```

[Federal Register Volume 81, Number 59 (Monday, March 28, 2016)]
[Rules and Regulations]
[Pages 17247-17299]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-06226]

[[Page 17247]]

Vol. 81

Monday,

No. 59

March 28, 2016

Part II

 Environmental Protection Agency

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40 CFR Part 58

 Revisions to Ambient Monitoring Quality Assurance and Other 
Requirements; Final Rule

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

[[Page 17248]]

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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.

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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 non-source 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:

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                        Category                          NAICS \a\ code
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State/territorial/local/tribal government...............          924110
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\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

[[Page 17249]]

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\
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    \1\ Links to the NAAQS final rules are available at: https://www3.epa.gov/ttn/naaqs/criteria.html.
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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\
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    \2\ The 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.
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    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\
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    \3\ https://aqs.epa.gov/aqsweb/codes/data/CertifyingAgenciesByMonitor.html.
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    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

[[Page 17250]]

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.
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    \4\ The 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.
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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

[[Page 17251]]

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

[[Page 17252]]

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

[[Page 17253]]

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 
cross-referencing 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).

[[Page 17254]]

    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-
in-6 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\
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    \5\ See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-
OAR-2002-0091-0017.
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    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-in-6 day frequency. The approval for such changes at STN stations, on 
a case-by-case 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.
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    \6\ http://www.epa.gov/ttn/amtic/specgen.html.
    \7\ The 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.
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    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

[[Page 17255]]

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 long-term 
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.
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    \8\ https://www.sdas.battelle.org/CSNAssessment/html/Default.html.
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    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

[[Page 17256]]

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.
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    \9\ http://www2.epa.gov/air-quality-analysis/treatment-data-influenced-exceptional-events#Proposed%20EE%20Rule.
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    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.
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    \10\ Hanley, 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.
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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.
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    \11\ Monitoring 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.
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    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

[[Page 17257]]

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.
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    \12\ See http://www.epa.gov/ttn/amtic/files/2014conference/monnaweinstock.pdf.
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    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 Sec.  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 cross-reference 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 non-criteria 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 
long-standing 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

[[Page 17258]]

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.
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    \13\ See 40 CFR part 50, appendix N, section 3.0(a) as revised 
on January 15, 2013 (78 FR 3278).
    \14\ See http://www.epa.gov/ttn/amtic/specguid.html and http://www.epa.gov/ttn/amtic/airtoxqa.html.
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    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.
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    \15\ See 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).
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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.
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    \16\ The 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.
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    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

[[Page 17259]]

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\
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    \17\ See https://www3.epa.gov/ttn/amtic/ncore.html for more 
information.
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    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 Pb-PM10. 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.
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    \18\ See 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.
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    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 non-source oriented monitoring following the collection 
of at least 3 years of data at each urban NCore site.\20\
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    \19\ Specific revisions are proposed in 40 CFR part 58, appendix 
D, section 3(b) and sections 4.5(b) and 4.5(c).
    \20\ The 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.
---------------------------------------------------------------------------

    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\
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    \21\ http://www.epa.gov/airquality/lead/actions.html#dec2014.
---------------------------------------------------------------------------

    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.

[[Page 17260]]

    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 cost-effectively 
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.
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    \22\ See http://www.epa.gov/ttn/amtic/specguid.html for CSN 
quality assurance project plan.
    \23\ See http://www.epa.gov/ttn/amtic/pamsguidance.html for PAMS 
technical assistance document.
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    The EPA received comments from a state and a consulting firm in 
support of

[[Page 17261]]

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

[[Page 17262]]

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 self-implementation 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 self-implementation 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.
---------------------------------------------------------------------------

    \24\ See http://www.epa.gov/ttn/amtic/npepqa.html.
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    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

[[Page 17263]]

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.
---------------------------------------------------------------------------

    \25\ McCabe, Janet G. (2014). Particle Pollution Quality 
Assurance. Memorandum to the Docket, EPA-HQ-OAR-2013.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \26\ See http://www.reginfo.gov/public/Forward?SearchTarget=PRA&textfield=ambient+air+protocol+gas.
---------------------------------------------------------------------------

    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

[[Page 17264]]

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.
---------------------------------------------------------------------------

    \27\ U.S. Environmental Protection Agency. ``EPA Needs an 
Oversight Program for Protocol Gases,'' Office of Inspector General 
Report No. 09-P-0235, 2009.
---------------------------------------------------------------------------

    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.
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    \28\ http://www.epa.gov/ttnamti1/files/ambient/qaqc/aapgvpimpplan.pdf.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \29\ QA Handbook for Air Pollution Measurement Vol. II Ambient 
Air Quality Monitoring Program at: http://www.epa.gov/ttn/amtic/qalist.html.
---------------------------------------------------------------------------

    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

[[Page 17265]]

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.
---------------------------------------------------------------------------

    \30\ Papp, 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.
---------------------------------------------------------------------------

    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\
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    \31\ A check similar to the QC check but implemented at a 
concentration closer to the higher end of the calibration range of 
the monitor.
    \32\ http://www.epa.gov/ttnamti1/files/ambient/pm25/datamang/20110217lowlevelstatmemo.pdf.
---------------------------------------------------------------------------

    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

[[Page 17266]]

represent 10-80 percent of routinely-collected 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 one-point 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 one-point 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.
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    \33\ http://www.epa.gov/ttnamti1/files/ambient/pm25/datamang/20110217lowlevelstatmemo.pdf.
---------------------------------------------------------------------------

    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

[[Page 17267]]

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 self-implementation 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 self-implement NPAP), the 
EPA identified the requirements necessary for self-implementing 
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 self-implementation 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 ([mu]g/m\3\). 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

[[Page 17268]]

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

    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 
[mu]g/m\3\ for data used in evaluations of precision and bias, meaning 
that only data equal to or greater than 3 [mu]g/m\3\ are used in 
estimates of precision and bias. This did

[[Page 17269]]

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 [mu]g/m\3\. One commenter was 
concerned about ``clean'' days that are below the 3 [mu]g/m\3\ 
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 [mu]g/m\3\, but on all valid 
collocated pairs (valid pairs below 3 [mu]g/m\3\ 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 [mu]g/m\3\. 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 [mu]g/
m\3\, which is well below the EPA requirement of 5 percent of the 
current Pb NAAQS level of 0.15 [mu]g/m\3\, or 0.0075 [mu]g/m\3\. 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 [mu]g/m\3\ to 0.002 [mu]g/m\3\ 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 [mu]g/m\3\ value will be retained for 
the previous Pb FRM that has subsequently been re-designated 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.
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    \35\ See 78 FR 40000, July 3, 2013.
    \36\ MDL 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.
    \37\ FEMS approved on or after March 4, 2010, have the required 
sensitivity to utilize the 0.002 [mu]g/m\3\ reporting limit with the 
exception of manual equivalent method EQLA-0813-803, the previous 
FRM based on flame atomic absorption spectroscopy.
---------------------------------------------------------------------------

    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 [mu]g/m\3\ 
(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 [mu]g/m\3\ 
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 [mu]g/
m\3\, 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 [mu]g/m\3\ had the number 
of available pairs increased to 172 with the lower 0.002 [mu]g/m\3\ 
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

[[Page 17270]]

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 [mu]g/m\3\ threshold should be applicable to the 
newer methods and is the reason for the dual thresholds.
---------------------------------------------------------------------------

    \38\ http://www.epa.gov/ttnamti1/files/ambient/pb/QAQA.pdf.
---------------------------------------------------------------------------

    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 [mu]g/m\3\ was 16.31. The average 3-year CV 
for a threshold of 0.02 [mu]g/m\3\ 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 [mu]g/m\3\. Therefore, the EPA 
took the 10x definition of LOQ and calculated 0.002 [mu]g/m\3\ 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

[[Page 17271]]

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.
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    \39\ Permitting 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.
---------------------------------------------------------------------------

    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

[[Page 17272]]

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.
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    \40\ Graded approach to Tribal QAPP and QMPs http://www.epa.gov/ttn/amtic/cpreldoc.html.
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    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 one-
point 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 self-
implementation 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 self-
implementation 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).
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    \41\ http://www.epa.gov/ttn/amtic/npepqa.html.
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    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 self-implementation 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

[[Page 17273]]

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.
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    \42\ http://www.epa.gov/ttn/amtic/aapgvp.html.
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    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.
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    \43\ QA Handbook for Air Pollution Measurement Vol. II Ambient 
Air Quality Monitoring Program at: http://www.epa.gov/ttn/amtic/qalist.html.
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    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 
one-point 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 routinely-collected 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

[[Page 17274]]

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.
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    \44\ See supporting information in Excess NO Issue paper, Mike 
Papp and Lewis Weinstock, Docket number EPA-HQ-OAR-2013-0619.
---------------------------------------------------------------------------

    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 long-standing 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 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 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.
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    \45\ http://www3.epa.gov/ttn/amtic/npepqa.html.
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    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 high-volume 
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

[[Page 17275]]

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 filter-
based). The current collocation requirements for FEMs require a filter-
based 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 [mu]g/m\3\ 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 [mu]g/m\3\ 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 [mu]g/m\3\ 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 [mu]g/m\3\. 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 [mu]g/m\3\, which is well below the EPA requirement of 
five percent of the current Pb NAAQS level of 0.15 [mu]g/m\3\, or 
0.0075 [mu]g/m\3\. 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 [mu]g/m\3\ to 0.002 
[mu]g/m\3\ 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 [mu]g/m\3\ value will be 
retained for the previous Pb FRM that has subsequently been re-
designated 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.
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    \46\ See 78 FR 40000, July 3, 2013.
    \47\ MDL 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.
    \48\ FEMs approved on or after March 4, 2010, have the required 
sensitivity to utilize the 0.002 [mu]g/m\3\ reporting limit with the 
exception of manual equivalent method EQLA-0813-803, the previous 
FRM based on flame atomic absorption spectroscopy.
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    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

[[Page 17276]]

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

0
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.

0
2. Revise Sec.  58.1 to read as follows:

Sec.  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

[[Page 17277]]

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 Sec.  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 high-
concentration 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 Sec.  53.11 or Sec.  
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 Sec.  53.11 or Sec.  
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 Sec.  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 (path-averaged 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

[[Page 17278]]

(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 
Sec.  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 
path-integrated 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 
Sec. Sec.  51.165 and 51.166 of this chapter, or the Administrator in 
the case of EPA-implemented permit programs under Sec.  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 Sec.  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 Sec.  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.

[[Page 17279]]

    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.

0
3. In Sec.  58.10:
0
a. Revise paragraphs (a)(1) and (a)(2).
0
b. Add paragraph (a)(12).
    The revisions and addition read as follows:

Sec.  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.
* * * * *

0
4. In Sec.  58.11, revise paragraph (a)(3) to read as follows:

Sec.  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.
* * * * *

0
5. In Sec.  58.12:
0
a. Revise paragraph (d)(1).
0
b. Revise paragraph (d)(3).
    The revisions read as follows:

Sec.  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-in-3 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-in-6 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 
Sec.  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

[[Page 17280]]

with nearby sites, and presence of other leveraged measurements.
* * * * *

0
6. In Sec.  58.14, revise paragraph (a) to read as follows:

Sec.  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 Sec.  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.
* * * * *

0
7. Revise Sec.  58.15 to read as follows:

Sec.  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.

0
8. In Sec.  58.16, revise paragraphs (a), (c), and (d) to read as 
follows:

Sec.  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 filter-
based 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.
* * * * *

0
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.

[[Page 17281]]

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

[[Page 17282]]

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 one-point 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

[[Page 17283]]

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.

----------------------------------------------------------------------------------------------------------------
                                                                     Concentration Range, ppm
                   Audit level                   ---------------------------------------------------------------
                                                        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 open-path 
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

[[Page 17284]]

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 self-implement 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 self-implementation 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.

----------------------------------------------------------------------------------------------------------------
                                                                                                    #Collocated
                                                                                    #Collocated      with same
          #Primary FEMS of a unique method designation              #Collocated     with an FRM       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;

[[Page 17285]]

    (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 
[micro]g/m\3\. 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

[[Page 17286]]

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:

------------------------------------------------------------------------
                                   Equivalent ambient Pb concentration,
              Range                             [mu]g/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 [mu]g Pb/filter or 
strip) and the corresponding measured concentrations (in [mu]g 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. Non-source 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

[[Page 17287]]

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 [micro]g/m\3\ (Methods approved after 3/04/2010, 
with exception of manual equivalent method EQLA-0813-803).
    (2) Pb: 0.02 [micro]g/m\3\ (Methods approved before 3/04/2010, 
and manual equivalent method EQLA-0813-803).
    (3) PM10 (Hi-Vol): 15 [micro]g/m\3\.
    (4) PM10 (Lo-Vol): 3 [micro]g/m\3\.
    (5) PM2.5: 3 [micro]g/m\3\.
    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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.000

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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.001

where n is the number of single point checks being aggregated; X\2\ 
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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.002

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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.003

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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.004

    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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.005

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:

[[Page 17288]]

[GRAPHIC] [TIFF OMITTED] TR28MR16.006

where n is the number of valid data pairs being aggregated, and X\2\ 
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.
[GRAPHIC] [TIFF OMITTED] TR28MR16.007

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-system-documents.
    (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-system-documents.
    (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/agency-wide-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.

[[Page 17289]]

                 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       Each analyzer.........  Once per 2 weeks.....  Audit concentration    One-Point QC.
                                      concentration 0.005-                                                   \1\ and measured
                                      0.08 ppm SO2, NO2,                                                     concentration. \2\
                                      O3, and.
                                     0.5 and 5 ppm CO......
Annual performance evaluation for    See section 3.1.2 of    Each analyzer.........  Once per year........  Audit concentration    Annual PE.
 SO2, NO2, O3, CO.                    this appendix.                                                         \1\ and measured
                                                                                                             concentration \2\
                                                                                                             for each level.
NPAP for SO2, NO2, O3, CO..........  Independent Audit.....  20% of sites each year  Once per year........  Audit concentration    NPAP.
                                                                                                             \1\ and measured
                                                                                                             concentration \2\
                                                                                                             for each level.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Particulate Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
Continuous \4\ method--collocated    Collocated samplers...  15%...................  1-in-12 days.........  Primary sampler        No Transaction
 quality control sampling PM2.5.                                                                             concentration and      reported as raw
                                                                                                             duplicate sampler      data.
                                                                                                             concentration. \3\
Manual method--collocated quality    Collocated samplers...  15%...................  1-in-12 days.........  Primary sampler        No Transaction
 control sampling PM10, PM2.5, Pb-                                                                           concentration and      reported as raw
 TSP, Pb-PM10.                                                                                               duplicate sampler      data.
                                                                                                             concentration. \3\
Flow rate verification PM10 (low     Check of sampler flow   Each sampler..........  Once every month.....  Audit flow rate and    Flow Rate
 Vol) PM2.5, Pb-PM10.                 rate.                                                                  measured flow rate     Verification.
                                                                                                             indicated by the
                                                                                                             sampler.
Flow rate verification PM10 (High-   Check of sampler flow   Each sampler..........  Once every quarter...  Audit flow rate and    Flow Rate
 Vol), Pb-TSP.                        rate.                                                                  measured flow rate     Verification.
                                                                                                             indicated by the
                                                                                                             sampler.
Semi-annual flow rate audit PM10,    Check of sampler flow   Each sampler,.........  Once every 6 months..  Audit flow rate and    Semi Annual Flow Rate
 TSP, PM10-2.5, PM2.5, Pb-TSP, Pb-    rate using                                                             measured flow rate     Audit.
 PM10.                                independent standard.                                                  indicated by the
                                                                                                             sampler.
Pb analysis audits Pb-TSP, Pb-PM10.  Check of analytical     Analytical............  Once each quarter....  Measured value and     Pb Analysis Audits.
                                      system with Pb audit                                                   audit value (ug Pb/
                                      strips/filters.                                                        filter) using AQS
                                                                                                             unit code 077.
Performance Evaluation Program       Collocated samplers...  (1) 5 valid audits for  Distributed over all   Primary sampler        PEP.
 PM2.5.                                                       primary QA orgs, with   4 quarters.            concentration and
                                                              5 sites..
                                                             (3) All samplers in 6
                                                              years.
Performance Evaluation Program Pb-   Collocated samplers...  (1) 1 valid audit and   Distributed over all   Primary sampler        PEP.
 TSP, Pb-PM10.                                                4 collocated samples    4 quarters.            concentration and
                                                              for primary QA orgs,                           performance
                                                              with 5 sites.                                 duplicate sampler
                                                                                                             concentration.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Effective concentration for open path analyzers.
\2\ Corrected concentration, if applicable for open path analyzers.
\3\ Both primary and collocated sampler values are reported as raw data.
\4\ PM2.5 is the only particulate criteria pollutant requiring collocation of continuous and manual primary monitors.

[[Page 17290]]

      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
----------------------------------------------------------------------------------------------------------------
                                                                                                      No. of
                                                                                                    collocated
                                                   Total No. of    Total No. of       No. of         with same
       Primary sampler method designation            monitors       collocated      collocated        method
                                                                                     with FRM       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
----------------------------------------------------------------------------------------------------------------

0
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

[[Page 17291]]

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 project-specific 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 routinely-collected 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

[[Page 17292]]

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 one-point 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.

----------------------------------------------------------------------------------------------------------------
                                                                     Concentration range, ppm
                   Audit level                   ---------------------------------------------------------------
                                                        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

[[Page 17293]]

 
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 open-path 
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 self-implement 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

[[Page 17294]]

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 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. 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 [mu]g/m\3\ 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 [micro]g/m\3\ 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.

[[Page 17295]]

    (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 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 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:

------------------------------------------------------------------------
                                              Equivalent ambient Pb
                 Range                     concentration, [micro]g/m\3\
------------------------------------------------------------------------
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 [micro]g Pb/filter or 
strip) and the corresponding measured concentrations (in [micro]g 
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 [micro]g/m\3\ (Methods approved after 3/04/2010, 
with exception of manual equivalent method EQLA-0813-803).
    (2) Pb: 0.02 [micro]g/m\3\ (Methods approved before 3/04/2010, 
and manual equivalent method EQLA-0813-803).
    (3) PM10 (Hi-Vol): 15 [micro]g/m\3\.
    (4) PM10 (Lo-Vol): 3 [micro]g/m\3\.
    (5) PM2.5: 3 [micro]g/m\3\.

[[Page 17296]]

    (c) The PM2.5 3 [micro]g/m\3\ 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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.008

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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.009

where n is the number of single point checks being aggregated; X\2\ 
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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.010

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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.011

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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.012

[[Page 17297]]

    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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.013

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:
[GRAPHIC] [TIFF OMITTED] TR28MR16.014

where n is the number of valid data pairs being aggregated, and X\2\ 
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.
[GRAPHIC] [TIFF OMITTED] TR28MR16.015

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-system-documents.
    (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-system-documents.
    (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/agency-wide-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

[[Page 17298]]

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      Each analyzer........  Once per 2 weeks.....  Audit concentration   One-Point QC.
                                     concentration 0.005-                                                 \1\ and measured
                                     0.08 ppm SO2, NO2,                                                   concentration \2\.
                                     O3, & 0.5 and 5 ppm
                                     CO.
Quarterly performance evaluation    See section 3.1.2 of   Each analyzer........  Once per quarter.....  Audit concentration   Annual PE.
 for SO2, NO2, O3, CO.               this appendix.                                                       \1\ and measured
                                                                                                          concentration \2\
                                                                                                          for each level.
NPAP for SO2, NO2, O3, CO3........  Independent Audit....  Each primary monitor.  Once per year........  Audit concentration   NPAP.
                                                                                                          \1\ and measured
                                                                                                          concentration \2\
                                                                                                          for each level.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Particulate Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
Collocated sampling PM10, PM2.5,    Collocated samplers..  1 per PSD Network per  Every 6 days or every  Primary sampler       No Transaction reported
 Pb.                                                        pollutant.             3 days if daily        concentration and     as raw data.
                                                                                   monitoring required.   duplicate sampler
                                                                                                          concentration \4\.
Flow rate verification PM10,        Check of sampler flow  Each sampler.........  Once every month.....  Audit flow rate and   Flow Rate Verification.
 PM2.5, Pb.                          rate.                                                                measured flow rate
                                                                                                          indicated by the
                                                                                                          sampler.
Semi-annual flow rate audit PM10,   Check of sampler flow  Each sampler.........  Once every 6 months    Audit flow rate and   Semi Annual Flow Rate
 PM2.5, Pb.                          rate using                                    or beginning, middle   measured flow rate    Audit.
                                     independent standard.                         and end of             indicated by the
                                                                                   monitoring.            sampler.
Pb analysis audits Pb-TSP, Pb-PM10  Check of analytical    Analytical...........  Each quarter.........  Measured value and    Pb Analysis Audits.
                                     system with Pb audit                                                 audit value (ug Pb/
                                     strips/filters.                                                      filter) using AQS
                                                                                                          unit code 077 for
                                                                                                          parameters:
                                                                                                         14129--Pb (TSP) LC
                                                                                                          FRM/FEM.
                                                                                                          85129--Pb (TSP) LC
                                                                                                          Non-FRM/FEM..
Performance Evaluation Program      Collocated samplers..  (1) 5 valid audits     Over all 4 quarters..  Primary sampler       PEP.
 PM2.5 \3\.                                                 for PQAOs with  5                            concentration.
                                                            sites..
                                                           (3) All samplers in 6
                                                            years.
Performance Evaluation Program Pb   Collocated samplers..  (1) 1 valid audit and  Over all 4 quarters..  Primary sampler       PEP.
 \3\.                                                       4 collocated samples                          concentration and
                                                            for PQAOs, with 5 sites..                               duplicate sampler
                                                                                                          concentration.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Effective 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.
\4\ Both primary and collocated sampler values are reported as raw data.

0
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

[[Page 17299]]

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
```