# UNITED STATES ENVIRONMEN TAL PROTECTION AGENCY

Office of Air Quality Planni ng and Standards (OAQPS)

Research Triangle Park, North Carolina 27711

December 14, 2012

MEMORANDUM

SUBJECT: Evaluation of the PM 2.5 

# 'Collocated PM 10 

# ' Data Substitution Routine,

2009-2011.

FROM: Mark Schmidt, Air Qualit y Analysis Group, OAQPS/OAR /s/

TO: PM NAAQS Review Docket (EPA-HQ-OAR-2007-0492)

This memorandum describes an evaluation of the PM 2.5 

# “collocated PM 10 

# ” data and

“maximum quarterly value” subst itution tests. Specifically, the goal of this analysis is to

quantify the utility of both test s and to determine if both are needed. The most recent design

value period (2009-2011) is us ed for this evaluation.

The EPA proposed both tests for inclusion into 40 CFR Part 50, appendix N, which

contains the codified data handling rules for making comparisons between reported ambient

PM 2.5 

# data and the PM 2.5 

# NAAQS (77 FR 39001 - 39002, June 29, 2012). As proposed, both data

substitution tests were to be us ed for validating “otherwise in complete” annual standard and 24-

hour standard design values that were equal or below their respective NAAQS levels. Both tests

are described in the 1999 PM 2.5 

# data handling guideline (U.S . EPA, 1999) and have been

implemented as standard operating procedur e for EPA design value computations.

In this assessment of 2009-2011 PM 2.5 

# design values which did not meet the nominal data

completeness requirements, the EPA found that collocated PM 10 

# test was almost entirely

# redundant with the maximum quarterly value test and therefore very infrequently needed as a

separate test. The results presented in Table 1 for each of the two PM 2.5 

# standards shows the

number (and percentage) of s ites that passed one, both, or ne ither of the two noted data

substitution tests.

For the annual NAAQS, the maximum quarter valu e test in 100 cases resulted in a test

design value (TDV

max 

# ) less than or equal to 12.0 μg/m 3 

# . There were only two other cases (2

percent) when TDV

max 

# was greater than 12.0 μg/m 3 

# but the TDV associated with the collocated

PM 10 

# test was less than 12.0 μg/m 3 

# . Similarly for the 24-hour NAAQS, the maximum quarter

value test in 116 cases resulte d in a test design value (TDV

max 

# ) less than or equal to 35 μg/m 3



# and again only 2 other sites (less than 2 percent) passed the collocated PM 10 

# test but not the

maximum quarterly value test. Furthermore, th e maximum quarterly value tests allowed the

annual and 24-hour design value to be validated approximately 5 times more often than through

the use of the collocated PM 10 

# test. Accordingly, the EPA has decided to not include the

collocated PM 10 

# data substitution tests in Appendix N, and thereby further simplifying the data

handling procedures for making compar isons to the annual and daily NAAQS.Data substitution for the PM2.5annual standard, 2009-2011 Data substitution for the PM2.524-hour standard, 2009-2011CategoryNumberPercent of total numberof nominallyincomplete sites for theannual standard forwhich the DV wasvalidated with one orboth data substitutiontestsCategoryNumberPercent of total numberof nominallyincomplete sites for the24-hr standard forwhich the DV wasvalidated with one orboth data substitutiontestsNumber of sites with nominally incomplete annual design valuesthat passed the "maximum quarterly value" data substitution test100 98.0%Number of sites with nominally incomplete 24-hour designvalues that passed the "maximum quarterly value" datasubstitution test116 98.3%Number of sites with nominally incomplete annual design valuesthat passed the "collocated PM10" data substitution test21 20.6%Number of sites with nominally incomplete 24-hour designvalues that passed the "collocated PM10" data substitution test26 22.0%Number of sites with nominally incomplete annual design valuesthat passed both data substitution tests19 18.6%Number of sites with nominally incomplete 24-hour designvalues that passed both data substitution tests24 20.3%Number of sites with nominally incomplete annual design valuesthat passed the "maximum quarterly value" data substitution testb t t th " ll t d PM10" d t b tit ti t t8179 4%Number of sites with nominally incomplete 24-hour designvalues that passed the "maximum quarterly value" datasubstitution test but not the "collocated PM10" data substitutiont t9278 0%Table 1. Site counts for 2009-2011 with respect to design values and data substitution testsbut not the"collocatedPM10"data substitution test81 79.4%test92 78.0%Number of sites with nominally incomplete annual design valuesthat passed the "collocated PM10" data substitution test" but notthe "maximum quarterly value" data substitution test2 2.0%Number of sites with nominally incomplete 24-hour designvalues that passed the "collocated PM10" data substitution test"but not the "maximum quarterly value" data substitution test2 1.7%Number of sites with nominally incomplete annual design valuesthat passed either data substitution test102 100.0%Number of sites with nominally incomplete 24-hour designvalues that passed either data substitution test118 100.0%Number100116216a212647b5 a / bNumber of sites with nominally incomplete 24-hour design values that passed the "collocated PM10" data substitution testTotal number of sites that could use the "collocated PM10" data substitution test to validate an otherwise incomplete PM2.5 design valueRatio of: Total number of sites that could use the "maximum quarterly value" data substitution test to validate an otherwise incomplete PM2.5 design value / TotalNumber of sites with nominally incomplete annual design values that passed the "maximum quarterly value" data substitution testCategoryData substitution for the both the PM2.5annual standard and the PM2.5 24-hour standard, 2009-2011Number of sites with nominally incomplete 24-hour design values that passed the "maximum quarterly value" data substitution testTotal number of sites that could use the "maximum quarterly value" data substitution test to validate an otherwise incomplete PM2.5 design valueNumber of sites with nominally incomplete annual design values that passed the "collocated PM10" data substitution test