

terms with the definition of key 

metadata fields that are important 

components of the Air Quality System 

(AQS).2

The EPA proposed to add the term 

‘‘Certifying Agency’’ to the list of 

definitions. The certifying agency field 

was added to the AQS in 2013 as part 

of the development of a revised process 

for states and the EPA Regions to meet 

the data certification requirements 

described in 40 CFR 58.15. The new 

term specifically describes any 

monitoring agency that is responsible 

for meeting data certification 

requirements for a set of monitors. In 

practice, a certifying agency is typically 

a state, local, or tribal agency depending 

on the particular data reporting 

arrangements that have been approved 

by an EPA Regional Office for a given 

state. A list of certifying agencies by 

individual monitor is available on the 

AQS–TTN Web site.3

The term ‘‘Chemical Speciation 

Network,’’ or CSN, was proposed for 

addition to the definition list. The CSN 

has been functionally defined as being 

composed of the Speciation Trends 

Network (STN) sites and the 

supplemental speciation sites that are 

collectively operated by monitoring 

agencies to obtain particulate matter up 

to 2.5 micrometers (PM2.5) chemical 

species data. 

The term ‘‘Implementation Plan’’ was 

proposed for addition to provide more 

specificity to current definitions that 

reference the word ‘‘plan’’ in their 

description. The EPA wishes to ensure 

that references to State Implementation 

Plans (SIPs) are not confused with 

references to Annual Monitoring 

Network Plans that are described in 40 

CFR 58.10. 

The EPA proposed to revise the term 

‘‘Local Agency’’ to clarify that such 

organizations are responsible for 

implementing portions of Annual 

Monitoring Network Plans. The current 

definition refers to the carrying out a 

plan that is not specifically defined, 

leading to possible confusion with SIPs. 

The EPA proposed to revise the term 

‘‘Meteorological Measurements’’ to 

clarify that such measurements refer to 

required parameters at the National Core 

Monitoring Program (NCore) and 

photochemical assessment monitoring 

stations (PAMS). 

The terms ‘‘Monitoring Agency’’ and 

‘‘Monitoring Organization’’ were 

proposed for clarification to include 

tribal monitoring agencies and to 

simplify the definition of monitoring 

organization to reference the definition 

of monitoring agency. 

The term ‘‘NCore’’ was proposed for 

revision to remove nitrogen dioxide 

(NO2) and lead in PM10 (Pb-PM10) as a 

required measurement and to expand 

the definition of basic meteorology to 

specifically reference the required 

measurements: Wind speed, wind 

direction, temperature, and relative 

humidity. The EPA clarifies that NO2

was never a required NCore 

measurement and that the current 

definition was erroneous on this issue. 

Additionally, the requirement to 

measure Pb-PM10 at NCore sites in areas 

over 500,000 population was proposed 

for elimination due to the extremely low 

concentrations being measured at these 

sites. 

The term ‘‘Near-road NO2 Monitor’’ 

was proposed for revision to ‘‘Near-road 

Monitor.’’ This revision is being made to 

broaden the definition of near-road 

monitors to include all monitors 

operating under the specific 

requirements described in 40 CFR part 

58, appendix D (sections 4.2.1, 4.3.2, 

4.7.1(b)(2)) and appendix E (section 

6.4(a), Table E–4) for near-road 

measurement of PM2.5 and carbon 

monoxide (CO) in addition to NO2. 

The term ‘‘Network Plan’’ was 

proposed for addition to clarify that any 

such references in 40 CFR part 58 refer 

to the annual monitoring network plan 

required in 40 CFR 58.10. 

The term ‘‘Plan’’ was proposed for 

deletion as its usage has been replaced 

with more specific references to either 

the annual monitoring network plan 

required in 40 CFR 58.10 or the SIP 

approved or promulgated pursuant to 

CAA section 110. 

The term ‘‘Population-oriented 

Monitoring (or sites)’’ was proposed for 


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4The EPA does note that other mechanisms can 

be used to extend the applicability of monitoring 

requirements to sites operated by other entities, e.g., 

industrial monitors. For example, states can 

develop Memorandum of Understanding (MOU’s) 

with the operators of such sites to ensure that the 

monitors are operated according to part 58 

requirements and that the resulting data are of 

known quality. 

deletion. This term, along with the 

related concept of population-oriented 

monitoring, was deleted from 40 CFR 

part 58 in the 2013 PM2.5 NAAQS final 

rule (78 FR 3235–3236). This was to 

ensure consistency with the 

longstanding definition of ambient air 

applied to the other NAAQS pollutants. 

The term ‘‘Primary Monitor’’ was 

proposed for addition to the definition 

list. The use of this term has become 

important in AQS to better define the 

processes used to calculate NAAQS 

design values when more than one 

monitor is being operated by a 

monitoring agency for a given pollutant 

at the same site. This term identifies the 

primary monitor used as the default 

data source in AQS for creating a 

combined site record for pollutants that 

allow site combinations per 40 CFR part 

50. 

The term ‘‘Primary Quality Assurance 

Organization’’ was proposed for revision 

to include the use of the acronym, 

‘‘PQAO,’’ and to note that a PQAO 

could include a group of monitoring 

organizations. 

The terms ‘‘PSD Monitoring 

Organization’’ and ‘‘PSD Monitoring 

Network’’ were proposed for addition to 

support the proposed new appendix B 

that will pertain specifically to QA 

requirements for prevention of 

significant deterioration (PSD) 

networks. 

The term ‘‘PSD Reviewing Authority’’ 

was proposed for addition to support 

the addition of appendix B to the part 

58 appendices and to clarify the 

identification of the lead authority in 

determining the applicability of QA 

requirements for PSD monitoring 

projects. 

The term ‘‘Reporting Organization’’ 

was proposed for revision to clarify that 

the term refers specifically to the 

reporting of data as defined in AQS. The 

AQS does allow the distinct designation 

of agency roles that include analyzing, 

certifying, collecting, reporting, and 

PQAO. 

The term ‘‘SLAMS’’ (state and local 

air monitoring stations) was proposed 

for clarification to indicate that the 

designation of a monitor as SLAMS 

generally refers to a monitor required 

under appendix D of part 58 and is 

needed to meet monitoring objectives. 

The SLAMS monitors make up 

networks that include NCore, PAMS, 

CSN, and other state or local agency 

sites that have been so designated in 

annual monitoring network plans. 

The terms ‘‘State Agency’’ and ‘‘STN’’ 

were proposed for minor wording 

changes for purposes of clarity only. 

The term ‘‘State Speciation Site’’ was 

proposed for deletion given the 

proposed addition of ‘‘Supplemental 

Speciation Station’’ to better describe 

the distinct elements of the CSN, which 

includes the STN stations that are 

required under section 4.7.4 of 

appendix D of part 58, and 

supplemental speciation stations that 

are operated for specific monitoring 

agency needs and are not considered to 

be required monitors under appendix D. 

We received relatively few comments 

on the proposed revisions to definitions. 

One commenter noted that the 

clarification of Meteorological 

Measurements should specify that those 

parameters are also required at SLAMS 

sites, which include both the NCore and 

PAMS sites. They noted the use of the 

undefined phrase ‘‘combined data 

record’’ in the Primary Monitor 

definition and recommended that a 

definition be provided. They also 

recommended that the EPA include an 

explanation of the term ‘‘Special 

Purpose Monitor’’ (SPM) in the 

definitions section of the preamble and 

not rely solely on the amended 

regulatory text. A commenter from a 

state air program noted that the 

proposed definition for ‘‘Monitoring 

Organization’’ includes the phrase ‘‘or 

other monitoring organization.’’ They 

believe the phrase is ambiguous and 

could extend the applicability of 

requirements such as technical systems 

audits to universities, contractors, and 

other government organizations. This 

commenter was concerned that the 

phrasing could expand the applicability 

of regulations, and that the phrase 

should be either defined or removed 

from the final definition verbiage. 

The EPA has made several revisions 

to definitions in response to these 

comments. The Meteorological 

Measurements definition has been 

amended to include a clarifying 

reference that SLAMS stations include 

sites that comprise the NCore and 

PAMS networks. Additionally, the 

words ‘‘or other monitoring 

organization’’ have been removed from 

the definition for Monitoring 

Organization to remove any ambiguity 

that monitoring regulations apply to 

entities other than state, local, or tribal 

agencies.4 The EPA does not believe 

that the definition for Primary Monitor 

needs to be amended as the term 

‘‘combined data record’’ is already 

defined as part of appendix N to Part 50 

(Interpretation of the National Ambient 

Air Quality Standards for PM2.5). The 

EPA acknowledges that the preamble to 

the proposal inadvertently failed to 

discuss a clarification to the Special 

Purpose Monitor definition included in 

the proposal. The proposed revision to 

this definition was the addition of two 

sentences that merely restated existing 

requirements already established in 40 

CFR 58.10 with regard to annual 

monitoring network plans and network 

assessments. The EPA believes that the 

proposed definition is a useful but 

minor revision that should be retained 

as proposed. No other comments were 

received on the proposed revisions to 

definitions and they will be finalized as 

proposed. 

C. Annual Monitoring Network Plan and 

Periodic Network Assessment 

The annual monitoring network plan 

process provides an important 

communications and planning pathway 

between monitoring agencies, EPA 

Regional Offices, and the general public. 

The network assessment process, 

required every 5 years, provides an 

opportunity to conduct more in-depth 

planning and analyses of current and 

future ambient monitoring needs and 

objectives to help ensure that 

monitoring programs respond to 

changing requirements, demographics, 

air quality trends, and updated 

technology. 

The EPA proposed several changes to 

the annual monitoring network plan 

process and related requirements. We 

received significant comment on these 

changes. Therefore, each individual 

proposed revision is discussed below 

along with relevant comments. 

Since the revision of the annual 

monitoring network plan process in 

2006, the EPA has received feedback 

about confusion concerning the 

difference between the process of 

obtaining public inspection versus 

comment, the responsibility of 

monitoring agencies to respond to 

public comment in their submitted 

annual monitoring network plans, and 

the responsibility of the EPA Regional 

Offices to obtain public comment 

depending on a monitoring agency’s 

prior action, as well as whether the 

annual monitoring network plan was 

modified based on discussions with the 

monitoring agency following plan 

submission. Accordingly, we proposed 

that the public inspection aspect of the 

requirement contained in 40 CFR 

58.10(a)(1) be revised to clearly indicate 

that obtaining public comment is a 

required part of the process, and that 

plans that are submitted to the EPA 


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Regional Offices should address such 

comments that were received during the 

public notice period. A related part of 

the annual monitoring network plan 

process is described in 40 CFR 

58.10(a)(2) with the distinction that this 

section pertains specifically to plans 

that propose SLAMS modifications and, 

thereby, also require specific approval 

from the EPA Regional Administrator. 

Consistent with the proposed change 

to the comment process described 

above, the EPA proposed changes to the 

text in 40 CFR 58.10(a)(1) to reflect the 

fact that public comments will have 

been required to be obtained by 

monitoring agencies prior to 

submission, and that the role of the EPA 

Regional Office would be to review the 

submitted plan together with public 

comments and any modifications to the 

plan based on these comments. 

A number of state monitoring 

agencies and two MJOs commented that 

the proposed requirement to solicit and 

address comments during the public 

inspection period would impose 

additional burden, inflexibility, and 

delays on the process by requiring that 

the comments be addressed before the 

original plan is submitted to the EPA. 

Some of these commenters estimated 

that it would take an additional two 

months compared with the current 

process to handle comments in this 

manner, and that they could only 

support the proposed change if the 

deadline for submittal was revised as 

well. They requested that the EPA waive 

this proposed requirement or make the 

procedure more flexible by allowing 

comments to be submitted later, perhaps 

as an amendment before the plan is 

approved, or even with the next year’s 

plan. Four state programs supported the 

proposed revision noting the 

importance of soliciting public input on 

the content of the plan and the 

perspective that states should take the 

lead in responding to comments versus 

the EPA. One of these states noted that 

they attempt to schedule a public 

comment period for every SLAMS 

modification. They also noted that 

flexibility would be needed in 

emergency situations that demand 

immediate changes to their network. 

Another of these states requested that 

the term ‘‘address’’ be clarified and 

noted that the timeliest way to handle 

comments and responses would be to 

include this information in an appendix 

to the plan when submitted to the EPA. 

A different perspective was offered by 

comments received from a joint 

environmental group submission. They 

commented that the proposed changes 

did not go far enough to ensure a 

meaningful public comment 

opportunity. They noted that annual 

monitoring network plans are integral 

parts of SIPs and that the CAA requires 

that SIP submittals and revisions be 

more formally publicly noticed. They 

suggested that the EPA require states to 

prominently advertise monitoring plans, 

allow at least 30 days for public 

comment, then either hold a public 

hearing or provide such an opportunity 

if requested. They also added that a 

separate notice and comment 

opportunity must be required on the 

EPA’s proposed action on a submitted 

plan or a related amendment to an 

approved plan, and that all of the 

suggested public comment requirements 

must also be applicable to the 5-year 

network assessment. 

The EPA recognizes the diversity of 

comments on this aspect of the 

proposal. Nearly all commenters 

recognized that fostering public 

involvement in the annual monitoring 

network plan is important and 

desirable. Those commenters supporting 

the proposal noted that their existing 

procedures already address the 

proposed requirements and that they 

found it desirable to be able to respond 

directly to stakeholders. Adverse 

comment was related to the implied 

additional burden of obtaining comment 

versus the current requirement of 

posting for public inspection, concern 

about limiting the flexibility to 

subsequently modify the plan following 

submission to the EPA, and the 

perceived impracticality of adequately 

responding to public comments in a 

timely manner. 

The EPA does not agree with the 

comments received from the joint 

environmental group submission on this 

aspect of the proposal. First, the final 

rule text requires annual monitoring 

network plans to be made available for 

at least 30 days of public inspection and 

comment and further requires 

monitoring agencies to address, as 

appropriate, any significant issues 

raised in public comment. Requiring at 

least 30 days of public participation and 

consideration of significant comments is 

consistent with the CAA and the 

Administrative Procedure Act (APA) 

and, at the same time, affords 

monitoring agencies with the flexibility 

and discretion to provide for additional 

time and public participation 

procedures. 

Second, the EPA disagrees that state 

action on an annual monitoring network 

plan triggers the same public 

participation requirements applicable to 

SIP adoption and revision. Section 

110(a)(2)(B) of the CAA provides that 

each SIP shall ‘‘provide for 

establishment and operation of 

appropriate devices, methods, systems, 

and procedures necessary to (i) monitor, 

compile, and analyze data on ambient 

air quality, and (ii) upon request, make 

such data available to the 

Administrator.’’ To meet these 

requirements, our September 2013 

Guidance on Infrastructure State 

Implementation Plan (SIP) Elements 

under Clean Air Act Sections 110(a)(1) 

and 110(a)(2) states that ‘‘the best 

practice for an air agency submitting an 

infrastructure SIP would be to submit, 

for inclusion into the SIP . . . , the 

statutory or regulatory provisions that 

provide the air agency or official with 

the authority and responsibility to 

perform’’ certain actions required under 

40 CFR part 58. (See 2013 iSIP 

Guidance, p. 22.) In other words, CAA 

section 110(a)(2)(B) simply requires that 

monitoring agencies have the legal 

authority to implement 40 CFR part 58; 

it does not treat annual monitoring 

network plans required under 40 CFR 

part 58 as ‘‘integral parts’’ of a SIP 

subject to public participation whenever 

such network plans are established or 

modified. 

Third, the EPA disagrees that EPA 

action on an annual monitoring network 

plan requires a separate notice and 

comment opportunity. The EPA reviews 

and acts on network plans through 

informal adjudications in which the 

EPA determines whether such network 

plans satisfy the requirements in 40 CFR 

58.10. Such adjudications are not 

rulemakings subject to the public 

participation requirements of the APA 

(see 5 U.S.C. 553), although they are 

final agency actions subject to judicial 

review (see 5 U.S.C. 706). The EPA’s 

decision to treat network plan decisions 

as case-by-case adjudications rather 

than ‘‘rules’’ reflects the fact that the 

EPA simply compares the information 

supplied in the network plan with the 

requirements of 40 CFR part 58 and 

notifies the relevant monitoring 

agencies that design and operate the 

corresponding networks whether their 

particular networks satisfy Part 58 or 

need further revision. 

Finally, the EPA disagrees that public 

notice and comment is required ‘‘at both 

the state and federal levels on the 5-year 

monitoring network assessments 

required at 40 CFR 58.10(d).’’ To the 

extent that the EPA takes ‘‘substantive 

action’’ on such assessments, such 

actions are not rulemakings subject to 

public participation requirements under 

the CAA or the APA. 

Given the relatively broad support for 

the concept of soliciting public 

comment as part of the annual 

monitoring network plan posting 

process, as well as the concern for the 


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implied logistical challenge of both 

obtaining comment and developing (and 

getting management approval for) 

adequate responses, while still meeting 

the required submission deadline of July 

1, the EPA believes that some 

modification of the proposed language 

is appropriate. As noted by several 

commenters, the implied burden to 

‘‘reference and address any such 

received comments’’ as described in the 

proposed regulatory language may be 

too difficult to achieve. As suggested by 

one commenter, it may be more 

practical for monitoring agencies to 

review and consider the comments, and 

only to modify the plan when 

‘‘appropriate and feasible.’’ By 

modifying the proposed language to 

provide more flexibility and discretion 

in addressing comments based on each 

agency’s technical evaluation of 

received comments and the associated 

management review chain, the EPA can 

finalize the generally supported goal of 

increasing public involvement in the 

process while lessening the burden on 

agencies that have not previously 

included the solicitation of public 

comment in their process. Accordingly, 

the EPA is revising the regulatory 

language in the last sentence of 40 CFR 

58.10(a)(1) from ‘‘The annual 

monitoring network plan must be made 

available for public inspection and 

comment for at least 30 days prior to 

submission to the EPA and the 

submitted plan shall reference and 

address any received comments’’ to 

‘‘The annual monitoring network plan 

must be made available for public 

inspection and comment for at least 30 

days prior to submission to the EPA and 

the submitted plan shall include and 

address, as appropriate, any received 

comments.’’ The EPA believes that this 

revised language, including the 

clarification that the plan ‘‘address, as 

appropriate, any received comments,’’ 

provides sufficient flexibility to 

monitoring agencies and ensures 

adequate public participation practices. 

Under this approach, all agencies will 

review public comments and make 

changes to the plan as appropriate in 

light of public comments, taking into 

account the requirement for timely 

submission of network plans. The EPA 

encourages states to provide responses 

to significant comments but 

understands that developing formal 

responses may potentially delay 

submission of the plan beyond the July 

1 deadline, in light of internal timelines 

and management review procedures. To 

avoid such delays, it would also be 

acceptable for states to submit the 

proposed plan with comments and any 

resulting changes, and where the EPA 

finds it necessary to discuss how the 

state considered and addressed specific 

comments, the EPA will follow up as 

part of our process for reviewing the 

plan for approval. 

Another aspect of the annual 

monitoring network plan requirements 

is the listing of required elements and 

site information in 40 CFR 58.10. The 

EPA proposed to add two requirements 

to this list as described below. First, the 

EPA proposed to require that a PAMS 

network description be specifically 

included in the 40 CFR 58.10(a) 

requirements for any monitoring 

agencies affected by PAMS 

requirements. The requirements for 

such a plan are already referenced in 

appendix D, sections 5.2 and 5.4 of this 

part. Second, the EPA proposed that 

‘‘long-term’’ SPMs, i.e., those SPMs 

operating for longer than 24 months 

whose data could be used to calculate 

design values for NAAQS pollutants in 

cases where the EPA-approved methods 

are being employed, should be 

identified in the 40 CFR 58.10(b) 

requirements along with a discussion of 

the rationale for keeping the monitor(s) 

as SPMs or potentially reclassifying to 

SLAMS. The EPA did not propose that 

such monitors must become SLAMS, 

only that the ongoing operation of such 

monitors and the rationale for retaining 

them as SPMs be explicitly discussed to 

avoid confusion, particularly because 

the monitoring data could be used to 

calculate design values regardless of 

whether the monitors are designated 

SPMs or SLAMs. Thus, there is 

potential for unintended complexities in 

the designations process if any design 

value SPMs would be discontinued 

without adequate discussion. 

Nine commenters addressed the above 

issues. Only one commenter specifically 

addressed the addition of the PAMS 

network description and that comment 

was ‘‘Support this action.’’ The 

remainder of comments addressed the 

issue of requiring an annual monitoring 

network plan discussion and rationale 

for whether longer-term SPMs should be 

retained as SPMs or reclassified to 

SLAMS. Three of these commenters 

were supportive of the proposed 

revision with several noting that they 

expected that monitoring agencies 

would still be granted discretion on the 

issues by the EPA Regional Offices. Two 

commenters suggested revised language 

to limit the proposed SPM discussion to 

only criteria pollutant monitors and also 

only those monitors utilizing federal 

reference methods (FRM) or federal 

equivalent methods (FEM). One 

commenter only supported the revision 

if the EPA could provide grant funding. 

Three commenters did not support the 

proposed revision, either because they 

interpreted the provision as meaning 

that the EPA was proposing that such 

longer-term SPMs be automatically 

converted to SLAMS in the absence of 

a justification, due to the belief that 

such a rationale would create a burden 

for monitoring agencies and that such a 

discussion is misplaced in the annual 

monitoring network plan, or because of 

the belief that ongoing discussions 

between the states and EPA Regional 

Offices are already sufficient to handle 

such issues, and that the additional 

requirement is an unnecessary limit on 

monitoring network flexibility. 

After consideration of these 

comments, the addition of the PAMS 

network description to the list of 

requirements in 40 CFR 58.10(a) will be 

finalized as proposed due to general 

support and lack of comment on this 

revision. 

The EPA will not finalize the 

proposed changes to 40 CFR 58.10(b). 

The EPA believes that some 

misunderstanding still exists as to the 

intent of the proposed addition of a 

required discussion and rationale 

concerning longer-term SPM monitors. 

Although preamble language explicitly 

stated that the EPA was not intending to 

propose an automatic conversion 

process for such SPMs, several 

commenters interpreted the proposal in 

that way. One commenter noted, ‘‘Also 

the mechanism is unclear for how SPMs 

not granted approval will convert to a 

SLAMS monitor.’’ It was not the EPA’s 

intention to imply any limitations on 

monitoring agency discretion to employ 

SPMs as part of their network design 

strategy, only to raise the awareness 

among all stakeholders of such 

situations when they occur, particularly 

with longer-term SPMs that may have 

design values approaching or exceeding 

the NAAQS. Comments regarding the 

need to limit the proposed requirement 

to FRMs or FEMs also indicate a 

misunderstanding of the proposed 

language as this limitation was already 

included in the regulatory language in 

the proposal. Given these apparent areas 

of confusion and the concern about 

additional burden that the inclusion of 

such a rationale would place on plan 

submitters, the EPA will not finalize 

this proposed change to 58.10(b). 

Nevertheless, we continue to believe 

that an open and robust discussion 

about such longer-term SPMs is an 

important part of interactions between 

monitoring agencies and EPA Regional 

Offices, particularly in the context of 

monitors utilizing EPA-approved 

methods that are measuring 

concentrations near the level of 


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applicable NAAQS. While continuing to 

support the use of SPMs to provide 

flexible options for investigating air 

quality problems, we encourage 

reference to these situations in annual 

monitoring network plans and 

thoughtful consideration of the pros and 

cons of converting such monitors to 

SLAMS particularly to avoid potential 

disruption of implementation actions 

due to discontinuance of important 

SPMs. 

The EPA proposed a minor edit to the 

annual monitoring network plan 

requirements to revise terminology 

referring to PM2.5 speciation monitoring. 

No comments were received on this 

issue and the change will be finalized as 

proposed. 

The EPA received comments on a 

general rewording of regulatory 

language that was included as part of 

the revisions to 40 CFR 58.10(a). 

Specifically, we revised the sentence 

‘‘The plan shall include a statement of 

purposes for each monitor and evidence 

that siting and operation of each 

monitor meets the requirements of 

appendices A, C, D, and E of this part, 

where applicable’’ to ‘‘The plan shall 

include a purpose statement for each 

monitor along with a statement of 

whether the operation of each monitor 

meets the requirements of appendices 

A, B, C, D, and E of this part, where 

applicable.’’ Additionally, the proposed 

language added the following sentence: 

‘‘The Regional Administrator may 

require the submission of additional 

information as needed to evaluate 

compliance with applicable 

requirements of Part 58 and its 

appendices.’’ 

One state monitoring agency noted 

that there was overlap between the 

monitoring objective and the purpose of 

a monitor as referenced in the regulatory 

language. They suggested that the terms 

be defined in the definitions section of 

the rule. They also suggested removing 

the purpose statement entirely as it 

appears duplicative with other annual 

monitoring plan requirements that are 

already present. Two MJOs referenced 

the statement concerning the Regional 

Administrator’s discretion to require the 

submission of additional information to 

evaluate the compliance of the 

submitted plan with part 58 and 

appendices. They commented that the 

proposed language was ‘‘vague and 

open-ended’’ and that the presence of 

this requirement would lead to 

significant differences among the EPA 

Regions concerning the level of detail 

needed to evaluate plan submittals. It 

was suggested that the EPA consider 

amending the language to more clearly 

define the circumstances when 

additional information would be 

needed. 

The EPA believes that some revision 

of the referenced language is 

appropriate to achieve the goal of 

providing monitoring agencies with a 

more explicit description of the 

documentation that is required in the 

plans as well as providing the EPA 

Regional Offices with a clear basis for 

review and approval. We agree with the 

comment that the requirement for a 

‘‘purpose statement’’ is vaguely worded 

and duplicative of existing requirements 

(in 40 CFR 58.10(b)) that pertain to 

factors such as monitoring objective and 

spatial scale. We also note the 

comments concerning the open-ended 

nature of the statement that the Regional 

Administrator has discretion to require 

the submission of additional 

information to evaluate the compliance 

of the submitted plan with Part 58 and 

appendices. The EPA observes that this 

type of statement is not unusual in the 

context of various monitoring 

requirements, particularly in the 

Network Design Criteria described in 

appendix D. We do not anticipate 

frequent requests for additional 

information in the context of the Annual 

Monitoring Network Plan requirements, 

but we would anticipate that additional 

information would be needed by 

Regional Offices when the reasons 

supporting compliance with the 

applicable requirements of part 58 and 

its appendices have changed from the 

previous year’s plan, or when a monitor 

has been added since the previous 

year’s plan was approved. 

Accordingly, the EPA is revising the 

proposed language by deleting the 

words ‘‘a purpose statement for each 

monitor along with’’ from the second 

sentence of 40 CFR 58.10(a)(1) and also 

revising the sentence ‘‘The Regional 

Administrator may require the 

submission of additional information as 

needed to evaluate compliance with 

applicable requirements of Part 58 and 

its appendices’’ to ‘‘The Regional 

Administrator may require additional 

information in support of this 

statement,’’ which is a somewhat 

narrower framing of the need for 

Regional Administrator discretion in the 

context of assuring whether the 

operation of each monitor meets the 

requirements of appendices A, B, C, D, 

and E of this part, as described in the 

submitted Annual Monitoring Network 

Plan. 

Finally, two public comments were 

received on preamble language in the 

proposal pertaining to the EPA’s 

discussion about the ability of Regional 

Offices to handle partial approvals of 

annual monitoring network plans in 

cases where one or more of the required 

elements is problematic. A joint 

environmental organization comment 

noted that the EPA’s discussion did not 

indicate a timeframe for the correction 

of deficiencies and, hence, the described 

partial approval process was unlawful 

and arbitrary. They further suggested 

that an appropriate time limit for the 

correction of deficiencies would be 90 

days. A MJO comment noted that a 

partial approval process is not an 

appropriate strategy for the longer term, 

although the process as it exists now has 

been found to be useful in some cases. 

This commenter supported language in 

the preamble discussion relating to an 

approval process while noting technical 

deficiencies, as long as such 

deficiencies were related to required 

elements of the plan. 

The EPA notes that the preamble 

discussion (79 FR 54360) was not tied 

to any proposed revisions to 

requirements or regulatory language, but 

was intended as an articulation of what 

we believe to be currently available 

flexibility in the handling of annual 

monitoring network plan submissions. 

The EPA agrees that deficiencies should 

be corrected and intends to work with 

monitoring agencies to address 

deficiencies in a timely manner. 

However, the EPA does not believe that 

the lack of a regulatory schedule for 

correcting deficiencies is unlawful or 

that it would be appropriate to establish 

one without having solicited comment 

on the topic in the proposal. 

Accordingly, no additional action was 

taken within the context of this 

rulemaking. 

D. Network Technical Requirements 

The Network Technical Requirements 

section provides a place for crossreferencing and clarifying the 

applicability of the various 

requirements that are described in the 

appendices to part 58. 

The EPA proposed to revise the 

language in 40 CFR 58.11(a)(3) to note 

the proposed revisions to appendix B to 

the QA requirements that would pertain 

to PSD monitoring sites. One supportive 

comment was received on this issue and 

the revision will be finalized as 

proposed. 

E. Operating Schedules 

The operating schedule requirements 

described in 40 CFR 58.12 pertain to the 

minimum required frequency of 

sampling for continuous analyzers (for 

example, hourly averages) and manual 

methods for particulate matter (PM) and 

Pb sampling (typically 24-hour averages 

for manual methods). 


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5See http://www.regulations.gov/

#!documentDetail;D=EPA-HQ-OAR-2002-0091- 

0017. 

6http://www.epa.gov/ttn/amtic/specgen.html. 

7The approval process has been delegated, in 

practice, to the Director of the Air Quality 

Assessment Division within the Office of Air 

Quality Planning and Standards. 

The EPA proposed to revise these 

requirements by (1) adding flexibility in 

the minimum required sampling for 

PM2.5 mass sampling and for PM2.5

speciation sampling; (2) modifying 

language pertaining to continuous mass 

monitoring to reflect revisions in 

regulatory language that were finalized 

in the 2013 PM NAAQS final rule; and 

(3) clarifying the applicability of certain 

criteria that can lead to an increase in 

the required sampling frequency, for 

example, to a daily schedule. Ten 

commenters responded to these 

proposed changes. Most of the 

comments were generally supportive of 

these changes as they provide additional 

flexibility and potential burden 

reductions for monitoring agencies. 

Some comments noted concern with 

specific changes to the period of time 

that a PM2.5 sampler would have to 

utilize an increased sampling frequency 

if triggered by design values. Additional 

details on these generally supportive 

comments are discussed below in the 

relevant sections. A joint environmental 

organization comment opposed all the 

sampling frequency changes; they noted 

concern for the increased risk of not 

detecting daily variations in PM2.5 by 

allowing samplers to follow reduced 

sampling schedules and also noted the 

lack of a cost analysis documenting the 

burden of monitoring as well as the fact 

that the EPA was not requiring 

additional monitoring to compensate for 

the reduced sampling frequency. 

With regard to the minimum required 

sampling frequency for manual PM2.5

samplers, current requirements state 

that at least a 1-in-3 day frequency is 

mandated for required SLAMS monitors 

without a collocated continuous 

monitor. The EPA believes that some 

regulatory flexibility is appropriate in 

situations where a particular monitor is 

highly unlikely to record a violation of 

the PM2.5 NAAQS, such as in areas with 

very low PM2.5 concentrations relative 

to the NAAQS and/or in urban areas 

with many more monitors than are 

required by appendix D (when a subset 

of those monitors is reading lower than 

other monitors in the area). The EPA 

specifically proposed that the required 

sampling frequency could be reduced to 

1-in-6 day sampling or another alternate 

schedule through a case-by-case 

approval by the EPA Regional 

Administrator. Such approvals could be 

based on factors that are already 

described in 40 CFR 58.12(d)(1)(ii) such 

as historical PM2.5 data assessments, the 

attainment status of the area, the 

location of design value sites, and the 

presence of continuous PM2.5 monitors 

at nearby locations. The EPA noted that 

the request for such reductions in 

sampling frequency would occur as part 

of the annual monitoring network plan 

process as operating schedules are a 

required part of the plans as stated in 40 

CFR 58.10(b)(4). For sites with a 

collocated continuous monitor, the EPA 

also proposed that the current 

regulatory flexibility to reduce to 1-in6 day sampling or a seasonal sampling 

schedule is appropriate based on factors 

described above and, in certain cases, 

may also be applicable to lower-reading 

SLAMS sites without a collocated 

continuous monitor, for example, to 

reduce frequency from 1-in-6 day 

sampling to a seasonal schedule. Such 

flexibility was proposed through 

changes in the regulatory language in 40 

CFR 58.12(d)(1)(i) and (ii). 

With the one exception noted earlier, 

supportive comments were received on 

this specific proposed revision. One 

MJO commented that flexibility is 

needed in specifying operating 

schedules, and that it is preferable to 

retain lower reading sites with a 

reduced sampling frequency rather than 

close them completely. Similar 

comments included ‘‘Support this 

action’’ and the observation that the 

proposed changes should reduce 

monitoring burden. Concerning the joint 

environmental organization comment 

noting the potential increased risk of not 

characterizing the risk from PM2.5 levels 

that might be missed when sampling 

frequency is reduced, the EPA notes that 

these case-by-case situations would be 

reviewed by EPA Regional Offices for 

approval, and that the pertinent 

approval criteria would include an 

assessment of prevailing PM2.5

concentrations and the availability of 

other manual or continuous monitors 

that would provide characterization in 

the general area. As stated in the 

proposal, we expect these sampling 

reduction requests to be made for lower 

reading sites so the impact on area 

design values would be negligible. We 

also note that the requests would be 

made through the annual monitoring 

network plan process and, therefore, 

would be open for public inspection 

and comment prior to potential 

approval by the EPA. On an overall 

basis, the EPA believes that it is 

important to have operational 

flexibilities with regard to sampling 

frequency to permit monitoring agencies 

to shift resources (e.g., higher sampling 

frequency samplers) to high priority 

areas; this flexibility supports the ability 

of the monitoring network to react to 

changing air quality trends and 

problems in a manner most protective of 

public health. Concerning the 

observation that the EPA has not 

provided an analysis of relevant costs, 

we note the public availability of such 

financial information in information 

collection request documents that are 

regularly updated and submitted for 

public comment according to Office of 

Management and Budget regulation.5

In consideration of the comments 

above, the EPA is finalizing the 

revisions to add flexibility to sampling 

frequency requirements for PM2.5 mass 

samplers as proposed. 

The EPA also proposed added 

flexibility in sampling frequency for 

PM2.5 CSN sites, specifically the STN 

sites that are currently operated at 

approximately 53 locations.6 The STN 

stations are currently required to sample 

on at least a 1-in-3 day frequency with 

no opportunity for flexibility. 

Justifications for the proposed 

additional flexibility include the 

conservation of resources for 

reinvestment in other needs within the 

CSN, rising analytical costs, and the 

availability of new technologies that 

provide continuous measurement of 

PM2.5 species. Accordingly, the EPA 

proposed that a reduction in sampling 

frequency from 1-in-3 day be 

permissible for manual PM2.5 samplers 

at STN stations, for example, to a 1-in6 day frequency. The approval for such 

changes at STN stations, on a case-bycase basis, would be made by the EPA 

Administrator as the authority for 

changes to STN has been retained at the 

Administrator level per appendix D of 

this part, section 4.7.4.7 Factors that 

would be considered as part of the 

decision would include an area’s design 

value, the role of the particular site in 

national health studies, the correlation 

of the site’s species data with nearby 

sites, and presence of other leveraged 

measurements. 

Few commenters specifically 

addressed this proposed change as the 

aforementioned comments pertaining to 

changes in sampling frequency for PM2.5

mass samplers were likely deemed 

pertinent to the CSN. Where this 

proposed change was mentioned 

specifically, monitoring agency 

comments noted support as a means of 

increasing flexibility and potentially 

protecting sites by reducing sampling 

frequency versus eliminating sites 

completely. The joint environmental 

organization comment stated that a 


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8https://www.sdas.battelle.org/CSNAssessment/

html/Default.html. 

reasoned justification for the change 

was not provided, and noted that 

speciation data are critical in 

development of SIP control strategies, 

health studies, modeling exercises, and 

investigation of air pollution episodes. 

The EPA notes the supportive 

comments from monitoring agencies 

and agrees that increasing flexibility 

with respect to sampling frequency as 

an alternative to site elimination was a 

motivation for the revision. With respect 

to the environmental organization 

comment noting concern about the 

additional flexibility and the potential 

for reduced sampling frequency, the 

EPA agrees with the observation that 

PM2.5 speciation data are critical to 

supporting many different monitoring 

objectives. Because we believe that 

PM2.5 speciation data are critical for the 

objectives noted above, we recently 

completed an in-depth assessment of 

the CSN with the goal of protecting, to 

the greatest extent possible, the longterm operation of the network.8 In the 

face of rising analytical costs and 

unchanging budgets, the EPA 

considered factors such as site 

reductions, changes in sampling 

frequency, and alterations in operational 

procedures to support long-term 

viability of the CSN. The results of the 

assessment were implemented in late 

2014 and early 2015, and the EPA 

believes the revised CSN continues to 

provide strong support for key 

monitoring objectives noted by the 

commenter and would do so even if 

sampling frequency were selectively 

reduced at a small number of STN sites 

based on substantive and suitable 

criteria. The EPA notes that a proposal 

to reduce sampling frequency would 

need to be accompanied by a technical 

rationale justifying the request and 

evaluating the impact on data users and 

the ability of the site to meet the 

aforementioned key objectives, for 

example, by employing new technology 

such as continuous monitoring of PM2.5

species, in lieu of the reduced number 

of filter samples. 

In consideration of the comments and 

detailed network assessment described 

above, the EPA is finalizing the 

revisions to add flexibility to sampling 

frequency requirements for the PM2.5

STN sites as proposed. 

The EPA proposed editorial revisions 

to 40 CFR 58.12(d)(1)(ii) to harmonize 

the language regarding the use of 

continuous FEM or approved regional 

methods (ARM) monitors to support 

sampling frequency flexibility for 

manual PM2.5 samplers with the current 

language in 40 CFR 58.12(d)(1)(iii) that 

was revised as part of 2013 PM NAAQS 

final rule. Specifically, the phrase 

‘‘unless it is identified in the monitoring 

agency’s annual monitoring network 

plan as not appropriate for comparison 

to the NAAQS and the EPA Regional 

Administrator has approved that the 

data from that monitor may be excluded 

from comparison to the NAAQS’’ was 

proposed for appending to the current 

regulatory language to reflect the new 

process that was finalized in the 2013 

PM NAAQS final rule that allows 

monitoring agencies to request that 

continuous PM2.5 FEM data be excluded 

from NAAQS comparison based on 

technical criteria described in 40 CFR 

58.11(e). We also proposed the addition 

of the phrase ‘‘and the EPA Regional 

Administrator has approved that the 

data from that monitor may be excluded 

from comparison to the NAAQS’’ to the 

revisions that were made with the 2013 

PM NAAQS. This revision was 

proposed to clearly indicate that two 

distinct actions are necessary for the 

data from a continuous PM2.5 FEM to be 

considered not comparable to the 

NAAQS; first, the identification of the 

relevant monitor(s) in an agency’s 

annual monitoring network plan, and, 

second, the approval by the EPA 

Regional Administrator of that request 

to exclude data. The language used by 

the EPA in the relevant sections of 40 

CFR 58.12 related to the initial request 

by monitoring agencies but did not 

specifically address the needed 

approval by the EPA. 

No comments specifically addressed 

these editorial changes in regulatory 

language and they will be finalized as 

proposed. 

Finally, the EPA proposed to clarify 

the applicability of statements in 40 

CFR 58.12(d)(1)(ii) and (iii) that 

reference the relationship of sampling 

frequency to site design values. 

Specifically, we proposed clarifications 

and revisions affecting the following 

statements: (1) ‘‘Required SLAMS 

stations whose measurements determine 

the design value for their area and that 

are within ±10 percent of the NAAQS; 

and all required sites where one or more 

24-hour values have exceeded the 

NAAQS each year for a consecutive 

period of at least 3 years are required to 

maintain at least a 1-in-3 day sampling 

frequency,’’ and (2) ‘‘Required SLAMS 

stations whose measurements determine 

the 24-hour design value for their area 

and whose data are within ±5 percent of 

the level of the 24-hour PM2.5 NAAQS 

must have a FRM or FEM operate on a 

daily schedule.’’ These revisions were 

proposed to avoid confusion among 

monitoring agencies and Regional 

Offices concerning the applicability of 

the sampling frequency adjustments 

since design values are recalculated 

annually and, in some situations, such 

revised design values can either fall 

below the comparative criteria or rise 

above the criteria. To provide some 

clarity to this situation as well as to 

provide a framework where changes in 

sampling frequency occur on a more 

consistent and predictable basis, the 

EPA proposed that design value-driven 

sampling frequency changes be 

maintained for a minimum 3-year 

period once such a change is triggered. 

Additionally, such changes in sampling 

frequency would be required to be 

implemented no later than January 1 of 

the year that follows the recalculation 

and certification of a triggering design 

value. 

A number of supportive comments 

were received on this specific issue 

from monitoring agencies. These 

comments ranged from unqualified 

support to more conditional support 

based on concerns related to funding 

levels and the overall burden of 

analyzing more PM2.5 filters when 

sampling frequency is increased. One 

agency commented that the proposed 

change ‘‘makes sense where the 

concentrations have reached a plateau 

or fluctuate back and forth from year to 

year.’’ However, concern was noted 

about waiting for 3 years to decrease 

sampling frequency when design values 

are clearly trending downward. Another 

state agency generally agreed with the 

proposed approach but requested 

clarifying language that the same criteria 

that would require an increase in 

sampling frequency for a 3-year period 

due to an increase in design values 

would also allow a decrease in sampling 

frequency for a 3-year period if the 

corresponding site design value 

decreased below a threshold. Other 

commenters expressed concern about 

the associated resource burdens noting 

that their gravimetric laboratories are 

already operating at full capacity and 

that an increase from 1-in-3 day 

sampling to daily sampling would triple 

the number of filters to be weighed. 

Accordingly, these commenters 

requested that the EPA allow the 

affected design value sampler to drop 

back to a reduced sampling frequency as 

soon as a design value fell out of the 

specific range and not be required to 

wait for the proposed 3-year period. One 

commenter expressed concern that the 

provision could trigger daily sampling 

even if the higher values were caused by 

a rare or exceptional event, and 

requested that the proposed revision be 

omitted. Finally, one state monitoring 


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9http://www2.epa.gov/air-quality-analysis/

treatment-data-influenced-exceptionalevents#Proposed%20EE%20Rule. 

10Hanley, T. (2015). Assessment of PM2.5 data to 

determine the number of sites that would be 

potentially required to increase their sample 

frequency to daily. Memorandum to the Docket, 

EPA–HQ–OAR–2013–0619. 

11Monitoring agencies, at their discretion, could 

submit the network modification plan in the year 

that the assessment is due if sufficient feedback had 

been received. On balance, the EPA believes that 

the extra year following the completion of the 

network assessment would be valuable to assure a 

productive outcome from the assessment process. 

agency expressed concern about the 

apparent deletion of PM10 monitoring 

requirements from 40 CFR 58.12, and 

also offered suggested revisions to the 

current requirements in 40 CFR 

58.12(e). 

The EPA notes the range of responses 

on this issue and acknowledges that in 

cases where the sampling frequency for 

a PM2.5 sampler is increased, for 

example from 1-in-3 day to daily 

sampling, the associated burden, which 

includes field support and gravimetric 

lab support, would increase for a 

minimum period of 3 years based on the 

proposed change. After that 3-year 

period of increased sampling, the 

sampling frequency would be eligible to 

be reduced if the triggering design value 

was no longer in the specified range 

(e.g., ±5 percent of the 24-hour PM2.5

NAAQS). The EPA agrees that the 

treatment of sampling frequency in 

situations where a sampler is no longer 

in the specific triggering range after a 3- 

year period of increased sampling, 

should be analogous to the treatment of 

sampling frequency in situations where 

a sampler first enters into the specific 

triggering range, for purposes of 

providing predictability to monitoring 

agencies in terms of anticipating 

operational burden. In other words, 

where the sampling frequency is 

reduced at a sampler after a 3-year 

period of increased sampling frequency 

(for example, where the design value 

falls out of the ±5 percent range), that 

sampler should not be subject to an 

increased sampling frequency 

requirement for at least 3 years. With 

regard to the concern that an 

exceptional event could trigger the 

increased burden of operating a higher 

sampling frequency sampler, we believe 

that this is a plausible situation that 

deserves additional consideration. 

Rather than trying to account for this 

situation in this rule, however, we 

believe it is best dealt with in the 

context of the ongoing process of 

developing guidance and proposed 

revisions to the Exceptional Events 

rule.9 Once those actions are finalized, 

the EPA will work with Regional Offices 

to clarify how to address this situation. 

On the related concern of a ‘‘rare’’ event 

triggering increased sampling frequency, 

the EPA notes that the form of the PM2.5

NAAQS is intended to address such 

year-to-year variations such that design 

values should not be overly affected by 

‘‘rare’’ occurrences of PM2.5

concentrations in any given year. With 

regard to the comment indicating an 

apparent deletion of the PM10 sampling 

frequency requirements in 40 CFR 

58.12(e), we note that such changes 

were not included as part of the 

proposal and those requirements 

remain. 

The EPA believes that this proposed 

revision to sampling frequency 

procedures is a necessary clarification to 

the regulatory change that was finalized 

in 2006, and will provide a more 

predictable and statistically robust 

process for making design value driven 

changes in sampling frequency. Based 

on the unqualified and qualified 

supportive comments, we are finalizing 

the regulatory language as proposed. 

While we are mindful of the potential 

for added burden in cases where PM2.5

samplers must move to a more frequent 

sampling frequency for a longer period 

of time based on this revision, we also 

note that the likelihood of such 

occurrences affecting monitoring 

agencies is relatively small. Based on an 

AQS retrieval conducted in August 

2014, fewer than ten PM2.5 monitors out 

of a pool of 980 FRM monitors were 

required to operate on a daily sampling 

frequency based on the rule provisions 

of 40 CFR 58.12(d)(1)(iii).10 While this 

analysis is not predictive in nature, we 

believe the overall risk of increasing 

burden on monitoring programs is quite 

small and an acceptable consequence of 

providing a more specific way of 

implementing an important aspect of 

the sampling frequency requirements. 

Alternatively, as noted in the regulatory 

text, monitoring agencies have the 

option of installing a continuous PM2.5

FEM monitor to satisfy this requirement 

and, thereby, avoid the consequence of 

handling an increased number of filters. 

F. System Modification 

The System Modification section 

pertains to the specific requirements 

that must be followed when monitoring 

agencies request changes to the SLAMS 

portion of their networks. 

In the 2006 monitoring amendments, 

the EPA finalized a requirement in 40 

CFR 58.14(a) for monitoring agencies to 

‘‘develop and implement a plan and 

schedule to modify the ambient air 

quality network that complies with the 

finding of the network assessments 

required every 5 years by 58.10(e).’’ 

Since 2006, there has been confusion 

between the EPA and monitoring 

agencies as to whether a separate plan 

was required to be submitted by 40 CFR 

58.14(a) relative to the annual 

monitoring network plan, with that 

separate plan devoted specifically to 

discussing the results of the 5-year 

network assessment. As explained in 

the monitoring proposal, the EPA did 

not intend for the submission of a 

distinct plan devoted specifically to the 

implementation of the 5-year network 

assessment. Accordingly, the EPA 

proposed to revise the regulatory 

language in 40 CFR 58.14(a) to clearly 

indicate that a separate plan is not 

needed to account for the findings of the 

5-year network assessment, and that the 

information concerning the 

implementation of the 5-year 

assessment, referred to in the proposed 

regulatory language as a ‘‘network 

modification plan,’’ shall be submitted 

as part of the annual monitoring 

network plan that is due no later than 

the year after the network assessment is 

due.11 According to the proposed 

schedule, the annual monitoring 

network plans that are due in 2016, 

2021, etc., would contain the 

information referencing the network 

assessments. 

A number of comments were received 

on this issue. Most of the commenters 

provided the perspective that the 

clarification in the regulatory text was 

useful but that additional clarification 

was needed to address how the phrase 

‘‘implement the findings’’ was used in 

the language. Five of these commenters 

noted that states should only have to 

address those changes in the network 

assessments that are specifically 

required by regulation, and that the EPA 

should clarify that monitoring agencies 

have the flexibility to discuss what 

findings they intend to implement and 

which findings they do not intend to 

implement. Two commenters noted that 

monitoring agencies should not have to 

summarize the findings of their network 

assessment in a network modification 

plan that is due one year after the 

assessment, but rather should have the 

flexibility to address and implement 

those findings that are appropriate 

based on available resources and 

changing priorities over some period of 

time. Two commenters supported the 

proposed language without additional 

elaboration. 

The EPA agrees with the comments 

requesting additional clarification. The 

intention of the proposed revision was 

to clarify the process for how and when 

monitoring agencies should deal with 


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Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 17257 

12See http://www.epa.gov/ttn/amtic/files/

2014conference/monnaweinstock.pdf. 

13See 40 CFR part 50, appendix N, section 3.0(a) 

as revised on January 15, 2013 (78 FR 3278). 

the results from these important 

network assessments, not to imply that 

all the results should be implemented or 

were necessarily required. The network 

assessment requirements detailed in 40 

CFR 58.10(d) reference a mix of required 

elements (e.g., meeting the monitoring 

objectives of appendix D) as well as 

useful but non-required elements such 

as evaluation of new technologies and 

the evaluation of the impact on data 

users of site discontinuance. To the 

extent that the EPA used the phrase 

‘‘implements the findings of the 

network assessment’’ in the proposed 

regulatory language of 40 CFR 58.14(a), 

the concern from monitoring agencies 

about specifying which results from the 

network assessment are required and 

not required is understandable. The 

EPA always intended that the results of 

the network assessments should be used 

as a flexible planning tool for informing 

the next 5 years of monitoring network 

operations, and the specificity being 

implied by the monitoring agency 

comments reflects a misreading of those 

intentions.12 The EPA disagrees with 

the comments suggesting that a network 

modification plan is unnecessary. Such 

a requirement has been a part of the 

monitoring regulations since the 

inception of the network assessment, 

and having the network modification 

plan submitted as part of the annual 

monitoring network plan insures public 

involvement in a key process that 

occurs on a relatively infrequent basis. 

To address the concerns noted above, 

the proposed regulatory language is 

being revised to replace ‘‘implements’’ 

with ‘‘addresses,’’ as follows: ‘‘The state, 

or where appropriate local, agency shall 

develop a network modification plan 

and schedule to modify the ambient air 

quality monitoring network that 

addresses the findings of the network 

assessment required every 5 years by 

§ 58.10(d).’’ With this revision, the EPA 

is indicating that the network 

modification plan should reference or 

‘‘address’’ the findings of the network 

assessment without the unintended 

implication that some of the findings are 

required network changes that must be 

implemented. The correct vehicle for 

the discussion of required elements that 

must be implemented is the annual 

monitoring network plan that is 

required to be submitted each year, as 

discussed earlier in section II.C of this 

preamble. 

The EPA also proposed to revise an 

incorrect cross-reference in the current 

text of 40 CFR 58.14(a) in which the 

network assessment requirement is 

noted as being contained in 40 CFR 

58.10(e) when the correct crossreference is 40 CFR 58.10(d). One 

supportive comment addressed this 

issue, and the revision will be finalized 

as proposed. 

G. Annual Air Monitoring Data 

Certification 

The data certification requirement is 

intended to provide ambient air quality 

data users with an indication that all 

required validation and reporting steps 

have been completed, and that the 

certified data sets are now considered 

final and appropriate for all uses 

including the calculation of design 

values and the determination of NAAQS 

attainment status. Current requirements 

include the certification of data 

collected at all monitors at SLAMS and 

monitors at SPMs using FRM, FEM, or 

ARM methods. In practice, this 

requirement includes a very wide range 

of measurements that are not limited to 

criteria pollutants but also extend to 

non-criteria pollutant measurements at 

PAMS stations, meteorological 

measurements at PAMS and NCore 

stations, and PM2.5 chemical speciation 

parameters. 

The EPA proposed several changes in 

the data certification requirements to 

accomplish a streamlining of this 

important process. First, to support the 

focus on certification of criteria 

pollutant measurements, the EPA 

proposed to revise relevant sections of 

40 CFR 58.15 to focus the requirement 

on FRM, FEM, and ARM monitors at 

SLAMS and at SPM stations rather than 

at all SLAMS, which also include PAMS 

and CSN measurements that may not 

utilize federally approved methods. 

Second, the EPA proposed that the 

required AQS reports be submitted to 

the Regional Administrator rather than 

through the Regional Administrator to 

the Administrator as is currently 

required. Finally, minor editorial 

changes were proposed in 40 CFR 58.15 

to generalize the title of the official 

responsible for data certification (senior 

official versus senior air pollution 

control officer) and to remove an 

outdated reference to the former due 

date for the data certification letter (July 

1 versus the current due date of May 1). 

Seven commenters specifically 

addressed the proposed changes to data 

certification. Three monitoring agencies, 

one MJO, and one consulting firm were 

supportive of the changes. One of these 

commenters also noted that the data 

certification and QA report hosted on 

the AQS system, the AMP600 report, 

should be modified to provide more 

useful data certification flag 

recommendations for regions and states. 

Another of these supportive 

commenters also stated that the EPA 

should ensure that QA practices and 

responsibilities remain in place to 

validate PAMS and PM2.5 chemical 

speciation data. A joint environmental 

group comment stated that the EPA had 

not provided a rational basis for the 

proposed changes, and that an 

inconsistency exists between proposing 

to retain the data certification process 

for criteria pollutants while stating that 

existing QA plans and procedures 

would be sufficient to validate noncriteria pollutant measurements. In this 

commenter’s view, the data certification 

process, as it exists today, appears to 

delay the availability of data for use in 

computing criteria pollutant design 

values, so perhaps the agency should 

consider eliminating the process 

entirely if it is deemed unnecessary. 

Finally, one commenter asked that the 

EPA consider moving the data 

certification deadline from May 1 back 

to July 1, and also to consider not 

requiring chemical speciation data to be 

certified. 

With regard to the adverse comment, 

the EPA notes that the proposed 

changes were made to protect the 

viability of the process in the face of a 

rapidly increasing volume of data 

subject to certification requirements 

versus the available resources at the 

monitoring agency and EPA level 

needed to meet the requirements and 

deadline. We continue to believe that 

the data certification process adds the 

greatest degree of value when focused 

on criteria pollutants that support the 

calculation of design values and the 

mandatory designations process. The 

review of design values occurs on an 

annual basis and there is a longstanding practice of waiting for criteria 

pollutant data to be certified before such 

calculations are completed.13 This 

process provides a basis for 

documenting that a state’s review of 

their data is complete and that the data 

are considered final for key purposes 

such as comparison to the NAAQS. The 

same annual pattern of regular data 

usage and oversight does not exist for 

non-criteria pollutants such as PAMS, 

PM2.5 chemical species, and air toxics 

data, and these data are not directly 

compared to the NAAQS. Therefore, the 

EPA believes that the applicability and 

visibility of the data certification 

process for these measurements is less 

critical. As stated in the proposal, there 

are existing standardized procedures 

and QA documents that provide a 

framework for assuring the quality of 


Lhorne on DSK5TPTVN1PROD with RULES2
17258 Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 

14See http://www.epa.gov/ttn/amtic/

specguid.html and http://www.epa.gov/ttn/amtic/

airtoxqa.html. 

15See http://www.epa.gov/ttn/amtic/files/

2014conference/mondatdewinter.pdf or access 

DART at http://www.airnowtech.org/dart/

dartwelcome.cfm (username and password 

required). 

16The EPA expects chemical speciation data to be 

reported within 30 days of PM2.5 mass data based 

on the revised analytical framework that took effect 

in late 2015. 

non-criteria pollutants,14 and we believe 

that the resulting quality of such data 

will not be compromised by their 

removal from the data certification 

process. With regard to the comment 

requesting that the data certification 

deadline be pushed back to July 1, the 

EPA notes that this deadline was not 

proposed for revision and, therefore, is 

not being considered in this final 

rulemaking. With regard to the comment 

about excluding chemical speciation 

data from the certification process, the 

EPA notes that this procedural change 

would occur as a result of the proposed 

revisions as explained above. 

After reviewing the comments, the 

EPA is finalizing the changes to data 

certification requirements as proposed. 

The EPA agrees with commenters that 

efforts to improve the validation 

procedures for non-criteria data should 

continue and the agency has invested in 

revised tools, such as the recently 

launched Data Analysis and Reporting 

Tool (DART) web resource that can 

assist monitoring agencies with the 

validation of data including PAMS and 

air toxics data.15 Improvements are also 

being made to the AMP600 report to 

improve the utility of the program for 

generating recommended certification 

flags for consideration by monitoring 

agencies and EPA Regional Offices 

during the annual review process. 

H. Data Submittal and Archiving 

Requirements 

The requirements described in 40 CFR 

58.16 address the specific 

measurements that must be reported to 

AQS as well as the relevant schedule for 

doing so. Required measurements 

include criteria pollutants in support of 

NAAQS monitoring objectives and 

public reporting; specific ozone (O3) and 

PM2.5 precursor measurements such as 

those obtained at PAMS, NCore, and 

CSN stations; selected meteorological 

measurements at PAMS and NCore 

stations; and associated QA data that 

support the assessment of precision and 

bias. In 1997, an additional set of 

required supplemental measurements 

was added to 40 CFR 58.16 in support 

of the newly promulgated FRM for 

PM2.5, described in 40 CFR part 50, 

appendix L. In the 2006 monitoring 

amendments, many of these 

supplemental measurements were 

removed from the requirements based 

on the EPA’s confidence that the PM2.5

FRM was meeting data quality 

objectives (see 71 FR 2748). At that 

time, reporting requirements were 

retained for average daily ambient 

temperature and average daily ambient 

pressure, as well as any applicable 

sampler flags, in addition to PM2.5 mass 

and field blank mass. 

The EPA believes that it is no longer 

necessary to require agencies to report 

the average daily temperature and 

average daily pressure from manual 

PM2.5 samplers, given the long-standing 

experience with the FRM and the 

ubiquitous availability of meteorological 

data, and these specific AQS reporting 

requirements were proposed for removal 

in the monitoring proposal. The EPA 

also proposed to remove similar 

language referenced elsewhere in 40 

CFR 58.16 that pertains to 

measurements at Pb sites as well as to 

other average temperature and average 

pressure measurements recorded by 

samplers or from nearby airports. For 

the reasons noted above, the EPA 

believes that meteorological data are 

more than adequately available from a 

number of sources, and that the removal 

of specific requirements for such data to 

be reported to AQS represents an 

opportunity for burden reduction. The 

EPA notes that the requirement to report 

specific meteorological data for NCore 

and PAMS stations remains unchanged 

given the importance of having on-site 

meteorological data to correlate with 

PM2.5 and O3 precursor measurements. 

The EPA also proposed a change to the 

data reporting schedule described in 40 

CFR 58.16(b) and (d) to provide 

additional flexibility for reporting PM2.5

chemical speciation data measured at 

CSN stations. Specifically, we proposed 

that such data be required to be reported 

to AQS within 6 months following the 

end of each quarterly reporting period, 

as is presently required for certain 

PAMS measurements such as volatile 

organic compounds. This change would 

provide an additional 90 days for PM2.5

chemical speciation data to be reported 

compared with the current requirement 

of reporting 90 days after the end of 

each quarterly reporting period. This 

change was proposed to provide both 

the EPA and monitoring agencies with 

potential data reporting flexibility as 

technological and procedural revisions 

are considered for the national 

analytical frameworks that support the 

CSN network. 

Seven commenters specifically 

addressed the proposed changes to data 

submittal and archiving requirements. 

One state monitoring agency, one MJO, 

and one consulting firm were 

supportive of all of the proposed 

changes in this rule section, with the 

consulting firm comment also noting 

that average temperature and pressure 

information should still be archived 

within monitoring programs for data 

validation purposes. Two state 

monitoring agencies expressed concerns 

about the proposed change in the 

reporting deadline for PM2.5 chemical 

speciation data by noting the impacts on 

their usage of the data, one agency 

noting that efforts to submit timely 

exceptional event demonstrations 

would be impacted by the longer period 

allowed for reporting data, and the other 

state agency noting that their use of the 

speciation data to validate PM2.5 FRM 

and ion (e.g., sulfate, nitrate) data would 

be impacted. 

With specific regard to the impact on 

state submissions of exceptional event 

data exclusion determinations, the EPA 

understands the impact of the 

additional 90-day delay in gaining 

access to PM2.5 chemical speciation 

data, but also notes that the relatively 

long timelines that currently exist 

within the exceptional events rule 

framework can typically accommodate 

an additional delay of 90 days without 

significant impact on the submitting 

agency. Accordingly, we do not believe 

that the additional 90 days being 

proposed for reporting PM2.5 chemical 

speciation data should materially 

impact the ability of submitters to 

develop exceptional event data 

exclusion determinations within 

allowable timeframes.16 Concerning the 

comment relating to the availability of 

PM2.5 chemical speciation data to QA 

practices for PM2.5 FRM data, the EPA 

acknowledges the comparative value of 

such data but believes that the existing 

availability of PM2.5 sampler diagnostic 

records, collocated FRM data, as well as 

the potential availability of continuous 

monitoring data from collocated 

monitors and/or nearby sites, should be 

more than sufficient to validate PM2.5

FRM data in the absence of more timely 

reported speciation data. 

In consideration of the comments 

noted above, the EPA is finalizing the 

changes to data submittal and archiving 

requirements as proposed. 

I. Network Design Criteria (Appendix D) 

Appendix D to part 58 contains 

important information about ambient 

monitoring objectives, site types, spatial 

scales, as well as other general and 

specific minimum requirements 


Lhorne on DSK5TPTVN1PROD with RULES2
Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 17259 

17See https://www3.epa.gov/ttn/amtic/ncore.html 

for more information. 

18See supporting information for reconsideration 

of existing requirements to monitor for lead at 

urban NCore site, Kevin Cavender, Docket number 

EPA–HQ–OAR–2013–0619, http://

www.regulations.gov/#!documentDetail;D=EPA–

HQ–OAR–2013–0619–0002. 

19Specific revisions are proposed in 40 CFR part 

58, appendix D, section 3(b) and sections 4.5(b) and 

4.5(c). 

20The EPA will review requests for shutdown 

under the provisions of 40 CFR 58.14. Although the 

EPA anticipates that these non-source oriented 

monitors will have design values well below the 

NAAQS and will be eligible to be discontinued after 

3 years of data have been collected, in the event that 

a monitor records levels approaching the NAAQS, 

it may not qualify to be discontinued. 

21http://www.epa.gov/airquality/lead/

actions.html#dec2014. 

concerning network size and design 

criteria. 

The EPA proposed two changes that 

affect the required suite of 

measurements in the NCore network. 

This multi-pollutant network became 

operational on January 1, 2011, and 

includes approximately 80 stations that 

are located in both urban and rural 

areas.17

The EPA proposed a minor change to 

section 3 of appendix D to part 58, the 

design criteria for NCore sites, 

specifically, the deletion of the 

requirement to measure speciated 

PM10–2.5 from the list of measurements 

in section 3(b). An identical revision 

was finalized in the text of 40 CFR 

58.16(a) in the 2013 p.m. NAAQS final 

rule (see 78 FR 3244). During this 

process, the EPA inadvertently failed to 

complete a similar change that was 

required in the language of section 3 of 

appendix D. Accordingly we proposed 

this change to align the NCore 

monitoring requirements between the 

two sections noted above. 

The EPA also proposed to delete the 

requirement to measure Pb at urban 

NCore sites, either as Pb in Total 

Suspended Particles (Pb-TSP) or as PbPM10. This requirement was finalized as 

part of the reconsideration of Pb 

monitoring requirements that occurred 

in 2010 (see 75 FR 81126). Since that 

time, non-source oriented Pb data has 

been measured at 50 urban NCore sites, 

with the majority of sites having already 

collected at least 2 years of data. In all 

cases, valid ambient Pb readings have 

been low, with maximum 3-month 

rolling averages typically reading 

around 0.01 micrograms per cubic meter 

as compared to the NAAQS level of 0.15 

micrograms per cubic meter.18 This is 

an expected result given the elimination 

of Pb from gasoline and the refocusing 

of the ambient network to characterize 

emissions at sites that have been placed 

in relative close proximity to the 

remaining industrial sources around a 

given threshold. We expect the vast 

majority of non-source sites to have the 

3 years of data necessary to calculate a 

design value following the completion 

of monitoring in 2015. Given the 

uniformly low readings being measured 

at these NCore sites, we believe it is 

appropriate to consider eliminating this 

requirement. As noted in the associated 

docket memo, non-source oriented Pb 

data will continue to be measured (as 

Pb-PM10) at the 27 National Air Toxics 

Trends Sites (NATTS) and at hundreds 

of PM2.5 speciation stations that 

comprise the CSN and IMPROVE 

networks. 

Accordingly, the EPA proposed to 

delete the requirement to monitor for 

non-source oriented Pb at NCore sites 

from appendix D of 40 CFR part 58.19

Given the requirement to collect a 

minimum of 3 years of Pb data in order 

to support the calculation of design 

values, the EPA proposed that 

monitoring agencies would be able to 

request permission to discontinue nonsource oriented monitoring following 

the collection of at least 3 years of data 

at each urban NCore site.20

Eight commenters specifically 

addressed the proposed changes to 

network design criteria. Five state or 

local monitoring agencies, one MJO, and 

one consulting firm were supportive of 

all of the proposed changes in this 

appendix, with several of the 

monitoring agencies characterizing their 

measurements of Pb at urban NCore 

sites as either ‘‘extremely low’’ or 

between 3 percent or 5 to 7 percent of 

the Pb NAAQS. One joint 

environmental group comment 

disagreed with the proposed change to 

Pb monitoring, noting the perspective 

that there is no safe level of Pb and that 

data even well below the level of the 

NAAQS could assist communities with 

finding ways of reducing Pb exposure 

and that such data would also assist 

researchers investigating the risks of Pb 

exposure for children. This commenter 

also noted that the EPA might propose 

to lower the Pb NAAQS in an upcoming 

rulemaking that was pending at the time 

when the comment was submitted. 

With regard to the adverse comment, 

the EPA notes in the referenced docket 

memo that well over 300 monitoring 

sites for Pb would remain in operation 

following the proposed termination of 

monitoring at urban NCore sites. These 

remaining sites would provide 

characterization of Pb in TSP, PM10, and 

PM2.5 in a variety of urban and rural 

locations including source oriented 

sites, neighborhood/community 

locations, and background areas. We 

also note that the EPA retains the 

authority to require additional Pb 

monitoring as determined by Regional 

Administrators per the rule language in 

appendix D, section 4.5(c). With regard 

to the reference to the EPA’s upcoming 

decision on the Pb NAAQS, we note 

that on December 19, 2014, based on a 

review of the full body of evidence, the 

EPA proposed to retain, without 

revision, the current NAAQS of 0.15 

micrograms per cubic meter (as a 3- 

month average in TSP) as requisite to 

protect public health and welfare.21

In consideration of the supportive 

comments noted above, the EPA is 

finalizing the changes to network design 

criteria as proposed. With specific 

regard to Pb monitoring at urban NCore 

sites, monitoring agencies should 

request permission from the EPA 

Regional Administrator to discontinue 

non-source oriented monitoring 

following the collection of at least 3 

years of complete data at each affected 

site. Monitoring agencies should work 

closely with their respective EPA 

Regional Offices to ensure review and 

coordination of these changes to the 

network and inclusion of such changes 

in annual monitoring network plans. 

III. Amendments to Quality Assurance 

Requirements 

A. Quality Assurance Requirements for 

Monitors Used in Evaluations for 

National Ambient Air Quality 

Standards—Appendix A 

1. General Information 

The following changes to monitoring 

requirements relate to appendix A to 

part 58. Changes that affect the overall 

appendix are discussed in this section 

of the preamble while changes specific 

to the various sections of the appendix 

will be addressed in subsequent 

sections of the preamble. The EPA notes 

that the entire regulatory text section for 

appendix A will be reprinted since this 

section is being reorganized for clarity 

as well as being selectively revised as 

described in detail below. Additionally, 

although the EPA proposed a new 

appendix B to apply to PSD monitors, 

much of the proposed content of 

appendix B was taken directly from the 

existing requirements for these monitors 

set forth in appendix A. It should be 

noted that a number of provisions from 

appendix A were reprinted in the 

regulatory text for appendix B solely for 

clarity, to assist the public in 

understanding the changes being 

proposed. The EPA did not solicit 

comment on those provisions and did 

not make any changes to those 

provisions in this rulemaking. 


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17260 Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 

22See http://www.epa.gov/ttn/amtic/

specguid.html for CSN quality assurance project 

plan. 23See http://www.epa.gov/ttn/amtic/

pamsguidance.html for PAMS technical assistance 

document. 

The QA requirements in appendix A 

have been developed for measuring the 

criteria pollutants of O3, NO2, sulfur 

dioxide (SO2), CO, Pb and PM (PM10

and PM2.5), and are minimum 

requirements for monitoring these 

ambient air pollutants for use in 

NAAQS attainment demonstrations. To 

emphasize the objective of this 

appendix, the EPA proposed to change 

the title of appendix A to ‘‘Quality 

Assurance Requirements for Monitors 

used in Evaluations of National 

Ambient Air Quality Standards,’’ and 

remove the terms SLAMS and SPMs 

from the title. We do, however, in the 

applicability paragraph, indicate that 

any monitor identified as SLAMS must 

meet the appendix A criteria in order to 

avoid any confusion about SLAMS 

monitors measuring criteria pollutants. 

Special purpose monitors may in fact be 

monitoring for a criteria pollutant for 

other objectives besides making 

comparisons to the NAAQS. Therefore, 

appendix A clarifies in the title and the 

applicability section that the QA 

requirements specified in this appendix 

are for criteria pollutant monitors that 

are designated, through the Part 58 

ambient air regulations and monitoring 

organization annual monitoring network 

plans, as eligible to be used for NAAQS 

evaluation purposes. The applicability 

section also provides a reporting 

mechanism in AQS to identify any 

criteria pollutant monitors that are not 

used for NAAQS evaluations. The 

criteria pollutants identified for NAAQS 

exclusion will require review and 

approval by the EPA Regional Offices 

and will increase transparency and 

efficiencies in the NAAQS designation, 

data quality evaluation and data 

certification processes. There were no 

adverse comments to the change in the 

title and, therefore, the title will be 

changed as proposed. 

The previous appendix A regulation 

had separate sections for automated 

(continuous) and manual method types. 

The EPA proposed to reformat the 

document by pollutant rather than by 

method type. The four gaseous 

pollutants (CO, NO2, SO2 and O3) will 

be contained in one section since the 

quality control (QC) requirements are 

very similar, and separate sections will 

be provided for PM10, PM2.5, and Pb. 

The EPA received one supportive 

comment from a consulting firm made 

on the proposed reformatting and no 

adverse comments. Therefore, appendix 

A and appendix B will be reformatted 

as proposed. 

In the 2006 monitoring rule revisions, 

the PSD QA requirements, which were 

previously in appendix B, were added 

to appendix A and appendix B was 

reserved. The PSD requirements, in 

most cases, mimicked appendix A in 

structure but because PSD monitoring is 

often operated only for a period of 1 

year, some of the frequencies of 

implementation of the PSD 

requirements are higher than the 

appendix A requirements. In addition, 

the agencies governing the 

implementation, assessment and 

approval of the QA requirements are 

different for PSD and ambient air 

monitoring for NAAQS decisions (i.e., 

the EPA Regions for appendix A versus 

PSD reviewing authorities for PSD). The 

combined regulations have caused 

confusion among monitoring 

organizations and those implementing 

PSD requirements, so the EPA proposed 

that the PSD requirements be moved 

back to a separate appendix B. This 

change would also provide more 

flexibility for revision if changes in 

either appendix are needed. 

The EPA received one supportive 

comment to adopt this change and 

received no adverse comments. 

Therefore, PSD QA requirements will be 

placed into appendix B as proposed. 

Finally, the EPA proposed that 

appendix A emphasize the use of PQAO 

and moved the definition and 

explanation to the beginning of the 

regulation in order to ensure that the 

application and use of PQAO in 

appendix A is clearly understood. The 

definition for PQAO was not proposed 

for change. Since the PQAO can be a 

consolidation of a number of local 

monitoring organizations, the EPA 

proposed to add a sentence clarifying 

that the agency identified as the PQAO 

(usually the state agency) will be 

responsible for overseeing that the 

appendix A requirements are being met 

by all local agencies within the PQAO. 

Current appendix A regulation requires 

PQAOs to be approved by the EPA 

Regions during network reviews or 

audits. The EPA believes this approval 

can occur at any time and proposed to 

eliminate wording that suggests that 

PQAO approvals can only occur during 

events like network reviews or audits. 

The EPA received one comment 

supporting the clarifying language 

suggesting it will reduce unnecessary 

work on the part of the monitoring 

agencies by combining and 

consolidating QA/QC activities and also 

fostering a unified approach to air 

monitoring across an entire state’s 

PQAO. The EPA received no adverse 

comments. Therefore, the EPA is 

finalizing the language as proposed. 

2. Quality System Requirements 

The EPA proposed to remove the QA 

requirements for PM10-2.5 (see current 

sections 3.2.6, 3.2.8, 3.3.6, 3.3.8, 4.3). 

Appendix A has traditionally been used 

to describe the QA requirements of the 

criteria pollutants used in making 

NAAQS attainment decisions. While the 

part 58 Ambient Air Monitoring 

regulation requires monitoring for the 

CSN, PAMS, and total oxides of 

nitrogen (NOy) for NCore, the QA 

requirements for these networks are 

found in technical assistance documents 

and not in appendix A. In 2006, the EPA 

proposed a PM10-2.5 NAAQS along with 

requisite QA requirements in appendix 

A. While the PM10-2.5 NAAQS was not 

promulgated, PM10-2.5 monitoring was 

required to be performed at NCore sites 

and the EPA proposed requisite QA 

requirements in appendix A. Some of 

the PM requirements, like collocation 

for precision and the performance 

evaluation programs for bias, are 

accomplished on a percentage of 

monitoring sites within a PQAO. For 

example, collocated sampling for PM2.5

and PM10 is required at approximately 

15 percent of the monitoring sites 

within a PQAO. Since virtually every 

NCore site is the responsibility of a 

different PQAO, the appendix A 

requirements for PM10-2.5, if 

implemented at the PQAO level, would 

have been required to be implemented 

at almost every NCore site, which would 

have been expensive and an unintended 

burden. Therefore, the EPA required the 

implementation of the PM10-2.5 QC 

requirements at a national level and 

worked with the EPA Regions and 

monitoring organizations to identify the 

sites that would implement the 

requirements. The implementation of 

the PM10-2.5 QC requirements at NCore 

sites fundamentally changed how QC is 

implemented in appendix A and has 

been a cause of confusion. Since 

PM10-2.5 is not a NAAQS pollutant and 

the QC requirements cannot be costeffectively implemented at a PQAO 

level, the EPA proposed to eliminate the 

PM10-2.5 requirements including flow 

rate verifications, semi-annual flow rate 

audits, collocated sampling procedures, 

and the PM10-2.5 Performance Evaluation 

Program (PEP). Similar to the technical 

assistance documents associated for the 

CSN 22 and PAMS 23 networks, the EPA 

will develop QA guidance for the 

PM10-2.5 network which will afford more 

flexibility for implementation and 

revision of QC activities for PM10-2.5. 

The EPA received comments from a 

state and a consulting firm in support of 


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the removal of these requirements and 

no adverse comments. Therefore, the 

EPA will remove the PM10-2.5 QA 

requirements as proposed. 

The EPA proposed that the QA Pb 

requirements of collocated sampling 

(see current section 3.3.4.3) and Pb 

performance evaluation procedures (see 

current section 3.3.4.4) for non-source 

oriented NCore sites be eliminated. The 

2010 Pb rule in 40 CFR part 58, 

appendix D, section 4.5(b), added a 

requirement to conduct non-source 

oriented Pb monitoring at each NCore 

site in a core based statistical area 

(CBSA) with a population of 500,000 or 

more. This requirement had some 

monitoring organizations implementing 

Pb monitoring at only their NCore sites. 

Since the appendix A requirements are 

focused on PQAOs, the QC 

requirements would increase at PQAOs 

who were required to implement Pb 

monitoring at their NCore site. Similar 

to the PM10-2.5 QA requirements, the 

requirement for Pb at NCore sites forced 

the EPA away from a focus on PQAOs 

to working with the EPA Regions and 

monitoring organizations for 

implementation of the Pb-PEP at NCore 

sites at national levels. Therefore, the 

EPA proposed to eliminate the 

collocation requirement and the Pb-PEP 

requirements at NCore sites while 

retaining the requirements for flow rate 

verifications and flow rate audits, which 

do not require additional monitors or 

independent sampling and analysis. 

Similar to the CSN and PAMS programs, 

the EPA will develop QA guidance for 

Pb monitoring in the NCore network, 

which will afford more flexibility for 

change/revision to accommodate Pb 

monitoring at non-source oriented 

NCore sites. Additionally, the EPA 

proposed to delete the requirement to 

measure Pb at these specific NCore sites, 

either as Pb-TSP or as Pb-PM10 (see 

section II.I). Such a revision would 

eliminate the need for any associated 

QA requirements including collocation, 

Pb-PEP or any QC requirements for 

these monitors. 

The EPA received two state comments 

and one MJO comment in support of the 

removal of this requirement and no 

adverse comments. Therefore, the EPA 

will remove the Pb QA requirements at 

non-source oriented NCore sites as 

proposed. As noted earlier in section 

II.I, the EPA is also finalizing the 

proposed deletion of Pb monitoring 

requirements at NCore sites from 

appendix D. 

The EPA proposed that quality 

management plan (QMP) (current 

section 2.1.1) and quality assurance 

project plan (QAPP) (current section 

2.1.2) submission and approval dates be 

reported by monitoring organizations 

and the EPA. This will allow for timely 

and accurate reporting of this 

information. From 2007 to 2011, the 

EPA tracked the submission and 

approval of QMPs and QAPPs by 

polling the EPA Regions each year and 

updating a spreadsheet that was posted 

on the Ambient Monitoring Technical 

Information Center (AMTIC) Web site. 

The development of the annual 

spreadsheet was time-consuming on the 

part of monitoring organizations and the 

EPA and, due to polling delays, took a 

significant amount of time to assemble 

a final version for posting. It is expected 

that simplified reporting by monitoring 

organizations and EPA to AQS will 

reduce entry errors and the burden of 

incorporating this information into 

annual spreadsheets, and increase 

transparency of this important quality 

system documentation. In order to 

reduce the initial burden of this data 

entry activity, the EPA populated AQS 

with the last set of updated QMP and 

QAPP data from the 2011 listing. 

Monitoring organizations will need to 

update AQS only when submitting new 

or revised versions of QAPP or QMPs 

(one or two fields) and the EPA can then 

add approval dates. 

The EPA received one state comment 

in support of this proposal, and two 

states, a consulting firm and one MJO 

commented expressing concern. One 

state commenter mentioned that the 

preamble indicates that the monitoring 

organizations would be responsible for 

submitting the dates associated with 

QMP and QAPP submittals and 

approvals and, if this was the intent of 

the proposed rule, AQS must be 

modified to allow monitoring 

organizations the ability to enter this 

data. The commenter also mentioned 

that the EPA’s AQS web application 

only allows monitoring organizations to 

view QAPP and QMP dates, but the 

functionality to enter or revise those 

dates is unavailable. The commenter 

mentioned other issues related to the 

current functionality of the system but 

not a disagreement with the proposed 

requirement to report the data. 

The MJO commenter mentioned that 

reporting to AQS was an unnecessary 

burden on state air monitoring agencies 

because the EPA Regional Offices 

receive these reports and the 

information is available to the public on 

the EPA AMTIC Web site. The 

consulting firm did not understand how 

shifting this burden to ‘‘monitoring 

organizations’’ would relieve the 

reporting burden on any organization 

other than the EPA. 

As mentioned in the proposal, the 

approach of reporting QAPP and QMP 

information to AMTIC was not only 

time-consuming for monitoring 

organizations but also for EPA who 

would work for 2 to 3 months to pull 

together this annual report. By reporting 

the information directly to AQS, the 

monitoring organization’s requirements 

are also reduced since they do not need 

to be polled every year to gather this 

information, review it for accuracy and 

completeness, and transmit it to the 

EPA Regional Office. The monitoring 

organizations will only need to report 

updates to AQS when they occur and 

will not be burdened with this request/ 

review process every year. 

In regard to the comment related to 

the current functionality of AQS, which 

did not allow agency reporting of the 

QMP/QAPP information, the EPA notes 

that AQS is now available for 

monitoring organizations, and EPA 

Regional Offices, to report this 

information that has currently been 

reported and revised by the EPA. 

Therefore, rather than posting a static 

table on AMTIC each year (which could 

change through-out the time period 

between updates), AMTIC can host a 

link to the most up-to-date information 

in AQS, which is a much more efficient 

method than the cumbersome annual 

collection and reporting method 

described above. Therefore, the EPA is 

finalizing the requirement as proposed. 

The EPA proposed that if a PQAO or 

monitoring organization has been 

delegated authority to review and 

approve their QAPP, an electronic copy 

must be submitted to the EPA Regional 

Office at the time it is submitted to the 

PQAO/monitoring organization’s QAPP 

approving authority. Submission of an 

electronic version to the EPA at the time 

of completion is not considered an 

added burden on the monitoring 

organization because such submission is 

already a standard practice as part of the 

review process for technical systems 

audits (TSA). 

The EPA did not receive any 

supporting or adverse comments to this 

proposal, but did receive a state 

comment suggesting that a copy of all 

approved QAPP’s be submitted annually 

rather than at the time when a QAPP is 

submitted or approved. The EPA notes 

that during recent systems audits, EPA 

auditors have found language in 

approved QAPPs that do not meet 

ambient air regulatory requirements. 

Non-conformance with a regulatory 

requirement can lead to data 

invalidation. In an effort to identify any 

non-conformance with regulatory 

requirements as early as possible, 

especially with monitoring 

organizations that have been delegated 

responsibility to approve their own 


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17262 Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 

24See http://www.epa.gov/ttn/amtic/

npepqa.html. 

QAPPs, the EPA believes it is important 

to have the opportunity to review these 

documents as early as possible to 

eliminate potential data invalidation 

issues. Therefore, the EPA is finalizing 

this language as proposed. 

In the QAPP requirement language, 

the EPA proposed to clarify that the 

QAPP include a list of sites and 

monitors associated with the QAPP. 

The EPA received a state comment 

that considered it a burden to update 

the QAPP every time a site or monitor 

is changed or is added. The commenter 

suggested adding that this information 

can be referenced in other publicly 

available documents. Since this section 

allows standard operating procedures to 

be referenced in the QAPP, the EPA will 

also allow the referencing of monitors 

and sites. 

The requirement to identify the sites/ 

monitors in a QAPP is a standard QAPP 

requirement and is why it is included in 

the regulation. However, the QAPP can 

refer to an official table that is updated 

annually that may be on a Web site or 

other official documentation (e.g., 

annual network plan). In addition, if the 

QAPP does contain this information, an 

addendum to the QAPP modifying this 

information (with reference to the 

QAPP) can be accomplished without 

having to physically edit the document 

each time a monitoring site is added 

because the addition of the site does not 

affect how the quality system is 

implemented. 

The EPA is finalizing the requirement 

as proposed, but is also clarifying that 

sites and monitors may be allowed to be 

referenced from other up-to-date 

sources. 

The EPA proposed to add some 

clarifying language to the section 

describing the National Performance 

Evaluation Program (NPEP) (current 

section 2.4) explaining selfimplementation of the performance 

evaluation by the monitoring 

organization. The clarification also adds 

the definition of ‘‘independent 

assessment’’ which is included in the 

PM2.5-PEP, Pb-PEP and National 

Performance Audit Program (NPAP) 

QAPPs, and is included in the selfimplementation memo sent to the 

monitoring organizations on an annual 

basis and posted on the AMTIC Web 

site.24 The clarification codifies in 

regulation what was in guidance, and 

provides a better reference for this 

information in addition to the annual 

memo sent to the monitoring 

organizations. 

The EPA received one state comment 

in support of the addition of the 

independent assessment definition and 

one state comment noting concern. 

The state comment of concern 

included a reference to the NPAP 

revisions that are proposed below 

(section 3.1.3) and does not appear to be 

related to the actual definition that was 

proposed in this section. Further, we 

note that the state that made the 

comment qualifies as eligible to conduct 

an ‘‘independent assessment’’ under the 

current definition that was proposed 

and has been defined in this way in 

annual self-implementation decision 

memorandums that have been sent to 

monitoring organizations since 2008. 

This definition has not changed and was 

expected to be achieved by monitoring 

organizations in order to self-implement 

the various performance evaluations 

defined in this section. Therefore, the 

EPA is finalizing the requirement as 

proposed. 

The EPA proposed to add clarifying 

language to the TSA section (current 

section 2.4). As described in more detail 

below, the current TSA requirements 

are clearly intended to be performed at 

the monitoring organization level. 

The EPA proposed a TSA frequency 

of 3 years for each PQAO, but included 

language that if a PQAO is made up of 

a number of monitoring organizations, 

all monitoring organizations within the 

PQAO should be audited within 6 years. 

This proposed language maintains the 3 

year TSA requirement as it applies to 

PQAOs but provided additional 

flexibility for the EPA Regions to audit 

every monitoring organization within 

the PQAO every 6 years. This revision 

was made to address logistical concerns 

at the EPA Regions, particularly for 

those Regions with very large PQAOs 

composed of many monitoring 

organizations. In the EPA’s view, the 

proposed revision did not materially 

affect the burden on monitoring 

organizations. 

The EPA received one state comment 

supporting the proposed revision as 

written, one comment by a joint 

environmental organization suggesting 

that we maintain the current 

requirement to audit each monitoring 

organization on a 3-year basis, and two 

state comments that suggested that the 

proposed revision was a burden to 

monitoring organizations. 

The comment from the joint 

environmental organization expressed 

concern with the potential for reduced 

frequency of the TSAs for monitoring 

organizations in consolidated PQAOs 

(proposed 6-year frequency versus 

current 3-year frequency). The 

commenter believed such a change 

could seriously jeopardize 

implementation of the Act and threaten 

public health by delaying NAAQS 

decisions. The commenter cited 

examples of recent invalidation of PM2.5

data that were based on findings from 

TSAs. In their view, delaying audit 

frequencies to once every 6 years (for a 

monitoring organization) raises the risk 

of even greater delay and disruption of 

nonattainment designations in areas that 

are violating NAAQS and have data 

quality issues at the pertinent 

monitoring organizations. 

Two commenters from state agencies 

felt that the proposed language would 

treat these monitoring organizations 

(within a PQAO) as individual entities, 

causing an increase in the number of 

TSAs and difficulty in ensuring 

consistency among monitoring 

organizations within the PQAO, and 

would disrupt monitoring organizations 

with the scheduling of these audits. The 

PQAO staff would be required to 

oversee the changes throughout the 

monitoring organizations, participate in 

each of the TSAs, track all corrective 

actions, verify implementation, and 

ensure consistency of implementation 

across all monitoring organizations. 

Commenters who were concerned 

with the proposed language to audit 

individual monitoring organizations 

within a PQAO may have been 

interpreting the current and earlier 

appendix A requirements somewhat 

differently than the original intent of the 

EPA. Since 1996, the TSA language in 

appendix A has been associated with 

auditing monitoring agencies or 

monitoring organizations, not PQAOs 

(note—the PQAO term was promulgated 

in 2006). For additional context, the 

following rule excerpts provide a 

chronological history of the TSA 

language in appendix A. 

Prior to 1998: ‘‘Agencies operating 

SLAMS network stations shall be subject 

to annual EPA systems audits of their 

ambient air monitoring program and are 

required to participate in EPA’s 

National Performance Audit Program.’’ 

1998: ‘‘Systems audits of the ambient 

air monitoring programs of agencies 

operating SLAMS shall be conducted at 

least every 3 years by the appropriate 

EPA Regional Office.’’ 

2005: ‘‘Systems audits of the ambient 

air monitoring programs of agencies 

operating SLAMS shall be conducted at 

least every 3 years by the appropriate 

Regional Office.’’ 

2006–2014 (prior to this proposed 

change): ‘‘Technical systems audits of 

each ambient air monitoring 

organization shall be conducted at least 

every 3 years by the appropriate EPA 


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25McCabe, Janet G. (2014). Particle Pollution 

Quality Assurance. Memorandum to the Docket, 

EPA–HQ–OAR–2013. 

26See http://www.reginfo.gov/public/

Forward?SearchTarget=PRA&textfield=ambient+

air+protocol+gas. 

Regional Office and reported to the 

AQS.’’ 

The EPA notes that the current 

definition (40 CFR 58.1) for a 

monitoring agency (prior to this 

proposal) was defined as ‘‘a state or 

local agency responsible for meeting the 

requirements of this part.’’ Monitoring 

organization was defined as a ‘‘state, 

local, or other monitoring organization 

responsible for operating a monitoring 

site for which the quality assurance 

regulations apply.’’ Neither definition 

described any consolidation of agencies 

into a PQAO; therefore, individual 

monitoring agencies or organizations 

were to receive a TSA by the EPA 

Region annually prior to 1998 and every 

3 years after 1998. 

As indicated by one of the 

commenters who suggested that the 

proposed language would treat 

monitoring organizations as individual 

entities, the TSA language was, in fact, 

defined to treat the monitoring agencies 

as individual entities. The value of this 

approach has been reaffirmed by recent 

TSAs where Regional Office auditors 

have found that monitoring 

organizations within consolidated 

PQAOs, in some cases, did not operate 

consistent quality systems. 

A commenter expressing concern 

about the proposed revision made the 

point that all monitoring organizations 

covered under the umbrella of the 

PQAO’s quality system would have to 

make changes in their operation each 

time a TSA at any of the monitoring 

organizations indicates an issue with 

that monitoring organization’s quality 

system. This comment reflects a concern 

(and a tacit acknowledgement) that 

monitoring organizations within a 

PQAO do not necessarily implement a 

consistent quality system and need to be 

audited at some frequency. The 

commenter is correct and the EPA 

agrees that an issue identified by a TSA 

at one monitoring organization within 

the PQAO should be reviewed by the 

PQAO to determine if corrective action 

should be instituted for all monitoring 

organizations operating in the PQAO. 

That is the specific concern that has 

driven the EPA’s regulations to 

consistently require TSAs at the 

monitoring organization level. The 

proposed TSA language provides for 

this review of the PQAO every 3 years 

and of all monitoring organizations 

within the PQAO within 6 years. 

A state agency commenter was also 

concerned that TSAs could affect the 

data certification process. The 

commenter was concerned that EPA 

concurrence with a PQAO’s data 

certification could be prohibited due to 

the lack of a TSA within the appropriate 

time frame. The EPA notes that TSA 

completeness requirements are reported 

on certification reports but do not affect 

the concurrence process itself and, 

therefore, do not penalize the PQAO if 

the TSA is not performed at the required 

frequency. 

In response to the comment from the 

joint environmental organization and 

based on the recent findings in the 

TSAs,25 the EPA Regions are providing 

more scrutiny on the PQAO 

requirements to ensure that monitoring 

organizations consolidated in PQAOs 

develop and document consistent 

quality practices. The EPA Headquarters 

and Regions are working together to 

develop a more consistent TSA process 

based on ‘‘lessons learned’’ from the 

PM2.5 TSAs findings identified in the 

joint environmental organization 

comment. In addition, Regions are 

scrutinizing PQAO quality systems to 

ensure a level of QA consistency of 

monitoring organizations within a 

PQAO and, where there are issues, 

either taking corrective actions or 

suggesting that monitoring organizations 

within a PQAO disaggregate. The EPA 

has also seen PQAOs developing better 

documents and training for monitoring 

organizations within PQAOs to improve 

quality system consistency. Based on 

the information presented above, the 

EPA believes that the proposal to allow 

monitoring organizations within a 

PQAO to be audited within a 6-year 

period is reasonable and is finalizing the 

requirement as proposed. 

In summary, the revised regulation 

specifies that EPA Regional Offices 

conduct TSAs of every PQAO at a 3-year 

frequency and that they should also 

perform a TSA on all monitoring 

organizations within the PQAO within 6 

years. Where resources permit, the EPA 

encourages the adoption of the practice 

of some PQAOs to perform their own 

agency-specific TSAs and monitoring 

site visits on member monitoring 

agencies in the intervening years 

between required EPA Regional Office 

TSAs. Such visits can help to 

proactively identify potential QA 

deficiencies before situations involving 

long-term data loss occur and can also 

serve to assure uniformity in procedures 

across PQAOs through periods of 

changing personnel, equipment, or EPA 

requirements. 

The EPA proposed to require 

monitoring organizations to complete an 

annual survey for the Ambient Air 

Protocol Gas Verification Program (AA– 

PGVP) (current section 2.6.1). Since 

2009, the EPA has had a separate 

information collection request 26

requiring monitoring organizations to 

complete an annual survey of the 

producers that supply their gas 

standards (for calibrations and QC) in 

order to be able to select standards from 

these producers for verification. The 

survey generally takes less than 10 

minutes to complete. The EPA proposed 

to add the requirement to complete the 

survey to appendix A. 

The EPA received one consulting firm 

comment suggesting that entry of data in 

the annual survey was a modest burden 

and another state comment of support 

without additional comment. There 

were no adverse comments on 

completing the annual survey. 

Therefore, the EPA is finalizing the 

language as proposed. 

In addition, the EPA proposed to add 

language that monitoring organizations 

participate, at the request of the EPA, in 

the AA–PGVP by sending a gas standard 

to one of the verification laboratories no 

more frequently than every 5 years. 

Since many monitoring organizations 

already volunteer to send in cylinders, 

this proposed new requirement is not 

expected to materially affect most 

agencies and will not affect those 

agencies that do not run gaseous 

ambient air monitors and, therefore, do 

not use gas standards. 

The EPA received three state 

comments supporting and one MJO and 

two state comments expressing concern 

about this aspect of the AA–PGVP 

requirement. The supportive responses 

included one organization already 

participating in the program and 

another that mentioned that the 

independent verification of cylinder 

contents has value for monitoring 

groups especially with respect to the 

lower target gas concentrations now 

employed in QA procedures. A third 

response supported the action with no 

additional comments. Comments 

expressing concern about the proposal 

were related to the extra cost associated 

with shipping a cylinder to the 

verification laboratory and the 

Department of Transportation (DOT) 

training required for shipping the 

cylinder. One commenter mentioned 

that the organizations are already 

required to use traceable or certified 

gases and another suggested that the 

EPA could also consider working with 

the standard gas vendors directly, 

potentially through a federally funded 

gas certification and verification 

program. A commenter suggested the 


Lhorne on DSK5TPTVN1PROD with RULES2
17264 Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 

27U.S. Environmental Protection Agency. ‘‘EPA 

Needs an Oversight Program for Protocol Gases,’’ 

Office of Inspector General Report No. 09–P–0235, 

2009. 

28http://www.epa.gov/ttnamti1/files/ambient/

qaqc/aapgvpimpplan.pdf. 29QA Handbook for Air Pollution Measurement 

Vol. II Ambient Air Quality Monitoring Program at: 

http://www.epa.gov/ttn/amtic/qalist.html. 

30Papp, M. (2015). Assessments of One-Point QC 

Data in Response to Comments on Revisions to the 

Ambient Air Quality Assurance Regulation 

contained in 40 CFR part 58, appendix A. 

Memorandum to the Docket, EPA–HQ–OAR–2013– 

0619. 

requirement is resource intensive 

because additional standard gases will 

need to be maintained for use while the 

audited cylinder is not in use. 

By way of background relating to the 

genesis of the AA–PGVP, the EPA notes 

that the Office of Research and 

Development (ORD) operated a protocol 

gas audit program that was discontinued 

in 1997. In the mid-2000 timeframe, the 

EPA received a number of comments 

from monitoring organizations that the 

program was needed and the current 

program (implemented in 2010) was 

created based on those comments. The 

monitoring organizations were 

concerned that they were receiving 

cylinders that were not meeting the 

protocol gas specifications even though 

the producers, as one commenter 

mentioned, are required to use traceable 

or certified gases. Information from a 

2009 Office of Inspector General report 

indicated some failures to meet protocol 

gas requirements by some protocol gas 

producers.27 Gas producers were also 

sharing concerns with the EPA that 

some producers were selling cylinders 

that were not properly verified. 

Although the EPA initially tried to 

develop a program that would be 

funded by the gas vendors, many of 

whom agreed to fund it, one producer 

lodged a protest and the EPA could not 

implement the program in this manner. 

In addition, the AA–PGVP is intended 

to be a blind verification of the 

producers, meaning it would be most 

advantageous for the producer not to 

know a cylinder is being sent to a 

verification lab and, therefore, the EPA 

tries not to request cylinders directly 

from gas producers. Although one 

commenter suggested that the EPA 

receive cylinders directly from the 

producer, this would defeat the purpose 

of the blind verification and the 

producers would have the opportunity 

to send a cylinder that may have had 

additional testing against its certified 

value. The AA–PGVP has been 

implemented since 2010 and the EPA is 

starting to see a drop in monitoring 

organization participation, yet we also 

received positive comments that the 

program is valuable in keeping the 

producers aware of the need for the 

quality of their gas standards. 

In response to the comment 

expressing concern about the cost of 

participating in the program and the 

logistical difficulty of properly being 

certified to ship cylinders, the EPA 

clarifies that with the current program, 

the EPA covers the cost of shipping the 

cylinders to and from the regional AA– 

PGVP verification laboratory. Online 

DOT training is offered to monitoring 

organizations and is valid for 3 years. So 

although there is an expense to the 

monitoring organization on the time to 

train, there is limited burden related to 

the rest of the program. The EPA is 

aware that additional standard gases 

will need to be maintained for use while 

the new cylinder is being sent for 

verification. Most monitoring 

organizations order new cylinders prior 

to expiration of older cylinders or before 

they run out of gas supply. There is 

normally a transition period where new 

cylinders are on hand and checked 

against the current cylinder before 

retiring the older cylinder. The AA– 

PGVP Implementation Plan 28 describes 

that during this change-out process, if 

the new cylinder is ordered with 

enough lead time (AA–PGVP estimates 

30–45 days from shipping through 

verification and cylinder return), it 

could be sent to the AA–PGVP 

verification laboratory and verified prior 

to use by monitoring organizations 

before it needed to be exchanged with 

an older cylinder. 

Based on the comments received and 

the EPA’s clarifications of the need for 

the current program, the EPA will 

codify the ICR requiring monitoring 

organizations to report the gas standard 

producers it uses on an annual basis and 

also finalize the proposed language 

allowing the agency to request cylinders 

from monitoring organizations no more 

frequently than every 5 years. 

3. Measurement Quality Checks for 

Gases 

The EPA proposed to lower the audit 

concentrations (current section 3.2.1) of 

the one-point QC checks to between 

0.005 and 0.08 parts per million (ppm) 

for SO2, NO2, and O3 (currently 0.01 to 

0.1 ppm), and to between 0.5 and 5 ppm 

for CO monitors (currently 1 and 10 

ppm). With the development of more 

sensitive monitoring instruments with 

lower detection limits, technical 

improvements in calibrators, and lower 

ambient air concentrations in general, 

the EPA felt this revision would better 

reflect the precision and bias of the 

ambient air data being measured at the 

site. Since the QC check concentrations 

are selected using the mean or median 

concentration of typical ambient air 

concentrations (guidance on this is 

provided in the QA Handbook 29), the 

EPA proposed to add some clarification 

to the current language by requiring 

monitoring organizations to select either 

the highest or lowest concentration in 

the ranges identified if their mean or 

median concentrations are above or 

below the prescribed range. 

The majority of the comments (19 of 

26 responding to the quality assurance 

proposal) received on appendix A were 

related to this proposed change. One 

state and one consulting firm 

commenter expressed support for the 

change but the majority of commenters 

expressed concern (16 state commenters 

and one MJO). Most of the commenters 

expressed similar technical concerns 

that: 

• The SLAMS network is in place 

mainly for decisions related to the 

NAAQS, so QC checks should be at the 

levels approximating the NAAQS 

values. 

• Some of the FRM or FEM that are 

still in use may operate acceptably at 

concentrations around the NAAQS, but 

the older versions of the approved 

monitors are not as sensitive at lower 

concentrations (i.e., mean or median 

concentrations), so QC checks at these 

lower levels are beyond the operational 

limits of the instrumentation. 

• The instrumentation necessary to 

challenge the monitors at the lower 

concentrations (calibrators with 

additional mass flow controllers or gas 

cylinders of lower concentrations) 

would be required to comply and, 

therefore, represent an added expense 

and burden. 

• The lower concentrations affect the 

percent difference statistic so there is 

more chance that the QC check will fail 

the acceptance requirements and, 

therefore, invalidate data that the 

monitoring organization feels is of 

acceptable quality. 

The EPA acknowledges these 

comments and has performed some 

evaluations on 2013 hourly gaseous data 

that are summarized in a memo placed 

in the docket.30 As summarized in the 

memo, the EPA generally believes that 

challenging ambient air analyzers with 

a one-point QC check at the level of the 

NAAQS provides an incomplete and 

potentially inaccurate representation of 

the precision and bias of the data 

actually reported to the AQS since, in 

most cases, the precision and bias 

estimates are performed at levels that 

are above 99 percent of the actual 

SLAMS data reported to AQS. The 


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31A check similar to the QC check but 

implemented at a concentration closer to the higher 

end of the calibration range of the monitor. 

32http://www.epa.gov/ttnamti1/files/ambient/

pm25/datamang/20110217lowlevelstatmemo.pdf. 

EPA’s analysis of QC check data shows 

that many monitoring agencies are 

successfully meeting measurement 

quality objectives at lower 

concentrations that are closer to the 

routine ambient data being reported to 

AQS. We recognize that some of these 

QC checks may be reported by 

monitoring organizations that have 

invested in the technology (i.e., 

analyzers, calibration devices and 

standards at NCore sites) necessary to 

adequately calibrate and estimate 

precision and bias at the concentrations 

measured at ambient levels. This 

analysis demonstrates that the 

technology is available to measure and 

report precision and bias at mean/

median ambient air concentration 

levels. 

At the same time, the EPA is aware 

that there are monitoring agencies that 

have not yet invested in some of these 

newer technologies and/or may not 

believe that the operation of more 

sensitive instrumentation and 

associated calibration equipment 

outside of the NCore framework is 

necessary to meet their monitoring 

objectives. In light of the comments 

received on this issue, the EPA will 

modify the proposed changes to QC 

check requirements. Specifically, we are 

finalizing the lower concentration 

ranges as proposed: 0.005 to 0.08 ppm 

for SO2, NO2, and O3, and between the 

prescribed range of 0.5 and 5 ppm for 

CO monitors. Additionally, rather than 

requiring that the range selected be at 

the mean or median concentration range 

at the site or the agencies network of 

sites, the current flexibility to select the 

QC check gas concentration within the 

prescribed range will remain 

unchanged. Specifically, monitoring 

agencies should relate the concentration 

of the QC check to the monitoring 

objective of the site; with SLAMS 

monitors primarily intended for NAAQS 

compliance utilizing concentrations at 

or near the level of the NAAQS (higher 

end of the required range), and trace gas 

monitors operating at NCore, 

background or trends sites related to the 

mean or median of the ambient air 

concentrations normally measured at 

those sites in order to appropriately 

reflect the precision and bias at these 

routine concentration ranges. The EPA 

also clarifies that if the mean or median 

concentrations at trace gas sites are 

below the method detection limits 

(MDL) of the instrument, or if 

concentrations are above the prescribed 

range, the agency can select the lowest 

or highest concentration in the range 

that can be practically achieved. In 

addition, the EPA will keep language 

suggesting that an additional QC check 

point is encouraged for those 

organizations that may have occasional 

high values or would like to confirm 

monitor linearity at the higher end of 

the operational range. It will also 

encourage monitoring organizations that 

are operating NAAQS compliance sites 

to include additional QC checks around 

the mean or median values. 

The EPA believes that providing 

monitoring organizations some 

flexibility in determining the QC check 

concentration range based on site 

monitoring objective and the sensitivity 

of its monitors should address the 

concerns that were noted in the 

comments on this aspect of the 

proposed requirement. However, the 

EPA reiterates that our analysis of 

reported data has shown that 

monitoring agencies can test and 

achieve acceptable precision and bias 

results at these lower concentration 

levels. Providing data users with 

estimates of precision and bias where 

the majority of our ambient air data are 

measured is an EPA programmatic goal 

and monitoring organizations should be 

working with the EPA Regional Offices 

to develop the budgets necessary for 

purchasing the updated equipment and 

revising related procedures. The EPA 

will continue to endorse this approach 

to make the QC checks more meaningful 

and we will consider future revisions to 

appendix A to either require QC checks 

at two concentration levels (i.e., one 

around the mean concentrations and 

one related to the NAAQS) or require 

the span check 31 to be reported to AQS. 

In addition, to alleviate concerns about 

failing the acceptance criteria at lower 

QC concentrations, the EPA will 

evaluate suggestions by monitoring 

organizations to raise acceptance criteria 

or look at alternative acceptance criteria 

(e.g., difference instead of percent 

difference). Since acceptance criteria are 

included in guidance, the EPA will have 

the opportunity to perform the 

evaluations without affecting the 

regulation. In 2011, the EPA developed 

similar guidance for lower 

concentration levels of the annual 

performance evaluation audits.32

The EPA proposed to remove 

reference to zero and span adjustments 

(current section 3.2.1.1) and revise the 

one-point QC language to simply require 

that the QC check be conducted before 

any calibration or adjustment to the 

monitor. Recent revisions of the QA 

Handbook discourage the 

implementation of frequent span 

adjustments so the proposed language 

helps to clarify that no adjustment be 

made prior to implementation of the 

one-point QC check. 

There were no comments made on 

this proposed revision so the EPA is 

finalizing this revision as proposed. 

The EPA proposed to remove the 

requirement (current section 3.2.2) to 

implement an annual performance 

evaluation for one monitor in each 

calendar quarter when monitoring 

organizations have fewer than four 

monitoring instruments. The minimum 

requirement for the annual performance 

evaluation for the primary monitor at a 

site is one per year. The current 

regulation requires evaluation of 25 

percent of the monitors per quarter so 

that the performance evaluations are 

performed in all four quarters. There are 

cases where some monitoring 

organizations have fewer than four 

primary monitors for a gaseous 

pollutant, and the current language 

suggests that a monitor already 

receiving a performance evaluation be 

re-audited to provide for performance 

evaluations in all four quarters. This 

proposed removal of the requirement for 

evaluation in every quarter reduces the 

burden for monitoring agencies 

operating smaller networks and does not 

change the requirement of an annual 

performance evaluation for each 

primary monitor. 

The EPA received one state comment 

in support of this revision and no 

adverse comments. Therefore, the EPA 

is finalizing this revision as proposed. 

The current annual performance 

evaluation language (current section 

3.2.2.1) requires that the audits be 

conducted by selecting three 

consecutive audit levels (currently five 

audit levels are provided in appendix 

A). Due to the implementation of the 

NCore network, the inception of trace 

gas monitors, and generally lower 

ambient air concentrations being 

measured, there is a need for audit 

levels at lower concentrations to more 

accurately represent the uncertainties 

present in much of the ambient data. 

The EPA proposed to expand the audit 

levels from five to ten and remove the 

requirement to audit three consecutive 

levels. The previous regulation 

suggested that the three audit levels 

bracket 80 percent of the ambient air 

concentrations measured by the 

analyzer, and monitoring organizations 

have requested the use of an audit point 

to establish monitor accuracy around 

the NAAQS levels. Therefore, the EPA 

proposed to revise the language so that 

two of the audit levels selected 


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33http://www.epa.gov/ttnamti1/files/ambient/

pm25/datamang/20110217lowlevelstatmemo.pdf. 

represent 10–80 percent of routinelycollected ambient concentrations either 

measured by the monitor or in the 

PQAOs network of monitors. The 

proposed revision allowed the third 

point to be selected at the NAAQS level 

(e.g., 75 ppb for SO2) or above the 

highest 3-year routine hourly 

concentration, whichever was greater. 

One state commenter and a consulting 

firm supported this proposal while six 

state commenters voiced concern. The 

comments expressing concern were 

similar to comments made on the onepoint QC check proposal described 

earlier, including: 

• The SLAMS network is in place 

mainly for decisions related to the 

NAAQS, so QC checks should be at the 

levels approximating the NAAQS 

values. 

• Some of the FRM or FEM that are 

still in use may operate acceptably at 

concentrations around the NAAQS, but 

these older methods are not as sensitive 

at lower concentrations (i.e., mean or 

median concentrations), so QC checks at 

these lower levels are beyond the limits 

of the instrumentation. 

• The instrumentation necessary to 

challenge the monitors at the lower 

concentrations (calibrators with 

additional mass flow controllers or gas 

cylinders of lower concentrations) 

would be required to comply and, 

therefore, represent an added expense 

and burden. 

• The lower concentrations affect the 

percent difference statistic so there is 

more chance that the QC check will fail 

the acceptance requirements and, 

therefore, invalidate data that the 

monitoring organization feels is of 

acceptable quality. 

The EPA believes that there are some 

distinctions between the annual 

performance evaluations and the onepoint QC checks, and although the 

comments on the proposed revisions are 

similar, a different response to the 

comments is appropriate as explained 

below. 

Where monitoring organizations 

typically utilize standards and 

equipment at each site to run one-point 

QC checks, the annual performance 

evaluations require less equipment 

since, in many cases, one set (or a few 

sets) of independent equipment is/are 

used to audit all sites in a network. 

Accordingly, the EPA believes that it is 

practical for monitoring agencies to 

procure and utilize audit equipment, 

including calibrators and gas standards 

that are capable of generating the lower 

concentrations that are typically 

measured at most sites in the U.S. 

Indeed, all monitoring agencies that 

operate NCore multi-pollutant stations 

should already own and be proficient in 

the operation of such equipment as the 

objectives of the NCore stations and the 

technology used (i.e., trace level gas 

monitors) are oriented to characterizing 

typical ambient concentrations. 

In order to make the requirements 

easier to comprehend and allow for 

more flexibility in audit point selection, 

the EPA will revise the proposed 

language to require three points to be 

selected: One point around two to three 

times the method detection limit of the 

instruments within the PQAO network, 

a second point less than or equal to the 

99 percentile of the data at the site or 

the network of sites within a PQAO or 

the next highest audit concentration 

level, and the third point around the 

primary NAAQS or the highest 3-year 

concentration at the site or the network 

of sites in the PQAO. This framework 

provides two audit points that reflect 99 

percent of the monitoring data and a 

third point at the highest 3-year 

concentration or the level of the 

NAAQS, whichever concentration the 

monitoring organization chooses. Since 

performance evaluation audits are only 

performed once a year at each site, the 

burden to perform these audits at 

suitable concentrations is reduced 

relative to the QC checks. Therefore, the 

revised audit approach should provide 

the flexibility requested by the 

commenters. Also, in 2011, the EPA 

adopted a more flexible acceptance 

criteria for the two lower concentration 

audit levels (option to use difference 

instead of percent difference) 33 that is 

not influenced by concentration, which 

should alleviate commenter’s concerns 

about acceptance criteria at the lower 

audit levels. Accordingly, the EPA is 

finalizing the changes to performance 

audit requirements as described above. 

The EPA proposed to revise the 

language (current section 3.2.2.2(a)) 

addressing the limits on excess nitric 

oxide (NO) that must be followed during 

gas phase titration (GPT) procedures 

involving NO2 audits. The previous NO 

limit (maintaining at least 0.08 ppm NO) 

was restrictive and required auditors to 

make numerous mid-audit adjustments 

during a GPT that resulted in making 

the NO2 audit a time-consuming 

procedure. Accordingly, we proposed a 

more general statement regarding GPT 

that acknowledges the ongoing usage of 

monitoring agency procedures and 

guidance documents that have 

successfully supported NO2 calibration 

activities. 

The EPA received one state comment 

in support of the proposed revision to 

the language on excess NO and no 

adverse comments. Therefore, the EPA 

is finalizing this revision as proposed. 

The EPA proposed to remove 

language (current section 3.2.2.2(b)) in 

the annual performance evaluation 

section that required Regional approval 

for audit gases for any monitors 

operating at ranges higher that 1.0 ppm 

for O3, SO2 and NO2 and greater than 50 

ppm for CO. The EPA does not need to 

approve a monitoring organization’s use 

of audit gases to audit above proposed 

concentration levels. Since data 

reported to AQS above the highest level 

may be flagged or rejected, the EPA 

proposed that PQAOs notify the EPA 

Regional Office of sites being audited at 

concentrations above level 10 so that 

reporting accommodations can be made. 

The EPA did not receive any 

comments on this proposed change. 

Therefore, the EPA is finalizing this 

revision as proposed. 

The EPA proposed to provide 

additional explanatory language in 

appendix A to describe the NPAP. The 

NPAP has been a long-standing program 

for the ambient air monitoring 

community. Since 2007, the EPA has 

distributed an annual decision 

memorandum to all monitoring 

organizations in order to determine 

whether the monitoring organization 

plans to self-implement the NPAP 

program or utilize the federally 

implemented program. In order to make 

this decision, the NPAP adequacy and 

independence requirements are 

described in this annual decision 

memorandum. The EPA proposed to 

include these same requirements in 

appendix A in a separate section for 

NPAP. In addition, the annual decision 

memorandum stated that 20 percent of 

the sites would be audited each year so 

that all sites would be audited in a 5- 

year period. Since there is a possibility 

that monitoring organizations may want 

certain higher priority sites audited 

more frequently, the EPA proposed to 

revise the language to require all sites to 

be audited within a 6-year period to 

provide more flexibility and discretion 

for monitoring agencies. This revision 

does not change the number of sites 

audited in any given year, but allows for 

increased frequency in auditing sites 

deemed as high priority. 

The EPA received one state comment 

and one consulting firm comment 

supporting this action and two state 

comments expressing concern. One 

commenter supported it without any 

additional comment while another 

made the point that the clarification 

simply added the definition of an 

‘‘independent assessment,’’ which has 

been widely circulated and understood 


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by state, local and tribal monitoring 

organizations for several years and is 

neutral with respect to burden. One 

state commenter mentioned that the 

proposed additions have changed the 

requirements for demonstrating 

independence and adequacy that were 

originally outlined in the memorandum, 

‘‘National Performance Audit Program/ 

PM2.5 Performance Evaluation Program 

Implementation Decision Memorandum 

for Calendar Year 2008,’’ by 

implementing training requirements, 

requiring separate audit equipment, and 

adding a requirement to perform a 

whole system check tested against an 

independent and qualified lab. The 

commenter suggested that the proposed 

changes impact the costs for the PQAO 

to implement the NPAP. 

A state commenter suggested that the 

description for NPAP was ‘‘inconsistent 

with what had been conveyed in the 

past and is more pertinent for the 

performance audit.’’ The commenter 

also suggested that proposed sections 

3.1.3.4(a)–(f) be removed and retained in 

guidance (annual memorandum). 

However, the 2008 version of the QA 

Handbook, as well as the current 2013 

version, provides the same definition of 

a Performance Evaluation as a type of 

audit in which the quantitative data 

generated in a measurement system are 

obtained independently and compared 

with routinely obtained data to evaluate 

the proficiency of an analyst, or a 

laboratory, and has included NPAP in 

this definition in both versions of the 

QA Handbook. Another state 

commenter also raised questions as to 

the objective of the program and 

suggested that the NPAP objective is 

already being accomplished with the 

annual performance evaluation. 

In response to changes in the NPAP 

requirement from the 2008 NPAP 

memo, each year the EPA requests that 

monitoring organizations make a 

decision with regard to selfimplementation of the NPAP program 

based on the current year’s decision 

memorandum, or allow for federal 

implementation of the program. The 

proposed regulatory language has been 

included in the decision memorandums 

for the past number of years that the 

EPA expected monitoring organizations 

to follow in order to self-implement. 

The EPA disagrees that the NPAP 

objectives have changed since the 

inception of the program. Early versions 

of NPAP included cylinders of 

unknown concentration being sent to 

monitoring organizations (mailed 

audits) who would challenge the 

analyzers with these standards and send 

the results back to the EPA for 

evaluation. This process was ‘‘blind,’’ 

meaning that the monitoring 

organization did not know the 

concentration of the standard they were 

auditing. It was completely independent 

of monitoring organization 

implementation and also established 

independence of the concentration 

being audited. At the same time the 

NPAP mailed audits were conducted, 

monitoring organizations continued to 

implement their annual performance 

evaluations. So, both NPAP and the 

annual performance programs have been 

implemented at the same time and 

NPAP, having a different objective, 

allowed for a level of independent 

auditing by the EPA. Due to complaints 

lodged on the length of time required to 

get results back from the NPAP 

‘‘mailable’’ program, the EPA instituted 

the current NPAP through the probe 

program while continuing its primary 

objective: providing independent, 

quantitative evaluations of data quality. 

Since the majority of monitoring 

organizations allow for federal 

implementation, which is reliably 

independent of monitoring organization 

implementation (only two monitoring 

organizations in the country selfimplement NPAP), the EPA identified 

the requirements necessary for selfimplementing monitoring organizations 

to maintain as close a level of 

independence and data quality 

consistency to federal implementation. 

Therefore, while one commenter 

suggested that the training requirements 

be revised to ensure that auditors have 

been trained in the procedures that 

PQAOs actually employ to satisfy this 

requirement, the EPA believes that the 

training be required to reflect 

consistency with the federal program in 

order to establish consistency in data 

quality across the NPAP program. The 

EPA provides the opportunity for 

monitoring organizations to make the 

self-implementation decision each year 

based on the requirements in the 

decision memorandum, which ensures 

the NPAP program is equitably and 

consistently implemented across all 

monitoring organizations. Therefore, the 

EPA is finalizing this revision as 

proposed, but is also providing some 

flexibility as requested in a state 

comment by inserting the following 

language into the relevant section of 

appendix A: 

OAQPS, in consultation with the relevant 

EPA Regional Office, may approve the 

PQAO’s plan to self-implement NPAP if the 

OAQPS determines that the PQAO’s selfimplementation plan is equivalent to the 

federal programs and adequate to meet the 

objectives of national consistency and data 

quality. 

4. Measurement Quality Checks for 

Particulate Monitors 

The EPA proposed to require that 

flow rate verifications (current section 

3.2.3) be reported to AQS. Particulate 

matter concentrations (e.g., PM2.5, PM10, 

Pb) are reported in mass per unit of 

volume (mg/m3). Flow rate verifications 

are implemented at required frequencies 

in order to ensure that the PM sampler 

is providing an accurate and repeatable 

measure of volume that is critical for the 

determination of concentration. If a 

given flow rate verification does not 

meet acceptance criteria, the EPA 

guidance suggests that data may be 

invalidated back to the most recent 

acceptable verification, which is why 

these checks are performed at higher 

frequencies. Implementation of the flow 

rate verification is currently a 

requirement, but reporting to AQS has 

only been a requirement for PM10

continuous instruments. This is the only 

QC requirement in appendix A that was 

not fully required for reporting for all 

PM pollutants and has been a cause of 

confusion. When performing TSAs, the 

EPA Regional Offices review the flow 

rate verification information. There are 

cases where it is difficult to find the 

flow rate verification information to 

ascertain completeness, data quality, 

and whether corrective actions have 

been implemented in the case of flow 

rate verification failures. In addition, the 

EPA Regions have mentioned that some 

of the monitoring organizations have 

been voluntarily reporting these data to 

AQS in an effort to increase 

transparency and reliability in data 

quality. In a recent review of 2012 data, 

out of the 1,110 SLAMS PM2.5 samplers 

providing flow rate audit data (which 

are required to be reported), flow rate 

verification data were also reported for 

543 samplers or about 49 percent for the 

samplers with flow rate audit data. With 

the development of a new QA 

transaction in AQS, we believe that the 

reporting of flow rate verification data 

would improve the evaluation of data 

quality for data certification and at 

national levels, provide consistent 

interpretation in the regulation for all 

PM pollutants without being overly 

burdensome (approximately 12 data 

points per sampler per year). 

The EPA received one state comment 

in support of this revision and no 

adverse comments. Therefore, the EPA 

is finalizing this revision as proposed. 

In addition, the flow rate verification 

requirements for all the particulate 

monitors suggest randomization of the 

implementation of flow rate 

verifications with respect to time of day, 

day of the week and routine service and 


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17268 Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 

34http://www.epa.gov/ttnamti1/qanews.html. 

adjustments. Since this is a suggestion, 

the EPA proposed to remove this 

language from the regulation and 

instead include it in QA guidance. 

The EPA noted that one consulting 

firm voiced concern about removing the 

suggestion for randomizing flow rate 

verifications. They stated that the 

‘‘randomization of QC procedures is a 

critical aspect of QA currently 

unacknowledged by the EPA, and that 

single point (precision) checks of 

gaseous monitors and flow rate 

verification checks on PM samplers are 

crucial to characterizing the precision, 

bias and accuracy of the data arising 

from those instruments. Diurnal and 

weekly rhythms exist in solar radiation, 

temperature, humidity, electrical power 

and traffic patterns. As standards 

decrease and monitoring 

instrumentation becomes more 

sensitive, the likelihood increases that 

interferences will occur in those 

instruments. One means of detecting 

such biases involves randomized QC 

checks since they occur out-of-sync 

with daily/weekly rhythms.’’ 

The EPA agrees with the technical 

rationale for randomization provided by 

the commenter, but also received 

comments that the regulation should 

provide requirements and that suggested 

practices should be referenced in 

guidance documents. Therefore, the 

EPA is finalizing this revision as 

proposed and will include the 

randomization suggestion in the next 

revision of the QA Handbook and in the 

PM2.5 method. 

The EPA proposed to add clarifying 

language to the PM2.5 collocation 

requirements (current section 3.2.5) that 

a site can only count for the collocation 

of the method designation of the 

primary monitor at that site. Precision is 

estimated at the PQAO level and 

required at 15 percent of the primary 

monitor sites for each method 

designation. When developing the 

collocation requirements, the EPA 

intended to have the collocated 

monitors distributed to as many sites as 

possible in order to capture as much of 

the temporal and spatial variability in 

the PQAO given that only 15 percent of 

the primary monitors within a method 

designation are collocated. Therefore, 

since there can be only one primary 

monitor at a site for any given time 

period, it was originally intended that 

the primary monitor and the QA 

collocated monitor (for the primary) at 

a monitoring site count as one 

collocation. This revision does not 

change the current regulation and does 

not increase or decrease burden, but is 

intended to provide clarity on how the 

PQAO identifies the number and types 

of monitors needed to achieve the 

collocation requirements. 

The EPA received one state and one 

consulting firm comment supporting 

this clarification and two state 

comments expressing concern. 

One commenter expressing concern 

did not support specifically forbidding 

collocation of multiple particulate 

monitors at a single site and made the 

following points. As the NCore sites 

were designed to provide a large suite 

of monitoring, the commenter felt it was 

an ideal location to deploy a range of 

instruments. The commenter 

mentioned, ‘‘where the array of PM10–2.5

monitors at a monitoring site include a 

PM2.5 FRM as the primary monitor, the 

operation of the continuous PM2.5 FEM 

is advantageous for collocation across 

the network. For the EPA not to allow 

this collocation directly contradicts the 

goal of the proposed rule by placing 

additional compliance and operating 

burdens on monitoring organizations 

and network operators.’’ A second 

commenter mentioned that the 

proposed ‘‘new requirement could 

result with the discontinuing a sampler 

at one location and creating more 

upkeep and maintenance for the 

samplers at different locations.’’ 

The EPA notes that the proposed 

language does not represent a new 

requirement, is not a revision to the 

current requirement, and merely 

represents a needed clarification of the 

current language because some 

monitoring organizations were 

misinterpreting the original language by 

allowing one site to provide multiple 

collocations. Since the original language 

identified that collocation for appendix 

A purposes requires the QA collocated 

monitor to be compared against the 

primary monitor at a site, and since 

there can only be one primary monitor 

at a site at any particular time, the EPA 

believes that the original language and 

intent were clear. Based on data 

assessments of collocated data in AQS, 

most monitoring organizations follow 

this requirement. Since the current 

requirement states that 15 percent of the 

primary monitors in each method 

designation must be collocated, and 

there can only be one primary monitor 

at a site, the current regulation (without 

the clarifying language) allows only one 

collocation to count for a given site. 

When the EPA became aware of 

potential confusion on this issue in 

2010, we provided guidance to both the 

EPA Regions and monitoring 

community through the QA EYE 

newsletter (Issue 9, page 3).34 The 

article and the table, which was based 

on the number of sites in a monitoring 

organization, were developed to 

articulate the intent of the regulation. 

The EPA supports the use of multiple 

monitors at sites like NCore, as one 

commenter suggested, for testing and 

evaluation purposes but not for 

conforming to the appendix A original 

requirements. However, as articulated in 

the current appendix A regulation, a 

collocated monitor can be used to 

achieve collocation requirements for 

more than one pollutant. For example, 

collocated manual PM10–2.5 monitors 

could be used to satisfy PM2.5

collocation, PM10 collocation, as well as 

PM10–Pb collocation. Therefore, the 

EPA is adding the clarification as 

proposed to ensure that the current 

requirement is not misinterpreted. 

The EPA proposed to provide more 

flexibility to monitoring organizations 

when selecting sites for collocation. 

Appendix A (current section 3.2.5.3) 

had required that 80 percent of the 

collocated monitors be deployed at sites 

within ±20 percent of the NAAQS and 

if the monitoring organization did not 

have sites within that range, then 60 

percent of the sites were to be deployed 

among the highest 25 percent of all sites 

within the network. Monitoring 

organizations found this difficult to 

achieve. Some monitoring organizations 

did not have many sites and, at times, 

due to permission, access, and limited 

space issues, the requirement was not 

always achievable. 

Realizing that the collocated monitors 

provide precision estimates for the 

PQAO (since only 15 percent of the sites 

for each method designation are 

collocated), while also acknowledging 

that sites that measure concentrations 

close to the NAAQS are important, the 

EPA proposed to require that 50 percent 

(down from 80 percent) of the 

collocated monitors be deployed at sites 

within ±20 percent of the NAAQS and, 

if the PQAO did not have sites within 

that range, then 50 percent of the sites 

are to be deployed among the highest 

sites within the network. Although this 

requirement does not change the 

number of sites requiring collocation, it 

does provide the PQAO additional 

flexibility in its choice of collocated 

sites. 

The EPA received three state 

comments and one consulting firm 

comment in general support of this 

proposal and no comments expressing 

concern. 

As with the previous requirement, the 

EPA has a cut-off value of 3 mg/m3 for 

data used in evaluations of precision 

and bias, meaning that only data equal 

to or greater than 3 mg/m3 are used in 

estimates of precision and bias. This did 


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35See 78 FR 40000, July 3, 2013. 36MDL is described as the minimum 

concentration of a substance that can be measured 

and reported with 99 percent confidence that the 

analyte concentration is greater than zero. 37FEMS approved on or after March 4, 2010, have 

the required sensitivity to utilize the 0.002 mg/m3

reporting limit with the exception of manual 

equivalent method EQLA–0813–803, the previous 

FRM based on flame atomic absorption 

spectroscopy. 

not change in the proposed regulation. 

Our expectation is that monitoring 

organizations will site collocated 

monitors in such a manner that they 

will likely collect collocated samples 

from sites that have values equal to or 

greater than 3 mg/m3. One commenter 

was concerned about ‘‘clean’’ days that 

are below the 3 mg/m3 threshold since 

the employment of this threshold would 

affect data completeness by excluding 

pairs on cleaner days. The EPA notes, 

however, that completeness is not 

calculated solely on data pairs with 

concentrations equal to or greater than 

3 mg/m3, but on all valid collocated 

pairs (valid pairs below 3 mg/m3 are 

expected to be reported to AQS). 

Therefore, as long as the monitoring 

agency collects and reports all 

collocated data at the required 

frequency, data completeness is not an 

issue. 

Another state commenter, in support 

of the proposal, suggested that the 

highest concentration site be selected 

for the first collocation and, if a second 

site is needed, then the second highest 

site be selected, and so on. While this 

is an alternative approach, the initial 

rationale for the revision was to provide 

more flexibility in site selection in cases 

where some sites (for example the 

highest concentration site) had access 

problems or some other issue that did 

not make it a good candidate for 

collocation. The wording in the 

proposed regulation is meant to ensure 

that some of the sites selected for 

collocation represent the locations with 

the highest concentrations in the 

respective monitoring agencies network 

while providing the flexibility to choose 

among those sites. 

Since there was general support for 

the proposal with no adverse comments, 

the EPA is finalizing this revision as 

proposed. 

5. Calculations for Data Quality 

Assessment 

In order to provide reasonable 

estimates of data quality, the EPA uses 

data above an established threshold 

concentration usually related to the 

detection limits of the measurement. 

Measurement pairs are selected for use 

in the precision and bias calculations 

only when both measurements are 

greater than or equal to a threshold 

concentration. 

For many years, the threshold 

concentration for Pb precision and bias 

data was 0.02 mg/m3. The EPA 

promulgated a new Pb FRM (78 FR 

40000) utilizing the Inductively 

Coupled Plasma Mass Spectrometry 

(ICP–MS) analysis technique in 2013 as 

a revision to appendix G of 40 CFR part 

50.35 This new FRM demonstrated 

MDLs 36 below 0.0002 mg/m3, which is 

well below the EPA requirement of 5 

percent of the current Pb NAAQS level 

of 0.15 mg/m3, or 0.0075 mg/m3. As a 

result of the increased sensitivity 

inherent in this new FRM, the EPA 

proposed to lower the acceptable Pb 

concentration (current section 4) from 

the current value of 0.02 mg/m3 to 0.002 

mg/m3 for measurements obtained using 

the new Pb FRM and other more 

recently approved equivalent methods 

that have the requisite increased 

sensitivity.37 The current 0.02 mg/m3

value will be retained for the previous 

Pb FRM that has subsequently been redesignated as FEM EQLA–0813–803, as 

well as older equivalent methods that 

were approved prior to the more recent 

work on developing more sensitive 

methods. Since ambient Pb 

concentrations are lower and methods 

more sensitive, lowering the threshold 

concentration will allow more 

collocated data to be evaluated, which 

will provide more representative 

estimates of precision and bias at 

current ambient Pb levels. 

The EPA received one state comment 

and one consulting firm comment in 

support of the proposal and one state 

comment expressing concern. 

The comment expressing concern 

related to a perception that data would 

be lost due to the increased possibility 

that data quality objectives (DQO) 

would not be met with the decreased 

threshold concentration. The 

commenter believed the change would 

increase the likelihood that collocated 

data would not meet the 20 percent 

coefficient of variation (CV) limit for 

precision as specified in appendix A, 

section 2.3.1.3. This would in turn 

decrease data completeness and, if data 

loss is great enough, could potentially 

render the data from an entire 

monitoring location useless for NAAQS 

compliance determinations. 

The EPA notes that invalidation of 

routine data based solely on the 

variability of collocated monitoring data 

is not required or recommended. The 

data validation guidance in the QA 

Handbook, which many monitoring 

organizations use to develop validation 

criteria, allows for these data to be 

reviewed in the context of other QC 

samples before decisions to invalidate 

data are made. Since the collocated data 

are only collected at approximately 15 

percent of the monitoring sites, the data 

set is meant to reflect the precision of 

the PQAO monitoring network and not 

to evaluate the validity of data from 

individual sites. Site data can be used 

to troubleshoot causes of variability and 

to take corrective actions, but is not 

intended to invalidate routine 

monitoring data unless a significant 

systemic issue is discovered. 

Based on the comment noted above, 

the EPA performed an evaluation of 

collocated Pb data collected in calendar 

years 2011–2013 to evaluate the amount 

of collocation information available 

when using the two reporting 

thresholds. In that time period, 7,063 

collocated measurements were taken. 

Within this data set, there were 2,521 

data pairs where both values were equal 

to or greater than 0.02 mg/m3 (i.e., only 

about 35 percent of the information 

collected could be used to estimate 

precision). In the most pertinent 

examples, there were cases where 

monitoring organizations collected valid 

ambient data and no collocated data 

could be used due to the current higher 

threshold. For example, one monitoring 

organization collected 173 collocated 

measurements and no value was equal 

to or greater than 0.02 mg/m3 and, 

therefore, there was no estimate of 

precision reported for this monitoring 

organization for a 3-year period. There 

were eight monitoring organizations that 

could not use any collocated results for 

2011–2013 and 22 monitoring 

organizations (about 50 percent of the 

monitoring organizations) that had less 

than 25 percent of their data used. In 

contrast, if the same data set is used, but 

the threshold is reduced to the proposed 

value of greater than or equal to 0.002 

mg/m3, then 6,418 measurements are 

available, which increases precision 

data availability from 35 percent to 91 

percent. As an example, the monitoring 

organization that had no collocated 

values (173 measurements) equal to or 

greater than 0.02 mg/m3 had the number 

of available pairs increased to 172 with 

the lower 0.002 mg/m3 threshold and 

had a precision estimate CV of 16.43, 

which is within the 3-year DQO goal of 

20 percent. 

The EPA acknowledges that using a 

lower threshold concentration will 

increase the estimate of precision since 

the required CV statistic is a derivation 

of the percent difference. When EPA 

evaluated the Pb data quality objectives 

to determine acceptable precision and 

bias for the new standard, we evaluated 

all collocated data in AQS including the 


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38http://www.epa.gov/ttnamti1/files/ambient/pb/

QAQA.pdf. 

lower concentration data.38 Since the 

collocated data are actual samples, they 

include measurement uncertainty for all 

phases of the measurement system 

including variability in EPA-provided 

filters, sampling handling, sampler flow 

differences, plumes from sources, 

laboratory contamination, as well as 

other types of measurement uncertainty 

mentioned by one commenter. In fact, 

the goal of the collocation is to provide 

an estimate of overall measurement 

imprecision between two sampling 

systems that are, in theory, sampling the 

same air. So although the commenter 

identifies this as a concern, providing a 

measure of the overall precision of the 

measurement system is what the 

collocated data are intended to evaluate. 

The commenter mentioned that 

changing the threshold based solely on 

the estimated FRM detection limit may 

not translate to other FEMs that may 

have different detection limits. At a 

minimum, all approved Pb methods are 

required to meet the method detection 

limit to be approved as equivalent. 

Therefore, the 0.002 mg/m3 threshold 

should be applicable to the newer 

methods and is the reason for the dual 

thresholds. 

Based on our review and evaluations, 

the EPA set the precision goal of a 90 

percent confidence limit for the CV of 

20 percent as mentioned by the 

commenter. This CV estimate is 

determined by aggregating 3 years of 

collocated data. In the evaluation of the 

2011–2013 data, the EPA evaluated data 

down to the lower threshold with the 

new methods capable of more 

sensitivity. The average 3-year precision 

estimate (2011–2013) for all monitoring 

organizations using the approved FRM 

and FEM methods and a threshold of 

0.002 mg/m3 was 16.31. The average 3- 

year CV for a threshold of 0.02 mg/m3

was 11.09. This is an increase of 

imprecision on average of 5 percent, but 

a significant increase in data availability 

from 35 percent to 90 percent. 

The commenter also suggested that 

the current threshold should remain in 

effect until a limit of quantitation (LOQ) 

test can be performed. Although there 

are a number of definitions for LOQ, 

some have defined it to be three times 

(3x) to ten times (10x) the MDL. The 

new Pb FRM by ICP–MS promulgated in 

2013 in 40 CFR part 50, appendix G, 

showed that the MDLs were below 

0.0002 mg/m3. Therefore, the EPA took 

the 10x definition of LOQ and 

calculated 0.002 mg/m3 as the level of 

the new threshold. 

Two commenters made similar points 

that, due to the fact that the CV is based 

on individual sample pair percent 

differences, the CV tends to increase at 

lower concentrations for a constant 

absolute difference. The EPA 

acknowledges this fact. On a related 

issue, when developing the 10 audit 

levels for annual performance 

evaluation checks, the EPA provided 

guidance on the two lower audit levels 

allowing for an absolute difference 

criteria as well as a percent difference 

criteria. Rather than eliminate close to 

55 percent of the collocated data, which 

is what is occurring now with the higher 

threshold, the EPA is finalizing the two 

thresholds as proposed and will also 

evaluate the use of an absolute 

difference acceptance criteria at lower 

concentration levels. 

The EPA proposed to remove the TSP 

threshold concentration for precision 

and bias since TSP is no longer a 

NAAQS-required pollutant and the EPA 

no longer has QC requirements for it. 

The EPA received one comment in 

support of this proposal and no adverse 

comments and is finalizing this revision 

as proposed. 

The EPA proposed to remove the 

statistical check currently described in 

section 4.1.5 of appendix A. The check 

was developed to perform a comparison 

of the one-point QC checks and the 

annual performance evaluation data 

performed by the same PQAO on 

gaseous instruments. The section 

suggests that 95 percent of all the bias 

estimates from the annual performance 

evaluation (reported as a percent 

difference) should fall within the 95 

percent probability interval developed 

using the one-point QC checks. The 

problem with this specific statistical 

check is that PQAOs with very good 

repeatability on the one-point QC check 

data had a hard time meeting this 

requirement since the probability 

interval became very tight, making it 

more difficult for better performing 

PQAOs to meet the requirement when 

comparing the one-point QC checks and 

performance evaluation data. Separate 

statistics to evaluate the one-point QC 

checks and the performance evaluations 

are already promulgated, so the removal 

of this check does not affect data quality 

assessments. 

The EPA received one comment in 

support of this proposal and no adverse 

comments and is finalizing this revision 

as proposed. 

Similar to the statistical comparison 

of performance evaluations data, the 

EPA proposed to remove the statistical 

check (current section 4.2.4) to compare 

the flow rate audit data and flow rate 

verification data for PM monitors. The 

existing language suggests that 95 

percent of all the flow rate audit data 

results (reported as percent difference) 

should fall within the 95 percent 

probability interval developed from the 

flow rate verification data for the PQAO. 

The problem, as with the one-point QC 

check comparison requirement for 

gaseous monitors, was that monitoring 

organizations with very good 

repeatability on the flow rate 

verifications had a hard time meeting 

this requirement since the probability 

interval became very tight, making it 

difficult for better performing PQAOs to 

meet the requirement. Separate statistics 

to evaluate the flow rate verifications 

and flow rate audits are already 

promulgated, so the removal of this 

check does not affect data quality 

assessments. 

The EPA received one comment in 

support of this proposal and no adverse 

comments and is finalizing this revision 

as proposed. 

B. Quality Assurance Requirements for 

Monitors Used in Evaluations of 

Prevention of Significant Deterioration 

Projects—Appendix B 

The EPA proposed to create appendix 

B to specify the minimum quality 

assurance requirements for the control 

and assessment of the quality of the 

ambient air monitoring data submitted 

to a PSD reviewing authority or the EPA 

by an organization operating an air 

monitoring station, or network of 

stations, operated in order to comply 

with Part 51 New Source Review— 

Prevention of Significant Deterioration 

(PSD). These proposed revisions to the 

quality assurance requirements 

applicable to PSD are, in the majority of 

cases, identical to the revisions 

proposed in appendix A. The majority 

of comments received for this rule 

focused on the appendix A 

requirements and were discussed in the 

previous section. Due to the similarity 

of the proposed changes for appendix A 

and appendix B, the EPA assumes that 

comments submitted in response to 

proposed appendix A revisions also 

reflect the sentiment of commenters 

concerning the proposed language in 

appendix B. Therefore, the preamble 

discussions that include responses to 

comments for appendix A should, in 

most cases, also apply to appendix B. 

Accordingly, the EPA will not duplicate 

those discussions in the following 

sections pertaining to appendix B, and 

we refer the reader back to the relevant 

appendix A discussions in section III.A. 

of the preamble, above. In the few cases 

where comments were made specifically 

for appendix B sections, those 


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39Permitting authority and reviewing authority 

are often used synonymously in PSD permitting. 

Since reviewing authority has been defined in 40 

CFR 51.166(b), it is used throughout appendix B. 

comments are discussed in the 

appropriate sections below. 

1. General Information 

The following changes to monitoring 

requirements impact Part 58—Ambient 

Air Quality Surveillance; Appendix B— 

Quality Assurance Requirements for 

Prevention of Significant Deterioration 

(PSD) Air Monitoring. Changes that 

affect the overall appendix are 

discussed in this section of the 

preamble while changes specific to the 

various sections of the appendix will be 

addressed in subsequent sections of the 

preamble. Since the PSD QA 

requirements have been included in 

appendix A since 2006, section 

headings refer to the current appendix 

A sections. 

The QA requirements in appendix B 

have been developed for measuring the 

criteria pollutants of O3, NO2, SO2, CO, 

PM2.5, PM10 and Pb and are minimum 

QA requirements for the control and 

assessment of the quality of the PSD 

ambient air monitoring data submitted 

to the PSD reviewing authority 39 or the 

EPA by an organization operating a 

network of PSD stations. 

In the 2006 monitoring rule revisions, 

the PSD QA requirements, which were 

previously in appendix B, were 

consolidated with appendix A and 

appendix B was reserved. The PSD 

requirements, in most cases, parallel 

appendix A in structure and content but 

because PSD monitoring is only 

required for a period of 1 year or less, 

some of the frequencies of 

implementation of the QC requirements 

for PSD are higher than the 

corresponding appendix A 

requirements. In addition, the agencies 

governing the implementation, 

assessment and approval of the QA 

requirements can be different: The PSD 

reviewing authorities for PSD 

monitoring and the EPA Regions for 

ambient air monitoring for NAAQS 

decisions. Since 2006, the combined 

regulations have caused confusion or 

misinterpretations of the regulations 

among the public and monitoring 

organizations implementing NAAQS or 

PSD requirements, and have resulted in 

failure, in some cases, to perform the 

necessary QC requirements. 

Accordingly, the EPA proposed that the 

PSD QA requirements be removed from 

appendix A and returned to appendix B. 

Separating the two sets of QA 

requirements would clearly distinguish 

the PSD QA requirements and allow 

more flexibility for future revisions to 

either monitoring program. 

With this final rule, the EPA would 

not change most of the QA requirements 

for PSD. Therefore, the discussion that 

follows will cover those sections of the 

PSD requirements that the EPA 

proposed to change from the current 

appendix A requirements. 

Commenters supported moving the 

PSD QA requirements to a distinct 

section with no adverse comments 

received, so the EPA is finalizing as 

proposed. 

The applicability section of appendix 

B clarifies that the PSD QA 

requirements are not assumed to be 

minimum requirements for data use in 

NAAQS attainment decisions. One 

reason for this distinction is in the 

flexibility allowed in PSD monitoring 

for the NPEP (current appendix A, 

section 2.4). The proposed PSD 

requirements allow the PSD reviewing 

authority to decide whether 

implementation of the NPEP will be 

performed. The NPEP, which is 

described in appendix A, includes the 

NPAP, the PM2.5 Performance 

Evaluation Program (PM2.5–PEP), and 

the Pb–PEP. Accordingly, under the 

proposed revision, if a PSD reviewing 

authority intended to use PSD data for 

any official comparison to the NAAQS 

beyond the permitting application, such 

as for attainment/nonattainment 

designations or clean data 

determinations, then all requirements in 

appendix B including implementation 

of the NPEP would apply. In this case, 

monitoring would more closely conform 

to the appendix A requirements. The 

EPA proposed this flexibility for PSD 

because the NPEP requires either federal 

implementation or implementation by a 

qualified individual, group or 

organization that is not part of the 

organization directly performing and 

accountable for the work being assessed. 

The NPEP may require specialized 

equipment, certified auditors and a 

number of activities which are 

enumerated in the sections associated 

with these programs. Arranging this 

type of support service may be more 

difficult for the operator of a single or 

small number of PSD monitoring 

stations operating for only a year or less. 

The EPA cannot accept funding from 

private contractors or industry, and 

federal implementation of the NPEP for 

PSD would face several funding and 

logistical hurdles. This creates an 

inequity in the NPEP implementation 

options available to the PSD monitoring 

organizations compared to the state/ 

local/tribal monitoring organizations for 

NAAQS compliance. The EPA has had 

success in training and certifying 

private contractors in various categories 

of performance evaluations conducted 

under NPEP, but many have not made 

the necessary investments in capital 

equipment to implement all categories 

of the performance evaluations. Since 

the monitoring objectives for the 

collection of data for PSD are not 

necessarily the same as the appendix A 

monitoring objectives, the EPA 

proposed to allow the PSD reviewing 

authority to determine whether a PSD 

monitoring project must implement the 

NPEP. 

The EPA only received comments in 

support of this proposed change, and is 

finalizing the change as proposed. 

The EPA proposed to clarify the 

definition of PSD PQAO. The PQAO 

was first defined in appendix A in 2006 

(current appendix A, section 3.1.1), 

when the PSD requirements were 

combined with appendix A. The 

definition is not substantially changed 

for PSD, but the EPA proposed to clarify 

that a PSD PQAO can only be associated 

with one PSD reviewing authority. 

Distinguishing among the PSD PQAOs 

that coordinate with a PSD reviewing 

authority would be consistent with 

discrete jurisdictions for PSD 

permitting, and it would simplify 

oversight of the QA requirements for 

each PSD network. 

Given that companies may apply for 

PSD permits throughout the U.S., it is 

expected that some PSD monitoring 

organizations will work with multiple 

reviewing authorities. The PSD PQAO 

code that may appear in the AQS data 

base and other records defines the PSD 

monitoring organization or a 

coordinated aggregation of such 

organizations that is responsible for a 

set of stations within one PSD reviewing 

authority that monitors the same 

pollutant and for which data quality 

assessments will be pooled. The PSD 

monitoring organizations that work with 

multiple PSD reviewing authorities 

would have individual PSD PQAO 

codes for each PSD reviewing authority. 

This approach will allow flexibility to 

develop appropriate quality systems for 

each PSD reviewing authority. 

The EPA did not receive any 

comment on this process and is 

finalizing the requirement as proposed. 

The EPA proposed to add definitions 

of ‘‘PSD monitoring organization’’ and 

‘‘PSD monitoring network’’ to 40 CFR 

58.1. The definitions have been 

developed to improve understanding of 

the appendix B regulations. 

Because the EPA uses the term 

‘‘monitoring organization’’ frequently in 

the NAAQS-associated ambient air 

regulations, the EPA wanted to provide 

a better definition of the term in the PSD 


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40 Graded approach to Tribal QAPP and QMPs 

http://www.epa.gov/ttn/amtic/cpreldoc.html. 41http://www.epa.gov/ttn/amtic/npepqa.html. 

QA requirements. Therefore, the EPA 

proposed the term ‘‘PSD monitoring 

organization’’ to identify ‘‘a source 

owner/operator, a government agency, 

or a contractor of the source or agency 

that operates an ambient air pollution 

monitoring network for PSD purposes.’’ 

The EPA also proposed to define 

‘‘PSD monitoring network’’ in order to 

distinguish ‘‘a set of stations that 

provide concentration information for a 

specific PSD permit.’’ The EPA will 

place both definitions in 40 CFR 58.1. 

The EPA did not receive any comment 

on these changes and is finalizing them 

as proposed. 

2. Quality System Requirements 

The EPA proposed to remove the 

PM10–2.5 requirements for flow rate 

verifications, semi-annual flow rate 

audits, collocated sampling procedures 

and PM10–2.5 PEP from appendix B 

(current appendix A, sections 3.2.6, 

3.2.8, 3.3.6, 3.3.8, 4.3). In 2006, the EPA 

proposed a PM10–2.5 NAAQS along with 

requisite QA requirements in appendix 

A. While the PM10–2.5 NAAQS was not 

promulgated, PM10–2.5 monitoring was 

required to be performed at NCore sites 

and the EPA proposed requisite QA 

requirements in appendix A. Since PSD 

monitoring is distinct from monitoring 

at NCore sites and PM10–2.5 is not a 

criteria pollutant, it will be removed 

from the PSD QA requirements. The 

EPA did not receive any comment on 

this proposed revision and is finalizing 

the requirement as proposed. 

The EPA proposed that the Pb QA 

requirements of collocated sampling 

(current appendix A, section 3.3.4.3) 

and Pb performance evaluation 

procedures (current appendix A, section 

3.3.4.4) for non-source oriented NCore 

sites be eliminated for PSD. The 2010 Pb 

rule in 40 CFR part 58, appendix D, 

section 4.5(b) added a requirement to 

conduct non-source oriented Pb 

monitoring at each NCore site in a CBSA 

with a population of 500,000 or more. 

Since PSD does not implement NCore 

sites, the EPA proposed to eliminate the 

Pb QA language specific to non-source 

oriented NCore sites from PSD while 

retaining the PSD QA requirements for 

routine Pb monitoring. 

The EPA received three supportive 

comments for the removal of this 

requirement and no adverse comments. 

Therefore, the EPA is finalizing the 

requirement as proposed. 

The EPA proposed that elements of 

QMPs and QAPPs which are separate 

documents described in appendix A, 

sections 2.1.1 and 2.1.2, can be 

combined into a single document for 

PSD monitoring networks. The QMP 

provides a ‘‘blueprint’’ of a PSD 

monitoring organization’s quality 

system. It includes quality policies and 

describes how the organization as a 

whole manages and implements its 

quality system regardless of what 

monitoring is being performed. The 

QAPP includes details for implementing 

a specific PSD monitoring activity. For 

PSD monitoring, the EPA believes the 

project-specific QAPP takes priority, but 

there are important aspects of the QMP 

that could be incorporated into the 

QAPP. The current appendix A 

requirements allow smaller 

organizations or organizations that do 

infrequent work with EPA to combine 

the QMP with the QAPP based on 

negotiations with the funding agency 

and provided guidance 40 on a graded 

approach to developing these 

documents. In the case of PSD QMPs 

and QAPPs, the EPA proposed that the 

PSD reviewing authority, which has the 

approval authority for these documents, 

also have the flexibility for allowing the 

PSD PQAO to combine pertinent 

elements of the QMP into the QAPP 

rather than requiring the submission of 

both QMP and QAPP documents 

separately. The EPA did not receive any 

comment on this and is finalizing the 

requirement as proposed. 

The EPA proposed to add language to 

the appendix B version of the DQO 

section (current appendix A, section 

2.3.1) which allows flexibility for the 

PSD reviewing authority and the PSD 

monitoring organization to determine if 

adherence to the DQOs specified in 

appendix A, which are the DQO goals 

for NAAQS decisions, are appropriate or 

whether project-specific goals are 

necessary. Allowing the PSD reviewing 

authority and the PSD monitoring 

organization flexibility to change the 

DQOs does not change the 

implementation requirements for the 

types and frequency of the QC checks in 

appendix B, but does give some 

flexibility in the acceptance of data for 

use in specific projects for which the 

PSD data are collected. As an example, 

the goal for acceptable measurement 

uncertainty for the collection of O3 data 

for NAAQS determinations is defined 

for precision as an upper 90 percent 

confidence limit for CV of 7 percent and 

for bias as an upper 95 percent 

confidence limit for the absolute bias of 

7 percent. The precision and bias 

estimates are made with 3 years of onepoint QC check data. A single or a few 

one-point QC checks over 7 percent 

would not have a significant effect on 

meeting the DQO goal. The PSD 

monitoring DQO, depending on the 

objectives of the PSD monitoring 

network, may require a stricter DQO 

goal or one less restrictive. Since PSD 

monitoring covers a period of 1 year or 

less, one-point QC checks over 7 percent 

will increase the likelihood of failing to 

meet the DQO goal since there would be 

fewer QC checks available in the 

monitoring period to estimate precision 

and bias. With fewer checks, any 

individual check will statistically have 

more influence over the precision or 

bias estimate. Realizing that PSD 

monitoring may have different 

monitoring objectives, the EPA 

proposed to add language that would 

allow decisions on DQOs to be 

determined through consultation 

between the appropriate PSD reviewing 

authority and PSD monitoring 

organization. The EPA did not receive 

any comment on this and is finalizing 

the requirement as proposed. 

The EPA proposed to add some 

clarifying language to the section 

describing the NPEP (current appendix 

A, section 2.4) to explain selfimplementation of the performance 

evaluation by the PSD monitoring 

organization. Self-implementation of 

NPEP has always been an option for 

monitoring organizations but the 

requirements for self-implementation 

were described in the technical 

implementation documents (i.e., 

implementation plans and QAPPs) for 

the program and in an annual selfimplementation decision memo that is 

distributed to monitoring 

organizations.41 These major 

requirements for self-implementation 

are proposed to be included in the 

appendix B sections pertaining to the 

NPEP program (NPAP, PM2.5–PEP and 

Pb–PEP). 

The NPEP clarification also adds a 

definition of ‘‘independent assessment.’’ 

The proposed definition is derived from 

the NPEP (NPAP, PM2.5–PEP, and Pb– 

PEP) QAPPs and guidance; it also 

appears in the annual selfimplementation memo described above. 

The clarification is not a new 

requirement but consolidates this 

information. 

Refer to comments related to NPEP in 

appendix A in III.A. As there were no 

comments specifically related to PSD, 

the EPA is finalizing the requirement as 

proposed. 

The EPA proposed to require PSD 

PQAOs to provide information to the 

PSD reviewing authority on the vendors 

of gas standards that they use (or will 

use) for the duration of the PSD 

monitoring project. A QAPP or 

monitoring plan may incorporate this 


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42http://www.epa.gov/ttn/amtic/aapgvp.html. 

43QA Handbook for Air Pollution Measurement 

Vol. II Ambient Air Quality Monitoring Program at: 

http://www.epa.gov/ttn/amtic/qalist.html. 

information. However, that document 

must then be updated if there is a 

change in the vendor used. The current 

regulation (current appendix A, section 

2.6.1) requires any gas vendor 

advertising and distributing ‘‘EPA 

Protocol Gas’’ to participate in the AA– 

PGVP. The EPA posts a list of these 

vendors on the AMTIC Web site.42 This 

is not expected to be a burden since 

information of this type is normally 

included in a QAPP or standard 

operating procedure for a monitoring 

activity. 

There were no adverse comments in 

appendix A or appendix B related to 

identifying vendors used to supply 

monitoring organization with gas 

standards. Therefore, the EPA is 

finalizing the requirement as proposed. 

3. Measurement Quality Checks for 

Gases 

The EPA proposed to lower the audit 

concentrations (current appendix A, 

section 3.2.1) of the one-point QC 

checks to 0.005 and 0.08 ppm for SO2, 

NO2, and O3 (currently 0.01 to 0.1 ppm), 

and to between 0.5 and 5 ppm for CO 

monitors (currently 1 and 10 ppm). 

With the development of more sensitive 

monitoring instruments with lower 

detection limits, technical 

improvements in calibrators, and lower 

ambient air concentrations in general, 

the EPA believes this revision will 

better reflect the precision and bias of 

the routinely-collected ambient air data. 

Because the audit concentrations are 

selected using the mean or median 

concentration of typical ambient air data 

(guidance on this is provided in the QA 

Handbook 43), the EPA proposed to add 

some clarification to the current 

language by requiring PSD monitoring 

organizations to select either the highest 

or lowest concentration in the ranges 

identified if the mean or median values 

of the routinely-collected concentrations 

are above or below the prescribed range. 

The EPA received a number of 

comments on this proposed 

requirement. Please refer to the 

appendix A comments in III.A. In light 

of the comments received, the EPA will 

maintain the concentration ranges as 

proposed: 0.005 to 0.08 ppm for SO2, 

NO2, and O3, and between the 

prescribed range of 0.5 and 5 ppm for 

CO monitors. However, rather than 

requiring that the range selected be at 

the mean or median concentration range 

at the site or the agencies network of 

sites, the QC check gas concentration 

selected within the prescribed range can 

be related to the monitoring objective of 

the site, with those monitors primarily 

intended for NAAQS compliance 

utilizing concentrations at or near the 

level of the NAAQS (higher end of the 

required range), and trace gas monitors 

operating at background or trends sites 

related to the mean or median of the 

ambient air concentrations normally 

measured at those sites in order to 

appropriately reflect the precision and 

bias at these routine concentration 

ranges. If the mean or median 

concentrations at trace gas sites are 

below the MDL of the instrument or 

above the prescribed range, the agency 

can select the lowest or highest 

concentration in the range that can be 

practically achieved. In the case of PSD 

monitoring, the EPA will add language 

requiring the PSD monitoring 

organization to consult with the PSD 

reviewing authority on the most 

appropriate one-point QC concentration 

based on the objectives of the 

monitoring activity. In addition, the 

EPA will keep language suggesting that 

an additional QC check point is 

encouraged for those organizations that 

may have occasional high values or 

would like to confirm the monitors’ 

linearity at the higher end of the 

operational range. 

In addition, to alleviate concerns 

about failing the acceptance criteria at 

lower QC concentrations, the EPA will 

evaluate suggestions by monitoring 

organizations to raise acceptance criteria 

or look at alternative acceptance criteria 

(e.g., difference instead of percent 

difference). Since acceptance criteria is 

included in guidance, the EPA will have 

the opportunity to perform the 

evaluations without effecting the 

regulation. 

The EPA proposed to remove the 

existing reference to zero and span 

adjustments (current appendix A, 

section 3.2.1.1) and to revise the onepoint QC language to simply require 

that the QC check be conducted before 

making any calibration or adjustment to 

the monitor. Recent revisions of the QA 

Handbook discourage the practice of 

making frequent span adjustments, so 

the proposed language helps to clarify 

that no adjustment be made prior to 

implementation of the one-point QC 

check. There were no comments made 

on this proposed revision, so the EPA is 

finalizing this revision as proposed. 

The current annual performance 

evaluation language (current appendix 

A, section 3.2.2.1) requires that the 

audits be conducted by selecting three 

consecutive audit levels (currently, 

appendix A recognizes five audit 

levels). Due to the implementation of 

the NCore network, the inception of 

trace gas monitors, and lower ambient 

air concentrations being measured 

under typical circumstances, there is a 

need for audit levels at lower 

concentrations to more accurately 

represent the uncertainties present in 

the ambient air data. The EPA proposed 

to expand the audit levels from five to 

ten and remove the requirement to audit 

three consecutive levels. The current 

regulation also requires that the three 

audit levels should bracket 80 percent of 

the ambient air concentrations 

measured by the analyzer. This current 

‘‘bracketing language’’ has caused some 

confusion, and monitoring organizations 

have requested the use of an audit point 

to establish monitor accuracy around 

the NAAQS levels. Therefore, the EPA 

proposed to revise the language so that 

two of the audit levels selected 

represent 10 to 80 percent of routinelycollected ambient concentrations either 

measured by the monitor or in the PSD 

PQAOs network of monitors. The 

proposed revision allows the third point 

to be selected at a concentration that is 

consistent with PSD-specific DQOs (e.g., 

the 75 ppb NAAQS level for SO2). 

The EPA received a number of 

comments on this proposal. Please refer 

to the appendix A comments in III.A. 

In addition to comments related to 

appendix A, the EPA received 

comments specific to PSD on this 

section. A commenter mentioned that 

for PSD, the performance evaluation 

(PE) is performed quarterly since PSD 

monitoring may occur for only 1 year. 

The current language required the audit 

to occur each calendar quarter and since 

PSD monitoring does not necessarily 

follow calendar quarters, it was 

suggested to revise the term ‘‘calendar 

quarter’’ to ‘‘quarterly.’’ The EPA will 

revise the PSD language to reflect 

implementing the quarterly PE on a 

quarter or 90-day frequency. A 

commenter felt that the requirement that 

PE personnel will be required to meet 

PE training and certification 

requirements was in error because the 

requirement for certification applies 

only to NPEP audits, not to quarterly 

performance evaluation audits, and 

there is no further regulatory discussion 

to support such an assertion. Because 

the EPA has provided more flexibility 

on implementing NPEP at PSD sites, we 

believed there needed to be an 

additional requirement that the 

personnel implementing these audits be 

trained and certified. However, as the 

commenter mentioned, there is no 

additional instruction on this, nor is 

there any mention of the organization 

required to do this training and 

certification. It is expected that any 


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44See supporting information in Excess NO Issue 

paper, Mike Papp and Lewis Weinstock, Docket 

number EPA–HQ–OAR–2013–0619. 45http://www3.epa.gov/ttn/amtic/npepqa.html. 

entity performing this activity would be 

trained and capable of performing these 

audits. Therefore, the EPA will remove 

the last sentence requiring training and 

certification. 

The EPA received a comment that 

suggested the PE language was not 

consistent with an earlier section (2.7) 

that only required the use of reference 

and equivalent method monitors as 

opposed to trace gas analyzers 

regardless of the concentrations 

measured. The commenter’s contention 

was that based upon the proposed 

language related to the selection of PE 

concentration, the PSD monitoring 

agency would be required to acquire 

trace gas instruments due to their 

sensitivity and the fact that their 

ambient air concentrations were low. 

They used examples of annual mean 

NO2 values around 1.9 ppb and SO2

concentrations of 1.0 ppb. However, the 

proposed PE language is consistent with 

the reference and equivalent language 

described in section 2.7 since trace gas 

analyzers are in fact reference and 

equivalent instruments and, therefore, 

are included in that description. 

Regardless of the proposed PE 

concentration range, it would seem that 

PSD monitoring organizations that are 

required to monitor at the low 

concentration ranges would want to 

select FRM or FEM instruments more 

capable of reliably measuring these 

concentrations. 

Based on the comments received 

related to appendices A and B, the EPA 

will revise the proposed language to 

require three points to be selected: One 

point around two to three times the 

method detection limit of the 

instruments within the PQAO network, 

a second point less than the 99 

percentile of the data at the site or the 

network of sites within a PQAO or the 

next highest audit concentration level, 

and the third point around the primary 

NAAQS or the highest 3-year 

concentration at the site or the network 

of sites in the PQAO. This provides two 

audit points that reflect 99 percent of 

the monitoring data and a third point at 

the highest 3-year concentration or the 

NAAQS, whichever concentration the 

PSD monitoring organization chooses. 

The EPA proposed to revise the 

language (current appendix A, section 

3.2.2.2(a)) addressing the limits on 

excess NO that must be followed during 

GPT procedures involving NO2 audits. 

The current NO limit (maintaining at 

least 0.08 ppm) is very restrictive and 

requires auditors to make numerous 

mid-audit adjustments during a GPT 

that result in making the NO2 audit a 

very time-consuming procedure. 

Monitoring agency staff have advised us 

that the observance of such excess NO 

limits has no apparent effect on NO2

calibrations being conducted with 

modern-day GPT-capable calibration 

equipment and, therefore, the 

requirements in the context of 

performing audits is unnecessary.44 We 

also note the increasing availability of 

the EPA-approved direct NO2 methods 

that do not utilize converters, rendering 

the use of GPT techniques that require 

the output of NO and NOX to be a 

potentially diminishingly used 

procedure in the future. Accordingly, 

we have proposed a more general 

statement regarding GPT that 

acknowledges the ongoing usage of 

monitoring agency procedures and 

guidance documents that have 

successfully supported NO2 calibration 

activities. The EPA believes that if such 

procedures have been successfully used 

during calibrations when instrument 

adjustments are potentially being made, 

then such procedures are appropriate 

for audit use when instruments are not 

subject to adjustment. 

The EPA received only supportive 

comments endorsing the proposed 

revision to the language on excess NO. 

Therefore, the EPA is finalizing this 

revision as proposed. 

The EPA proposed to remove 

language (current appendix A, section 

3.2.2.2(b)) in the annual performance 

evaluation section that requires 

Regional approval for audit gases for 

any monitors operating at ranges higher 

that 1.0 ppm for O3, SO2 and NO2 and 

greater than 50 ppm for CO. The EPA 

does not need to approve a monitoring 

organization’s use of audit gases to audit 

above proposed concentration levels 

since the EPA has identified the 

requirements for all audit gases used in 

the program in current appendix A, 

section 2.6.1. There should be very few 

cases where a PE needs to be performed 

above level 10, but there may be some 

legitimate instances (e.g., an SO2 audit 

in areas impacted by volcanic 

emissions). Since data reported to AQS 

above the highest level may be rejected 

(if PSD PE data are reported to AQS), 

the EPA proposes that PQAOs notify the 

PSD reviewing authority of sites 

auditing at concentrations above level 

10 so that reporting accommodations 

can be made. There were no comments 

made on this proposed revision, so the 

EPA is finalizing this revision as 

proposed. 

The EPA proposed to describe the 

NPAP (current appendix A, section 2.4) 

in more detail. The NPAP is a longstanding program for the ambient air 

monitoring community. The NPAP is a 

performance evaluation, which is a type 

of audit where quantitative data are 

collected independently in order to 

evaluate the proficiency of an analyst, 

monitoring instrument or laboratory. 

This program has been briefly 

mentioned in section 2.4 of the current 

appendix A requirements. In appendix 

A, the EPA proposed to add language 

consistent with an annual decision 

memorandum 45 distributed to all state 

and local monitoring organizations in 

order to determine whether the 

monitoring organization plans to selfimplement the NPAP program or utilize 

the federally implemented program. In 

order to make this decision, the NPAP 

adequacy and independence 

requirements are described in the 

decision memorandum. The EPA 

proposed to include these same 

requirements in appendix B in a 

separate section for NPAP. As described 

in the applicability section, the 

implementation of NPAP is at the 

discretion of the PSD reviewing 

authority but must be implemented if 

data are used in any NAAQS 

determinations. Since PSD monitoring 

is implemented at shorter intervals 

(usually a year) and with fewer 

monitors, if NPAP is performed, it is 

required to be performed annually on 

each monitor operated in the PSD 

network. 

See appendix A for comments and 

discussions related to this section. The 

EPA is finalizing this revision as 

proposed. 

4. Measurement Quality Checks for 

Particulate Monitors 

The EPA proposed to have one flow 

rate verification frequency requirement 

for all PM PSD monitors. The current 

regulations (current appendix A, table 

A–2) provide for monthly flow rate 

verifications for most samplers used to 

monitor PM2.5, PM10 and Pb and 

quarterly flow rate verifications for 

high-volume PM10 or TSP samplers (for 

Pb). With longer duration NAAQS 

monitoring, the quarterly verification 

frequencies are adequate for these highvolume PM10 or TSP samplers. 

However, with the short duration of 

PSD monitoring, the EPA believes that 

monthly flow rate verifications are more 

appropriate to ensure that any sampler 

flow rate problems are identified more 

quickly and to reduce the potential for 

a significant amount of data invalidation 

that could extend monitoring activities. 

The EPA received one comment in 

support of this revision and no adverse 


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46See 78 FR 40000, July 3, 2013. 

47MDL is described as the minimum 

concentration of a substance that can be measured 

and reported with 99 percent confidence that the 

analyte concentration is greater than zero. 

48FEMs approved on or after March 4, 2010, have 

the required sensitivity to utilize the 0.002 mg/m3

reporting limit with the exception of manual 

equivalent method EQLA–0813–803, the previous 

FRM based on flame atomic absorption 

spectroscopy. 

comments. Therefore, the EPA is 

finalizing this revision as proposed. 

The EPA proposed to grant more 

flexibility to PSD monitoring 

organizations when selecting PM2.5

method designations for sites that 

require collocation. Appendix A 

(current section 3.2.5.2(b)) requires that 

if a primary monitor is a FEM, then the 

first QC collocated monitor must be a 

FRM monitor. Most of the FEM 

monitors are continuous monitors while 

the FRM monitors are filter-based. 

Continuous monitors (which are all 

FEMs) may be advantageous for use at 

the more remote PSD monitoring 

locations, since the site operator would 

not need to visit a site as often to 

retrieve filters (current FRMs are filterbased). The current collocation 

requirements for FEMs require a filterbased FRM for collocation, which 

would mean a visit to retrieve the FRM 

filters at least 1 week after the QC 

collocated monitor operated. Therefore, 

the EPA proposed that the FRM be 

selected as the QC collocated monitor 

unless the PSD PQAO submits a waiver 

request to the PSD reviewing authority 

to allow for collocation with a FEM. If 

the request for a waiver is approved, 

then the QC monitor must be the same 

method designation as the primary FEM 

monitor. The EPA did not receive any 

comments on this proposal and is 

finalizing this revision as proposed. 

The EPA proposed to allow the PSD 

reviewing authority to waive the PM2.5

3 mg/m3 concentration validity 

threshold for implementation of the 

PM2.5–PEP in the last quarter of PSD 

monitoring. The PM2.5–PEP (current 

appendix A, section 3.2.7) requires five 

valid PM2.5–PEP audits per year for 

PM2.5 monitoring networks with less 

than or equal to five sites and eight 

valid PM2.5–PEP audits per year with 

PM2.5 monitoring networks greater than 

five sites. Any PEP samples collected 

with a concentration less than 3 mg/m3

are not considered valid, since they 

cannot be used for bias estimates, and 

re-sampling is required at a later date. 

With NAAQS-related monitoring, which 

aggregates the PM2.5–PEP data over a 3- 

year period, re-sampling is easily 

accomplished. Due to the relatively 

short-term nature of most PSD 

monitoring, the likelihood of measuring 

low concentrations in many areas 

attaining the PM2.5 standard and the 

time required to weigh filters collected 

in performance evaluations, a PSD 

monitoring organization’s QAPP may 

contain a provision to waive the 3 mg/ 

m3 threshold for validity of performance 

evaluations conducted in the last 

quarter of monitoring, subject to 

approval by the PSD reviewing 

authority. The EPA did not receive any 

comments on this proposed waiver and 

is finalizing this revision as proposed. 

5. Calculations for Data Quality 

Assessment 

In order to allow reasonable estimates 

of data quality, the EPA uses data above 

an established threshold concentration 

usually related to the detection limits of 

the measurement method. Measurement 

pairs are selected for use in the 

precision and bias calculations only 

when both measurements are above a 

threshold concentration. 

For many years, the threshold 

concentration for Pb precision and bias 

data has been 0.02 mg/m3. The EPA 

promulgated a new Pb FRM utilizing the 

ICP–MS analysis technique in 2013 as a 

revision to appendix G of 40 CFR part 

50.46 This new FRM demonstrated 

MDLs 47 below 0.0002 mg/m3, which is 

well below the EPA requirement of five 

percent of the current Pb NAAQS level 

of 0.15 mg/m3, or 0.0075 mg/m3. As a 

result of the increased sensitivity 

inherent in this new FRM, the EPA 

proposed to lower the acceptable Pb 

concentration (current section 4) from 

the current value of 0.02 mg/m3 to 0.002 

mg/m3 for measurements obtained using 

the new Pb FRM and other more 

recently approved equivalent methods 

that have the requisite increased 

sensitivity.48 The current 0.02 mg/m3

value will be retained for the previous 

Pb FRM that has subsequently been redesignated as FEM EQLA–0813–803 as 

well as older equivalent methods that 

were approved prior to the more recent 

work on developing more sensitive 

methods. Since ambient Pb 

concentrations are lower and methods 

more sensitive, lowering the threshold 

concentration will allow much more 

collocated information to be evaluated, 

which will provide more representative 

estimates of precision and bias. 

See comments related to this proposal 

in the appendix A section. The EPA will 

establish two thresholds as proposed 

and will evaluate the use of an absolute 

difference acceptance criteria at lower 

concentration levels. 

The EPA also proposed to remove the 

TSP threshold concentration since TSP 

is no longer a NAAQS-required 

pollutant and the EPA no longer has QC 

requirements for it. The EPA received 

one comment in support of this 

proposed change and no adverse 

comments and is finalizing this revision 

as proposed. 

The EPA proposed to remove the 

statistical check currently described in 

section 4.1.5 of appendix A. The check 

was developed to perform a comparison 

of the one-point QC checks and the 

annual performance evaluation data 

performed by the same PQAO. The 

section suggests that 95 percent of all 

the bias estimates of the annual 

performance evaluations (reported as a 

percent difference) should fall within 

the 95 percent probability interval 

developed using the one-point QC 

checks. The problem with this check is 

that PQAOs with very good repeatability 

on the one-point QC check data had a 

hard time meeting this requirement 

since the probability interval became 

very tight, making it more difficult for 

better performing PQAOs to meet the 

requirement. Separate statistics to 

evaluate the one-point QC checks and 

the performance evaluations are already 

promulgated, so the removal of this 

check does not affect data quality 

assessments. The EPA received one 

comment in support of this proposal 

and no adverse comments and is 

finalizing this revision as proposed. 

Similar to the statistical comparison 

of performance evaluation data, the EPA 

proposed to remove the statistical check 

(current appendix A, section 4.2.4) to 

compare the flow rate audit data and 

flow rate verification data. The existing 

language suggests that 95 percent of all 

the flow rate audit data (reported as 

percent difference) should fall within 

the 95 percent probability interval 

developed from the flow rate 

verification data for the PQAO. The 

problem, as with the one-point QC 

check, was that monitoring 

organizations with very good 

repeatability on the flow rate 

verifications had a hard time meeting 

this requirement since the probability 

interval became very tight, making it 

difficult for better performing PQAOs to 

meet the requirement. Separate statistics 

to evaluate the flow rate verifications 

and flow rate audits are already 

promulgated, so the removal of this 

check does not affect data quality 

assessments. The EPA received one 

comment in support of this proposal 

and no adverse comments and is 

finalizing this revision as proposed. 

The EPA proposed to remove the 

reporting requirements that are 

currently in section 5 of appendix A 

because they do not pertain to PSD 

monitoring (current sections 5.1, 5.1.1 

and 5.1.2.1). Since PSD organizations 


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are not required to certify their data to 

the EPA nor report to AQS, the EPA will 

remove language related to these 

requirements and language that required 

the EPA to calculate and report the 

measurement uncertainty for the entire 

calendar year. The EPA will retain the 

quarterly PSD reporting requirements 

(current section 5.2 in appendix A) and 

require that those requirements be 

consistent with 40 CFR 58.16 as it 

pertains to PSD ambient air quality data 

and QC data, as described in appendix 

B. The EPA did not receive any 

comment on this revision and is 

finalizing this revision as proposed. 

IV. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

This action is not a significant 

regulatory action and was, therefore, not 

submitted to the Office of Management 

and Budget (OMB) for review. 

B. Paperwork Reduction Act (PRA) 

This action does not impose any new 

information collection burden under the 

PRA. OMB has previously approved the 

information collection activities 

contained in the existing regulations 

and has assigned OMB control number 

2060–0084. While the EPA believes that 

the net effect of the requirement changes 

is a decrease in overall burden, the 

current information collection request 

calculation tools examine key air 

monitoring tasks on somewhat of a 

macro level and are therefore not 

sufficiently detailed to show a material 

change in burden compared with the 

existing requirements. 

C. Regulatory Flexibility Act (RFA) 

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. This action will not 

impose any requirements on small 

entities. This action finalizes minor 

changes and clarifications to existing 

monitoring requirements and 

definitions. 

D. Unfunded Mandates Reform Act 

This action does not contain an 

unfunded federal mandate of $100 

million or more as described in UMRA, 

2 U.S.C. 1531–1538, and does not 

significantly or uniquely affect small 

governments. The revisions to the 

monitoring requirements impose no 

enforceable duty on any state, local, or 

tribal governments or the private sector 

beyond those duties already established 

in the CAA. 

E. Executive Order 13132: Federalism 

This action 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. 

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). Tribes have the opportunity to 

seek treatment in a manner similar to a 

state for the purpose of installing and 

operating a monitoring network 

consisting of one or more monitors and 

to then install and operate such a 

network, but are not required to do so. 

With regard to any tribes that may 

currently be operating a monitoring 

network, as well as any tribes that may 

operate a monitoring network in the 

future, this action finalizes minor 

changes and clarifications to existing 

monitoring requirements and will not 

materially impact the time required to 

operate monitoring networks. Thus, 

consultation under the Executive Order 

13175 is not required for this action. 

The EPA will work through tribal 

resources such as the Tribal Air 

Monitoring Support Center to ensure a 

complete understanding of these 

revisions. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

The EPA interprets Executive Order 

13045 as applying only to those 

regulatory actions that concern 

environmental health or safety risks that 

the EPA has reason to believe may 

disproportionately affect children, per 

the definition of ‘‘covered regulatory 

action’’ in section 2–202 of the 

Executive Order. This action is not 

subject to Executive Order 13045 

because it does not concern an 

environmental health risk or safety risk. 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not subject to Executive 

Order 13211, because it is not a 

significant regulatory action under 

Executive Order 12866. 

I. National Technology Transfer and 

Advancement Act 

This action does not involve technical 

standards. 

J. Executive Order 12898: Federal 

Actions to Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

The EPA believes the human health or 

environmental risk addressed by this 

action will not have potential 

disproportionately high and adverse 

human health or environmental effects 

on minority, low-income or indigenous 

populations. This action finalizes minor 

changes and clarifications to existing 

monitoring requirements and 

definitions. 

K. Congressional Review Act 

This action is subject to the CRA, and 

the EPA will submit a rule report to 

each House of the Congress and to the 

Comptroller General of the United 

States. This action is not a ‘‘major rule’’ 

as defined by 5 U.S.C. 804(2). 

List of Subjects in 40 CFR Part 58 

Environmental protection, 

Administrative practice and procedure, 

Air pollution control, Intergovernmental 

relations. 

Dated: March 10, 2016. 

Gina McCarthy, 

Administrator. 

Part 58, chapter I, title 40 of the Code 

of Federal Regulations is amended as 

follows: 

PART 58—AMBIENT AIR QUALITY 

SURVEILLANCE 

■ 1. The authority citation for part 58 

continues to read as follows: 

Authority: 42 U.S.C. 7403, 7405, 7410, 

7414, 7601, 7611, 7614, and 7619. 

■ 2. Revise § 58.1 to read as follows: 

§ 58.1 Definitions. 

As used in this part, all terms not 

defined herein have the meaning given 

them in the Clean Air Act. 

AADT means the annual average daily 

traffic. 

Act means the Clean Air Act as 

amended (42 U.S.C. 7401, et seq.) 

Additive and multiplicative bias 

means the linear regression intercept 

and slope of a linear plot fitted to 

corresponding candidate and reference 

method mean measurement data pairs. 

Administrator means the 

Administrator of the Environmental 

Protection Agency (EPA) or his or her 

authorized representative. 

Air quality system (AQS) means the 

EPA’s computerized system for storing 

and reporting of information relating to 

ambient air quality data. 

Approved regional method (ARM) 

means a continuous PM2.5 method that 

has been approved specifically within a 


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state or local air monitoring network for 

purposes of comparison to the NAAQS 

and to meet other monitoring objectives. 

AQCR means air quality control 

region. 

Area-wide means all monitors sited at 

neighborhood, urban, and regional 

scales, as well as those monitors sited at 

either micro- or middle-scale that are 

representative of many such locations in 

the same CBSA. 

Certifying agency means a state, local, 

or tribal agency responsible for meeting 

the data certification requirements in 

accordance with § 58.15 for a unique set 

of monitors. 

Chemical Speciation Network (CSN) 

includes Speciation Trends Network 

stations (STN) as specified in paragraph 

4.7.4 of appendix D of this part and 

supplemental speciation stations that 

provide chemical species data of fine 

particulate. 

CO means carbon monoxide. 

Combined statistical area (CSA) is 

defined by the U.S. Office of 

Management and Budget as a 

geographical area consisting of two or 

more adjacent Core Based Statistical 

Areas (CBSA) with employment 

interchange of at least 15 percent. 

Combination is automatic if the 

employment interchange is 25 percent 

and determined by local opinion if more 

than 15 but less than 25 percent. 

Core-based statistical area (CBSA) is 

defined by the U.S. Office of 

Management and Budget, as a statistical 

geographic entity consisting of the 

county or counties associated with at 

least one urbanized area/urban cluster 

of at least 10,000 population, plus 

adjacent counties having a high degree 

of social and economic integration. 

Metropolitan Statistical Areas (MSAs) 

and micropolitan statistical areas are the 

two categories of CBSA (metropolitan 

areas have populations greater than 

50,000; and micropolitan areas have 

populations between 10,000 and 

50,000). In the case of very large cities 

where two or more CBSAs are 

combined, these larger areas are referred 

to as combined statistical areas (CSAs) 

Corrected concentration pertains to 

the result of an accuracy or precision 

assessment test of an open path analyzer 

in which a high-concentration test or 

audit standard gas contained in a short 

test cell is inserted into the optical 

measurement beam of the instrument. 

When the pollutant concentration 

measured by the analyzer in such a test 

includes both the pollutant 

concentration in the test cell and the 

concentration in the atmosphere, the 

atmospheric pollutant concentration 

must be subtracted from the test 

measurement to obtain the corrected 

concentration test result. The corrected 

concentration is equal to the measured 

concentration minus the average of the 

atmospheric pollutant concentrations 

measured (without the test cell) 

immediately before and immediately 

after the test. 

Design value means the calculated 

concentration according to the 

applicable appendix of part 50 of this 

chapter for the highest site in an 

attainment or nonattainment area. 

EDO means environmental data 

operations. 

Effective concentration pertains to 

testing an open path analyzer with a 

high-concentration calibration or audit 

standard gas contained in a short test 

cell inserted into the optical 

measurement beam of the instrument. 

Effective concentration is the equivalent 

ambient-level concentration that would 

produce the same spectral absorbance 

over the actual atmospheric monitoring 

path length as produced by the highconcentration gas in the short test cell. 

Quantitatively, effective concentration 

is equal to the actual concentration of 

the gas standard in the test cell 

multiplied by the ratio of the path 

length of the test cell to the actual 

atmospheric monitoring path length. 

Federal equivalent method (FEM) 

means a method for measuring the 

concentration of an air pollutant in the 

ambient air that has been designated as 

an equivalent method in accordance 

with part 53 of this chapter; it does not 

include a method for which an 

equivalent method designation has been 

canceled in accordance with § 53.11 or 

§ 53.16. 

Federal reference method (FRM) 

means a method of sampling and 

analyzing the ambient air for an air 

pollutant that is specified as a reference 

method in an appendix to part 50 of this 

chapter, or a method that has been 

designated as a reference method in 

accordance with this part; it does not 

include a method for which a reference 

method designation has been canceled 

in accordance with § 53.11 or § 53.16 of 

this chapter. 

HNO3 means nitric acid. 

Implementation plan means an 

implementation plan approved or 

promulgated by the EPA pursuant to 

section 110 of the Act. 

Local agency means any local 

government agency, other than the state 

agency, which is charged by a state with 

the responsibility for carrying out a 

portion of the annual monitoring 

network plan required by § 58.10. 

Meteorological measurements means 

measurements of wind speed, wind 

direction, barometric pressure, 

temperature, relative humidity, solar 

radiation, ultraviolet radiation, and/or 

precipitation that occur at SLAMS 

stations including the NCore and PAMS 

networks. 

Metropolitan Statistical Area (MSA) 

means a CBSA associated with at least 

one urbanized area of 50,000 population 

or greater. The central-county, plus 

adjacent counties with a high degree of 

integration, comprise the area. 

Monitor means an instrument, 

sampler, analyzer, or other device that 

measures or assists in the measurement 

of atmospheric air pollutants and which 

is acceptable for use in ambient air 

surveillance under the applicable 

provisions of appendix C to this part. 

Monitoring agency means a state, 

local or tribal agency responsible for 

meeting the requirements of this part. 

Monitoring organization means a 

monitoring agency responsible for 

operating a monitoring site for which 

the quality assurance regulations apply. 

Monitoring path for an open path 

analyzer means the actual path in space 

between two geographical locations over 

which the pollutant concentration is 

measured and averaged. 

Monitoring path length of an open 

path analyzer means the length of the 

monitoring path in the atmosphere over 

which the average pollutant 

concentration measurement (pathaveraged concentration) is determined. 

See also, optical measurement path 

length. 

Monitoring planning area (MPA) 

means a contiguous geographic area 

with established, well-defined 

boundaries, such as a CBSA, county or 

state, having a common area that is used 

for planning monitoring locations for 

PM2.5. A MPA may cross state 

boundaries, such as the Philadelphia 

PA–NJ MSA, and be further subdivided 

into community monitoring zones. The 

MPAs are generally oriented toward 

CBSAs or CSAs with populations 

greater than 200,000, but for 

convenience, those portions of a state 

that are not associated with CBSAs can 

be considered as a single MPA. 

NATTS means the national air toxics 

trends stations. This network provides 

hazardous air pollution ambient data. 

NCore means the National Core 

multipollutant monitoring stations. 

Monitors at these sites are required to 

measure particles (PM2.5 speciated 

PM2.5, PM10–2.5), O3, SO2, CO, nitrogen 

oxides (NO/NOy), and meteorology 

(wind speed, wind direction, 

temperature, relative humidity). 

Near-road monitor means any 

approved monitor meeting the 

applicable specifications described in 

40 CFR part 58, appendix D (sections 

4.2.1, 4.3.2, 4.7.1(b)(2)) and appendix E 


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(section 6.4(a), Table E–4) for near-road 

measurement of PM2.5, CO, or NO2. 

Network means all stations of a given 

type or types. 

Network Plan means the Annual 

Monitoring Network Plan described in 

§ 58.10. 

NH3 means ammonia. 

NO2 means nitrogen dioxide. 

NO means nitrogen oxide. 

NOX means the sum of the 

concentrations of NO2 and NO. 

NOy means the sum of all total 

reactive nitrogen oxides, including NO, 

NO2, and other nitrogen oxides referred 

to as NOZ.

O3 means ozone. 

Open path analyzer means an 

automated analytical method that 

measures the average atmospheric 

pollutant concentration in situ along 

one or more monitoring paths having a 

monitoring path length of 5 meters or 

more and that has been designated as a 

reference or equivalent method under 

the provisions of part 53 of this chapter. 

Optical measurement path length 

means the actual length of the optical 

beam over which measurement of the 

pollutant is determined. The pathintegrated pollutant concentration 

measured by the analyzer is divided by 

the optical measurement path length to 

determine the path-averaged 

concentration. Generally, the optical 

measurement path length is: 

(1) Equal to the monitoring path 

length for a (bistatic) system having a 

transmitter and a receiver at opposite 

ends of the monitoring path; 

(2) Equal to twice the monitoring path 

length for a (monostatic) system having 

a transmitter and receiver at one end of 

the monitoring path and a mirror or 

retroreflector at the other end; or 

(3) Equal to some multiple of the 

monitoring path length for more 

complex systems having multiple passes 

of the measurement beam through the 

monitoring path. 

PAMS means photochemical 

assessment monitoring stations. 

Pb means lead. 

PM means particulate matter, 

including but not limited to PM10, 

PM10C, PM2.5, and PM10–2.5. 

PM2.5 means particulate matter with 

an aerodynamic diameter less than or 

equal to a nominal 2.5 micrometers as 

measured by a reference method based 

on appendix L of part 50 and designated 

in accordance with part 53 of this 

chapter, by an equivalent method 

designated in accordance with part 53, 

or by an approved regional method 

designated in accordance with appendix 

C to this part. 

PM10 means particulate matter with 

an aerodynamic diameter less than or 

equal to a nominal 10 micrometers as 

measured by a reference method based 

on appendix J of part 50 of this chapter 

and designated in accordance with part 

53 of this chapter or by an equivalent 

method designated in accordance with 

part 53. 

PM10C means particulate matter with 

an aerodynamic diameter less than or 

equal to a nominal 10 micrometers as 

measured by a reference method based 

on appendix O of part 50 of this chapter 

and designated in accordance with part 

53 of this chapter or by an equivalent 

method designated in accordance with 

part 53. 

PM10¥2.5 means particulate matter 

with an aerodynamic diameter less than 

or equal to a nominal 10 micrometers 

and greater than a nominal 2.5 

micrometers as measured by a reference 

method based on appendix O to part 50 

of this chapter and designated in 

accordance with part 53 of this chapter 

or by an equivalent method designated 

in accordance with part 53. 

Point analyzer means an automated 

analytical method that measures 

pollutant concentration in an ambient 

air sample extracted from the 

atmosphere at a specific inlet probe 

point, and that has been designated as 

a reference or equivalent method in 

accordance with part 53 of this chapter. 

Primary monitor means the monitor 

identified by the monitoring 

organization that provides concentration 

data used for comparison to the 

NAAQS. For any specific site, only one 

monitor for each pollutant can be 

designated in AQS as primary monitor 

for a given period of time. The primary 

monitor identifies the default data 

source for creating a combined site 

record for purposes of NAAQS 

comparisons. 

Primary quality assurance 

organization (PQAO) means a 

monitoring organization, a group of 

monitoring organizations or other 

organization that is responsible for a set 

of stations that monitor the same 

pollutant and for which data quality 

assessments can be pooled. Each criteria 

pollutant sampler/monitor at a 

monitoring station must be associated 

with only one PQAO. 

Probe means the actual inlet where an 

air sample is extracted from the 

atmosphere for delivery to a sampler or 

point analyzer for pollutant analysis. 

PSD monitoring network means a set 

of stations that provide concentration 

information for a specific PSD permit. 

PSD monitoring organization means a 

source owner/operator, a government 

agency, or a contractor of the source or 

agency that operates an ambient air 

pollution monitoring network for PSD 

purposes. 

PSD reviewing authority means the 

state air pollution control agency, local 

agency, other state agency, tribe, or 

other agency authorized by the 

Administrator to carry out a permit 

program under §§ 51.165 and 51.166 of 

this chapter, or the Administrator in the 

case of EPA-implemented permit 

programs under § 52.21 of this chapter. 

PSD station means any station 

operated for the purpose of establishing 

the effect on air quality of the emissions 

from a proposed source for purposes of 

prevention of significant deterioration 

as required by § 51.24(n) of this chapter. 

Regional Administrator means the 

Administrator of one of the ten EPA 

Regional Offices or his or her authorized 

representative. 

Reporting organization means an 

entity, such as a state, local, or tribal 

monitoring agency, that reports air 

quality data to the EPA. 

Site means a geographic location. One 

or more stations may be at the same site. 

SLAMS means state or local air 

monitoring stations. The SLAMS 

include the ambient air quality 

monitoring sites and monitors that are 

required by appendix D of this part and 

are needed for the monitoring objectives 

of appendix D, including NAAQS 

comparisons, but may serve other data 

purposes. The SLAMS includes NCore, 

PAMS, CSN, and all other state or 

locally operated criteria pollutant 

monitors, operated in accordance to this 

part, that have not been designated and 

approved by the Regional Administrator 

as SPM stations in an annual monitoring 

network plan. 

SO2 means sulfur dioxide. 

Special purpose monitor (SPM) 

station means a monitor included in an 

agency’s monitoring network that the 

agency has designated as a special 

purpose monitor station in its annual 

monitoring network plan and in the 

AQS, and which the agency does not 

count when showing compliance with 

the minimum requirements of this 

subpart for the number and siting of 

monitors of various types. Any SPM 

operated by an air monitoring agency 

must be included in the periodic 

assessments and annual monitoring 

network plan required by § 58.10 and 

approved by the Regional 

Administrator. 

State agency means the air pollution 

control agency primarily responsible for 

development and implementation of a 

State Implementation Plan under the 

Act. 

Station means a single monitor, or a 

group of monitors, located at a 

particular site. 


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STN station means a PM2.5 chemical 

speciation station designated to be part 

of the speciation trends network. This 

network provides chemical species data 

of fine particulate. 

Supplemental speciation station 

means a PM2.5 chemical speciation 

station that is operated for monitoring 

agency needs and not part of the STN. 

Traceable means that a local standard 

has been compared and certified, either 

directly or via not more than one 

intermediate standard, to a National 

Institute of Standards and Technology 

(NIST)-certified primary standard such 

as a NIST-traceable Reference Material 

(NTRM) or a NIST-certified Gas 

Manufacturer’s Internal Standard 

(GMIS). 

TSP (total suspended particulates) 

means particulate matter as measured 

by the method described in appendix B 

of Part 50. 

Urbanized area means an area with a 

minimum residential population of at 

least 50,000 people and which generally 

includes core census block groups or 

blocks that have a population density of 

at least 1,000 people per square mile 

and surrounding census blocks that 

have an overall density of at least 500 

people per square mile. The Census 

Bureau notes that under certain 

conditions, less densely settled territory 

may be part of each Urbanized Area. 

VOCs means volatile organic 

compounds. 

■ 3. In § 58.10: 

■ a. Revise paragraphs (a)(1) and (a)(2). 

■ b. Add paragraph (a)(12). 

The revisions and addition read as 

follows: 

§ 58.10 Annual monitoring network plan 

and periodic network assessment. 

(a)(1) Beginning July 1, 2007, the 

state, or where applicable local, agency 

shall submit to the Regional 

Administrator an annual monitoring 

network plan which shall provide for 

the documentation of the establishment 

and maintenance of an air quality 

surveillance system that consists of a 

network of SLAMS monitoring stations 

that can include FRM, FEM, and ARM 

monitors that are part of SLAMS, NCore, 

CSN, PAMS, and SPM stations. The 

plan shall include a statement of 

whether the operation of each monitor 

meets the requirements of appendices 

A, B, C, D, and E of this part, where 

applicable. The Regional Administrator 

may require additional information in 

support of this statement. The annual 

monitoring network plan must be made 

available for public inspection and 

comment for at least 30 days prior to 

submission to the EPA and the 

submitted plan shall include and 

address, as appropriate, any received 

comments. 

(2) Any annual monitoring network 

plan that proposes network 

modifications (including new or 

discontinued monitoring sites, new 

determinations that data are not of 

sufficient quality to be compared to the 

NAAQS, and changes in identification 

of monitors as suitable or not suitable 

for comparison against the annual PM2.5

NAAQS) to SLAMS networks is subject 

to the approval of the EPA Regional 

Administrator, who shall approve or 

disapprove the plan within 120 days of 

submission of a complete plan to the 

EPA. 

* * * * * 

(12) A detailed description of the 

PAMS network being operated in 

accordance with the requirements of 

appendix D to this part shall be 

submitted as part of the annual 

monitoring network plan for review by 

the EPA Administrator. The PAMS 

Network Description described in 

section 5 of appendix D may be used to 

meet this requirement. 

* * * * * 

■ 4. In § 58.11, revise paragraph (a)(3) to 

read as follows: 

§ 58.11 Network technical requirements. 

(a) * * * 

(3) The owner or operator of an 

existing or a proposed source shall 

follow the quality assurance criteria in 

appendix B to this part that apply to 

PSD monitoring when operating a PSD 

site. 

* * * * * 

■ 5. In § 58.12: 

■ a. Revise paragraph (d)(1). 

■ b. Revise paragraph (d)(3). 

The revisions read as follows: 

§ 58.12 Operating schedules. 

* * * * * 

(d) * * * 

(1)(i) Manual PM2.5 samplers at 

required SLAMS stations without a 

collocated continuously operating PM2.5

monitor must operate on at least a 1-in3 day schedule unless a waiver for an 

alternative schedule has been approved 

per paragraph (d)(1)(ii) of this section. 

(ii) For SLAMS PM2.5 sites with both 

manual and continuous PM2.5 monitors 

operating, the monitoring agency may 

request approval for a reduction to 1-in6 day PM2.5 sampling or for seasonal 

sampling from the EPA Regional 

Administrator. Other requests for a 

reduction to 1-in-6 day PM2.5 sampling 

or for seasonal sampling may be 

approved on a case-by-case basis. The 

EPA Regional Administrator may grant 

sampling frequency reductions after 

consideration of factors (including but 

not limited to the historical PM2.5 data 

quality assessments, the location of 

current PM2.5 design value sites, and 

their regulatory data needs) if the 

Regional Administrator determines that 

the reduction in sampling frequency 

will not compromise data needed for 

implementation of the NAAQS. 

Required SLAMS stations whose 

measurements determine the design 

value for their area and that are within 

±10 percent of the annual NAAQS, and 

all required sites where one or more 24- 

hour values have exceeded the 24-hour 

NAAQS each year for a consecutive 

period of at least 3 years are required to 

maintain at least a 1-in-3 day sampling 

frequency until the design value no 

longer meets these criteria for 3 

consecutive years. A continuously 

operating FEM or ARM PM2.5 monitor 

satisfies this requirement unless it is 

identified in the monitoring agency’s 

annual monitoring network plan as not 

appropriate for comparison to the 

NAAQS and the EPA Regional 

Administrator has approved that the 

data from that monitor may be excluded 

from comparison to the NAAQS. 

(iii) Required SLAMS stations whose 

measurements determine the 24-hour 

design value for their area and whose 

data are within ±5 percent of the level 

of the 24-hour PM2.5 NAAQS must have 

an FRM or FEM operate on a daily 

schedule if that area’s design value for 

the annual NAAQS is less than the level 

of the annual PM2.5 standard. A 

continuously operating FEM or ARM 

PM2.5 monitor satisfies this requirement 

unless it is identified in the monitoring 

agency’s annual monitoring network 

plan as not appropriate for comparison 

to the NAAQS and the EPA Regional 

Administrator has approved that the 

data from that monitor may be excluded 

from comparison to the NAAQS. The 

daily schedule must be maintained until 

the referenced design value no longer 

meets these criteria for 3 consecutive 

years. 

(iv) Changes in sampling frequency 

attributable to changes in design values 

shall be implemented no later than 

January 1 of the calendar year following 

the certification of such data as 

described in § 58.15. 

* * * * * 

(3) Manual PM2.5 speciation samplers 

at STN stations must operate on at least 

a 1-in-3 day sampling frequency unless 

a reduction in sampling frequency has 

been approved by the EPA 

Administrator based on factors such as 

area’s design value, the role of the 

particular site in national health studies, 

the correlation of the site’s species data 


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with nearby sites, and presence of other 

leveraged measurements. 

* * * * * 

■ 6. In § 58.14, revise paragraph (a) to 

read as follows: 

§ 58.14 System modification. 

(a) The state, or where appropriate 

local, agency shall develop a network 

modification plan and schedule to 

modify the ambient air quality 

monitoring network that addresses the 

findings of the network assessment 

required every 5 years by § 58.10(d). The 

network modification plan shall be 

submitted as part of the Annual 

Monitoring Network Plan that is due no 

later than the year after submittal of the 

network assessment. 

* * * * * 

■ 7. Revise § 58.15 to read as follows: 

§ 58.15 Annual air monitoring data 

certification. 

(a) The state, or where appropriate 

local, agency shall submit to the EPA 

Regional Administrator an annual air 

monitoring data certification letter to 

certify data collected by FRM, FEM, and 

ARM monitors at SLAMS and SPM sites 

that meet criteria in appendix A to this 

part from January 1 to December 31 of 

the previous year. The head official in 

each monitoring agency, or his or her 

designee, shall certify that the previous 

year of ambient concentration and 

quality assurance data are completely 

submitted to AQS and that the ambient 

concentration data are accurate to the 

best of her or his knowledge, taking into 

consideration the quality assurance 

findings. The annual data certification 

letter is due by May 1 of each year. 

(b) Along with each certification 

letter, the state shall submit to the 

Regional Administrator an annual 

summary report of all the ambient air 

quality data collected by FRM, FEM, 

and ARM monitors at SLAMS and SPM 

sites. The annual report(s) shall be 

submitted for data collected from 

January 1 to December 31 of the 

previous year. The annual summary 

serves as the record of the specific data 

that is the object of the certification 

letter. 

(c) Along with each certification 

letter, the state shall submit to the 

Regional Administrator a summary of 

the precision and accuracy data for all 

ambient air quality data collected by 

FRM, FEM, and ARM monitors at 

SLAMS and SPM sites. The summary of 

precision and accuracy shall be 

submitted for data collected from 

January 1 to December 31 of the 

previous year. 

■ 8. In § 58.16, revise paragraphs (a), (c), 

and (d) to read as follows: 

§ 58.16 Data submittal and archiving 

requirements. 

(a) The state, or where appropriate, 

local agency, shall report to the 

Administrator, via AQS all ambient air 

quality data and associated quality 

assurance data for SO2; CO; O3; NO2; 

NO; NOy; NOX; Pb–TSP mass 

concentration; Pb–PM10 mass 

concentration; PM10 mass concentration; 

PM2.5 mass concentration; for filterbased PM2.5 FRM/FEM, the field blank 

mass; chemically speciated PM2.5 mass 

concentration data; PM10–2.5 mass 

concentration; meteorological data from 

NCore and PAMS sites; and metadata 

records and information specified by the 

AQS Data Coding Manual (https://

www.epa.gov/sites/production/files/

2015-09/documents/aqs_data_coding_

manual_0.pdf). Air quality data and 

information must be submitted directly 

to the AQS via electronic transmission 

on the specified schedule described in 

paragraphs (b) and (d) of this section. 

* * * * * 

(c) Air quality data submitted for each 

reporting period must be edited, 

validated, and entered into the AQS 

(within the time limits specified in 

paragraphs (b) and (d) of this section) 

pursuant to appropriate AQS 

procedures. The procedures for editing 

and validating data are described in the 

AQS Data Coding Manual and in each 

monitoring agency’s quality assurance 

project plan. 

(d) The state shall report VOC and if 

collected, carbonyl, NH3, and HNO3

data from PAMS sites, and chemically 

speciated PM2.5 mass concentration data 

to AQS within 6 months following the 

end of each quarterly reporting period 

listed in paragraph (b) of this section. 

* * * * * 

■ 9. Revise Appendix A to part 58 to 

read as follows: 

Appendix A to Part 58—Quality 

Assurance Requirements for Monitors 

used in Evaluations of National 

Ambient Air Quality Standards 

1. General Information 

2. Quality System Requirements 

3. Measurement Quality Check Requirements 

4. Calculations for Data Quality Assessments 

5. Reporting Requirements 

6. References 

1. General Information 

1.1 Applicability. (a) This appendix 

specifies the minimum quality system 

requirements applicable to SLAMS and other 

monitor types whose data are intended to be 

used to determine compliance with the 

NAAQS (e.g., SPMs, tribal, CASTNET, 

NCore, industrial, etc.), unless the EPA 

Regional Administrator has reviewed and 

approved the monitor for exclusion from 

NAAQS use and these quality assurance 

requirements. 

(b) Primary quality assurance organizations 

are encouraged to develop and maintain 

quality systems more extensive than the 

required minimums. Additional guidance for 

the requirements reflected in this appendix 

can be found in the ‘‘Quality Assurance 

Handbook for Air Pollution Measurement 

Systems,’’ Volume II (see reference 10 of this 

appendix) and at a national level in 

references 1, 2, and 3 of this appendix. 

1.2 Primary Quality Assurance 

Organization (PQAO). A PQAO is defined as 

a monitoring organization or a group of 

monitoring organizations or other 

organization that is responsible for a set of 

stations that monitors the same pollutant and 

for which data quality assessments will be 

pooled. Each criteria pollutant sampler/

monitor must be associated with only one 

PQAO. In some cases, data quality is assessed 

at the PQAO level. 

1.2.1 Each PQAO shall be defined such 

that measurement uncertainty among all 

stations in the organization can be expected 

to be reasonably homogeneous as a result of 

common factors. Common factors that should 

be considered in defining PQAOs include: 

(a) Operation by a common team of field 

operators according to a common set of 

procedures; 

(b) Use of a common quality assurance 

project plan (QAPP) or standard operating 

procedures; 

(c) Common calibration facilities and 

standards; 

(d) Oversight by a common quality 

assurance organization; and 

(e) Support by a common management 

organization (i.e., state agency) or laboratory. 

Since data quality assessments are made 

and data certified at the PQAO level, the 

monitoring organization identified as the 

PQAO will be responsible for the oversight 

of the quality of data of all monitoring 

organizations within the PQAO. 

1.2.2 Monitoring organizations having 

difficulty describing its PQAO or in assigning 

specific monitors to primary quality 

assurance organizations should consult with 

the appropriate EPA Regional Office. Any 

consolidation of monitoring organizations to 

PQAOs shall be subject to final approval by 

the appropriate EPA Regional Office. 

1.2.3 Each PQAO is required to 

implement a quality system that provides 

sufficient information to assess the quality of 

the monitoring data. The quality system 

must, at a minimum, include the specific 

requirements described in this appendix. 

Failure to conduct or pass a required check 

or procedure, or a series of required checks 

or procedures, does not by itself invalidate 

data for regulatory decision making. Rather, 

PQAOs and the EPA shall use the checks and 

procedures required in this appendix in 

combination with other data quality 

information, reports, and similar 

documentation that demonstrate overall 

compliance with Part 58. Accordingly, the 

EPA and PQAOs shall use a ‘‘weight of 

evidence’’ approach when determining the 

suitability of data for regulatory decisions. 


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The EPA reserves the authority to use or not 

use monitoring data submitted by a 

monitoring organization when making 

regulatory decisions based on the EPA’s 

assessment of the quality of the data. 

Consensus built validation templates or 

validation criteria already approved in 

QAPPs should be used as the basis for the 

weight of evidence approach. 

1.3 Definitions. 

(a) Measurement Uncertainty. A term used 

to describe deviations from a true 

concentration or estimate that are related to 

the measurement process and not to spatial 

or temporal population attributes of the air 

being measured. 

(b) Precision. A measurement of mutual 

agreement among individual measurements 

of the same property usually under 

prescribed similar conditions, expressed 

generally in terms of the standard deviation. 

(c) Bias. The systematic or persistent 

distortion of a measurement process which 

causes errors in one direction. 

(d) Accuracy. The degree of agreement 

between an observed value and an accepted 

reference value. Accuracy includes a 

combination of random error (imprecision) 

and systematic error (bias) components 

which are due to sampling and analytical 

operations. 

(e) Completeness. A measure of the amount 

of valid data obtained from a measurement 

system compared to the amount that was 

expected to be obtained under correct, 

normal conditions. 

(f) Detection Limit. The lowest 

concentration or amount of target analyte that 

can be determined to be different from zero 

by a single measurement at a stated level of 

probability. 

1.4 Measurement Quality Checks. The 

measurement quality checks described in 

section 3 of this appendix shall be reported 

to AQS and are included in the data required 

for certification. 

1.5 Assessments and Reports. Periodic 

assessments and documentation of data 

quality are required to be reported to the 

EPA. To provide national uniformity in this 

assessment and reporting of data quality for 

all networks, specific assessment and 

reporting procedures are prescribed in detail 

in sections 3, 4, and 5 of this appendix. On 

the other hand, the selection and extent of 

the quality assurance and quality control 

activities used by a monitoring organization 

depend on a number of local factors such as 

field and laboratory conditions, the 

objectives for monitoring, the level of data 

quality needed, the expertise of assigned 

personnel, the cost of control procedures, 

pollutant concentration levels, etc. Therefore, 

quality system requirements in section 2 of 

this appendix are specified in general terms 

to allow each monitoring organization to 

develop a quality system that is most 

efficient and effective for its own 

circumstances while achieving the data 

quality objectives described in this appendix. 

2. Quality System Requirements 

A quality system (reference 1 of this 

appendix) is the means by which an 

organization manages the quality of the 

monitoring information it produces in a 

systematic, organized manner. It provides a 

framework for planning, implementing, 

assessing and reporting work performed by 

an organization and for carrying out required 

quality assurance and quality control 

activities. 

2.1 Quality Management Plans and 

Quality Assurance Project Plans. All PQAOs 

must develop a quality system that is 

described and approved in quality 

management plans (QMP) and QAPPs to 

ensure that the monitoring results: 

(a) Meet a well-defined need, use, or 

purpose (reference 5 of this appendix); 

(b) Provide data of adequate quality for the 

intended monitoring objectives; 

(c) Satisfy stakeholder expectations; 

(d) Comply with applicable standards 

specifications; 

(e) Comply with statutory (and other legal) 

requirements; and 

(f) Reflect consideration of cost and 

economics. 

2.1.1 The QMP describes the quality 

system in terms of the organizational 

structure, functional responsibilities of 

management and staff, lines of authority, and 

required interfaces for those planning, 

implementing, assessing and reporting 

activities involving environmental data 

operations (EDO). The QMP must be suitably 

documented in accordance with EPA 

requirements (reference 2 of this appendix), 

and approved by the appropriate Regional 

Administrator, or his or her representative. 

The quality system described in the QMP 

will be reviewed during the systems audits 

described in section 2.5 of this appendix. 

Organizations that implement long-term 

monitoring programs with EPA funds should 

have a separate QMP document. Smaller 

organizations, organizations that do 

infrequent work with the EPA or have 

monitoring programs of limited size or scope 

may combine the QMP with the QAPP if 

approved by, and subject to any conditions 

of the EPA. Additional guidance on this 

process can be found in reference 10 of this 

appendix. Approval of the recipient’s QMP 

by the appropriate Regional Administrator or 

his or her representative may allow 

delegation of authority to the PQAOs 

independent quality assurance function to 

review and approve environmental data 

collection activities adequately described and 

covered under the scope of the QMP and 

documented in appropriate planning 

documents (QAPP). Where a PQAO or 

monitoring organization has been delegated 

authority to review and approve their QAPP, 

an electronic copy must be submitted to the 

EPA region at the time it is submitted to the 

PQAO/monitoring organization’s QAPP 

approving authority. The QAPP will be 

reviewed by the EPA during systems audits 

or circumstances related to data quality. The 

QMP submission and approval dates for 

PQAOs/monitoring organizations must be 

reported to AQS either by the monitoring 

organization or the EPA Region. 

2.1.2 The QAPP is a formal document 

describing, in sufficient detail, the quality 

system that must be implemented to ensure 

that the results of work performed will satisfy 

the stated objectives. PQAOs must develop 

QAPPs that describe how the organization 

intends to control measurement uncertainty 

to an appropriate level in order to achieve the 

data quality objectives for the EDO. The 

quality assurance policy of the EPA requires 

every EDO to have a written and approved 

QAPP prior to the start of the EDO. It is the 

responsibility of the PQAO/monitoring 

organization to adhere to this policy. The 

QAPP must be suitably documented in 

accordance with EPA requirements (reference 

3 of this appendix) and include standard 

operating procedures for all EDOs either 

within the document or by appropriate 

reference. The QAPP must identify each 

PQAO operating monitors under the QAPP as 

well as generally identify the sites and 

monitors to which it is applicable either 

within the document or by appropriate 

reference. The QAPP submission and 

approval dates must be reported to AQS 

either by the monitoring organization or the 

EPA Region. 

2.1.3 The PQAO/monitoring 

organization’s quality system must have 

adequate resources both in personnel and 

funding to plan, implement, assess and 

report on the achievement of the 

requirements of this appendix and it’s 

approved QAPP. 

2.2 Independence of Quality Assurance. 

The PQAO must provide for a quality 

assurance management function, that aspect 

of the overall management system of the 

organization that determines and implements 

the quality policy defined in a PQAO’s QMP. 

Quality management includes strategic 

planning, allocation of resources and other 

systematic planning activities (e.g., planning, 

implementation, assessing and reporting) 

pertaining to the quality system. The quality 

assurance management function must have 

sufficient technical expertise and 

management authority to conduct 

independent oversight and assure the 

implementation of the organization’s quality 

system relative to the ambient air quality 

monitoring program and should be 

organizationally independent of 

environmental data generation activities. 

2.3. Data Quality Performance 

Requirements. 

2.3.1 Data Quality Objectives. The DQOs, 

or the results of other systematic planning 

processes, are statements that define the 

appropriate type of data to collect and 

specify the tolerable levels of potential 

decision errors that will be used as a basis 

for establishing the quality and quantity of 

data needed to support the monitoring 

objectives (reference 5 of this appendix). The 

DQOs will be developed by the EPA to 

support the primary regulatory objectives for 

each criteria pollutant. As they are 

developed, they will be added to the 

regulation. The quality of the conclusions 

derived from data interpretation can be 

affected by population uncertainty (spatial or 

temporal uncertainty) and measurement 

uncertainty (uncertainty associated with 

collecting, analyzing, reducing and reporting 

concentration data). This appendix focuses 

on assessing and controlling measurement 

uncertainty. 

2.3.1.1 Measurement Uncertainty for 

Automated and Manual PM2.5 Methods. The 

goal for acceptable measurement uncertainty 

is defined for precision as an upper 90 


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percent confidence limit for the coefficient of 

variation (CV) of 10 percent and ±10 percent 

for total bias. 

2.3.1.2 Measurement Uncertainty for 

Automated O3 Methods. The goal for 

acceptable measurement uncertainty is 

defined for precision as an upper 90 percent 

confidence limit for the CV of 7 percent and 

for bias as an upper 95 percent confidence 

limit for the absolute bias of 7 percent. 

2.3.1.3 Measurement Uncertainty for Pb 

Methods. The goal for acceptable 

measurement uncertainty is defined for 

precision as an upper 90 percent confidence 

limit for the CV of 20 percent and for bias 

as an upper 95 percent confidence limit for 

the absolute bias of 15 percent. 

2.3.1.4 Measurement Uncertainty for 

NO2. The goal for acceptable measurement 

uncertainty is defined for precision as an 

upper 90 percent confidence limit for the CV 

of 15 percent and for bias as an upper 95 

percent confidence limit for the absolute bias 

of 15 percent. 

2.3.1.5 Measurement Uncertainty for SO2.

The goal for acceptable measurement 

uncertainty for precision is defined as an 

upper 90 percent confidence limit for the CV 

of 10 percent and for bias as an upper 95 

percent confidence limit for the absolute bias 

of 10 percent. 

2.4 National Performance Evaluation 

Programs. The PQAO shall provide for the 

implementation of a program of independent 

and adequate audits of all monitors providing 

data for NAAQS compliance purposes 

including the provision of adequate resources 

for such audit programs. A monitoring plan 

(or QAPP) which provides for PQAO 

participation in the EPA’s National 

Performance Audit Program (NPAP), the 

PM2.5 Performance Evaluation Program 

(PM2.5-PEP) program and the Pb Performance 

Evaluation Program (Pb-PEP) and indicates 

the consent of the PQAO for the EPA to apply 

an appropriate portion of the grant funds, 

which the EPA would otherwise award to the 

PQAO for these QA activities, will be 

deemed by the EPA to meet this requirement. 

For clarification and to participate, PQAOs 

should contact either the appropriate EPA 

regional quality assurance (QA) coordinator 

at the appropriate EPA Regional Office 

location, or the NPAP coordinator at the EPA 

Air Quality Assessment Division, Office of 

Air Quality Planning and Standards, in 

Research Triangle Park, North Carolina. The 

PQAOs that plan to implement these 

programs (self-implement) rather than use 

the federal programs must meet the adequacy 

requirements found in the appropriate 

sections that follow, as well as meet the 

definition of independent assessment that 

follows. 

2.4.1 Independent assessment. An 

assessment performed by a qualified 

individual, group, or organization that is not 

part of the organization directly performing 

and accountable for the work being assessed. 

This auditing organization must not be 

involved with the generation of the ambient 

air monitoring data. An organization can 

conduct the performance evaluation (PE) if it 

can meet this definition and has a 

management structure that, at a minimum, 

will allow for the separation of its routine 

sampling personnel from its auditing 

personnel by two levels of management. In 

addition, the sample analysis of audit filters 

must be performed by a laboratory facility 

and laboratory equipment separate from the 

facilities used for routine sample analysis. 

Field and laboratory personnel will be 

required to meet PE field and laboratory 

training and certification requirements to 

establish comparability to federally 

implemented programs. 

2.5 Technical Systems Audit Program. 

Technical systems audits of each PQAO shall 

be conducted at least every 3 years by the 

appropriate EPA Regional Office and 

reported to the AQS. If a PQAO is made up 

of more than one monitoring organization, all 

monitoring organizations in the PQAO 

should be audited within 6 years (two TSA 

cycles of the PQAO). As an example, if a state 

has five local monitoring organizations that 

are consolidated under one PQAO, all five 

local monitoring organizations should 

receive a technical systems audit within a 6- 

year period. Systems audit programs are 

described in reference 10 of this appendix. 

2.6 Gaseous and Flow Rate Audit 

Standards. 

2.6.1 Gaseous pollutant concentration 

standards (permeation devices or cylinders of 

compressed gas) used to obtain test 

concentrations for CO, SO2, NO, and NO2

must be traceable to either a National 

Institute of Standards and Technology (NIST) 

Traceable Reference Material (NTRM) or a 

NIST-certified Gas Manufacturer’s Internal 

Standard (GMIS), certified in accordance 

with one of the procedures given in reference 

4 of this appendix. Vendors advertising 

certification with the procedures provided in 

reference 4 of this appendix and distributing 

gases as ‘‘EPA Protocol Gas’’ for ambient air 

monitoring purposes must participate in the 

EPA Ambient Air Protocol Gas Verification 

Program or not use ‘‘EPA’’ in any form of 

advertising. Monitoring organizations must 

provide information to the EPA on the gas 

producers they use on an annual basis and 

those PQAOs purchasing standards will be 

obligated, at the request of the EPA, to 

participate in the program at least once every 

5 years by sending a new unused standard to 

a designated verification laboratory. 

2.6.2 Test concentrations for O3 must be 

obtained in accordance with the ultraviolet 

photometric calibration procedure specified 

in appendix D to Part 50 of this chapter and 

by means of a certified NIST-traceable O3

transfer standard. Consult references 7 and 8 

of this appendix for guidance on transfer 

standards for O3. 

2.6.3 Flow rate measurements must be 

made by a flow measuring instrument that is 

NIST-traceable to an authoritative volume or 

other applicable standard. Guidance for 

certifying some types of flowmeters is 

provided in reference 10 of this appendix. 

2.7 Primary Requirements and Guidance. 

Requirements and guidance documents for 

developing the quality system are contained 

in references 1 through 11 of this appendix, 

which also contain many suggested 

procedures, checks, and control 

specifications. Reference 10 describes 

specific guidance for the development of a 

quality system for data collected for 

comparison to the NAAQS. Many specific 

quality control checks and specifications for 

methods are included in the respective 

reference methods described in Part 50 of 

this chapter or in the respective equivalent 

method descriptions available from the EPA 

(reference 6 of this appendix). Similarly, 

quality control procedures related to 

specifically designated reference and 

equivalent method monitors are contained in 

the respective operation or instruction 

manuals associated with those monitors. 

3. Measurement Quality Check Requirements 

This section provides the requirements for 

PQAOs to perform the measurement quality 

checks that can be used to assess data 

quality. Data from these checks are required 

to be submitted to the AQS within the same 

time frame as routinely-collected ambient 

concentration data as described in 40 CFR 

58.16. Table A–1 of this appendix provides 

a summary of the types and frequency of the 

measurement quality checks that will be 

described in this section. 

3.1. Gaseous Monitors of SO2, NO2, O3, 

and CO. 

3.1.1 One-Point Quality Control (QC) 

Check for SO2, NO2, O3, and CO. (a) A onepoint QC check must be performed at least 

once every 2 weeks on each automated 

monitor used to measure SO2, NO2, O3 and 

CO. With the advent of automated calibration 

systems, more frequent checking is strongly 

encouraged. See Reference 10 of this 

appendix for guidance on the review 

procedure. The QC check is made by 

challenging the monitor with a QC check gas 

of known concentration (effective 

concentration for open path monitors) 

between the prescribed range of 0.005 and 

0.08 parts per million (ppm) for SO2, NO2, 

and O3, and between the prescribed range of 

0.5 and 5 ppm for CO monitors. The QC 

check gas concentration selected within the 

prescribed range should be related to the 

monitoring objectives for the monitor. If 

monitoring at an NCore site or for trace level 

monitoring, the QC check concentration 

should be selected to represent the mean or 

median concentrations at the site. If the mean 

or median concentrations at trace gas sites 

are below the MDL of the instrument the 

agency can select the lowest concentration in 

the prescribed range that can be practically 

achieved. If the mean or median 

concentrations at trace gas sites are above the 

prescribed range the agency can select the 

highest concentration in the prescribed 

range. An additional QC check point is 

encouraged for those organizations that may 

have occasional high values or would like to 

confirm the monitors’ linearity at the higher 

end of the operational range or around 

NAAQS concentrations. If monitoring for 

NAAQS decisions, the QC concentration can 

be selected at a higher concentration within 

the prescribed range but should also consider 

precision points around mean or median 

monitor concentrations. 

(b) Point analyzers must operate in their 

normal sampling mode during the QC check 

and the test atmosphere must pass through 

all filters, scrubbers, conditioners and other 

components used during normal ambient 

sampling and as much of the ambient air 

inlet system as is practicable. The QC check 


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must be conducted before any calibration or 

adjustment to the monitor. 

(c) Open path monitors are tested by 

inserting a test cell containing a QC check gas 

concentration into the optical measurement 

beam of the instrument. If possible, the 

normally used transmitter, receiver, and as 

appropriate, reflecting devices should be 

used during the test, and the normal 

monitoring configuration of the instrument 

should be altered as little as possible to 

accommodate the test cell for the test. 

However, if permitted by the associated 

operation or instruction manual, an alternate 

local light source or an alternate optical path 

that does not include the normal atmospheric 

monitoring path may be used. The actual 

concentration of the QC check gas in the test 

cell must be selected to produce an effective 

concentration in the range specified earlier in 

this section. Generally, the QC test 

concentration measurement will be the sum 

of the atmospheric pollutant concentration 

and the QC test concentration. As such, the 

result must be corrected to remove the 

atmospheric concentration contribution. The 

corrected concentration is obtained by 

subtracting the average of the atmospheric 

concentrations measured by the open path 

instrument under test immediately before 

and immediately after the QC test from the 

QC check gas concentration measurement. If 

the difference between these before and after 

measurements is greater than 20 percent of 

the effective concentration of the test gas, 

discard the test result and repeat the test. If 

possible, open path monitors should be 

tested during periods when the atmospheric 

pollutant concentrations are relatively low 

and steady. 

(d) Report the audit concentration of the 

QC gas and the corresponding measured 

concentration indicated by the monitor to 

AQS. The percent differences between these 

concentrations are used to assess the 

precision and bias of the monitoring data as 

described in sections 4.1.2 (precision) and 

4.1.3 (bias) of this appendix. 

3.1.2 Annual performance evaluation for 

SO2, NO2, O3, or CO. A performance 

evaluation must be conducted on each 

primary monitor once a year. This can be 

accomplished by evaluating 25 percent of the 

primary monitors each quarter. The 

evaluation should be conducted by a trained 

experienced technician other than the 

routine site operator. 

3.1.2.1 The evaluation is made by 

challenging the monitor with audit gas 

standards of known concentration from at 

least three audit levels. One point must be 

within two to three times the method 

detection limit of the instruments within the 

PQAOs network, the second point will be 

less than or equal to the 99th percentile of 

the data at the site or the network of sites in 

the PQAO or the next highest audit 

concentration level. The third point can be 

around the primary NAAQS or the highest 3- 

year concentration at the site or the network 

of sites in the PQAO. An additional 4th level 

is encouraged for those agencies that would 

like to confirm the monitors’ linearity at the 

higher end of the operational range. In rare 

circumstances, there may be sites measuring 

concentrations above audit level 10. Notify 

the appropriate EPA region and the AQS 

program in order to make accommodations 

for auditing at levels above level 10. 

Audit level 

Concentration Range, ppm 

O3 SO2 NO2 CO 

1 ....................................................................................................................... 0.004–0.0059 0.0003–0.0029 0.0003–0.0029 0.020–0.059 

2 ....................................................................................................................... 0.006–0.019 0.0030–0.0049 0.0030–0.0049 0.060–0.199 

3 ....................................................................................................................... 0.020–0.039 0.0050–0.0079 0.0050–0.0079 0.200–0.899 

4 ....................................................................................................................... 0.040–0.069 0.0080–0.0199 0.0080–0.0199 0.900–2.999 

5 ....................................................................................................................... 0.070–0.089 0.0200–0.0499 0.0200–0.0499 3.000–7.999 

6 ....................................................................................................................... 0.090–0.119 0.0500–0.0999 0.0500–0.0999 8.000–15.999 

7 ....................................................................................................................... 0.120–0.139 0.1000–0.1499 0.1000–0.2999 16.000–30.999 

8 ....................................................................................................................... 0.140–0.169 0.1500–0.2599 0.3000–0.4999 31.000–39.999 

9 ....................................................................................................................... 0.170–0.189 0.2600–0.7999 0.5000–0.7999 40.000–49.999 

10 ..................................................................................................................... 0.190–0.259 0.8000–1.000 0.8000–1.000 50.000–60.000 

3.1.2.2 The NO2 audit techniques may 

vary depending on the ambient monitoring 

method. For chemiluminescence-type NO2

analyzers, gas phase titration (GPT) 

techniques should be based on EPA guidance 

documents and monitoring agency 

experience. The NO2 gas standards may be 

more appropriate than GPT for direct NO2

methods that do not employ converters. Care 

should be taken to ensure the stability of 

such gas standards prior to use. 

3.1.2.3 The standards from which audit 

gas test concentrations are obtained must 

meet the specifications of section 2.6.1 of this 

appendix. The gas standards and equipment 

used for the performance evaluation must not 

be the same as the standards and equipment 

used for one-point QC, calibrations, span 

evaluations or NPAP. 

3.1.2.4 For point analyzers, the 

evaluation shall be carried out by allowing 

the monitor to analyze the audit gas test 

atmosphere in its normal sampling mode 

such that the test atmosphere passes through 

all filters, scrubbers, conditioners, and other 

sample inlet components used during normal 

ambient sampling and as much of the 

ambient air inlet system as is practicable. 

3.1.2.5 Open-path monitors are evaluated 

by inserting a test cell containing the various 

audit gas concentrations into the optical 

measurement beam of the instrument. If 

possible, the normally used transmitter, 

receiver, and, as appropriate, reflecting 

devices should be used during the 

evaluation, and the normal monitoring 

configuration of the instrument should be 

modified as little as possible to accommodate 

the test cell for the evaluation. However, if 

permitted by the associated operation or 

instruction manual, an alternate local light 

source or an alternate optical path that does 

not include the normal atmospheric 

monitoring path may be used. The actual 

concentrations of the audit gas in the test cell 

must be selected to produce effective 

concentrations in the evaluation level ranges 

specified in this section of this appendix. 

Generally, each evaluation concentration 

measurement result will be the sum of the 

atmospheric pollutant concentration and the 

evaluation test concentration. As such, the 

result must be corrected to remove the 

atmospheric concentration contribution. The 

corrected concentration is obtained by 

subtracting the average of the atmospheric 

concentrations measured by the open path 

instrument under test immediately before 

and immediately after the evaluation test (or 

preferably before and after each evaluation 

concentration level) from the evaluation 

concentration measurement. If the difference 

between the before and after measurements is 

greater than 20 percent of the effective 

concentration of the test gas standard, 

discard the test result for that concentration 

level and repeat the test for that level. If 

possible, open path monitors should be 

evaluated during periods when the 

atmospheric pollutant concentrations are 

relatively low and steady. Also, if the openpath instrument is not installed in a 

permanent manner, the monitoring path 

length must be reverified to be within ±3 

percent to validate the evaluation since the 

monitoring path length is critical to the 

determination of the effective concentration. 

3.1.2.6 Report both the evaluation 

concentrations (effective concentrations for 

open-path monitors) of the audit gases and 

the corresponding measured concentration 

(corrected concentrations, if applicable, for 

open path monitors) indicated or produced 

by the monitor being tested to AQS. The 

percent differences between these 

concentrations are used to assess the quality 

of the monitoring data as described in section 

4.1.1 of this appendix. 

3.1.3 National Performance Audit 

Program (NPAP). 

The NPAP is a performance evaluation 

which is a type of audit where quantitative 

data are collected independently in order to 

evaluate the proficiency of an analyst, 

monitoring instrument or laboratory. Due to 

the implementation approach used in the 


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program, NPAP provides a national 

independent assessment of performance 

while maintaining a consistent level of data 

quality. Details of the program can be found 

in reference 11 of this appendix. The 

program requirements include: 

3.1.3.1 Performing audits of the primary 

monitors at 20 percent of monitoring sites per 

year, and 100 percent of the sites every 6 

years. High-priority sites may be audited 

more frequently. Since not all gaseous 

criteria pollutants are monitored at every site 

within a PQAO, it is not required that 20 

percent of the primary monitors for each 

pollutant receive an NPAP audit each year 

only that 20 percent of the PQAOs 

monitoring sites receive an NPAP audit. It is 

expected that over the 6-year period all 

primary monitors for all gaseous pollutants 

will receive an NPAP audit. 

3.1.3.2 Developing a delivery system that 

will allow for the audit concentration gasses 

to be introduced to the probe inlet where 

logistically feasible. 

3.1.3.3 Using audit gases that are verified 

against the NIST standard reference methods 

or special review procedures and validated 

annually for CO, SO2 and NO2, and at the 

beginning of each quarter of audits for O3. 

3.1.3.4 As described in section 2.4 of this 

appendix, the PQAO may elect, on an annual 

basis, to utilize the federally implemented 

NPAP program. If the PQAO plans to selfimplement NPAP, the EPA will establish 

training and other technical requirements for 

PQAOs to establish comparability to 

federally implemented programs. In addition 

to meeting the requirements in sections 

3.1.3.1 through 3.1.3.3 of this appendix, the 

PQAO must: 

(a) Utilize an audit system equivalent to 

the federally implemented NPAP audit 

system and is separate from equipment used 

in annual performance evaluations. 

(b) Perform a whole system check by 

having the NPAP system tested against an 

independent and qualified EPA lab, or 

equivalent. 

(c) Evaluate the system with the EPA NPAP 

program through collocated auditing at an 

acceptable number of sites each year (at least 

one for an agency network of five or less 

sites; at least two for a network with more 

than five sites). 

(d) Incorporate the NPAP in the PQAO’s 

quality assurance project plan. 

(e) Be subject to review by independent, 

EPA-trained personnel. 

(f) Participate in initial and update 

training/certification sessions. 

3.1.3.5 OAQPS, in consultation with the 

relevant EPA Regional Office, may approve 

the PQAO’s plan to self-implement NPAP if 

the OAQPS determines that the PQAO’s selfimplementation plan is equivalent to the 

federal programs and adequate to meet the 

objectives of national consistency and data 

quality. 

3.2 PM2.5. 

3.2.1 Flow Rate Verification for PM2.5. A 

one-point flow rate verification check must 

be performed at least once every month (each 

verification minimally separated by 14 days) 

on each monitor used to measure PM2.5. The 

verification is made by checking the 

operational flow rate of the monitor. If the 

verification is made in conjunction with a 

flow rate adjustment, it must be made prior 

to such flow rate adjustment. For the 

standard procedure, use a flow rate transfer 

standard certified in accordance with section 

2.6 of this appendix to check the monitor’s 

normal flow rate. Care should be used in 

selecting and using the flow rate 

measurement device such that it does not 

alter the normal operating flow rate of the 

monitor. Report the flow rate of the transfer 

standard and the corresponding flow rate 

measured by the monitor to AQS. The 

percent differences between the audit and 

measured flow rates are used to assess the 

bias of the monitoring data as described in 

section 4.2.2 of this appendix (using flow 

rates in lieu of concentrations). 

3.2.2 Semi-Annual Flow Rate Audit for 

PM2.5. Audit the flow rate of the particulate 

monitor twice a year. The two audits should 

ideally be spaced between 5 and 7 months 

apart. The EPA strongly encourages more 

frequent auditing. The audit should 

(preferably) be conducted by a trained 

experienced technician other than the 

routine site operator. The audit is made by 

measuring the monitor’s normal operating 

flow rate(s) using a flow rate transfer 

standard certified in accordance with section 

2.6 of this appendix. The flow rate standard 

used for auditing must not be the same flow 

rate standard used for verifications or to 

calibrate the monitor. However, both the 

calibration standard and the audit standard 

may be referenced to the same primary flow 

rate or volume standard. Care must be taken 

in auditing the flow rate to be certain that the 

flow measurement device does not alter the 

normal operating flow rate of the monitor. 

Report the audit flow rate of the transfer 

standard and the corresponding flow rate 

measured by the monitor to AQS. The 

percent differences between these flow rates 

are used to evaluate monitor performance. 

3.2.3 Collocated Quality Control 

Sampling Procedures for PM2.5. For each pair 

of collocated monitors, designate one 

sampler as the primary monitor whose 

concentrations will be used to report air 

quality for the site, and designate the other 

as the quality control monitor. There can be 

only one primary monitor at a monitoring 

site for a given time period. 

3.2.3.1 For each distinct monitoring 

method designation (FRM or FEM) that a 

PQAO is using for a primary monitor, the 

PQAO must have 15 percent of the primary 

monitors of each method designation 

collocated (values of 0.5 and greater round 

up); and have at least one collocated quality 

control monitor (if the total number of 

monitors is less than three). The first 

collocated monitor must be a designated 

FRM monitor. 

3.2.3.2 In addition, monitors selected for 

collocation must also meet the following 

requirements: 

(a) A primary monitor designated as an 

EPA FRM shall be collocated with a quality 

control monitor having the same EPA FRM 

method designation. 

(b) For each primary monitor designated as 

an EPA FEM used by the PQAO, 50 percent 

of the monitors designated for collocation, or 

the first if only one collocation is necessary, 

shall be collocated with a FRM quality 

control monitor and 50 percent of the 

monitors shall be collocated with a monitor 

having the same method designation as the 

FEM primary monitor. If an odd number of 

collocated monitors is required, the 

additional monitor shall be a FRM quality 

control monitor. An example of the 

distribution of collocated monitors for each 

unique FEM is provided below. Table A–2 of 

this appendix demonstrates the collocation 

procedure with a PQAO having one type of 

primary FRM and multiple primary FEMs. 

#Primary FEMS of a unique method designation #Collocated #Collocated 

with an FRM 

#Collocated 

with same 

method 

designation 

1–9 ............................................................................................................................................... 1 1 0 

10–16 ........................................................................................................................................... 2 1 1 

17–23 ........................................................................................................................................... 3 2 1 

24–29 ........................................................................................................................................... 4 2 2 

30–36 ........................................................................................................................................... 5 3 2 

37–43 ........................................................................................................................................... 6 3 3 

3.2.3.3 Since the collocation requirements 

are used to assess precision of the primary 

monitors and there can only be one primary 

monitor at a monitoring site, a site can only 

count for the collocation of the method 

designation of the primary monitor at that 

site. 

3.2.3.4 The collocated monitors should be 

deployed according to the following protocol: 

(a) Fifty percent of the collocated quality 

control monitors should be deployed at sites 

with annual average or daily concentrations 

estimated to be within plus or minus 20 

percent of either the annual or 24-hour 

NAAQS and the remainder at the PQAOs 

discretion; 


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(b) If an organization has no sites with 

annual average or daily concentrations 

within ±20 percent of the annual NAAQS or 

24-hour NAAQS, 50 percent of the collocated 

quality control monitors should be deployed 

at those sites with the annual mean 

concentrations or 24-hour concentrations 

among the highest for all sites in the network 

and the remainder at the PQAOs discretion. 

(c) The two collocated monitors must be 

within 4 meters (inlet to inlet) of each other 

and at least 2 meters apart for flow rates 

greater than 200 liters/min or at least 1 meter 

apart for samplers having flow rates less than 

200 liters/min to preclude airflow 

interference. A waiver allowing up to 10 

meters horizontal distance and up to 3 meters 

vertical distance (inlet to inlet) between a 

primary and collocated sampler may be 

approved by the Regional Administrator for 

sites at a neighborhood or larger scale of 

representation during the annual network 

plan approval process. Sampling and 

analytical methodologies must be the 

consistently implemented for both primary 

and collocated quality control samplers and 

for all other samplers in the network. 

(d) Sample the collocated quality control 

monitor on a 1-in-12 day schedule. Report 

the measurements from both primary and 

collocated quality control monitors at each 

collocated sampling site to AQS. The 

calculations for evaluating precision between 

the two collocated monitors are described in 

section 4.2.1 of this appendix. 

3.2.4 PM2.5 Performance Evaluation 

Program (PEP) Procedures. The PEP is an 

independent assessment used to estimate 

total measurement system bias. These 

evaluations will be performed under the 

NPEP as described in section 2.4 of this 

appendix or a comparable program. 

Performance evaluations will be performed 

annually within each PQAO. For PQAOs 

with less than or equal to five monitoring 

sites, five valid performance evaluation 

audits must be collected and reported each 

year. For PQAOs with greater than five 

monitoring sites, eight valid performance 

evaluation audits must be collected and 

reported each year. A valid performance 

evaluation audit means that both the primary 

monitor and PEP audit concentrations are 

valid and above 3 mg/m3. Siting of the PEP 

monitor must be consistent with section 

3.2.3.4(c). However, any horizontal distance 

greater than 4 meters and any vertical 

distance greater than one meter must be 

reported to the EPA regional PEP 

coordinator. Additionally for every monitor 

designated as a primary monitor, a primary 

quality assurance organization must: 

3.2.4.1 Have each method designation 

evaluated each year; and, 

3.2.4.2 Have all FRM, FEM or ARM 

samplers subject to a PEP audit at least once 

every 6 years, which equates to 

approximately 15 percent of the monitoring 

sites audited each year. 

3.2.4.3. Additional information 

concerning the PEP is contained in reference 

10 of this appendix. The calculations for 

evaluating bias between the primary monitor 

and the performance evaluation monitor for 

PM2.5 are described in section 4.2.5 of this 

appendix. 

3.3PM10. 

3.3.1 Flow Rate Verification for PM10 Low 

Volume Samplers (less than 200 liter/

minute). A one-point flow rate verification 

check must be performed at least once every 

month (each verification minimally separated 

by 14 days) on each monitor used to measure 

PM10. The verification is made by checking 

the operational flow rate of the monitor. If 

the verification is made in conjunction with 

a flow rate adjustment, it must be made prior 

to such flow rate adjustment. For the 

standard procedure, use a flow rate transfer 

standard certified in accordance with section 

2.6 of this appendix to check the monitor’s 

normal flow rate. Care should be taken in 

selecting and using the flow rate 

measurement device such that it does not 

alter the normal operating flow rate of the 

monitor. The percent differences between the 

audit and measured flow rates are reported 

to AQS and used to assess the bias of the 

monitoring data as described in section 4.2.2 

of this appendix (using flow rates in lieu of 

concentrations). 

3.3.2 Flow Rate Verification for PM10

High Volume Samplers (greater than 200 

liters/minute). For PM10 high volume 

samplers, the verification frequency is one 

verification every 90 days (quarter) with 4 in 

a year. Other than verification frequency, 

follow the same technical procedure as 

described in section 3.3.1 of this appendix. 

3.3.3 Semi-Annual Flow Rate Audit for 

PM10. Audit the flow rate of the particulate 

monitor twice a year. The two audits should 

ideally be spaced between 5 and 7 months 

apart. The EPA strongly encourages more 

frequent auditing. The audit should 

(preferably) be conducted by a trained 

experienced technician other than the 

routine site operator. The audit is made by 

measuring the monitor’s normal operating 

flow rate using a flow rate transfer standard 

certified in accordance with section 2.6 of 

this appendix. The flow rate standard used 

for auditing must not be the same flow rate 

standard used for verifications or to calibrate 

the monitor. However, both the calibration 

standard and the audit standard may be 

referenced to the same primary flow rate or 

volume standard. Care must be taken in 

auditing the flow rate to be certain that the 

flow measurement device does not alter the 

normal operating flow rate of the monitor. 

Report the audit flow rate of the transfer 

standard and the corresponding flow rate 

measured by the monitor to AQS. The 

percent differences between these flow rates 

are used to evaluate monitor performance. 

3.3.4 Collocated Quality Control 

Sampling Procedures for Manual PM10. 

Collocated sampling for PM10 is only 

required for manual samplers. For each pair 

of collocated monitors, designate one 

sampler as the primary monitor whose 

concentrations will be used to report air 

quality for the site and designate the other as 

the quality control monitor. 

3.3.4.1 For manual PM10 samplers, a 

PQAO must: 

(a) Have 15 percent of the primary 

monitors collocated (values of 0.5 and greater 

round up); and 

(b) Have at least one collocated quality 

control monitor (if the total number of 

monitors is less than three). 

3.3.4.2 The collocated quality control 

monitors should be deployed according to 

the following protocol: 

(a) Fifty percent of the collocated quality 

control monitors should be deployed at sites 

with daily concentrations estimated to be 

within plus or minus 20 percent of the 

applicable NAAQS and the remainder at the 

PQAOs discretion; 

(b) If an organization has no sites with 

daily concentrations within plus or minus 20 

percent of the NAAQS, 50 percent of the 

collocated quality control monitors should be 

deployed at those sites with the daily mean 

concentrations among the highest for all sites 

in the network and the remainder at the 

PQAOs discretion. 

(c) The two collocated monitors must be 

within 4 meters (inlet to inlet) of each other 

and at least 2 meters apart for flow rates 

greater than 200 liters/min or at least 1 meter 

apart for samplers having flow rates less than 

200 liters/min to preclude airflow 

interference. A waiver allowing up to 10 

meters horizontal distance and up to 3 meters 

vertical distance (inlet to inlet) between a 

primary and collocated sampler may be 

approved by the Regional Administrator for 

sites at a neighborhood or larger scale of 

representation. This waiver may be approved 

during the annual network plan approval 

process. Sampling and analytical 

methodologies must be the consistently 

implemented for both collocated samplers 

and for all other samplers in the network. 

(d) Sample the collocated quality control 

monitor on a 1-in-12 day schedule. Report 

the measurements from both primary and 

collocated quality control monitors at each 

collocated sampling site to AQS. The 

calculations for evaluating precision between 

the two collocated monitors are described in 

section 4.2.1 of this appendix. 

(e) In determining the number of collocated 

quality control sites required for PM10, 

monitoring networks for lead (Pb–PM10) 

should be treated independently from 

networks for particulate matter (PM), even 

though the separate networks may share one 

or more common samplers. However, a single 

quality control monitor that meets the 

collocation requirements for Pb-PM10 and 

PM10 may serve as a collocated quality 

control monitor for both networks. Extreme 

care must be taken when using the filter from 

a quality control monitor for both PM10 and 

Pb analysis. A PM10 filter weighing should 

occur prior to any Pb analysis. 

3.4 Pb. 

3.4.1 Flow Rate Verification for Pb–PM10

Low Volume Samplers (less than 200 liter/ 

minute). A one-point flow rate verification 

check must be performed at least once every 

month (each verification minimally separated 

by 14 days) on each monitor used to measure 

Pb. The verification is made by checking the 

operational flow rate of the monitor. If the 

verification is made in conjunction with a 

flow rate adjustment, it must be made prior 

to such flow rate adjustment. For the 

standard procedure, use a flow rate transfer 

standard certified in accordance with section 

2.6 of this appendix to check the monitor’s 

normal flow rate. Care should be taken in 

selecting and using the flow rate 

measurement device such that it does not 


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alter the normal operating flow rate of the 

monitor. The percent differences between the 

audit and measured flow rates are reported 

to AQS and used to assess the bias of the 

monitoring data as described in section 4.2.2 

of this appendix (using flow rates in lieu of 

concentrations). 

3.4.2 Flow Rate Verification for Pb High 

Volume Samplers (greater than 200 liters/ 

minute). For high volume samplers, the 

verification frequency is one verification 

every 90 days (quarter) with four in a year. 

Other than verification frequency, follow the 

same technical procedure as described in 

section 3.4.1 of this appendix. 

3.4.3 Semi-Annual Flow Rate Audit for 

Pb. Audit the flow rate of the particulate 

monitor twice a year. The two audits should 

ideally be spaced between 5 and 7 months 

apart. The EPA strongly encourages more 

frequent auditing. The audit should 

(preferably) be conducted by a trained 

experienced technician other than the 

routine site operator. The audit is made by 

measuring the monitor’s normal operating 

flow rate using a flow rate transfer standard 

certified in accordance with section 2.6 of 

this appendix. The flow rate standard used 

for auditing must not be the same flow rate 

standard used for verifications or to calibrate 

the monitor. However, both the calibration 

standard and the audit standard may be 

referenced to the same primary flow rate or 

volume standard. Care must be taken in 

auditing the flow rate to be certain that the 

flow measurement device does not alter the 

normal operating flow rate of the monitor. 

Report the audit flow rate of the transfer 

standard and the corresponding flow rate 

measured by the monitor to AQS. The 

percent differences between these flow rates 

are used to evaluate monitor performance. 

3.4.4 Collocated Quality Control 

Sampling for TSP Pb for monitoring sites 

other than non-source oriented NCore. For 

each pair of collocated monitors for manual 

TSP Pb samplers, designate one sampler as 

the primary monitor whose concentrations 

will be used to report air quality for the site, 

and designate the other as the quality control 

monitor. 

3.4.4.1 A PQAO must: 

(a) Have 15 percent of the primary 

monitors (not counting non-source oriented 

NCore sites in PQAO) collocated. Values of 

0.5 and greater round up; and 

(b) Have at least one collocated quality 

control monitor (if the total number of 

monitors is less than three). 

3.4.4.2 The collocated quality control 

monitors should be deployed according to 

the following protocol: 

(a) 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. 

(b) The two collocated monitors must be 

within 4 meters (inlet to inlet) of each other 

and at least 2 meters apart for flow rates 

greater than 200 liters/min or at least 1 meter 

apart for samplers having flow rates less than 

200 liters/min to preclude airflow 

interference. 

(c) Sample the collocated quality control 

monitor on a 1-in-12 day schedule. Report 

the measurements from both primary and 

collocated quality control monitors at each 

collocated sampling site to AQS. The 

calculations for evaluating precision between 

the two collocated monitors are described in 

section 4.2.1 of this appendix. 

3.4.5 Collocated Quality Control 

Sampling for Pb–PM10 at monitoring sites 

other than non-source oriented NCore. If a 

PQAO is monitoring for Pb–PM10 at sites 

other than at a non-source oriented NCore 

site then the PQAO must: 

3.4.5.1 Have 15 percent of the primary 

monitors (not counting non-source oriented 

NCore sites in PQAO) collocated. Values of 

0.5 and greater round up; and 

3.4.5.2 Have at least one collocated 

quality control monitor (if the total number 

of monitors is less than three). 

3.4.5.3 The collocated monitors should be 

deployed according to the following protocol: 

(a) Fifty percent of the collocated quality 

control monitors should be deployed at sites 

with the highest 3-month average 

concentrations and the remainder at the 

PQAOs discretion. 

(b) The two collocated monitors must be 

within 4 meters (inlet to inlet) of each other 

and at least 2 meters apart for flow rates 

greater than 200 liters/min or at least 1 meter 

apart for samplers having flow rates less than 

200 liters/min to preclude airflow 

interference. A waiver allowing up to 10 

meters horizontal distance and up to 3 meters 

vertical distance (inlet to inlet) between a 

primary and collocated sampler may be 

approved by the Regional Administrator for 

sites at a neighborhood or larger scale of 

representation. This waiver may be approved 

during the annual network plan approval 

process. Sampling and analytical 

methodologies must be the consistently 

implemented for both collocated samplers 

and for all other samplers in the network. 

(c) Sample the collocated quality control 

monitor on a 1-in-12 day schedule. Report 

the measurements from both primary and 

collocated quality control monitors at each 

collocated sampling site to AQS. The 

calculations for evaluating precision between 

the two collocated monitors are described in 

section 4.2.1 of this appendix. 

(d) In determining the number of 

collocated quality control sites required for 

Pb–PM10, monitoring networks for PM10

should be treated independently from 

networks for Pb–PM10, even though the 

separate networks may share one or more 

common samplers. However, a single quality 

control monitor that meets the collocation 

requirements for Pb–PM10 and PM10 may 

serve as a collocated quality control monitor 

for both networks. Extreme care must be 

taken when using a using the filter from a 

quality control monitor for both PM10 and Pb 

analysis. A PM10 filter weighing should occur 

prior to any Pb analysis. 

3.4.6 Pb Analysis Audits. Each calendar 

quarter, audit the Pb reference or equivalent 

method analytical procedure using filters 

containing a known quantity of Pb. These 

audit filters are prepared by depositing a Pb 

standard on unexposed filters and allowing 

them to dry thoroughly. The audit samples 

must be prepared using batches of reagents 

different from those used to calibrate the Pb 

analytical equipment being audited. Prepare 

audit samples in the following concentration 

ranges: 

Range Equivalent ambient Pb 

concentration, μg/m 3

1 ........ 30–100% of Pb NAAQS. 

2 ........ 200–300% of Pb NAAQS. 

(a) Extract the audit samples using the 

same extraction procedure used for exposed 

filters. 

(b) Analyze three audit samples in each of 

the two ranges each quarter samples are 

analyzed. The audit sample analyses shall be 

distributed as much as possible over the 

entire calendar quarter. 

(c) Report the audit concentrations (in mg 

Pb/filter or strip) and the corresponding 

measured concentrations (in mg Pb/filter or 

strip) to AQS using AQS unit code 077. The 

percent differences between the 

concentrations are used to calculate 

analytical accuracy as described in section 

4.2.6 of this appendix. 

3.4.7 Pb PEP Procedures for monitoring 

sites other than non-source oriented NCore. 

The PEP is an independent assessment used 

to estimate total measurement system bias. 

These evaluations will be performed under 

the NPEP described in section 2.4 of this 

appendix or a comparable program. Each 

year, one performance evaluation audit must 

be performed at one Pb site in each primary 

quality assurance organization that has less 

than or equal to five sites and two audits at 

PQAOs with greater than five sites. Nonsource oriented NCore sites are not counted. 

Siting of the PEP monitor must be consistent 

with section 3.4.5.3(b). However, any 

horizontal distance greater than 4 meters and 

any vertical distance greater than 1 meter 

must be reported to the EPA regional PEP 

coordinator. In addition, each year, four 

collocated samples from PQAOs with less 

than or equal to five sites and six collocated 

samples at PQAOs with greater than five sites 

must be sent to an independent laboratory, 

the same laboratory as the performance 

evaluation audit, for analysis. The 

calculations for evaluating bias between the 

primary monitor and the performance 

evaluation monitor for Pb are described in 

section 4.2.4 of this appendix. 

4. Calculations for Data Quality Assessments 

(a) Calculations of measurement 

uncertainty are carried out by the EPA 

according to the following procedures. The 

PQAOs must report the data to AQS for all 

measurement quality checks as specified in 

this appendix even though they may elect to 

perform some or all of the calculations in this 

section on their own. 

(b) The EPA will provide annual 

assessments of data quality aggregated by site 

and PQAO for SO2, NO2, O3 and CO and by 

PQAO for PM10, PM2.5, and Pb. 

(c) At low concentrations, agreement 

between the measurements of collocated 

quality control samplers, expressed as 


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relative percent difference or percent 

difference, may be relatively poor. For this 

reason, collocated measurement pairs are 

selected for use in the precision and bias 

calculations only when both measurements 

are equal to or above the following limits: 

(1) Pb: 0.002 mg/m3 (Methods approved 

after 3/04/2010, with exception of manual 

equivalent method EQLA–0813–803). 

(2) Pb: 0.02 mg/m3 (Methods approved 

before 3/04/2010, and manual equivalent 

method EQLA–0813–803). 

(3) PM10 (Hi-Vol): 15 mg/m3. 

(4) PM10 (Lo-Vol): 3 mg/m3. 

(5) PM2.5: 3 mg/m3. 

4.1 Statistics for the Assessment of QC 

Checks for SO2, NO2, O3 and CO. 

4.1.1 Percent Difference. Many of the 

measurement quality checks start with a 

comparison of an audit concentration or 

value (flow rate) to the concentration/value 

measured by the monitor and use percent 

difference as the comparison statistic as 

described in equation 1 of this section. For 

each single point check, calculate the percent 

difference, di, as follows: 

where meas is the concentration indicated by 

the PQAO’s instrument and audit is the audit 

concentration of the standard used in the QC 

check being measured. 

4.1.2 Precision Estimate. The precision 

estimate is used to assess the one-point QC 

checks for SO2, NO2, O3, or CO described in 

section 3.1.1 of this appendix. The precision 

estimator is the coefficient of variation upper 

bound and is calculated using equation 2 of 

this section: 

where n is the number of single point checks 

being aggregated; X2 0.1,n–1 is the 10th 

percentile of a chi-squared distribution with 

n–1 degrees of freedom. 

4.1.3 Bias Estimate. The bias estimate is 

calculated using the one-point QC checks for 

SO2, NO2, O3, or CO described in section 

3.1.1 of this appendix. The bias estimator is 

an upper bound on the mean absolute value 

of the percent differences as described in 

equation 3 of this section: 

where n is the number of single point checks 

being aggregated; t0.95,n–1 is the 95th quantile 

of a t-distribution with n–1 degrees of 

freedom; the quantity AB is the mean of the 

absolute values of the d i ′ s and is calculated 

using equation 4 of this section: 

and the quantity AS is the standard deviation 

of the absolute value of the di ′ s and is 

calculated using equation 5 of this section: 

4.1.3.1 Assigning a sign (positive/

negative) to the bias estimate. Since the bias 

statistic as calculated in equation 3 of this 

appendix uses absolute values, it does not 

have a tendency (negative or positive bias) 

associated with it. A sign will be designated 

by rank ordering the percent differences of 

the QC check samples from a given site for 

a particular assessment interval. 

4.1.3.2 Calculate the 25th and 75th 

percentiles of the percent differences for each 

site. The absolute bias upper bound should 

be flagged as positive if both percentiles are 

positive and negative if both percentiles are 

negative. The absolute bias upper bound 

would not be flagged if the 25th and 75th 

percentiles are of different signs. 

4.2 Statistics for the Assessment of PM10,

PM2.5, and Pb. 

4.2.1 Collocated Quality Control Sampler 

Precision Estimate for PM10, PM2.5 and Pb. 

Precision is estimated via duplicate 

measurements from collocated samplers. It is 

recommended that the precision be 

aggregated at the PQAO level quarterly, 

annually, and at the 3-year level. The data 

pair would only be considered valid if both 

concentrations are greater than or equal to 

the minimum values specified in section 4(c) 

of this appendix. For each collocated data 

pair, calculate the relative percent difference, 

di, using equation 6 of this appendix: 

where Xi is the concentration from the 

primary sampler and Yi is the concentration 

value from the audit sampler. The coefficient 

of variation upper bound is calculated using 

equation 7 of this appendix: 


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where n is the number of valid data pairs 

being aggregated, and X2 0.1,n–1 is the 10th 

percentile of a chi-squared distribution with 

n–1 degrees of freedom. The factor of 2 in the 

denominator adjusts for the fact that each di

is calculated from two values with error. 

4.2.2 One-Point Flow Rate Verification 

Bias Estimate for PM10, PM2.5 and Pb. For 

each one-point flow rate verification, 

calculate the percent difference in volume 

using equation 1 of this appendix where 

meas is the value indicated by the sampler’s 

volume measurement and audit is the actual 

volume indicated by the auditing flow meter. 

The absolute volume bias upper bound is 

then calculated using equation 3, where n is 

the number of flow rate audits being 

aggregated; t0.95,n–1 is the 95th quantile of a 

t-distribution with n-1 degrees of freedom, 

the quantity AB is the mean of the absolute 

values of the di′s and is calculated using 

equation 4 of this appendix, and the quantity 

AS in equation 3 of this appendix is the 

standard deviation of the absolute values if 

the di′s and is calculated using equation 5 of 

this appendix. 

4.2.3 Semi-Annual Flow Rate Audit Bias 

Estimate for PM10, PM2.5 and Pb. Use the 

same procedure described in section 4.2.2 for 

the evaluation of flow rate audits. 

4.2.4 Performance Evaluation Programs 

Bias Estimate for Pb. The Pb bias estimate is 

calculated using the paired routine and the 

PEP monitor as described in section 3.4.7. 

Use the same procedures as described in 

section 4.1.3 of this appendix. 

4.2.5 Performance Evaluation Programs 

Bias Estimate for PM2.5. The bias estimate is 

calculated using the PEP audits described in 

section 4.1.3 of this appendix. The bias 

estimator is based on the mean percent 

differences (Equation 1). The mean percent 

difference, D, is calculated by Equation 8 

below. 

where nj is the number of pairs and 

d1,d2,...dnj are the biases for each pair to be 

averaged. 

4.2.6 Pb Analysis Audit Bias Estimate. 

The bias estimate is calculated using the 

analysis audit data described in section 3.4.6. 

Use the same bias estimate procedure as 

described in section 4.1.3 of this appendix. 

5. Reporting Requirements 

5.1 Reporting Requirements. For each 

pollutant, prepare a list of all monitoring 

sites and their AQS site identification codes 

in each PQAO and submit the list to the 

appropriate EPA Regional Office, with a copy 

to AQS. Whenever there is a change in this 

list of monitoring sites in a PQAO, report this 

change to the EPA Regional Office and to 

AQS. 

5.1.1 Quarterly Reports. For each quarter, 

each PQAO shall report to AQS directly (or 

via the appropriate EPA Regional Office for 

organizations not direct users of AQS) the 

results of all valid measurement quality 

checks it has carried out during the quarter. 

The quarterly reports must be submitted 

consistent with the data reporting 

requirements specified for air quality data as 

set forth in 40 CFR 58.16. The EPA strongly 

encourages early submission of the quality 

assurance data in order to assist the PQAOs 

ability to control and evaluate the quality of 

the ambient air data. 

5.1.2 Annual Reports. 

5.1.2.1 When the PQAO has certified 

relevant data for the calendar year, the EPA 

will calculate and report the measurement 

uncertainty for the entire calendar year. 

6. References 

(1) American National Standard— 

Specifications and Guidelines for Quality 

Systems for Environmental Data Collection 

and Environmental Technology Programs. 

ANSI/ASQC E4–2014. February 2014. 

Available from American Society for Quality 

Control, 611 East Wisconsin Avenue, 

Milwaukee, WI 53202. 

(2) EPA Requirements for Quality 

Management Plans. EPA QA/R–2. EPA/240/ 

B–01/002. March 2001, Reissue May 2006. 

Office of Environmental Information, 

Washington DC 20460. http://www.epa.gov/

quality/agency-wide-quality-systemdocuments. 

(3) EPA Requirements for Quality 

Assurance Project Plans for Environmental 

Data Operations. EPA QA/R–5. EPA/240/B– 

01/003. March 2001, Reissue May 2006. 

Office of Environmental Information, 

Washington DC 20460. http://www.epa.gov/

quality/agency-wide-quality-systemdocuments. 

(4) EPA Traceability Protocol for Assay and 

Certification of Gaseous Calibration 

Standards. EPA–600/R–12/531. May, 2012. 

Available from U.S. Environmental 

Protection Agency, National Risk 

Management Research Laboratory, Research 

Triangle Park NC 27711. http://cfpub.epa.

gov/si/si_public_record_report.cfm?dir

EntryId=245292. 

(5) Guidance for the Data Quality 

Objectives Process. EPA QA/G–4. EPA/240/ 

B–06/001. February, 2006. Office of 

Environmental Information, Washington DC 

20460. http://www.epa.gov/quality/agencywide-quality-system-documents. 

(6) List of Designated Reference and 

Equivalent Methods. Available from U.S. 

Environmental Protection Agency, National 

Exposure Research Laboratory, Human 

Exposure and Atmospheric Sciences 

Division, MD–D205–03, Research Triangle 

Park, NC 27711. http://www3.epa.gov/ttn/

amtic/criteria.html. 

(7) Transfer Standards for the Calibration 

of Ambient Air Monitoring Analyzers for 

Ozone. EPA–454/B–13–004 U.S. 

Environmental Protection Agency, Research 

Triangle Park, NC 27711, October, 2013. 

http://www3.epa.gov/ttn/amtic/

qapollutant.html. 

(8) Paur, R.J. and F.F. McElroy. Technical 

Assistance Document for the Calibration of 

Ambient Ozone Monitors. EPA–600/4–79– 

057. U.S. Environmental Protection Agency, 

Research Triangle Park, NC 27711, 

September, 1979. http://www.epa.gov/ttn/

amtic/cpreldoc.html. 

(9) Quality Assurance Handbook for Air 

Pollution Measurement Systems, Volume 1— 

A Field Guide to Environmental Quality 

Assurance. EPA–600/R–94/038a. April 1994. 

Available from U.S. Environmental 

Protection Agency, ORD Publications Office, 

Center for Environmental Research 

Information (CERI), 26 W. Martin Luther 

King Drive, Cincinnati, OH 45268. http://

www3.epa.gov/ttn/amtic/qalist.html. 

(10) Quality Assurance Handbook for Air 

Pollution Measurement Systems, Volume II: 

Ambient Air Quality Monitoring Program 

Quality System Development. EPA–454/B– 

13–003. http://www3.epa.gov/ttn/amtic/

qalist.html. 

(11) National Performance Evaluation 

Program Standard Operating Procedures. 

http://www3.epa.gov/ttn/amtic/

npapsop.html. 


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TABLE A–1 OF APPENDIX A TO PART 58—MINIMUM DATA ASSESSMENT REQUIREMENTS FOR NAAQS RELATED CRITERIA

POLLUTANT MONITORS

Method Assessment method Coverage Minimum 

frequency 

Parameters 

reported 

AQS assessment 

type 

Gaseous Methods (CO, NO2, SO2, O3) 

One-Point QC for 

SO2, NO2, O3, CO.

Response check at 

concentration 

0.005–0.08 ppm 

SO2, NO2, O3, and.

0.5 and 5 ppm CO ....

Each analyzer ........... Once per 2 weeks ..... Audit concentration 1

and measured concentration. 2

One-Point QC. 

Annual performance 

evaluation for SO2, 

NO2, O3, CO.

See section 3.1.2 of 

this appendix.

Each analyzer ........... Once per year ........... Audit concentration 1

and measured concentration 2 for 

each level.

Annual PE. 

NPAP for SO2, NO2, 

O3, CO.

Independent Audit ..... 20% of sites each 

year.

Once per year ........... Audit concentration 1

and measured concentration 2 for 

each level.

NPAP. 

Particulate Methods 

Continuous 4 method—collocated quality control sampling 

PM2.5.

Collocated samplers 15% ........................... 1-in-12 days .............. Primary sampler concentration and duplicate sampler 

concentration. 3

No Transaction reported as raw data. 

Manual method—collocated quality control sampling PM10, 

PM2.5, Pb–TSP, 

Pb–PM10.

Collocated samplers 15% ........................... 1-in-12 days .............. Primary sampler concentration and duplicate sampler 

concentration. 3

No Transaction reported as raw data. 

Flow rate verification 

PM10 (low Vol) 

PM2.5, Pb–PM10.

Check of sampler 

flow rate.

Each sampler ............ Once every month .... Audit flow rate and 

measured flow rate 

indicated by the 

sampler.

Flow Rate 

Verification. 

Flow rate verification 

PM10 (High-Vol), 

Pb–TSP.

Check of sampler 

flow rate.

Each sampler ............ Once every quarter ... Audit flow rate and 

measured flow rate 

indicated by the 

sampler.

Flow Rate 

Verification. 

Semi-annual flow rate 

audit PM10, TSP, 

PM10–2.5, PM2.5, 

Pb–TSP, Pb–PM10.

Check of sampler 

flow rate using 

independent standard.

Each sampler, ........... Once every 6 months Audit flow rate and 

measured flow rate 

indicated by the 

sampler.

Semi Annual Flow 

Rate Audit. 

Pb analysis audits 

Pb–TSP, Pb–PM10.

Check of analytical 

system with Pb 

audit strips/filters.

Analytical ................... Once each quarter .... Measured value and 

audit value (ug Pb/ 

filter) using AQS 

unit code 077.

Pb Analysis Audits. 

Performance Evaluation Program PM2.5.Collocated samplers (1) 5 valid audits for 

primary QA orgs, 

with <= 5 sites..

(2) 8 valid audits for 

primary QA orgs, 

with >5 sites..

(3) All samplers in 6 

years.

Distributed over all 4 

quarters.

Primary sampler concentration and performance evaluation sampler concentration.PEP. 

Performance Evaluation Program Pb– 

TSP, Pb–PM10.

Collocated samplers (1) 1 valid audit and 4 

collocated samples 

for primary QA 

orgs, with <=5 

sites..

(2) 2 valid audits and 

6 collocated samples for primary QA 

orgs with >5 sites.

Distributed over all 4 

quarters.

Primary sampler concentration and performance evaluation sampler concentration. Primary 

sampler concentration and duplicate 

sampler concentration.

PEP. 

1Effective concentration for open path analyzers. 

2 Corrected concentration, if applicable for open path analyzers. 

3Both primary and collocated sampler values are reported as raw data. 

4PM2.5 is the only particulate criteria pollutant requiring collocation of continuous and manual primary monitors. 


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TABLE A–2 OF APPENDIX A TO PART 58—SUMMARY OF PM2.5 NUMBER AND TYPE OF COLLOCATION (15% COLLOCATION

REQUIREMENT) REQUIRED USING AN EXAMPLE OF A PQAO THAT HAS 54 PRIMARY MONITORS (54 SITES) WITH ONE

FEDERAL REFERENCE METHOD TYPE AND THREE TYPES OF APPROVED FEDERAL EQUIVALENT METHODS

Primary sampler method designation Total No. of 

monitors 

Total No. of 

collocated 

No. of 

collocated 

with FRM 

No. of 

collocated 

with same 

method 

designation 

as primary 

FRM ................................................................................................................. 20 3 3 3 

FEM (A) ........................................................................................................... 20 3 2 1 

FEM (B) ........................................................................................................... 2 1 1 0 

FEM (C) ........................................................................................................... 12 2 1 1 

■ 10. Add Appendix B to part 58 to read 

as follows: 

Appendix B to Part 58—Quality 

Assurance Requirements for Prevention 

of Significant Deterioration (PSD) Air 

Monitoring 

1. General Information 

2. Quality System Requirements 

3. Measurement Quality Check Requirements 

4. Calculations for Data Quality Assessments 

5. Reporting Requirements 

6. References 

1. General Information 

1.1 Applicability. 

(a) This appendix specifies the minimum 

quality assurance requirements for the 

control and assessment of the quality of the 

ambient air monitoring data submitted to a 

PSD reviewing authority or the EPA by an 

organization operating an air monitoring 

station, or network of stations, operated in 

order to comply with Part 51 New Source 

Review—Prevention of Significant 

Deterioration (PSD). Such organizations are 

encouraged to develop and maintain quality 

assurance programs more extensive than the 

required minimum. Additional guidance for 

the requirements reflected in this appendix 

can be found in the ‘‘Quality Assurance 

Handbook for Air Pollution Measurement 

Systems,’’ Volume II (Ambient Air) and 

‘‘Quality Assurance Handbook for Air 

Pollution Measurement Systems,’’ Volume IV 

(Meteorological Measurements) and at a 

national level in references 1, 2, and 3 of this 

appendix. 

(b) It is not assumed that data generated for 

PSD under this appendix will be used in 

making NAAQS decisions. However, if all 

the requirements in this appendix are 

followed (including the NPEP programs) and 

reported to AQS, with review and 

concurrence from the EPA region, data may 

be used for NAAQS decisions. With the 

exception of the NPEP programs (NPAP, 

PM2.5 PEP, Pb–PEP), for which 

implementation is at the discretion of the 

PSD reviewing authority, all other quality 

assurance and quality control requirements 

found in the appendix must be met. 

1.2 PSD Primary Quality Assurance 

Organization (PQAO). A PSD PQAO is 

defined as a monitoring organization or a 

coordinated aggregation of such 

organizations that is responsible for a set of 

stations within one PSD reviewing authority 

that monitors the same pollutant and for 

which data quality assessments will be 

pooled. Each criteria pollutant sampler/ 

monitor must be associated with only one 

PSD PQAO. 

1.2.1 Each PSD PQAO shall be defined 

such that measurement uncertainty among all 

stations in the organization can be expected 

to be reasonably homogeneous, as a result of 

common factors. A PSD PQAO must be 

associated with only one PSD reviewing 

authority. Common factors that should be 

considered in defining PSD PQAOs include: 

(a) Operation by a common team of field 

operators according to a common set of 

procedures; 

(b) Use of a common QAPP and/or 

standard operating procedures; 

(c) Common calibration facilities and 

standards; 

(d) Oversight by a common quality 

assurance organization; and 

(e) Support by a common management 

organization or laboratory. 

1.2.2 PSD monitoring organizations 

having difficulty describing its PQAO or in 

assigning specific monitors to a PSD PQAO 

should consult with the PSD reviewing 

authority. Any consolidation of PSD PQAOs 

shall be subject to final approval by the PSD 

reviewing authority. 

1.2.3 Each PSD PQAO is required to 

implement a quality system that provides 

sufficient information to assess the quality of 

the monitoring data. The quality system 

must, at a minimum, include the specific 

requirements described in this appendix. 

Failure to conduct or pass a required check 

or procedure, or a series of required checks 

or procedures, does not by itself invalidate 

data for regulatory decision making. Rather, 

PSD PQAOs and the PSD reviewing authority 

shall use the checks and procedures required 

in this appendix in combination with other 

data quality information, reports, and similar 

documentation that demonstrate overall 

compliance with parts 51, 52 and 58 of this 

chapter. Accordingly, the PSD reviewing 

authority shall use a ‘‘weight of evidence’’ 

approach when determining the suitability of 

data for regulatory decisions. The PSD 

reviewing authority reserves the authority to 

use or not use monitoring data submitted by 

a PSD monitoring organization when making 

regulatory decisions based on the PSD 

reviewing authority’s assessment of the 

quality of the data. Generally, consensus 

built validation templates or validation 

criteria already approved in quality 

assurance project plans (QAPPs) should be 

used as the basis for the weight of evidence 

approach. 

1.3 Definitions. 

(a) Measurement Uncertainty. A term used 

to describe deviations from a true 

concentration or estimate that are related to 

the measurement process and not to spatial 

or temporal population attributes of the air 

being measured. 

(b) Precision. A measurement of mutual 

agreement among individual measurements 

of the same property usually under 

prescribed similar conditions, expressed 

generally in terms of the standard deviation. 

(c) Bias. The systematic or persistent 

distortion of a measurement process which 

causes errors in one direction. 

(d) Accuracy. The degree of agreement 

between an observed value and an accepted 

reference value. Accuracy includes a 

combination of random error (imprecision) 

and systematic error (bias) components 

which are due to sampling and analytical 

operations. 

(e) Completeness. A measure of the amount 

of valid data obtained from a measurement 

system compared to the amount that was 

expected to be obtained under correct, 

normal conditions. 

(f) Detectability. The low critical range 

value of a characteristic that a method 

specific procedure can reliably discern. 

1.4 Measurement Quality Check 

Reporting. The measurement quality checks 

described in section 3 of this appendix, are 

required to be submitted to the PSD 

reviewing authority within the same time 

frame as routinely-collected ambient 

concentration data as described in 40 CFR 

58.16. The PSD reviewing authority may as 

well require that the measurement quality 

check data be reported to AQS. 

1.5 Assessments and Reports. Periodic 

assessments and documentation of data 

quality are required to be reported to the PSD 

reviewing authority. To provide national 

uniformity in this assessment and reporting 

of data quality for all networks, specific 

assessment and reporting procedures are 

prescribed in detail in sections 3, 4, and 5 of 

this appendix. 

2. Quality System Requirements 

A quality system (reference 1 of this 

appendix) is the means by which an 

organization manages the quality of the 

monitoring information it produces in a 


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systematic, organized manner. It provides a 

framework for planning, implementing, 

assessing and reporting work performed by 

an organization and for carrying out required 

quality assurance and quality control 

activities. 

2.1 Quality Assurance Project Plans. All 

PSD PQAOs must develop a quality system 

that is described and approved in quality 

assurance project plans (QAPP) to ensure that 

the monitoring results: 

(a) Meet a well-defined need, use, or 

purpose (reference 5 of this appendix); 

(b) Provide data of adequate quality for the 

intended monitoring objectives; 

(c) Satisfy stakeholder expectations; 

(d) Comply with applicable standards 

specifications; 

(e) Comply with statutory (and other legal) 

requirements; and 

(f) Assure quality assurance and quality 

control adequacy and independence. 

2.1.1 The QAPP is a formal document 

that describes these activities in sufficient 

detail and is supported by standard operating 

procedures. The QAPP must describe how 

the organization intends to control 

measurement uncertainty to an appropriate 

level in order to achieve the objectives for 

which the data are collected. The QAPP must 

be documented in accordance with EPA 

requirements (reference 3 of this appendix). 

2.1.2 The PSD PQAO’s quality system 

must have adequate resources both in 

personnel and funding to plan, implement, 

assess and report on the achievement of the 

requirements of this appendix and it’s 

approved QAPP. 

2.1.3 Incorporation of quality 

management plan (QMP) elements into the 

QAPP. The QMP describes the quality system 

in terms of the organizational structure, 

functional responsibilities of management 

and staff, lines of authority, and required 

interfaces for those planning, implementing, 

assessing and reporting activities involving 

environmental data operations (EDO). The 

PSD PQAOs may combine pertinent elements 

of the QMP into the QAPP rather than 

requiring the submission of both QMP and 

QAPP documents separately, with prior 

approval of the PSD reviewing authority. 

Additional guidance on QMPs can be found 

in reference 2 of this appendix. 

2.2 Independence of Quality Assurance 

Management. The PSD PQAO must provide 

for a quality assurance management function 

for its PSD data collection operation, that 

aspect of the overall management system of 

the organization that determines and 

implements the quality policy defined in a 

PSD PQAO’s QAPP. Quality management 

includes strategic planning, allocation of 

resources and other systematic planning 

activities (e.g., planning, implementation, 

assessing and reporting) pertaining to the 

quality system. The quality assurance 

management function must have sufficient 

technical expertise and management 

authority to conduct independent oversight 

and assure the implementation of the 

organization’s quality system relative to the 

ambient air quality monitoring program and 

should be organizationally independent of 

environmental data generation activities. 

2.3 Data Quality Performance 

Requirements. 

2.3.1 Data Quality Objectives (DQOs). 

The DQOs, or the results of other systematic 

planning processes, are statements that 

define the appropriate type of data to collect 

and specify the tolerable levels of potential 

decision errors that will be used as a basis 

for establishing the quality and quantity of 

data needed to support air monitoring 

objectives (reference 5 of the appendix). The 

DQOs have been developed by the EPA to 

support attainment decisions for comparison 

to national ambient air quality standards 

(NAAQS). The PSD reviewing authority and 

the PSD monitoring organization will be 

jointly responsible for determining whether 

adherence to the EPA developed NAAQS 

DQOs specified in appendix A of this part are 

appropriate or if DQOs from a projectspecific systematic planning process are 

necessary. 

2.3.1.1 Measurement Uncertainty for 

Automated and Manual PM2.5 Methods. The 

goal for acceptable measurement uncertainty 

for precision is defined as an upper 90 

percent confidence limit for the coefficient of 

variation (CV) of 10 percent and plus or 

minus 10 percent for total bias. 

2.3.1.2 Measurement Uncertainty for 

Automated Ozone Methods. The goal for 

acceptable measurement uncertainty is 

defined for precision as an upper 90 percent 

confidence limit for the CV of 7 percent and 

for bias as an upper 95 percent confidence 

limit for the absolute bias of 7 percent. 

2.3.1.3 Measurement Uncertainty for Pb 

Methods. The goal for acceptable 

measurement uncertainty is defined for 

precision as an upper 90 percent confidence 

limit for the CV of 20 percent and for bias 

as an upper 95 percent confidence limit for 

the absolute bias of 15 percent. 

2.3.1.4 Measurement Uncertainty for 

NO2. The goal for acceptable measurement 

uncertainty is defined for precision as an 

upper 90 percent confidence limit for the CV 

of 15 percent and for bias as an upper 95 

percent confidence limit for the absolute bias 

of 15 percent. 

2.3.1.5 Measurement Uncertainty for SO2.

The goal for acceptable measurement 

uncertainty for precision is defined as an 

upper 90 percent confidence limit for the CV 

of 10 percent and for bias as an upper 95 

percent confidence limit for the absolute bias 

of 10 percent. 

2.4 National Performance Evaluation 

Program. Organizations operating PSD 

monitoring networks are required to 

implement the EPA’s national performance 

evaluation program (NPEP) if the data will be 

used for NAAQS decisions and at the 

discretion of the PSD reviewing authority if 

PSD data are not used for NAAQS decisions. 

The NPEP includes the National Performance 

Audit Program (NPAP), the PM2.5

Performance Evaluation Program (PM2.5-PEP) 

and the Pb Performance Evaluation Program 

(Pb-PEP). The PSD QAPP shall provide for 

the implementation of NPEP including the 

provision of adequate resources for such 

NPEP if the data will be used for NAAQS 

decisions or if required by the PSD reviewing 

authority. Contact the PSD reviewing 

authority to determine the best procedure for 

implementing the audits which may include 

an audit by the PSD reviewing authority, a 

contractor certified for the activity, or 

through self-implementation which is 

described in sections below. A determination 

of which entity will be performing this audit 

program should be made as early as possible 

and during the QAPP development process. 

The PSD PQAOs, including contractors that 

plan to implement these programs on behalf 

of PSD PQAOs, that plan to implement these 

programs (self-implement) rather than use 

the federal programs, must meet the 

adequacy requirements found in the 

appropriate sections that follow, as well as 

meet the definition of independent 

assessment that follows. 

2.4.1 Independent Assessment. An 

assessment performed by a qualified 

individual, group, or organization that is not 

part of the organization directly performing 

and accountable for the work being assessed. 

This auditing organization must not be 

involved with the generation of the routinelycollected ambient air monitoring data. An 

organization can conduct the performance 

evaluation (PE) if it can meet this definition 

and has a management structure that, at a 

minimum, will allow for the separation of its 

routine sampling personnel from its auditing 

personnel by two levels of management. In 

addition, the sample analysis of audit filters 

must be performed by a laboratory facility 

and laboratory equipment separate from the 

facilities used for routine sample analysis. 

Field and laboratory personnel will be 

required to meet the performance evaluation 

field and laboratory training and certification 

requirements. The PSD PQAO will be 

required to participate in the centralized field 

and laboratory standards certification and 

comparison processes to establish 

comparability to federally implemented 

programs. 

2.5 Technical Systems Audit Program. 

The PSD reviewing authority or the EPA may 

conduct system audits of the ambient air 

monitoring programs or organizations 

operating PSD networks. The PSD monitoring 

organizations shall consult with the PSD 

reviewing authority to verify the schedule of 

any such technical systems audit. Systems 

audit programs are described in reference 10 

of this appendix. 

2.6 Gaseous and Flow Rate Audit 

Standards. 

2.6.1 Gaseous pollutant concentration 

standards (permeation devices or cylinders of 

compressed gas) used to obtain test 

concentrations for carbon monoxide (CO), 

sulfur dioxide (SO2), nitrogen oxide (NO), 

and nitrogen dioxide (NO2) must be traceable 

to either a National Institute of Standards and 

Technology (NIST) Traceable Reference 

Material (NTRM) or a NIST-certified Gas 

Manufacturer’s Internal Standard (GMIS), 

certified in accordance with one of the 

procedures given in reference 4 of this 

appendix. Vendors advertising certification 

with the procedures provided in reference 4 

of this appendix and distributing gases as 

‘‘EPA Protocol Gas’’ must participate in the 

EPA Protocol Gas Verification Program or not 

use ‘‘EPA’’ in any form of advertising. The 

PSD PQAOs must provide information to the 

PSD reviewing authority on the gas vendors 

they use (or will use) for the duration of the 

PSD monitoring project. This information can 


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be provided in the QAPP or monitoring plan, 

but must be updated if there is a change in 

the producer used. 

2.6.2 Test concentrations for ozone (O3) 

must be obtained in accordance with the 

ultraviolet photometric calibration procedure 

specified in appendix D to Part 50, and by 

means of a certified NIST-traceable O3

transfer standard. Consult references 7 and 8 

of this appendix for guidance on transfer 

standards for O3. 

2.6.3 Flow rate measurements must be 

made by a flow measuring instrument that is 

NIST-traceable to an authoritative volume or 

other applicable standard. Guidance for 

certifying some types of flow-meters is 

provided in reference 10 of this appendix. 

2.7 Primary Requirements and Guidance. 

Requirements and guidance documents for 

developing the quality system are contained 

in references 1 through 11 of this appendix, 

which also contain many suggested 

procedures, checks, and control 

specifications. Reference 10 describes 

specific guidance for the development of a 

quality system for data collected for 

comparison to the NAAQS. Many specific 

quality control checks and specifications for 

methods are included in the respective 

reference methods described in Part 50 or in 

the respective equivalent method 

descriptions available from the EPA 

(reference 6 of this appendix). Similarly, 

quality control procedures related to 

specifically designated reference and 

equivalent method monitors are contained in 

the respective operation or instruction 

manuals associated with those monitors. For 

PSD monitoring, the use of reference and 

equivalent method monitors are required. 

3. Measurement Quality Check Requirements 

This section provides the requirements for 

PSD PQAOs to perform the measurement 

quality checks that can be used to assess data 

quality. Data from these checks are required 

to be submitted to the PSD reviewing 

authority within the same time frame as 

routinely-collected ambient concentration 

data as described in 40 CFR 58.16. Table B– 

1 of this appendix provides a summary of the 

types and frequency of the measurement 

quality checks that are described in this 

section. Reporting these results to AQS may 

be required by the PSD reviewing authority. 

3.1 Gaseous monitors of SO2, NO2, O3, and 

CO. 

3.1.1 One-Point Quality Control (QC) 

Check for SO2, NO2, O3, and CO. (a) A onepoint QC check must be performed at least 

once every 2 weeks on each automated 

monitor used to measure SO2, NO2, O3 and 

CO. With the advent of automated calibration 

systems, more frequent checking is strongly 

encouraged and may be required by the PSD 

reviewing authority. See Reference 10 of this 

appendix for guidance on the review 

procedure. The QC check is made by 

challenging the monitor with a QC check gas 

of known concentration (effective 

concentration for open path monitors) 

between the prescribed range of 0.005 and 

0.08 parts per million (ppm) for SO2, NO2, 

and O3, and between the prescribed range of 

0.5 and 5 ppm for CO monitors. The QC 

check gas concentration selected within the 

prescribed range should be related to 

monitoring objectives for the monitor. If 

monitoring for trace level monitoring, the QC 

check concentration should be selected to 

represent the mean or median concentrations 

at the site. If the mean or median 

concentrations at trace gas sites are below the 

MDL of the instrument the agency can select 

the lowest concentration in the prescribed 

range that can be practically achieved. If the 

mean or median concentrations at trace gas 

sites are above the prescribed range the 

agency can select the highest concentration 

in the prescribed range. The PSD monitoring 

organization will consult with the PSD 

reviewing authority on the most appropriate 

one-point QC concentration based on the 

objectives of the monitoring activity. An 

additional QC check point is encouraged for 

those organizations that may have occasional 

high values or would like to confirm the 

monitors’ linearity at the higher end of the 

operational range or around NAAQS 

concentrations. If monitoring for NAAQS 

decisions the QC concentration can be 

selected at a higher concentration within the 

prescribed range but should also consider 

precision points around mean or median 

concentrations. 

(b) Point analyzers must operate in their 

normal sampling mode during the QC check 

and the test atmosphere must pass through 

all filters, scrubbers, conditioners and other 

components used during normal ambient 

sampling and as much of the ambient air 

inlet system as is practicable. The QC check 

must be conducted before any calibration or 

adjustment to the monitor. 

(c) Open-path monitors are tested by 

inserting a test cell containing a QC check gas 

concentration into the optical measurement 

beam of the instrument. If possible, the 

normally used transmitter, receiver, and as 

appropriate, reflecting devices should be 

used during the test and the normal 

monitoring configuration of the instrument 

should be altered as little as possible to 

accommodate the test cell for the test. 

However, if permitted by the associated 

operation or instruction manual, an alternate 

local light source or an alternate optical path 

that does not include the normal atmospheric 

monitoring path may be used. The actual 

concentration of the QC check gas in the test 

cell must be selected to produce an effective 

concentration in the range specified earlier in 

this section. Generally, the QC test 

concentration measurement will be the sum 

of the atmospheric pollutant concentration 

and the QC test concentration. As such, the 

result must be corrected to remove the 

atmospheric concentration contribution. The 

corrected concentration is obtained by 

subtracting the average of the atmospheric 

concentrations measured by the open path 

instrument under test immediately before 

and immediately after the QC test from the 

QC check gas concentration measurement. If 

the difference between these before and after 

measurements is greater than 20 percent of 

the effective concentration of the test gas, 

discard the test result and repeat the test. If 

possible, open path monitors should be 

tested during periods when the atmospheric 

pollutant concentrations are relatively low 

and steady. 

(d) Report the audit concentration of the 

QC gas and the corresponding measured 

concentration indicated by the monitor. The 

percent differences between these 

concentrations are used to assess the 

precision and bias of the monitoring data as 

described in sections 4.1.2 (precision) and 

4.1.3 (bias) of this appendix. 

3.1.2 Quarterly performance evaluation 

for SO2, NO2, O3, or CO. Evaluate each 

primary monitor each monitoring quarter (or 

90 day frequency) during which monitors are 

operated or a least once (if operated for less 

than one quarter). The quarterly performance 

evaluation (quarterly PE) must be performed 

by a qualified individual, group, or 

organization that is not part of the 

organization directly performing and 

accountable for the work being assessed. The 

person or entity performing the quarterly PE 

must not be involved with the generation of 

the routinely-collected ambient air 

monitoring data. A PSD monitoring 

organization can conduct the quarterly PE 

itself if it can meet this definition and has a 

management structure that, at a minimum, 

will allow for the separation of its routine 

sampling personnel from its auditing 

personnel by two levels of management. The 

quarterly PE also requires a set of equipment 

and standards independent from those used 

for routine calibrations or zero, span or 

precision checks. 

3.1.2.1 The evaluation is made by 

challenging the monitor with audit gas 

standards of known concentration from at 

least three audit levels. One point must be 

within two to three times the method 

detection limit of the instruments within the 

PQAOs network, the second point will be 

less than or equal to the 99th percentile of 

the data at the site or the network of sites in 

the PQAO or the next highest audit 

concentration level. The third point can be 

around the primary NAAQS or the highest 3- 

year concentration at the site or the network 

of sites in the PQAO. An additional 4th level 

is encouraged for those PSD organizations 

that would like to confirm the monitor’s 

linearity at the higher end of the operational 

range. In rare circumstances, there may be 

sites measuring concentrations above audit 

level 10. These sites should be identified to 

the PSD reviewing authority. 

Audit level 

Concentration range, ppm 

O3 SO2 NO2 CO 

1 ....................................................................................................................... 0.004–0.0059 0.0003–0.0029 0.0003–0.0029 0.020–0.059 

2 ....................................................................................................................... 0.006–0.019 0.0030–0.0049 0.0030–0.0049 0.060–0.199 


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Audit level 

Concentration range, ppm 

O3 SO2 NO2 CO 

3 ....................................................................................................................... 0.020–0.039 0.0050–0.0079 0.0050–0.0079 0.200–0.899 

4 ....................................................................................................................... 0.040–0.069 0.0080–0.0199 0.0080–0.0199 0.900–2.999 

5 ....................................................................................................................... 0.070–0.089 0.0200–0.0499 0.0200–0.0499 3.000–7.999 

6 ....................................................................................................................... 0.090–0.119 0.0500–0.0999 0.0500–0.0999 8.000–15.999 

7 ....................................................................................................................... 0.120–0.139 0.1000–0.1499 0.1000–0.2999 16.000–30.999 

8 ....................................................................................................................... 0.140–0.169 0.1500–0.2599 0.3000–0.4999 31.000–39.999 

9 ....................................................................................................................... 0.170–0.189 0.2600–0.7999 0.5000–0.7999 40.000–49.999 

10 ..................................................................................................................... 0.190–0.259 0.8000–1.000 0.8000–1.000 50.000–60.000 

3.1.2.2 The NO2 audit techniques may 

vary depending on the ambient monitoring 

method. For chemiluminescence-type NO2

analyzers, gas phase titration (GPT) 

techniques should be based on the EPA 

guidance documents and monitoring agency 

experience. The NO2 gas standards may be 

more appropriate than GPT for direct NO2

methods that do not employ converters. Care 

should be taken to ensure the stability of 

such gas standards prior to use. 

3.1.2.3 The standards from which audit 

gas test concentrations are obtained must 

meet the specifications of section 2.6.1 of this 

appendix. 

3.1.2.4 For point analyzers, the 

evaluation shall be carried out by allowing 

the monitor to analyze the audit gas test 

atmosphere in its normal sampling mode 

such that the test atmosphere passes through 

all filters, scrubbers, conditioners, and other 

sample inlet components used during normal 

ambient sampling and as much of the 

ambient air inlet system as is practicable. 

3.1.2.5 Open-path monitors are evaluated 

by inserting a test cell containing the various 

audit gas concentrations into the optical 

measurement beam of the instrument. If 

possible, the normally used transmitter, 

receiver, and, as appropriate, reflecting 

devices should be used during the 

evaluation, and the normal monitoring 

configuration of the instrument should be 

modified as little as possible to accommodate 

the test cell for the evaluation. However, if 

permitted by the associated operation or 

instruction manual, an alternate local light 

source or an alternate optical path that does 

not include the normal atmospheric 

monitoring path may be used. The actual 

concentrations of the audit gas in the test cell 

must be selected to produce effective 

concentrations in the evaluation level ranges 

specified in this section of this appendix. 

Generally, each evaluation concentration 

measurement result will be the sum of the 

atmospheric pollutant concentration and the 

evaluation test concentration. As such, the 

result must be corrected to remove the 

atmospheric concentration contribution. The 

corrected concentration is obtained by 

subtracting the average of the atmospheric 

concentrations measured by the open-path 

instrument under test immediately before 

and immediately after the evaluation test (or 

preferably before and after each evaluation 

concentration level) from the evaluation 

concentration measurement. If the difference 

between the before and after measurements is 

greater than 20 percent of the effective 

concentration of the test gas standard, 

discard the test result for that concentration 

level and repeat the test for that level. If 

possible, open-path monitors should be 

evaluated during periods when the 

atmospheric pollutant concentrations are 

relatively low and steady. Also, if the openpath instrument is not installed in a 

permanent manner, the monitoring path 

length must be reverified to be within ±3 

percent to validate the evaluation, since the 

monitoring path length is critical to the 

determination of the effective concentration. 

3.1.2.6 Report both the evaluation 

concentrations (effective concentrations for 

open-path monitors) of the audit gases and 

the corresponding measured concentration 

(corrected concentrations, if applicable, for 

open-path monitors) indicated or produced 

by the monitor being tested. The percent 

differences between these concentrations are 

used to assess the quality of the monitoring 

data as described in section 4.1.1 of this 

appendix. 

3.1.3 National Performance Audit 

Program (NPAP). As stated in sections 1.1 

and 2.4, PSD monitoring networks may be 

subject to the NPEP, which includes the 

NPAP. The NPAP is a performance 

evaluation which is a type of audit where 

quantitative data are collected independently 

in order to evaluate the proficiency of an 

analyst, monitoring instrument and 

laboratory. Due to the implementation 

approach used in this program, NPAP 

provides for a national independent 

assessment of performance with a consistent 

level of data quality. The NPAP should not 

be confused with the quarterly PE program 

described in section 3.1.2. The PSD 

organizations shall consult with the PSD 

reviewing authority or the EPA regarding 

whether the implementation of NPAP is 

required and the implementation options 

available. Details of the EPA NPAP can be 

found in reference 11 of this appendix. The 

program requirements include: 

3.1.3.1 Performing audits on 100 percent 

of monitors and sites each year including 

monitors and sites that may be operated for 

less than 1 year. The PSD reviewing authority 

has the authority to require more frequent 

audits at sites they consider to be high 

priority. 

3.1.3.2 Developing a delivery system that 

will allow for the audit concentration gasses 

to be introduced at the probe inlet where 

logistically feasible. 

3.1.3.3 Using audit gases that are verified 

against the National Institute for Standards 

and Technology (NIST) standard reference 

methods or special review procedures and 

validated annually for CO, SO2 and NO2, and 

at the beginning of each quarter of audits for 

O3. 

3.1.3.4 The PSD PQAO may elect to selfimplement NPAP. In these cases, the PSD 

reviewing authority will work with those 

PSD PQAOs to establish training and other 

technical requirements to establish 

comparability to federally implemented 

programs. In addition to meeting the 

requirements in sections 3.1.1.3 through 

3.1.3.3, the PSD PQAO must: 

(a) Ensure that the PSD audit system is 

equivalent to the EPA NPAP audit system 

and is an entirely separate set of equipment 

and standards from the equipment used for 

quarterly performance evaluations. If this 

system does not generate and analyze the 

audit concentrations, as the EPA NPAP 

system does, its equivalence to the EPA 

NPAP system must be proven to be as 

accurate under a full range of appropriate 

and varying conditions as described in 

section 3.1.3.6. 

(b) Perform a whole system check by 

having the PSD audit system tested at an 

independent and qualified EPA lab, or 

equivalent. 

(c) Evaluate the system with the EPA NPAP 

program through collocated auditing at an 

acceptable number of sites each year (at least 

one for a PSD network of five or less sites; 

at least two for a network with more than five 

sites). 

(d) Incorporate the NPAP into the PSD 

PQAO’s QAPP. 

(e) Be subject to review by independent, 

EPA-trained personnel. 

(f) Participate in initial and update 

training/certification sessions. 

3.2 PM2.5. 

3.2.1 Flow Rate Verification for PM2.5. A 

one-point flow rate verification check must 

be performed at least once every month (each 

verification minimally separated by 14 days) 

on each monitor used to measure PM2.5. The 

verification is made by checking the 

operational flow rate of the monitor. If the 

verification is made in conjunction with a 

flow rate adjustment, it must be made prior 

to such flow rate adjustment. For the 

standard procedure, use a flow rate transfer 

standard certified in accordance with section 

2.6 of this appendix to check the monitor’s 

normal flow rate. Care should be used in 

selecting and using the flow rate 

measurement device such that it does not 

alter the normal operating flow rate of the 

monitor. Flow rate verification results are to 

be reported to the PSD reviewing authority 

quarterly as described in section 5.1. 

Reporting these results to AQS is encouraged. 

The percent differences between the audit 


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and measured flow rates are used to assess 

the bias of the monitoring data as described 

in section 4.2.2 of this appendix (using flow 

rates in lieu of concentrations). 

3.2.2 Semi-Annual Flow Rate Audit for 

PM2.5. Every 6 months, audit the flow rate of 

the PM2.5 particulate monitors. For shortterm monitoring operations (those less than 

1 year), the flow rate audits must occur at 

start up, at the midpoint, and near the 

completion of the monitoring project. The 

audit must be conducted by a trained 

technician other than the routine site 

operator. The audit is made by measuring the 

monitor’s normal operating flow rate using a 

flow rate transfer standard certified in 

accordance with section 2.6 of this appendix. 

The flow rate standard used for auditing 

must not be the same flow rate standard used 

for verifications or to calibrate the monitor. 

However, both the calibration standard and 

the audit standard may be referenced to the 

same primary flow rate or volume standard. 

Care must be taken in auditing the flow rate 

to be certain that the flow measurement 

device does not alter the normal operating 

flow rate of the monitor. Report the audit 

flow rate of the transfer standard and the 

corresponding flow rate measured by the 

monitor. The percent differences between 

these flow rates are used to evaluate monitor 

performance. 

3.2.3 Collocated Sampling Procedures for 

PM2.5. A PSD PQAO must have at least one 

collocated monitor for each PSD monitoring 

network. 

3.2.3.1 For each pair of collocated 

monitors, designate one sampler as the 

primary monitor whose concentrations will 

be used to report air quality for the site, and 

designate the other as the QC monitor. There 

can be only one primary monitor at a 

monitoring site for a given time period. 

(a) If the primary monitor is a FRM, then 

the quality control monitor must be a FRM 

of the same method designation. 

(b) If the primary monitor is a FEM, then 

the quality control monitor must be a FRM 

unless the PSD PQAO submits a waiver for 

this requirement, provides a specific reason 

why a FRM cannot be implemented, and the 

waiver is approved by the PSD reviewing 

authority. If the waiver is approved, then the 

quality control monitor must be the same 

method designation as the primary FEM 

monitor. 

3.2.3.2 In addition, the collocated 

monitors should be deployed according to 

the following protocol: 

(a) The collocated quality control 

monitor(s) should be deployed at sites with 

the highest predicted daily PM2.5

concentrations in the network. If the highest 

PM2.5 concentration site is impractical for 

collocation purposes, alternative sites 

approved by the PSD reviewing authority 

may be selected. If additional collocated sites 

are necessary, the PSD PQAO and the PSD 

reviewing authority should determine the 

appropriate location(s) based on data needs. 

(b) The two collocated monitors must be 

within 4 meters of each other and at least 2 

meters apart for flow rates greater than 200 

liters/min or at least 1 meter apart for 

samplers having flow rates less than 200 

liters/min to preclude airflow interference. A 

waiver allowing up to 10 meters horizontal 

distance and up to 3 meters vertical distance 

(inlet to inlet) between a primary and 

collocated quality control monitor may be 

approved by the PSD reviewing authority for 

sites at a neighborhood or larger scale of 

representation. This waiver may be approved 

during the QAPP review and approval 

process. Sampling and analytical 

methodologies must be the consistently 

implemented for both collocated samplers 

and for all other samplers in the network. 

(c) Sample the collocated quality control 

monitor on a 6-day schedule for sites not 

requiring daily monitoring and on a 3-day 

schedule for any site requiring daily 

monitoring. Report the measurements from 

both primary and collocated quality control 

monitors at each collocated sampling site. 

The calculations for evaluating precision 

between the two collocated monitors are 

described in section 4.2.1 of this appendix. 

3.2.4 PM2.5 Performance Evaluation 

Program (PEP) Procedures. As stated in 

sections 1.1 and 2.4 of this appendix, PSD 

monitoring networks may be subject to the 

NPEP, which includes the PM2.5 PEP. The 

PSD monitoring organizations shall consult 

with the PSD reviewing authority or the EPA 

regarding whether the implementation of 

PM2.5 PEP is required and the 

implementation options available for the 

PM2.5 PEP. For PSD PQAOs with less than or 

equal to five monitoring sites, five valid 

performance evaluation audits must be 

collected and reported each year. For PSD 

PQAOs with greater than five monitoring 

sites, eight valid performance evaluation 

audits must be collected and reported each 

year. Additionally, within the five or eight 

required audits, each type of method 

designation (FRM/FEM designation) used as 

a primary monitor in the PSD network shall 

be audited. For a PE to be valid, both the 

primary monitor and PEP audit 

measurements must meet quality control 

requirements and be above 3 mg/m3 or a 

predefined lower concentration level 

determined by a systematic planning process 

and approved by the PSD reviewing 

authority. Due to the relatively short-term 

nature of most PSD monitoring, the 

likelihood of measuring low concentrations 

in many areas attaining the PM2.5 standard 

and the time required to weigh filters 

collected in PEs, a PSD monitoring 

organization’s QAPP may contain a provision 

to waive the 3 mg/m3 threshold for validity 

of PEs conducted in the last quarter of 

monitoring, subject to approval by the PSD 

reviewing authority. 

3.3 PM10. 

3.3.1 Flow Rate Verification for PM10. A 

one-point flow rate verification check must 

be performed at least once every month (each 

verification minimally separated by 14 days) 

on each monitor used to measure PM10. The 

verification is made by checking the 

operational flow rate of the monitor. If the 

verification is made in conjunction with a 

flow rate adjustment, it must be made prior 

to such flow rate adjustment. For the 

standard procedure, use a flow rate transfer 

standard certified in accordance with section 

2.6 of this appendix to check the monitor’s 

normal flow rate. Care should be taken in 

selecting and using the flow rate 

measurement device such that it does not 

alter the normal operating flow rate of the 

monitor. The percent differences between the 

audit and measured flow rates are used to 

assess the bias of the monitoring data as 

described in section 4.2.2 of this appendix 

(using flow rates in lieu of concentrations). 

3.3.2 Semi-Annual Flow Rate Audit for 

PM10. Every 6 months, audit the flow rate of 

the PM10 particulate monitors. For short-term 

monitoring operations (those less than 1 

year), the flow rate audits must occur at start 

up, at the midpoint, and near the completion 

of the monitoring project. Where possible, 

the EPA strongly encourages more frequent 

auditing. The audit must be conducted by a 

trained technician other than the routine site 

operator. The audit is made by measuring the 

monitor’s normal operating flow rate using a 

flow rate transfer standard certified in 

accordance with section 2.6 of this appendix. 

The flow rate standard used for auditing 

must not be the same flow rate standard used 

for verifications or to calibrate the monitor. 

However, both the calibration standard and 

the audit standard may be referenced to the 

same primary flow rate or volume standard. 

Care must be taken in auditing the flow rate 

to be certain that the flow measurement 

device does not alter the normal operating 

flow rate of the monitor. Report the audit 

flow rate of the transfer standard and the 

corresponding flow rate measured by the 

monitor. The percent differences between 

these flow rates are used to evaluate monitor 

performance 

3.3.3 Collocated Sampling Procedures for 

Manual PM10. A PSD PQAO must have at 

least one collocated monitor for each PSD 

monitoring network. 

3.3.3.1 For each pair of collocated 

monitors, designate one sampler as the 

primary monitor whose concentrations will 

be used to report air quality for the site, and 

designate the other as the quality control 

monitor. 

3.3.3.2 In addition, the collocated 

monitors should be deployed according to 

the following protocol: 

(a) The collocated quality control 

monitor(s) should be deployed at sites with 

the highest predicted daily PM10

concentrations in the network. If the highest 

PM10 concentration site is impractical for 

collocation purposes, alternative sites 

approved by the PSD reviewing authority 

may be selected. 

(b) The two collocated monitors must be 

within 4 meters of each other and at least 2 

meters apart for flow rates greater than 200 

liters/min or at least 1 meter apart for 

samplers having flow rates less than 200 

liters/min to preclude airflow interference. A 

waiver allowing up to 10 meters horizontal 

distance and up to 3 meters vertical distance 

(inlet to inlet) between a primary and 

collocated sampler may be approved by the 

PSD reviewing authority for sites at a 

neighborhood or larger scale of 

representation. This waiver may be approved 

during the QAPP review and approval 

process. Sampling and analytical 

methodologies must be the consistently 

implemented for both collocated samplers 

and for all other samplers in the network. 


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(c) Sample the collocated quality control 

monitor on a 6-day schedule or 3-day 

schedule for any site requiring daily 

monitoring. Report the measurements from 

both primary and collocated quality control 

monitors at each collocated sampling site. 

The calculations for evaluating precision 

between the two collocated monitors are 

described in section 4.2.1 of this appendix. 

(d) In determining the number of 

collocated sites required for PM10, PSD 

monitoring networks for Pb-PM10 should be 

treated independently from networks for 

particulate matter (PM), even though the 

separate networks may share one or more 

common samplers. However, a single quality 

control monitor that meets the collocation 

requirements for Pb-PM10 and PM10 may 

serve as a collocated quality control monitor 

for both networks. Extreme care must be 

taken if using the filter from a quality control 

monitor for both PM10 and Pb analysis. PM10

filter weighing should occur prior to any Pb 

analysis. 

3.4 Pb. 

3.4.1 Flow Rate Verification for Pb. A 

one-point flow rate verification check must 

be performed at least once every month (each 

verification minimally separated by 14 days) 

on each monitor used to measure Pb. The 

verification is made by checking the 

operational flow rate of the monitor. If the 

verification is made in conjunction with a 

flow rate adjustment, it must be made prior 

to such flow rate adjustment. Use a flow rate 

transfer standard certified in accordance with 

section 2.6 of this appendix to check the 

monitor’s normal flow rate. Care should be 

taken in selecting and using the flow rate 

measurement device such that it does not 

alter the normal operating flow rate of the 

monitor. The percent differences between the 

audit and measured flow rates are used to 

assess the bias of the monitoring data as 

described in section 4.2.2 of this appendix 

(using flow rates in lieu of concentrations). 

3.4.2 Semi-Annual Flow Rate Audit for 

Pb. Every 6 months, audit the flow rate of the 

Pb particulate monitors. For short-term 

monitoring operations (those less than 1 

year), the flow rate audits must occur at start 

up, at the midpoint, and near the completion 

of the monitoring project. Where possible, 

the EPA strongly encourages more frequent 

auditing. The audit must be conducted by a 

trained technician other than the routine site 

operator. The audit is made by measuring the 

monitor’s normal operating flow rate using a 

flow rate transfer standard certified in 

accordance with section 2.6 of this appendix. 

The flow rate standard used for auditing 

must not be the same flow rate standard used 

to in verifications or to calibrate the monitor. 

However, both the calibration standard and 

the audit standard may be referenced to the 

same primary flow rate or volume standard. 

Great care must be taken in auditing the flow 

rate to be certain that the flow measurement 

device does not alter the normal operating 

flow rate of the monitor. Report the audit 

flow rate of the transfer standard and the 

corresponding flow rate measured by the 

monitor. The percent differences between 

these flow rates are used to evaluate monitor 

performance. 

3.4.3 Collocated Sampling for Pb. A PSD 

PQAO must have at least one collocated 

monitor for each PSD monitoring network. 

3.4.3.1 For each pair of collocated 

monitors, designate one sampler as the 

primary monitor whose concentrations will 

be used to report air quality for the site, and 

designate the other as the quality control 

monitor. 

3.4.3.2 In addition, the collocated 

monitors should be deployed according to 

the following protocol: 

(a) The collocated quality control 

monitor(s) should be deployed at sites with 

the highest predicted daily Pb concentrations 

in the network. If the highest Pb 

concentration site is impractical for 

collocation purposes, alternative sites 

approved by the PSD reviewing authority 

may be selected. 

(b) The two collocated monitors must be 

within 4 meters of each other and at least 2 

meters apart for flow rates greater than 200 

liters/min or at least 1 meter apart for 

samplers having flow rates less than 200 

liters/min to preclude airflow interference. A 

waiver allowing up to 10 meters horizontal 

distance and up to 3 meters vertical distance 

(inlet to inlet) between a primary and 

collocated sampler may be approved by the 

PSD reviewing authority for sites at a 

neighborhood or larger scale of 

representation. This waiver may be approved 

during the QAPP review and approval 

process. Sampling and analytical 

methodologies must be the consistently 

implemented for both collocated samplers 

and all other samplers in the network. 

(c) Sample the collocated quality control 

monitor on a 6-day schedule if daily 

monitoring is not required or 3-day schedule 

for any site requiring daily monitoring. 

Report the measurements from both primary 

and collocated quality control monitors at 

each collocated sampling site. The 

calculations for evaluating precision between 

the two collocated monitors are described in 

section 4.2.1 of this appendix. 

(d) In determining the number of 

collocated sites required for Pb-PM10, PSD 

monitoring networks for PM10 should be 

treated independently from networks for PbPM10, even though the separate networks 

may share one or more common samplers. 

However, a single quality control monitor 

that meets the collocation requirements for 

Pb-PM10 and PM10 may serve as a collocated 

quality control monitor for both networks. 

Extreme care must be taken if using a using 

the filter from a quality control monitor for 

both PM10 and Pb analysis. The PM10 filter 

weighing should occur prior to any Pb 

analysis. 

3.4.4 Pb Analysis Audits. Each calendar 

quarter, audit the Pb reference or equivalent 

method analytical procedure using filters 

containing a known quantity of Pb. These 

audit filters are prepared by depositing a Pb 

standard on unexposed filters and allowing 

them to dry thoroughly. The audit samples 

must be prepared using batches of reagents 

different from those used to calibrate the Pb 

analytical equipment being audited. Prepare 

audit samples in the following concentration 

ranges: 

Range Equivalent ambient 

Pb concentration, μg/m3

1 ........... 30–100% of Pb NAAQS. 

2 ........... 200–300% of Pb NAAQS. 

(a) Audit samples must be extracted using 

the same extraction procedure used for 

exposed filters. 

(b) Analyze three audit samples in each of 

the two ranges each quarter samples are 

analyzed. The audit sample analyses shall be 

distributed as much as possible over the 

entire calendar quarter. 

(c) Report the audit concentrations (in mg 

Pb/filter or strip) and the corresponding 

measured concentrations (in mg Pb/filter or 

strip) using AQS unit code 077 (if reporting 

to AQS). The percent differences between the 

concentrations are used to calculate 

analytical accuracy as described in section 

4.2.5 of this appendix. 

3.4.5 Pb Performance Evaluation Program 

(PEP) Procedures. As stated in sections 1.1 

and 2.4, PSD monitoring networks may be 

subject to the NPEP, which includes the Pb 

PEP. The PSD monitoring organizations shall 

consult with the PSD reviewing authority or 

the EPA regarding whether the 

implementation of Pb-PEP is required and 

the implementation options available for the 

Pb-PEP. The PEP is an independent 

assessment used to estimate total 

measurement system bias. Each year, one PE 

audit must be performed at one Pb site in 

each PSD PQAO network that has less than 

or equal to five sites and two audits for PSD 

PQAO networks with greater than five sites. 

In addition, each year, four collocated 

samples from PSD PQAO networks with less 

than or equal to five sites and six collocated 

samples from PSD PQAO networks with 

greater than five sites must be sent to an 

independent laboratory for analysis. The 

calculations for evaluating bias between the 

primary monitor and the PE monitor for Pb 

are described in section 4.2.4 of this 

appendix. 

4. Calculations for Data Quality Assessments 

(a) Calculations of measurement 

uncertainty are carried out by PSD PQAO 

according to the following procedures. The 

PSD PQAOs should report the data for all 

appropriate measurement quality checks as 

specified in this appendix even though they 

may elect to perform some or all of the 

calculations in this section on their own. 

(b) At low concentrations, agreement 

between the measurements of collocated 

samplers, expressed as relative percent 

difference or percent difference, may be 

relatively poor. For this reason, collocated 

measurement pairs will be selected for use in 

the precision and bias calculations only 

when both measurements are equal to or 

above the following limits: 

(1) Pb: 0.002 mg/m3 (Methods approved 

after 3/04/2010, with exception of manual 

equivalent method EQLA–0813–803). 

(2) Pb: 0.02 mg/m3 (Methods approved 

before 3/04/2010, and manual equivalent 

method EQLA–0813–803). 

(3) PM10 (Hi-Vol): 15 mg/m3. 

(4) PM10 (Lo-Vol): 3 mg/m3. 

(5) PM2.5: 3 mg/m3. 


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(c) The PM2.5 3 mg/m3 limit for the 

PM2.5¥PEP may be superseded by mutual 

agreement between the PSD PQAO and the 

PSD reviewing authority as specified in 

section 3.2.4 of the appendix and detailed in 

the approved QAPP. 

4.1 Statistics for the Assessment of QC 

Checks for SO2, NO2, O3 and CO. 

4.1.1 Percent Difference. Many of the 

measurement quality checks start with a 

comparison of an audit concentration or 

value (flow-rate) to the concentration/value 

measured by the monitor and use percent 

difference as the comparison statistic as 

described in equation 1 of this section. For 

each single point check, calculate the percent 

difference, di, as follows: 

where meas is the concentration indicated by 

the PQAO’s instrument and audit is the audit 

concentration of the standard used in the QC 

check being measured. 

4.1.2 Precision Estimate. The precision 

estimate is used to assess the one-point QC 

checks for SO2, NO2, O3, or CO described in 

section 3.1.1 of this appendix. The precision 

estimator is the coefficient of variation upper 

bound and is calculated using equation 2 of 

this section: 

where n is the number of single point checks 

being aggregated; X2 0.1,n–1 is the 10th 

percentile of a chi-squared distribution with 

n–1 degrees of freedom. 

4.1.3 Bias Estimate. The bias estimate is 

calculated using the one-point QC checks for 

SO2, NO2, O3, or CO described in section 

3.1.1 of this appendix. The bias estimator is 

an upper bound on the mean absolute value 

of the percent differences as described in 

equation 3 of this section: 

where n is the number of single point checks 

being aggregated; t0.95,n–1 is the 95th quantile 

of a t-distribution with n–1 degrees of 

freedom; the quantity AB is the mean of the 

absolute values of the di′s and is calculated 

using equation 4 of this section: 

and the quantity AS is the standard deviation 

of the absolute value of the di′s and is 

calculated using equation 5 of this section: 


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4.1.3.1 Assigning a sign (positive/

negative) to the bias estimate. Since the bias 

statistic as calculated in equation 3 of this 

appendix uses absolute values, it does not 

have a tendency (negative or positive bias) 

associated with it. A sign will be designated 

by rank ordering the percent differences of 

the QC check samples from a given site for 

a particular assessment interval. 

4.1.3.2 Calculate the 25th and 75th 

percentiles of the percent differences for each 

site. The absolute bias upper bound should 

be flagged as positive if both percentiles are 

positive and negative if both percentiles are 

negative. The absolute bias upper bound 

would not be flagged if the 25th and 75th 

percentiles are of different signs. 

4.2 Statistics for the Assessment of PM10,

PM2.5, and Pb. 

4.2.1 Collocated Quality Control Sampler 

Precision Estimate for PM10, PM2.5 and Pb. 

Precision is estimated via duplicate 

measurements from collocated samplers. It is 

recommended that the precision be 

aggregated at the PQAO level quarterly, 

annually, and at the 3-year level. The data 

pair would only be considered valid if both 

concentrations are greater than or equal to 

the minimum values specified in section 4(c) 

of this appendix. For each collocated data 

pair, calculate the relative percent difference, 

di, using equation 6 of this appendix: 

where Xi is the concentration from the 

primary sampler and Yi is the concentration 

value from the audit sampler. The coefficient 

of variation upper bound is calculated using 

equation 7 of this appendix: 

where n is the number of valid data pairs 

being aggregated, and X2 0.1,n–1 is the 10th 

percentile of a chi-squared distribution with 

n–1 degrees of freedom. The factor of 2 in the 

denominator adjusts for the fact that each di

is calculated from two values with error. 

4.2.2 One-Point Flow Rate Verification 

Bias Estimate for PM10, PM2.5 and Pb. For 

each one-point flow rate verification, 

calculate the percent difference in volume 

using equation 1 of this appendix where 

meas is the value indicated by the sampler’s 

volume measurement and audit is the actual 

volume indicated by the auditing flow meter. 

The absolute volume bias upper bound is 

then calculated using equation 3, where n is 

the number of flow rate audits being 

aggregated; t0.95,n–1 is the 95th quantile of a 

t-distribution with n–1 degrees of freedom, 

the quantity AB is the mean of the absolute 

values of the di′s and is calculated using 

equation 4 of this appendix, and the quantity 

AS in equation 3 of this appendix is the 

standard deviation of the absolute values if 

the di′s and is calculated using equation 5 of 

this appendix. 

4.2.3 Semi-Annual Flow Rate Audit Bias 

Estimate for PM10, PM2.5 and Pb. Use the 

same procedure described in section 4.2.2 for 

the evaluation of flow rate audits. 

4.2.4 Performance Evaluation Programs 

Bias Estimate for Pb. The Pb bias estimate is 

calculated using the paired routine and the 

PEP monitor as described in section 3.4.5. 

Use the same procedures as described in 

section 4.1.3 of this appendix. 

4.2.5 Performance Evaluation Programs 

Bias Estimate for PM2.5. The bias estimate is 

calculated using the PEP audits described in 

section 4.1.3 of this appendix. The bias 

estimator is based on the mean percent 

differences (Equation 1). The mean percent 

difference, D, is calculated by Equation 8 

below. 

where nj is the number of pairs and 

d1,d2,...dnj are the biases for each pair to be 

averaged. 

4.2.6 Pb Analysis Audit Bias Estimate. 

The bias estimate is calculated using the 

analysis audit data described in section 3.4.4. 

Use the same bias estimate procedure as 

described in section 4.1.3 of this appendix. 

5. Reporting Requirements 

5.1. Quarterly Reports. For each quarter, 

each PSD PQAO shall report to the PSD 

reviewing authority (and AQS if required by 

the PSD reviewing authority) the results of all 

valid measurement quality checks it has 

carried out during the quarter. The quarterly 

reports must be submitted consistent with 

the data reporting requirements specified for 

air quality data as set forth in 40 CFR 58.16 

and pertain to PSD monitoring. 

6. References 

(1) American National Standard— 

Specifications and Guidelines for Quality 

Systems for Environmental Data Collection 

and Environmental Technology Programs. 

ANSI/ASQC E4–2014. February 2014. 

Available from American Society for Quality 

Control, 611 East Wisconsin Avenue, 

Milwaukee, WI 53202. 

(2) EPA Requirements for Quality 

Management Plans. EPA QA/R–2. EPA/240/ 

B–01/002. March 2001, Reissue May 2006. 

Office of Environmental Information, 

Washington, DC 20460. http://www.epa.gov/ 

quality/agency-wide-quality-systemdocuments. 

(3) EPA Requirements for Quality 

Assurance Project Plans for Environmental 

Data Operations. EPA QA/R–5. EPA/240/B– 

01/003. March 2001, Reissue May 2006. 

Office of Environmental Information, 

Washington, DC 20460. http://www.epa.gov/ 

quality/agency-wide-quality-systemdocuments. 

(4) EPA Traceability Protocol for Assay and 

Certification of Gaseous Calibration 

Standards. EPA–600/R–12/531. May, 2012. 

Available from U.S. Environmental 

Protection Agency, National Risk 

Management Research Laboratory, Research 

Triangle Park, NC 27711. http://

cfpub.epa.gov/si/si_public_record_

report.cfm?dirEntryId=245292. 

(5) Guidance for the Data Quality 

Objectives Process. EPA QA/G–4. EPA/240/

B–06/001. February, 2006. Office of 

Environmental Information, Washington, DC 

20460. http://www.epa.gov/quality/agencywide-quality-system-documents. 

(6) List of Designated Reference and 

Equivalent Methods. Available from U.S. 

Environmental Protection Agency, National 

Exposure Research Laboratory, Human 

Exposure and Atmospheric Sciences 

Division, MD–D205–03, Research Triangle 


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17298 Federal Register / Vol. 81, No. 59 / Monday, March 28, 2016 / Rules and Regulations 

Park, NC 27711. http://www3.epa.gov/ttn/

amtic/criteria.html. 

(7) Transfer Standards for the Calibration 

of Ambient Air Monitoring Analyzers for 

Ozone. EPA–454/B–13–004 U.S. 

Environmental Protection Agency, Research 

Triangle Park, NC 27711, October, 2013. 

http://www3.epa.gov/ttn/amtic/

qapollutant.html. 

(8) Paur, R.J. and F.F. McElroy. Technical 

Assistance Document for the Calibration of 

Ambient Ozone Monitors. EPA–600/4–79– 

057. U.S. Environmental Protection Agency, 

Research Triangle Park, NC 27711, 

September, 1979. http://www.epa.gov/ttn/

amtic/cpreldoc.html. 

(9) Quality Assurance Handbook for Air 

Pollution Measurement Systems, Volume 1— 

A Field Guide to Environmental Quality 

Assurance. EPA–600/R–94/038a. April 1994. 

Available from U.S. Environmental 

Protection Agency, ORD Publications Office, 

Center for Environmental Research 

Information (CERI), 26 W. Martin Luther 

King Drive, Cincinnati, OH 45268. http://

www3.epa.gov/ttn/amtic/qalist.html. 

(10) Quality Assurance Handbook for Air 

Pollution Measurement Systems, Volume II: 

Ambient Air Quality Monitoring Program 

Quality System Development. EPA–454/B– 

13–003. http://www3.epa.gov/ttn/amtic/

qalist.html. 

(11) National Performance Evaluation 

Program Standard Operating Procedures. 

http://www3.epa.gov/ttn/amtic/

npapsop.html. 

TABLE B–1—MINIMUM DATA ASSESSMENT REQUIREMENTS FOR NAAQS RELATED CRITERIA POLLUTANT PSD MONITORS

Method Assessment method Coverage Minimum frequency Parameters reported AQS 

Assessment type 

Gaseous Methods (CO, NO2, SO2, O3) 

One-Point QC for SO2, 

NO2, O3, CO.

Response check at concentration 0.005–0.08 

ppm SO2, NO2, O3, & 

0.5 and 5 ppm CO.

Each analyzer ................... Once per 2 weeks ............ Audit concentration 1 and 

measured concentration 2.

One-Point QC. 

Quarterly performance 

evaluation for SO2, NO2, 

O3, CO.

See section 3.1.2 of this 

appendix.

Each analyzer ................... Once per quarter .............. Audit concentration 1 and 

measured concentration 2 for each level.

Annual PE. 

NPAP for SO2, NO2, O3, 

CO3.

Independent Audit ............ Each primary monitor ....... Once per year ................... Audit concentration 1 and 

measured concentration 2 for each level.

NPAP. 

Particulate Methods 

Collocated sampling PM10, 

PM2.5, Pb.

Collocated samplers ......... 1 per PSD Network per 

pollutant.

Every 6 days or every 3 

days if daily monitoring 

required.

Primary sampler concentration and duplicate 

sampler concentration 4.

No Transaction reported as raw 

data. 

Flow rate verification PM10, 

PM2.5, Pb.

Check of sampler flow rate Each sampler .................... Once every month ............ Audit flow rate and measured flow rate indicated 

by the sampler.

Flow Rate 

Verification. 

Semi-annual flow rate audit 

PM10, PM2.5, Pb.

Check of sampler flow rate 

using independent 

standard.

Each sampler .................... Once every 6 months or 

beginning, middle and 

end of monitoring.

Audit flow rate and measured flow rate indicated 

by the sampler.

Semi Annual Flow 

Rate Audit. 

Pb analysis audits Pb-TSP, 

Pb-PM10.

Check of analytical system 

with Pb audit strips/filters.

Analytical .......................... Each quarter ..................... Measured value and audit 

value (ug Pb/filter) using 

AQS unit code 077 for 

parameters: 

14129—Pb (TSP) LC 

FRM/FEM 

85129—Pb (TSP) LC NonFRM/FEM. 

Pb Analysis Audits. 

Performance Evaluation 

Program PM2.5 3.

Collocated samplers ......... (1) 5 valid audits for 

PQAOs with <= 5 sites..

(2) 8 valid audits for 

PQAOs with > 5 sites. 

(3) All samplers in 6 years 

Over all 4 quarters ............ Primary sampler concentration and performance evaluation sampler 

concentration.

PEP. 

Performance Evaluation 

Program Pb 3.

Collocated samplers ......... (1) 1 valid audit and 4 collocated samples for 

PQAOs, with <=5 sites. 

(2) 2 valid audits and 6 

collocated samples for 

PQAOs with >5 sites. 

Over all 4 quarters ............ Primary sampler concentration and performance evaluation sampler 

concentration. Primary 

sampler concentration 

and duplicate sampler 

concentration.

PEP. 

1Effective concentration for open path analyzers. 

2 Corrected concentration, if applicable for open path analyzers. 

3 NPAP, PM2.5 PEP and Pb-PEP must be implemented if data is used for NAAQS decisions otherwise implementation is at PSD reviewing authority discretion. 4Both primary and collocated sampler values are reported as raw data. 

■ 11. In Appendix D to part 58, revise 

paragraph 3(b), remove and reserve 

paragraph 4.5(b), and revise paragraph 

4.5(c) to read as follows: 

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, O3, SO2, CO, NO/NOY, wind speed, 

wind direction, relative humidity, and 

ambient temperature. 

(1) Although the measurement of NOy is 

required in support of a number of 

monitoring objectives, available commercial 

instruments may indicate little difference in 

their measurement of NOy compared to the 

conventional measurement of NOX, 

particularly in areas with relatively fresh 

sources of nitrogen emissions. Therefore, in 

areas with negligible expected difference 

between NOy and NOX measured 

concentrations, the Administrator may allow 

for waivers that permit NOX monitoring to be 

substituted for the required NOy monitoring 

at applicable NCore sites. 

(2) The EPA recognizes that, in some cases, 

the physical location of the NCore site may 

not be suitable for representative 

meteorological measurements due to the 

site’s physical surroundings. It is also 

possible that nearby meteorological 

measurements may be able to fulfill this data 

need. In these cases, the requirement for 


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meteorological monitoring can be waived by 

the Administrator. 

* * * * * 

4.5 * * * 

(b) [Reserved] 

(c) The EPA Regional Administrator may 

require additional monitoring beyond the 

minimum monitoring requirements 

contained in paragraph 4.5(a) of this 

appendix where the likelihood of Pb air 

quality violations is significant or where the 

emissions density, topography, or population 

locations are complex and varied. The 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. 2016–06226 Filed 3–25–16; 8:45 am] 

BILLING CODE 6560–50–P 


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