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Instructions and Template for Requesting that data from 

PM2.5 Continuous FEMs are not compared to the NAAQS.

Section A - SUMMARY and INSTRUCTIONS:

1. Background:

As part of the PM NAAQS final rule published on January 15th, 2013 (78 FR 3086), EPA 

has developed criteria for monitoring agencies to use, if they choose, that allow for PM2.5 

continuous FEM or ARM data to be set aside and not used for determining NAAQS calculations, 

if certain performance criteria are not met. The regulatory requirements for this provision are 

detailed in §58.11 (e) – Network Technical Requirements. This template has been developed 

to provide an illustration of the level of detail that may be useful to include in a request to an 

EPA Regional Office to set aside certain data for comparison to the NAAQS. Such requests are 

normally expected to be included in an Annual Monitoring Network Plan; however, requests 

may be sought at any time of the year. Monitoring agencies are not required to follow the 

recommendations in this template; however, doing so should provide uniform documentation

for developing such requests and ensuring that EPA Regional offices have the appropriate 

information to consider and approve, where appropriate, such requests.

2. Instructions:

I. Review Network – Specifically, review which PM2.5 samplers and monitors and at 

which sites are supporting the PM2.5 Network Design Criteria. Ensure that your 

network meets both the minimally required sites and any additional SLAMS 

identified from your most recently annual monitoring network plan according to 

Appendix D to Part 58.

II. Review the data comparability of the PM2.5 continuous monitors - Monitoring 

agencies, should review the comparability of their PM2.5 continuous monitors related 

to collocated FRMs. This should include both pre-FEM and FEM PM2.5 continuous 

monitors. Section C below identifies options for performing these assessments.

III. Identify which, if any, PM2.5 continuous FEMs are candidates for requesting 

exclusion of data –

a. At this point, we also recommend reaching out informally to your EPA 

Regional Office technical contacts to ensure there is a common 

understanding of the monitors and sites in play for the request. 
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IV. Draft Request for Exclusion of Data – Using the application template in section B 

below, or other similar level of documentation, identify and document the 

information necessary to support a request to exclude data.

V. Seek Monitoring Agency Approval – Each monitoring agency should ensure the 

appropriate management level who normally signs off on the annual monitoring 

network plan is supportive and signs off on the request to exclude PM2.5 continuous 

FEM data.

VI. Submit Request to Exclude PM2.5 Continuous FEM Data to your EPA Regional Office –

We recommend sending this to the same contact point as you normally send your 

annual monitoring network plan to. We also recommend you cc the EPA Regional 

Office Technical staff who would be reviewing the information.

a. For Annual Monitoring Network Plans:

i. Make available for Public input per §58.10 (a)(1) and §58.10 (c).

ii. Submit to EPA Regional Office by July 1.

iii. EPA Regional Offices have 120 days to respond. However, Regions 

may, at their discretion, respond sooner, even if only addressing the 

exclusion of data.

b. For letter requests outside the scope of an Annual Monitoring Network Plan

i. Submit to EPA Regional Office

ii. Ensure next Annual Monitoring Network Plan characterizes status of 

PM2.5 continuous FEMs as of the time a plan is submitted. This could 

be:

1. We are using the PM2.5 continuous FEM data for NAAQS and 

AQI, or just AQI; or

2. We do not intend to use the PM2.5 continuous FEM data 

pending approval by EPA. However, we are meeting the 

monitoring requirements by...

3. The following PM2.5 continuous FEMs have been approved to 

exclude from comparison to the NAAQS

VII. Follow the AQS data coding information detailed in section 6 below - If exclusion of 

PM2.5 Continuous FEM data is approved by the EPA Regional office.
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VIII. Include status of PM2.5 Continuous FEM monitors in subsequent Annual Monitoring 

Network Plans.

3. Applicability:

The monitoring requirements are specified by regulation in 40 CFR Part 58. These 

requirements are applicable to State, and where delegated, local air monitoring agencies that 

operate criteria pollutant monitors. In Section 4.7 of Appendix D to Part 58, EPA specifies 

minimum monitoring requirements for PM2.5 to operate at State and Local Air Monitoring 

Stations. For stations to be compared to the NAAQS, the monitor must be an approved FRM, 

FEM, or ARM. The monitoring regulations also provide that each CBSA must operate a 

minimum number of PM2.5 continuous monitors; however, this requirement does not need to 

be met with a continuous FEM or ARM. Consequently, the monitoring requirements for PM2.5 

can be met with a combination of filter-based FRMs/FEMs and pre-FEM continuous monitors or 

with continuous FEMs at each required SLAMS. 

In 2006, EPA published performance criteria and field testing requirements for approval 

of Class III PM2.5 continuous FEMs and PM2.5 continuous ARMs. Subsequently, several PM2.5 

continuous monitors have been approved1 as FEMs. As monitoring agencies implemented 

PM2.5 continuous FEMs in their networks, the EPA assessed the available data from these 

monitors and included a summary of that assessment in the PM Policy Assessment in April of 

20112.

Recognizing that in some cases monitoring agencies were still testing and working to 

optimize the performance of their PM2.5 continuous FEMs, but were beyond the 24 month 

period that allows data from an approved method to be set aside using the provisions 

described in §58.20 on Special Purpose Monitoring (SPMs), EPA proposed and finalized a new 

provision to allow PM2.5 FEM data to be set aside for comparison to the NAAQS under certain 

conditions, even if more than 24 months of data are collected.

Therefore, this provision to allow PM2.5 continuous FEM data to be set aside for 

comparison to the NAAQS is applicable, when in accordance with Annual Monitoring Network 

Plan provisions described in §58.10 (b)(13), the monitoring agency has assessed and meets the 

criteria described in §58.11 (e), and has also sought and received approval from the applicable 

EPA Regional office.

The EPA also encourages monitoring agencies to perform assessments of their PM2.5

continuous data for methods that are intended to be the primary monitor and for PM2.5

continuous monitors operated in their network that were acquired prior to the approval of 

 

1 EPA maintains a list of designated FRMs and FEMs on the web at: http://www.epa.gov/ttn/amtic/criteria.html

2 US EPA (2011). Policy Assessment for the Review of the Particulate Matter National Ambient Air Quality 

Standards. Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle 

Park, NC. EPA 452/R-11-003. April 2011. Available: 

http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_2007_pa.html.
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continuous FEMs. The regular assessment of such data will help ensure data are meeting the 

performance goals for their intended use, even if the monitoring agency does not intend to 

request exclusion of these data. 

4. Decision Matrix on use of Data:

As explained in the PM NAAQS final rule, PM2.5 continuous monitors may be used for 

the NAAQS and in AQI reports; they may be excluded from comparison to the NAAQS when 

approved by the EPA Regional Office, but still provide data useful for inclusion in AQI reports; or 

the data may be of such poor comparability to a collocated FRM, that the data should not be 

used either for comparison to the NAAQS or in AQI reports, also when approved by the EPA 

Regional Office. The following flow chart provides an illustration of the expected most common 

decisions associated with operating a PM2.5 continuous FEM, how the data should be stored, 

and the uses of the data. 

Continuous 

PM2.5 FEM

Monitoring Agency 

has confidence in the 

FEM

Use Monitor Type of 

“SLAMS”

May be used as 

the Primary 

Monitor in 88101

FRM is retained 

as the Primary; 

Parameter code of 

88101 is used with 

FEM as backup

Parameter Code = 88101

Monitor Type = SLAMS

FRM or FEM can be the 

primary monitor

Monitoring Agency would 

like to evaluate the FEM 

and is unsure if data 

should be used for 

NAAQS. Use two Monitor 

Types – ”Special Purpose” 

and “Non-Regulatory”

Parameter Code = 88502

Monitor Type = SLAMS

Identify 

Continuous FEM 

in each years 

annual plan 

Request Regional 

Approval to set 

aside PM2.5

continuous FEM 

data. Request 

can be part of 

annual plan or as 

a separate letter

Parameter Code = 88501

Monitor Type = Special 

Purpose

Note: ”non-regulatory” is 

not needed in this 

parameter code

DECISION TREE

Evaluating the 

FEM performance 

and data meets 

comparability 

criteria

Evaluating the 

FEM performance 

and data does not 

meet comparability 

criteria

Data used for NAAQS 

and AQI

Data is used for AQI, 

but not NAAQS

Data not used for NAAQS 

or AQI

The dashed line represents a case that is not widely expected, but can happen. 

Monitoring agency is responsible for ensuring that an approved method is operating 

as the primary monitor when site is a required SLAMS

W/Regional Approval
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5. Test Specifications:

The network technical requirements for requesting exclusion of data from comparison 

to the NAAQS are identified in §58.11 (e). These requirements refer to the performance criteria 

described in table C-4 to subpart C of part 53. To accommodate the differences in how routine 

monitoring agencies operate their networks, several additional provisions are described in 

§58.11 (e). When a topic is not addressed in §58.11 (e), then test specification from table C-4 

applies. Options for generating the required statistical information necessary when applying 

for exclusion of data are detailed in Section C below.

The following table details the combination of §53 Table C-4 and the provisions from §58.11 (e). 

Table A-1: Test Specifications:

Test Specification

From Table C-4

(PM2.5 Class III)

Related information 

from §58.11 (e) How to use in application

Test Specifications as identified in §53 Table C-4

Acceptable concentration 

range (Rj), μg/m3.

3 – 200

The acceptable 

concentration range may 

include values down to 0 

μg/m3

Use a concentration range of 

either:

0 – 200 or

3 – 200 μg/m3

(One page assessment tool utilizes all data)

Minimum number of test 

sites 4

1; however, generally all 

collocated monitors in an 

agency’s network are 

included as separate 

assessments

Include all sites in the agency’s 

network with collocated (FRM to 

continuous FEM) data for the 

period of interest. Each monitor

pair is assessed separately

Minimum number of 

candidate method 

samplers or analyzers

Per site.

3 1

Include each PM2.5 continuous 

FEM in the agencies network on its 

own (i.e., do not average multiple 

PM2.5 FEMs prior to comparing to 

a collocated FRM)

Minimum number of 

reference method

samplers per site.

3 1

Include the primary PM2.5 FRM on 

its own (i.e., do not average 

multiple PM2.5 FRMs prior to 

comparing to a continuous FEM)

Minimum number of 

acceptable sample sets 

per site. Each season: 

Total, each site:

23

(46 for two-season 

sites)

All seasons must be covered

All seasons must be covered with 

at least 23 data points in each 

season.

Precision of replicate 

reference method 

measurements,

respectively; 

RP each site.

<= 10%

Calculated as root 

mean square

Since multiple FRMs and 

FEMs may not be present at 

each site; the precision 

statistic requirement does 

not apply, even if precision 

data are available

The inclusion of precision data is 

optional, and not meeting it is not

cause to request excluding data. 

Monitoring agencies will have 

access to a precision statistic for 

FRMs at the PQAO level, but not 

necessarily at every site.

Precision of PM2.5 

candidate method, CP, 

each site.

<= 15%

Calculated as root 

mean square
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Test Specification

From Table C-4

(PM2.5 Class III)

Related information 

from §58.11 (e) How to use in application

Slope of regression 

relationship 1+/- 0.10 1+/- 0.10

Intercept of regression 

relationship, μg/m3.

Between: 15.05 –

(17.32 x slope). 

But not less than -

2.0; and 15.05 –

(13.20 x slope), 

but not more than 

+ 2.0.

Between: 15.05 – (17.32 x slope). 

But not less than -2.0; and 15.05 –

(13.20 x slope), but not more than 

+ 2.0.

(This is illustrated in Figure C-2 

to subpart C of Part 53)

Correlation of reference 

method and candidate 

method measurements.

(Note: this is correlation and not 

correlation squared.)

See Figure C-4

>= 0.93 or >=0.95

depending on the 

concentration 

correlation 

coefficient

Include the correlation statistic, 

but do not use in recommendation 

to include or exclude data

Additional Specifications Identified in §58.11 (e)

Period of time to include 

in assessment.

No more than thirty-six 

consecutive months of data 

in total aggregated 

together.

Include up to last 36 months of 

data. Generally this will be full 

years of data (i.e., January through 

December). 
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6. Data Reporting and Coding:

Monitoring agencies will need to code information associated with their PM2.5 continuous monitoring data such that the AQS

and data users understand whether to use PM2.5 continuous data in PM2.5 design value calculations and under what provisions it may 

be substituted, if the primary PM2.5 method at a site is not available. Monitoring agencies are to load PM2.5 continuous FEM data to 

PM2.5 Local Conditions (parameter code 88101), until such time as they are approved by their EPA Regional Office to exclude data in 

NAAQS calculations, per §58.10 (b)(13). The following table provides the most commonly expected options for reporting PM2.5 data.

Table A-2: Data Reporting and Coding

Scenario

Parameter 

Name

Parameter 

Code

Monitor 

Type

Primary Monitor

(Identified at site 

level as “Primary 

Monitor Periods”)

Are data 

substituted on 

days that the 

Primary monitor 

is not available?

Eligible for NAAQS 

comparison

Eligible for 

AQI 

reporting

PM2.5 continuous FEM data is acceptable

and the Primary Monitor.

PM2.5 Local 

Conditions 88101 SLAMS Continuous FEM Yes, if available Yes Yes

PM2.5 continuous FEM data is acceptable, 

but FRM is retained as the Primary 

Monitor.

PM2.5 Local 

Conditions 88101 SLAMS FRM Yes Yes Yes

PM2.5 Continuous FEM is being tested and 

is less than 24 months old; FRM is 

retained as the Primary Monitor.

PM2.5 Local 

Conditions 88101

SPM and 

NonregulatoryFRM No

No, if discontinued 

within 24 months of 

start-up [§58.20(d)]

Generally, 

no. But it 

can be.

PM2.5 Continuous FEM is being run as an 

SPM; more than 24 months of data are 

collected, but a request and approval to 

exclude the data has not been made.

PM2.5 Local 

Conditions 88101 SPM FRM

Yes, data collected 

for more than 24 

months are eligible 

for comparison to 

the NAAQS.

Yes Yes

PM2.5 Continuous FEM has been operating 

for more than 24 months and the monitor 

has been approved for exclusion to the 

NAAQS per §58.11 (e). However, data are 

appropriate for reporting the AQI. 

Acceptable 

PM2.5 AQI 88502 SLAMS FRM No No Yes

PM2.5 Continuous FEM has been operating 

for more than 24 months and the monitor 

has been approved for exclusion to the 

NAAQS per §58.11 (e). Also, data are not 

appropriate for reporting the AQI.

PM2.5 Raw 

Data 88501 SPM FRM No No No
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Section B – APPLICATION TEMPLATE FOR EXCLUSION OF CERTAIN PM2.5 CONTINUOUS FEM DATA FROM COMPARISON TO THE 

NAAQS:

The following application is written as if included as a section of an annual monitoring network plan. A letter application to the 

Region in advance of an annual monitoring network plan can be written even more concise. 

Introduction:

Our monitoring program has historically operated PM2.5 continuous monitors primarily to support forecasting and reporting 

of the Air Quality Index (AQI). These monitors supply data every hour to update the AQI on our web site as well as on national web 

sites such as AIRNow (www.airnow.gov). We have been using these monitors since the early part of the last decade as we 

implemented the PM2.5 monitoring program. Over the last few years, a number of PM2.5 continuous monitors have been approved 

as Federal Equivalent Methods (FEMs). By utilizing an approved FEM, any subsequent data produced from the method may be 

eligible for comparison to EPA’s health based standard known as the NAAQS. The primary advantage of operating a PM2.5 

continuous FEM is that it can support both the AQI, while also supplying data that are eligible for comparison to the NAAQS. Thus, a 

network utilizing PM2.5 continuous FEMs can minimize the number of filter-based FRMs operated in the network, which are primarily 

used for comparison to the NAAQS. These filter-based FRMs are resource intensive in that they require field operations as well as 

pre- and post-sampling laboratory analysis which results in data not being available for approximately 2-4 weeks after sample 

collection.

Our monitoring program has been working with PM2.5 continuous FEMs including deployment at a few sites to evaluate their 

performance. Although the PM2.5 continuous FEMs are automated methods, these methods still require careful attention in their 

set-up, operation, and validation of data. Once we were able to collect enough data we began to evaluate the performance of these 

methods compared to collocated FRMs. That evaluation is explained further below and includes our recommendations on the use of 

the data from these methods.

Request for Exclusion of PM2.5 Continuous FEM data from Comparison to the NAAQS:
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In accordance with the PM NAAQS rule published on January 15th, 2013 (78 FR 3086) and specific to the provisions detailed in 

§58.10 (b)(13) and §58.11 (e) we are requesting that data from the following monitors be set aside for comparison to the NAAQS. 

While our agency is working to optimize the monitoring instrumentation we use to meet all of our monitoring objectives, we are not 

yet at a point where the comparability of the PM2.5 continuous FEMs operated in our network (or a sub-set of our network)

compared to collocated FRMs is acceptable such that we are comfortable using the continuous FEM data for comparison to the 

NAAQS. After assessing the comparability of the PM2.5 FEMs to the collocated FRMs for our network, we have determined that the 

sites listed below do not meet the comparability requirements. Detailed one-page assessments from which the information 

described below was obtained are included at the end of this section.

Table – Request for Exclusion of PM2.5 Continuous FEM Data

Site Name City Site ID

Cont

POC

Method 

Description

PM2.5

Cont.

Begin 

Date

PM2.5

Cont End 

Date

Continuous/ 

FRM

Sampler 

pairs per 

season

Slope

(m)

Intercept

(y)

Meets bias 

requirement

Correlation

(r)

Sites with PM2.5 continuous FEMs that are collocated with FRMs:

Winter = 

Spring = 

Summer = 

Fall = 

Total = 

Winter = 

Spring = 

Summer = 

Fall = 

Total = 

Winter = 

Spring = 

Summer = 

Fall = 

Total = 

Winter = 

Spring = 

Summer = 

Fall = 

Total = 
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Sites with PM2.5 continuous FEMs that are not collocated with FRMs:

Period of Exclusion of Data from the PM2.5 Continuous FEMs:

The above table details the period of available data by monitor for which we are basing our recommendation to exclude 

PM2.5 continuous FEM data. Per EPA Regional Office approval, we will load or move as necessary these data to EPA’s AQS database 

in a manner where the data are only used for the appropriate monitoring objective(s) (i.e., use data for both the NAAQS and AQI, 

just the AQI, or neither the NAAQS or AQI). Additionally, we will continue to load any new data generated for the next 18 months 

(intended to represent the period until December 31 of 2014) in the same manner or until such time as we request and receive 

approval from the EPA Regional Office to change the monitoring objectives that the data from the PM2.5 continuous FEMs can 

support.

PM2.5 Continuous FEM data for Reporting the AQI:

(We will use it for the AQI)

While we are requesting the monitors above not be used for comparison to the NAAQS, we do believe that the data are of sufficient 

comparability to collocated FRMs that they be used in AQI reporting. Therefore, with EPA Regional Office approval we will report 

these data on our web site and to AIRNow (www.airnow.gov). Additionally, we intend to store the data in EPA’s AQS database that 

is used for “acceptable AQI” reporting (i.e., parameter code 88502) so that data users will know that these data are appropriate for 

use in AQI calculations.

(We will not use it for the AQI)
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In our assessment of the comparability of the PM2.5 continuous FEMs to collocated FRMs, we believe that the data would not be 

appropriate for reporting the AQI. However, we will continue to utilize our pre-FEM PM2.5 continuous monitors to support our realtime reporting needs. We will store the data from the PM2.5 continuous FEMs that in parameter code 88501 so that it is available for 

data users with the caveat that it will not be used in NAAQS or AQI calculations.

Continued Operation of PM2.5 Monitors to Support NAAQS and AQI Reporting

While we are requesting that data from the monitors listed above be set aside for comparison to the NAAQS, we will 

continue to operate PM2.5 FRMs to support the objective of comparison to the NAAQS. We will also operate our PM2.5 continuous 

monitors for use in AQI reporting. Each of these FRM and PM2.5 continuous monitors will be operated at the locations previously 

described in this plan and at the locations that meet the objectives of the Network Design Criteria for Ambient Air Quality 

Monitoring described in Appendix D to Part 58.

Assessments:

The following one-page assessments are locations where our agency has collocated PM2.5 FRM and continuous FEM 

monitors. Each of these assessments is represented in the “Table – Request for Exclusion of PM2.5 Continuous FEM Data” above.
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Section C –GENERATING THE REQUIRED STATISTICAL INFORMATION:

There are multiple options to generate the statistical information required in §58.11 (e). Monitoring agencies could:

 Run the one-page assessment “PM2.5 continuous monitor comparability assessment tool“ available on AMTIC. When data from both a PM2.5 

FRM and collocated continuous FEM are loaded to AQS, this tool provides the necessary statistical information to use in an application to exclude 

data. The comparability assessment tool and a technical note explaining its use are available on the web at: 

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

 Utilize one of the spreadsheet templates also available on AMTIC that were originally developed to support FEM and ARM applications. The file: 

“This spreadsheet can be used for assessing collocated FRM and continuous data at sites with up to 366 data pairs (XLT file)” may be the most 

useful file as it allows up to 365 data pairs to be included. This file is also available at http://www.epa.gov/ttn/amtic/contmont.html

 Develop your own spreadsheet or utilize statistical software with the equations identified in 40 CFR Part 53. These equations include: Slope -

equation 19, intercept - equation 20, and the correlation coefficient (not correlation squared) - equation 21.

Interpreting the one-page assessment:

To ensure clarity in interpreting the one page assessments, we are providing the following example. The bottom line is that if 

the overall bias requirement for a PM2.5 continuous FEM is not met when compared to a collocated FRM, for a period of up to the 

last 36 months, then a monitoring agency may request that the data be set aside to use in design values calculations. When 

approved by the applicable Regional Office these data will be stored separately in AQS and not used in design value calculations.

This is just an example and does not constitute an official action to request or approve exclusion of data.

Site 

Name City Site ID

Cont

POC

Method 

Description

PM2.5

Cont.

Begin 

Date

PM2.5

Cont End 

Date

Continuous/ 

FRM

Sampler 

pairs per 

season

Slope

(m)

Intercept

(y)

Meets bias 

requireme

nt

Correlation

(r)

Sites with PM2.5 continuous FEMs that are collocated with FRMs:

Oldtown Baltimore 24-510-0040 3

Met-One BAM 

1020 w/VSCC FEM

Jan 1

2011

Dec. 31

2012

Winter = 150

Spring = 127

Summer = 121

Fall = 149

Total = 547

1.06 +1.49 no 0.96
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Determining if the bias criteria has been met:

In most cases determining whether the combination of the multiplicative 

(slope) and additive (intercept) bias is inside or outside the required test 

specification can be done simply by inspecting the Additive (y) vs. 

Multiplicative (x) Bias figure on the middle left side of the one-page 

assessment. Use the “A” from the chart as it represents all data. In this 

case A appears to be just outside the box, which indicates that this bias 

does not meet the acceptance criteria.

However, in some cases an agency may want to ensure that the 

combination of the multiplicative (slope) and additive (intercept) bias is 

outside the required test specifications. To do that, answer the questions 

below including solving for the allowable intercept.

From Part 53, Table C-4:

Does the Slope of regression relationship meet the test specification of 

1+/- 0.10

 Yes, the slope of 1.06 is within 1 +/- 0.10

Does the Intercept (μg/m3) of the regression relationship meet the test 

specification of between: 15.05 – (17.32 x slope), but not less than -2.0; 

and 15.05 – (13.20 x slope), but not more than + 2.0.

15.05-(17.32 x 1.06) = -3.31, which is more negative than -2.0. Therefore 

use -2.0 as the most negative the intercept can be with a slope of 1.06.

15.05 – (13.20 x 1.06) = 1.058, which is within the maximum +2.0. 

Therefore use 1.058 (rounded to 1.06) as the most positive the intercept 

can be with a slope of 1.06.

No, the intercept of +1.49 is outside the bounds of -2.0 to +1.06 

that is allowed for a slope of 1.06 and therefore this confirms that the 

overall bias has not been met.
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Section D – FREQUENTLY ASKED QUESTIONS:

1. If the EPA Regional Office agrees that data should not be compared to the NAAQS, does that mean we can no longer run the 

site?

No. This only means data are approved as excluded from the NAAQS. A request to no longer run a site per §58.14 is still 

necessary.

 

2. When submitting a request for exclusion of continuous PM2.5 FEM data, does the request have to be part of the annual 

monitoring network plan?

Requests for exclusion of continuous PM2.5 FEM data can be made either as part of the annual monitoring network plan or in a 

separate request to the applicable EPA Regional Office. However, any changes in the monitors supporting the network should 

still be listed in the next and subsequent annual monitoring network plans.

3. If our agency includes a request for exclusion of continuous PM2.5 FEM data as part of the annual monitoring network plan 

and there are other issues in the plan holding up its approval, can the exclusion of continuous PM2.5 FEM data be approved 

without approval of the whole plan?

Yes, the EPA Regional Office may approve the exclusion of certain continuous PM2.5 FEM data without approving the whole 

Annual Monitoring Network plan.

4. Is there a difference in the applicability of this provision to exclude certain data based upon whether the site is required or 

not?

§58.14 requires that “For required SLAMS where the agency identifies that the PM2.5 Class III FEM or ARM does not produce 

data of sufficient quality for comparison to the NAAQS, the monitoring agency must ensure that an operating FRM or other 
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filter-based FEM meeting the sample frequency requirements described in §58.12 or other Class III PM2.5 FEM or ARM with 

data of sufficient quality is operating and reporting data to meet the network design criteria described in appendix D to this 

part”. For other sites that are intended to be part of the SLAMS network, but beyond the minimum monitoring requirements, 

the monitoring agency needs to address moving forward how it will ensure an appropriate method is operating at the station. 

If the monitoring agency is requesting a change to a SLAMS other than provided for in §58.11 (e), (for example, no longer 

operating a site) it must do so in accordance with all other provisions of the monitoring regulations. Saying it another way, 

EPA Regional approval to set aside PM2.5 continuous FEM data for comparison the NAAQS, does not constitute approval to 

shut down a SLAMS. 

5. What if any differences are there between continuous PM2.5 FEM data that should be considered invalid and data that should 

be considered valid but excluded from comparison to the NAAQS per §58.11 (e).

Data that are invalid should be based on some aspect of data validation that has not been met. For example, a flow rate that 

has not met the requirements for a valid flow. Data that may be excluded involve monitors where all the data validation 

procedures appear valid as required by or described in the applicable SOP or QAPP; however, the performance compared to a 

collocated FRM appears to be beyond the acceptable performance criteria described above.

6. In our monitoring program, we previously, changed the hardware of an otherwise approved continuous PM2.5 FEM. Is this 

allowed? How should we address the use of the data?

We advocate maintaining the manufacturer recommended hardware and software configurations and to not break the 

method in any way. The only exception to this should be those cases where the monitoring agency is working to improve their 

method in such a manner such that the method may be eligible for approval as an ARM.

7. Does our agency need to apply for this every year? 
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There is no explicit requirement that the data from a PM2.5 continuous monitor be re-evaluated each year as compared to 

collocated FRMs for purposes of continuing to exclude data as eligible in NAAQS calculations. However, all operating sites, 

monitors, and their objectives and other related information are required to be included in each annual monitoring network 

plan per §58.10. We also believe that it would be appropriate to evaluate and list the statistical performance criteria 

associated with each PM2.5 continuous FEM as aerosol composition can change over time and as the method may be 

improved both in terms of the operations as well as vendor initialed improvements in things like firmware. At a minimum a 

comprehensive examination of the methods used in each network should be evaluated as part of the five year assessments. 

8. If our agency has a site with an operating PM2.5 FRM and collocated continuous FEM and the data are within the performance 

criteria identified in Table C-4 of part 53; however, we still have concerns with using the data from the PM2.5 continuous FEM, 

how do I ensure that only the FRM data are used in a design value calculation?

The requirements of Appendix N to Part 50, provide that a site level design value calculation is made with the primary monitor 

and with the average of all other valid data from approved methods when the primary monitor is not available on a given 

day. Thus, to avoid using PM2.5 continuous FEM data in a design value calculation, the FRM would need to be operated on a 

daily sampling schedule. Note: even in this case valid data from the PM2.5 continuous FEM would be substituted on any day 

that the FRM data were not valid.

9. How should our agency approach a case where after examining the performance of a PM2.5 continuous FEM compared to a 

collocated FRM, we believe our operation of that method was not fully optimized; however, after a certain date, a change in 

the operation of the method was made such that we are now getting acceptable data comparability compared to the 

collocated FRM. 

To the extent that an improvement in the PM2.5 continuous FEM was made, and data before the change does not meet the 

performance criteria, while data after the change indicates that it is does meet the expected performance criteria, a 
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monitoring agency may request that only the data before the change in operation be excluded, so long as all other criteria in 

§58.11 (e) are met.

10. With regard to the question above on excluding data that does not meet the expected performance criteria before a change 

in the method, while data after the change indicates it does, to what extent can the data generated before the change be 

used to support other monitoring objectives.

PM2.5 continuous FEM data that are approved by the EPA Regional Office for exclusion from comparison to the NAAQS as per 

§58.11 (e), may still be used for comparison to the Air Quality Index (AQI), if appropriate, either as is, or if necessary, with a 

data correction.