UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: JAN 4 2011

SUBJECT: Technical Support Document Regarding Ozone Monitoring Data —Pennsylvania;

Clean Data Determination for the Pittsburgh-Beaver Valley 8-Hour Ozone

Nonattainment Area

?41 .-4

P .

FROM: Maria A. Pino, Air Quality Planning Specialist

Office of Air Program Planning

TO: File

THRU: MarilñPbwers, Acting Associate Director

Office’’f Air Program Planning

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

Environmental Protection Agency’s (EPA’s) proposed determination that the Pittsburgh-Beaver

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 is classified as a subpart 1

nonattainment area for the 1997 8-hour ozone NAAQS. See 40 CFR 81.339.

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 CFR 50.10 and appendix I. The determination is based on the most recent three 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 and averaged over the three-year period (the

monitoring site’s ozone design value) must not exceed the ozone standard. The level ofthe 1997

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

convention described in 40 CFR part 50, appendix I, the 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 CFR 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 CFR 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 of 214 monitoring days.

II. Certified Air Quality Monitoring Data, 2007 - 2009

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

data into AQS, and EPA concurred on Pennsylvania’s data. Attached is the AQS report

containing 8-hour ozone data for the Pittsburgh Area for the 2007 to 2009 ozone monitoring

seasons. Table 1, below, summarizes the data found in that report

As shown in Table 1, all 2007-2009 8-hour ozone design values for the Pittsburgh Area are 0.0 84

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 data.

Table 1: 2007-2009 Pittsburgh Area 8-Hour Ozone Design Values & Data Completeness

4th Highest Value Percent Completeness

(ppm) 2007-2009 (valid monitored days I required

DesF’n days)

County Site ID Value 2007-

2007 2008 2009 (ppm) 2007 2008 2009 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 99 100

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

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III. Preliminary Air Quality Monitoring Data, 2010

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 ofthe quarter. For the fourth quarter ofthe

year, October 1 through December 31, states are required to submit data into AQS by the end of

March the following year. Thus, Pennsylvania has until March 2011 to submit ozone monitoring

data for October 2010 into AQS. However, Pennsylvania submitted its October 2010 monitoring

data early. The attached AQS report contains 8-hour ozone data for the Pittsburgh Area for the

entire 2010 ozone monitoring season.

Also according to 40 CFR Part 58, by May 1 of each year, states are required to submit to EPA

an “annual air monitoring data certification letter” to certify that the previous year of ambient

concentration and quality assurance data are completely submitted to AQS and are accurate. For

2010 data, Pennsylvania is required to submit the certification letter by May 1, 2011. Until

Pennsylvania certifies its 2010 data, EPA will consider it “preliminary.”

As shown in Table 2, all preliminary 2008-20 10 8-hour ozone design values for the Pittsburgh

Area are 0.0 84 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, preliminary data indicates that the Pittsburgh Area continues to

meet the 1997 8-hour ozone NAAQS, considering 2008-2010 data.

Table 2: Preliminary 2008-2010 Pittsburgh Area 8-Hour Ozone Design Values & Data

Completeness

County Site ID

4th Highest Value

(ppm)

2008 2009 2010*

Preliminary

2008-20 10

Design

Value (ppm)

Percent Completeness

(valid monitored days / required

days)

2008 2009 2010* 2008-2010

average”

Allegheny 420030008 0.079 0.069 0.080 .

Allegheny 420030010 0.074 0.067 0.074 —

Allegheny 420030067 0.075 0.069 0.078 —

Allegheny 420031005 0.085 0.077 0.083

Armstrong 420050001 0.078 0.071 0.079 —

Beaver 420070002 0.073 0.066 0.075 —

Beaver 420070005 0.075 0.068 0.077 C

Beaver 420070014 0.074 0.068 0.073 0

100 98 96.

97 99 92

99 100 98

100 98 99

100 100 100

97 97 97

95 97 97

Washington 421250005 0.071 0.068 0.072

98

96

96

95

0 070

100 100 86

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 0.069 100 100 98 99

Westmoreland 421290008 0.075 0.065 0.076 0.072 100 97 97 98

99 100 99 99

Note: The asterisk (*) signifies preliminary values.

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Attachments:

- EPA AQS Quick Look Report (AMP45O), dated December 28, 2010, containing 2007- 2009

ozone air quality data for Pittsburgh Area.

- EPA AQS Quick Look Report (AMP45O), dated December 28, 2010, containing preliminary

2010 ozone air quality data for Pittsburgh Area.

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