DATE: 

SUBJECT: 

FROM: 

TO: 

THRU: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION III 

1650 Arch Street 

Philadelphia, Pennsylvania 19103 

NOV 0 7 Z01Z 

Technical Support Document Regarding Ozone Monitoring Data; Pennsylvania; 

Determinations of Attainment of the 1997 8-Hour Ozone Standard for the 

Pittsburgh-Beay_er Valley Moderate Nonattainment Area 

71/~t/ikl JA..-u.r 

Maria A. Pino. Senior Air Quality Planning Specialist 

Office of Air Program Planning 

File (\ 

Office 

Donna 

of 

Mastro, 

Air Program 

Acting 

Planning 

Associate Directol ~ ~ 

This document provides a technical review of the air quality monitoring data used to support the 

proposed determination by the Environmental Protection Agency (EPA) that the PittsburghBeaver Valley 8-hour ozone nonattainment area (the Pittsburgh Area) has attained the 1997 

ozone national ambient air quality standard (NAAQS). 

A. BACKGROUND 

The Pittsburgh Area includes Allegheny, Armstrong, Beaver, Butler, Fayette, Washington, and 

Westmoreland Counties in Pennsylvania. The Pittsburgh Area was originally classified under 

the more general subpart 1 nonattainment provisions of the Clean Air Act (CAA) for the 1997 8-

hour ozone NAAQS. However, on April27, 2012, EPA finalized revisions to the 2004 Phase 1 

Implemeptation Rule for the 1997 8-hour ozone NAAQS that specified requirements to meet the 

1997 ozone NAAQS. The revisions to the Phase 1 Implementation Rule are EPA's response to a 

December 22, 2006 decision by the United States Court of Appeals for the District of Columbia 

Circuit. See South Coast Air Quality Management Dist. v. EPA, 472 F.3d 882 (D.C. Cir. 2006). 

As a result of that rulemaking action, classifications for 16 ozone nonattainment areas originally 

classified under subpart 1 for the 1997 ozone NAAQS, including the Pittsburgh Area, were 

revised under subpart 2. The Pittsburgh Area was reclassified as a moderate nonattainment area 

for the 1997 ozone NAAQS. (77 FR 28424, May 14, 2012). The moderate area attainment data 

was June 15, 2010. 
B. EVALUATION OF AIR QUALITY MONITORING DATA 

I. Data Requirements 

The criteria for determining if an area is attaining the 1997 8-hour ozone NAAQS are set out in 

40 CPR 50.10 and appendix I. The determination is based on the three most recent, complete, 

consecutive calendar years of quality assured air quality monitoring data at all ozone monitoring 

sites in the area. To attain this standard, the annual fourth-high daily maximum 8-hour ozone 

concentrations measured at each monitor averaged over the three-year period (the monitoring 

site's ozone design value) must not exceed the ozone standard. The level of the 1997 8-hour 

NAAQS for ozone is 0.08 parts per million (ppm). Based on an ozone data rounding convention 

described in 40 CPR part 50, appendix I, the 1997 8-hour standard is met if ozone design value is 

0.084 ppm (84 ppb) or lower. When the design value is less than or equal to 0.084 ppm at each 

monitoring site within the area, the area meets the NAAQS. 

The data must be collected and quality-assured in accordance with 40 CPR part 58, and must be 

recorded in EPA's Air Quality System (AQS). The data supporting attainment ofthe standard 

must be complete in accordance with•40 CPR part 50, appendix I. The data completeness 

requirement is met when the average percent of days with valid ambient monitoring data is 

greater than 90%, and no single year has less than 75% data completeness. 

For the Pittsburgh Area, the ozone season extends from the beginning of April through the end of 

October. A complete ozone season consists of214 monitoring days. 

II. Certified Air Quality Monitoring Data, 2007- 2011 

EPA has determined that the ozone monitoring network for the Pittsburgh Area is adequate. 1 

First, the number of monitors in the Pittsburgh Area meets the minimum regulatory requirements 

given in 40 CPR part 58, appendix D, section 4.1. Second, the monitoring network in place is in 

accordance with Pennsylvania's most recent annual monitoring network plan approved by EPA, 

as required by 40 CPR 58.10. During the 2007-2009,2008-2010, and 2009-2011 monitoring 

periods, the Pittsburgh Area had in place a total of 13 ozone monitoring sites whose data was 

eligible for comparison to the 1997 8-hour ozone NAAQS. 

The Commonwealth of Pennsylvania submitted complete, quality assured air quality monitoring 

data into AQS, and EPA concurred on Pennsylvania's data. Attached are AQS reports 

containing 8-hour ozone data for the Pittsburgh Area for the 2007 to 2011 ozone monitoring 

seasons. Tables 1, 2, and 3, below, summarizes the data found in those reports. 

1 EPA approved the Commonwealth of Pennsylvania's August 4, 2011 annual ambient monitoring netWork plan in a 

December 6, 2011 letter from Shawn M. Garvin, Regional Administrator of EPA Region ill, to Michael L. Krancer, 

Secretary of the Pennsylvania Department of Environmental Protection. 

2 
T a bl e 1 : 2007 -2009 P"tt • s b ureu I A 8 H rea - our 0 zone Desagn " VI a ues &DtC a a omp1I e t eness 

4th Highest Value Percent Completeness (ppm) 2007-2009 (valid monitored days/required days) 

County Site ID Design 

Value 

2007 2008 2009 (ppm) 2007 2008 2009 2007-2009 

average 

Allegheny 420030008 0.083 0.079 0.069 0.077 99 100 98 99 

Allegheny 420030010 0.081 0.074 0.067 0.074 100 97 99 99 

Allegheny 420030067 0.077 0.075 0.069 0.073 94 99 100 98 

Allegheny 420031005 0.086 0.085 0.077 0.082 94 100 98 97 

Armstrong 420050001 0.083 0.078 0.071 0.077 100 100 100 100 

Beaver 420070002 0.080 0.073 0.066 0.073 96 97 97 97 

Beaver 420070005 0.072 0.075 0.068 0.071 99 95 97 97 

Beaver 420070014 0.077 0.074 0.068 0.073 100 100 100 100 

Washington 421250005 0.077 0.071 0.068 0.072 99 99 100 99 

Washington 421250200 0.073 0.069 0.063 0.068 100 100 99 roo 

Washington 421255001 0.075 0.077 0.065 0.072 100 89 97 95 

Westmoreland 421290006 0.079 0.072 0.064 0.071 100 100 100 100 

Westmoreland 421290008 0.077 0.075 0.065 0.072 99 100 97 99 

T a bl e 2 : 2008 -2010 p· atts b I A 8 H ureh rea - our 0 zone D . esien VI a ues &D ata C om pJ eteness 

4th Highest Value Percent Completeness (ppm) 2008-2010 (valid monitored days I required days) 

Design County Site ID Value 

2008 2009 2010 (ppm) 2008 2009 2010 2008-2010 

average 

Allegheny 420030008 0.079 0.069 0.080 0.076 100 98 96 98 

Allegheny 420030010 0.074 0.067 0.074 0.071 97 99 92 96 

Allegheny 420030067 0.075 0.069 0.078 0.074 99 100 98 99 

Allegheny 420031005 0.085 0.077 0.083 0.08 1 100 98 99 99 

Armstrong 420050001 0.078 0.071 0.079 0.076 100 100 100 100 

Beaver 420070002 0.073 0.066 0.075 0.07 1 97 97 97 97 

Beaver 420070005 0.075 0.068 0.077 0.073 95 97 97 96 

Beaver 420070014 0.074 0.068 0.073 0.071 100 100 86 95 

Washington 421250005 0.071 0.068 0.072 0.070 99 100 99 99 

Washington 421250200 0.069 0.063 0.073 0.068 100 99 99 99 

Washington 421255001 0.077 0.065 0.071 0.071 89 97 97 94 

; Westmoreland 421290006 0.072 0.064 0.070 0.0.68 100 100 98 99 

Westmoreland 421290008 0.075 0.065 0.076 0.072 100 97 97 98 

3 
T a e bl 3 2009 2011 p· b I A 8 H 0 . . - Itts urg11 rea - our zone D' es1gn VI a ues &DtC a a omp1e I t eness 

I 4th Highest Value 

2009-2011 Percent Completeness (ppm) 

County Site ID Design (valid monitored days I required days) 

Value 

2009 2010 2011 (ppm) 2009 2010 2011 2009-2011 

average 

Allegheny 420030008 0.069 0.080 0.074 0.074 98 96 100 

Allegheny 420030010 0.067 0.074 0.074 0.071 99 92 93 

Allegheny 420030067 0.069 0.078 0.078 0.075 100 98 100 

Allegheny 420031005 0.077 0.083 0.080 0.080 98 99 100 

Armstrong 420050001 0.071 0.079 0.069 0.073 100 100 100 

Beaver 420070002 0.066 0.075 0.068 0.069 97 97 98 

Beaver 420070005 0.068 0.077 0.071 0.072 97 . 97 99 

Beaver 420070014 0.068 0.073 0.072 0.071 100 86 97 

Washington 421250005 0.068 0.072 0.068 0.069 100 99 99 

Washington 421250200 0.063 0.073 0.069 0.068 99 99 99 

Washington 421255001 0.065 0.071 0.071 0.069 97 97 95 

Westmoreland 421290006 0.064 0.070 0.072 0.068 100 98 100 

Westmoreland 421290008 0.065 0.076 0.068 0.069 97 97 100 

As shown in Tables 1, 2, and 3, above, al12007-2009, 2008-2010, and 2009-2011 8-hour ozone 

design values for the Pittsburgh Area are 0.084 ppm or less. In addition, all monitors meet the 

completeness requirements of an average percent of days with valid ambient monitoring data 

greater than 90%, and no single year has less than 75%. Therefore, the Pittsburgh Area meets 

the 1997 8-hour ozone NAAQS, considering 2007-2009,2008-2010, and 2009-2011 data. 

III. Preliminary Air Quality Monitoring Data, 2012 

Preliminary 2012 data reviewed by EPA is consistent with continued attainment. According to 

40 CFR Part 58, states are required to submit air quality monitoring data for each calendar 

quarter no later than 90 days after the end of the quarter. States are required to certify that data 

for a given year is quality assured and accurate by May 1 of the following year. Therefore, 

Pennsylvania has until May 1, 2013 to certify data for the 2012 ozone season. 

Attachments: 

98 

95 

99 

99 

100 

97 

98 

94 

99 

99 

96 

99 

98 

- EPA AQS Quick Look Report (AMP450), Report Request ID: 820199, dated December 28, 

2010, containing 2007- 2009 ozone air quality data for Pittsburgh Area. 

- EPA AQS Quick Look Report (AMP450), Report Request ID: 990457, dated May 8, 2012, 

containing 2009-2011 ozone air quality data for Pittsburgh Area. 

4