1 

DATE: 25 August 2015 

SUBJECT: Technical Support Document Regarding Ozone Monitoring Data – Determinations 

of Attainment, 1-Year Attainment Date Extensions, and Reclassifications for Marginal Areas 

under the 2008 8-Hour Ozone National Ambient Air Quality Standard (NAAQS)

FROM: Butch Stackhouse, Environmental Protection Specialist 

H. Lynn Dail, Environmental Scientist 

Robert Lingard, Environmental Protection Specialist

TO: Air and Radiation Docket 

THRU: Scott Mathias, Associate Director 

Air Quality Policy Division 

Megan Brachtl, Group Leader 

State and Local Programs Group 

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

Environmental Protection Agency’s (EPA) proposed determinations of attainment or failure to 

attain by the statutory attainment date of July 20, 2015 for the Marginal ozone NAAQS 

nonattainment areas, designated May 21, 2012 (77 FR 30088) and identified in List 1, “2008 

Ozone Marginal Nonattainment Areas.” The TSD also provides the air quality monitoring data 

and state certifications that support determinations that certain areas qualify for a 1-year 

extension of their attainment date. 

List 1: 2008 Ozone NAAQS Marginal Nonattainment Areas 

Atlanta, GA 

Allentown-Bethlehem-Easton, PA 

Baton Rouge, LA 

Calaveras County, CA 

Charlotte-Gastonia-Rock Hill, ND-SC1

Chicago-Naperville, IL-IN-WI 

Chico (Butte County), CA 

Cincinnati, OH-KY-IN 

Cleveland-Lorain, OH 

Columbus, OH 

Denver-Boulder-Greeley-Fort Collins-Loveland, CO 

Dukes County, MA 

Greater Connecticut, CT 

Houston-Galveston-Brazoria, TX 

 

1

 On July 28, 2015, the EPA redesignated the North Carolina portion of the Charlotte-Rock Hill, NC-SC 

nonattainment area for 2008 8-hr Ozone, effective August 27, 2015. See 80 FR 44873. 
2 

Imperial County, CA 

Jamestown, NY 

Kern County (Eastern Kern), CA 

Knoxville, TN2

Lancaster, PA 

Mariposa County, CA 

Memphis, TN-MS-AR 

Nevada County (Western part), CA 

New York-N. New Jersey-Long Island, NY-NJ-CT 

Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE 

Phoenix-Mesa, AZ 

Pittsburg-Beaver Valley, PA 

Reading, PA 

San Diego County, CA 

San Francisco Bay Area, CA 

San Luis Obispo County (Eastern San Luis Obispo), CA 

Seaford, DE 

Sheboygan, WI 

St. Louis-St., Charles-Farmington, MO-IL 

Tuscan Buttes, CA 

Upper Green River Basin, WY 

Washington, DC-MD-VA 

I. BACKGROUND 

On May 21, 2012 (77 FR 30088) and June 11, 2012 (77 FR 34221), EPA designated as 

nonattainment any area that was violating the 2008 8-hour ozone NAAQS based on the three 

most recent years (2008–2010) of air monitoring data. There are 36 areas identified above that 

were classified as Marginal nonattainment areas under the 2008 ozone NAAQS. Marginal areas 

are required to attain the 2008 ozone NAAQS no later than July 20, 2015. See 40 CFR 51.1103. 

Partial counties are identified with “(P)” in the area county listings below. 

The Allentown-Bethlehem-Easton 8-hour ozone nonattainment area is located in Eastern 

Pennsylvania and consists of Carbon, Lehigh and Northampton Counties. The Atlanta 8-hour 

ozone nonattainment area is located in Northern Georgia and consists of Bartow, Cherokee, 

Clayton, Cobb, Coweta, Dekalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Newton, 

Paulding and Rockdale Counties. 

The Baton Rouge 8-hour ozone nonattainment area is located in South Central Louisiana and 

consists of Ascension, East Baton Rouge, Iberville, Livingston and West Baton Rouge Parishes. 

The Calaveras County, California 8-hour ozone nonattainment area is located in Central 

California, west of the City of Stockton and consists of Calaveras County. The Charlotte-Rock 

 

2

 On July 13, 2015, the EPA redesignated to attainment the Knoxville, TN nonattainment area for 2008 8-hr Ozone, 

effective August 12, 2015. See 80 FR 39970. 
3 

Hill, North Carolina 8-hour ozone nonattainment area is located in southwestern North Carolina 

on the border with South Carolina and consists of Cabarrus (P), Gaston (P), Iredell (P), Lincoln 

(P), Mecklenburg, Rowan (P), and Union (P) Counties in North Carolina and consists of York 

County in South Carolina. The Chicago-Naperville 8-hour ozone nonattainment area 

encompasses three states consisting of Northeastern Illinois, Northwestern Indiana and 

Southeastern Wisconsin and consists of Cook, Du Page, Grundy (P), Kane, Kendall (P), Lake, 

McHenry and Will Counties in Illinois, Lake and Porter Counties in Indiana and Kenosha 

County (P) in Wisconsin. The Chico (Butte County) 8-hour nonattainment area is located in 

North Central California and consists of Butte County. The Cincinnati 8-hour nonattainment 

area encompasses three bordering states at Southeastern Indiana, Northern Kentucky and 

Southwestern Ohio, and consists of Dearborn County (P) in Indiana, Boone (P), Campbell (P) 

and Kenton (P) Counties in Kentucky, Butler, Clermont, Clinton, Hamilton and Warren Counties 

in Ohio. The Cleveland-Akron-Lorain 8-hour ozone nonattainment area is located in North 

Central Ohio on Lake Erie and consists of Ashtabula, Cuyahoga, Geauga, Lake, Lorain, Medina, 

Portage and Summit Counties. The Columbus 8-hour ozone nonattainment area is located in 

Southwestern Ohio and consists of Delaware, Fairfield, Franklin, Knox, Licking and Madison 

Counties. 

The Denver-Boulder-Greeley-Ft. Collins-Loveland 8-hour ozone nonattainment area is located in 

Central Colorado and consists of Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, 

Jefferson, Larimer (P) and Weld (P) Counties. The Dukes County 8-hour ozone nonattainment 

area is an island located offshore of Eastern Massachusetts. 

The Greater Connecticut 8-hour ozone nonattainment area encompasses a majority of 

Connecticut and consists of Hartford, Litchfield, New London, Tolland and Windham Counties. 

The Houston-Galveston-Brazoria 8-hour ozone nonattainment area is located in Eastern Texas 

and consists of Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery and 

Waller Counties. 

The Imperial County 8-hour ozone nonattainment area is located in Southern California and is 

limited to Imperial County. The Jamestown 8-hour ozone nonattainment area is located in 

Western New York and is limited to Chautauqua County. 

The Kern County 8-hour ozone nonattainment area is located in Southern California, north of 

Los Angeles and is limited to Kern County (P). The Knoxville 8-hour ozone nonattainment area 

is located in Eastern Tennessee and consists of Anderson (P), Blount and Knox Counties. 

The Lancaster 8-hour ozone nonattainment area is located in Eastern Pennsylvania and is limited 

to Lancaster County. 

The Mariposa County 8-hour ozone nonattainment area is located in Central California and is 

limited to Mariposa County. The Memphis 8-hour ozone nonattainment area encompasses 

Eastern Arkansas, Northern Mississippi and Western Tennessee, and consists of Crittenden 

County in Arkansas, De Soto County (P) in Mississippi and Shelby County in Tennessee. 
4 

The Nevada County 8-hour ozone nonattainment area is located in Central California and is 

limited to Nevada County (P). The New York-N. New Jersey-Long Island 8-hour ozone 

nonattainment area encompasses Connecticut, New Jersey and New York and consists of 

Fairfield, Middlesex and New Haven Counties in Connecticut, Bergen, Essex, Hudson, 

Hunterdon, Middlesex, Monmouth, Morris, Passaic, Somerset, Sussex, Union and Warren 

Counties in New Jersey and in New York consists of Bronx, Kings, Nassau, New York, Queens, 

Richmond, Rockland, Suffolk and Westchester Counties. 

The Philadelphia-Wilmington-Atlantic City 8-hour ozone nonattainment area encompasses 

Delaware, Maryland, New Jersey and Pennsylvania and consists of New Castle County in 

Delaware, Cecil County in Maryland, Atlantic, Burlington, Camden, Cape May, Cumberland, 

Gloucester, Mercer, Ocean and Salem Counties in New Jersey and in Pennsylvania consists of 

Bucks, Chester, Delaware, Montgomery and Philadelphia Counties. The Phoenix Mesa 8-hour 

ozone nonattainment area is located in South Central Arizona and consists of Maricopa (P) and 

Pinal (P) Counties. The Pittsburgh-Beaver Valley 8-hour ozone nonattainment area is located in 

Western Pennsylvania and consists of Allegheny, Armstrong, Beaver, Butler, Fayette, 

Washington and Westmoreland Counties. 

The Reading 8-hour ozone nonattainment area is located in and limited to Berks County, 

Pennsylvania. 

The San Diego County 8-hour ozone nonattainment area is located in Southern California and 

consists of San Diego County (P). The San Francisco Bay Area 8-hour ozone nonattainment 

area is located on the West Central Shore of California and consists of Alameda, Contra Costa, 

Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano (P) and Sonoma (P) Counties. The 

San Luis Obispo 8-hour ozone nonattainment area is located in the Eastern part of San Luis 

Obispo, California. The Sheboygan 8-hour ozone nonattainment area is located in Eastern 

Wisconsin on the Lake Michigan shore and is limited to Sheboygan County. The St. Louis-St. 

Charles-Farmington 8-hour ozone nonattainment area encompasses Illinois and Missouri and 

consists of Madison, Monroe and St. Clair Counties in Illinois and in Missouri consists of 

Franklin, Jefferson, St. Charles and St. Louis Counties and St. Louis City in Missouri. 

The Tuscan Buttes 8-hour ozone nonattainment area is located in California and consists of part 

of Tehama County (P). 

The Upper Green River Basin 8-hour ozone nonattainment area in Southwestern Wyoming and 

consists of Lincoln, Sublette and Sweetwater (P) Counties. 

The Washington, DC-MD-VA 8-hour ozone nonattainment area encompasses the District of 

Columbia, Southern Maryland and Northern Virginia and consists of the entire district of the 

District of Columbia, the counties of Calvert, Charles, Frederick, Montgomery and Prince 

George’s in Maryland, and in Virginia consists of Alexandria, Arlington County, Fairfax, Fairfax 

County, Falls Church, Loudoun County, Manassas, Manassas Park and Prince William Counties. 

The individual state maps with the boundaries and counties included in each nonattainment area 

are available from the EPA’s Green Book website at 
5 

http://www.epa.gov/oar/oaqps/greenbk/hnmapa.html. The maps are available for downloading at 

http://www.epa.gov/oar/oaqps/greenbk/map_download.html. The list of counties in each of the 

Marginal nonattainment areas is available at http://www.epa.gov/oar/oaqps/greenbk/hnc.html. 

For the exact boundaries of the 2008 8-hour ozone nonattainment areas classified as Marginal 

which are the subject of this document, refer to the applicable table entitled “2008 8-Hour Ozone 

NAAQS (Primary and secondary)” for the particular state in 40 CFR Part 81, Subpart C—

Section 107 Attainment Status Designations. 

II. EVALUATION OF AIR QUALITY MONITORING DATA 

A. Data Requirements 

The criteria for determining if an area is attaining the 2008 ozone NAAQS are set out in 40 CFR 

50.15 and appendix P to 40 CFR part 50. The determination is based on the most recent three 

consecutive calendar years of complete, quality-assured air quality monitoring data at all 

regulatory ozone monitoring sites in the area. To attain this standard, at each regulatory monitor 

the annual fourth-highest daily maximum 8-hour average ozone concentrations averaged over the 

three-year period (the ozone design value, or “DV”) must not exceed the ozone standard. The 

level of the 2008 NAAQS for ozone is 0.075 parts per million (ppm). Based on an ozone data 

rounding convention described in 40 CFR part 50, appendix P, the standard is met if the DV is 

0.075 ppm (equivalent to 75 parts per billion) or lower. When the DV is less than or equal to 

0.075 ppm at each monitoring site within the area, the area attains the NAAQS. 

The data must be collected and quality-assured in accordance with 40 CFR part 58. The data 

supporting attainment of the standard must be complete in accordance with 40 CFR part 50, 

appendix P. The data completeness requirement is met when at least 90% of days in the required 

ozone monitoring season (see Appendix D to 40 CFR 58) have valid ambient monitoring data, 

averaged over three years, and no single year has less than 75% data completeness. For example, 

the ozone season for the Washington, DC-MD-VA nonattainment area extends from the 

beginning of April through the end of October, thus the complete ozone season for this area 

consists of 214 monitoring days and the 75% annual data completeness requirement is met with 

at least 160 days of valid ambient monitoring data during this area’s annual ozone season. 

State and local monitoring network plans are subject to approval by EPA on an annual basis, and 

any interim modifications to those plans must also be approved by EPA. The annual monitoring 

network plan process is provided in 40 CFR 58.10 and the requirements governing system 

modifications and discontinuations are laid out in 40 CFR 58.14. Where state or local agencies 

seek to modify the ambient air quality monitoring networks by discontinuing a monitor station, 

the EPA may approve such modifications subject to the criteria established in 40 CFR 58.14(c). 

EPA may not approve such discontinuation if doing so would compromise data collection 

needed for implementation of a NAAQS. If a monitor has been discontinued subject to 40 CFR 

58.14 such that the discontinuation results in insufficient data to calculate a valid design value 

according to Appendix P to 40 CFR Part 50, EPA will determine the applicable area’s attainment 

status based on the remaining monitors in the area.

 
6 

B. Certified Air Quality Monitoring Data, 2012-2014

The 2008 ozone NAAQS nonattainment areas identified in List 1 above submitted quality 

assured air quality monitoring data to the EPA’s Air Quality System (AQS) for calendar years 

2012, 2013, and 2014. The states then certified that data with a data certification letter sent to the

applicable EPA Regional Administrator. A monitor level summary report from the AQS of the 8-

hour ozone data for the 36 areas is provided in “Exhibit 1: 2008 Designated Marginal 

Nonattainment Areas for 2008 8-Hour Ozone NAAQS 2012-2014 Design Values & Data 

Completeness” located in the Appendix to this document.

III. Data Analysis and Determinations of Attainment

The 2008 nonattainment areas identified in List 1 above were classified as Marginal for the 2008 

8-hour ozone NAAQS. Because these areas were classified as Marginal ozone nonattainment 

areas, the statutory ozone attainment date, as prescribed by section 181(a) of the Clean Air Act 

(CAA) and as implemented by 40 CFR 51.1103, is July 20, 2015. (See 80 FR 12264 at 12313, 

March 6, 2015). 

A. EPA’s Determinations of Attainment for Nonattainment Areas that have Attained the 

2008 Ozone NAAQS by the Applicable Attainment Date 

The EPA is proposing to determine, in accordance with section 181(b)(2)(A) of the CAA and the 

provisions of the EPA’s SIP Requirements Rule for the 2008 ozone NAAQS (see 40 CFR 

51.1103), that 17 of 36 Marginal nonattainment areas have attained the 2008 ozone NAAQS by 

the applicable deadline for that standard, which is July 20, 2015. This proposed determination is 

based upon three years of complete, quality-assured and certified 2012-2014 data, in accordance 

with 40 CFR part 58 and recorded in EPA’s AQS database.3

Table 1 lists all 17 Marginal areas for which EPA is proposing a determination of attainment by 

the July 20, 2015 attainment date. Table 1 provides the 2012-2014 design values and data 

completeness status for the monitors in each of the 17 areas that were operating during the period 

2012-2014. The data included meets the data completeness requirements of Appendix P, except 

where otherwise noted. Table 1 also shows the annual fourth highest daily maximum, DV, 

percent of days per year with valid ambient monitoring data, and the average percent of days 

with valid ambient monitoring data. 

 

3

 Some areas attained the standard with 2011, 2012 and 2013 data and maintained the standard in 2014. 
7 

Table 1 - Marginal 2008 8-Hour Ozone NAAQS Nonattainment Areas Qualifying for a Determination of Attainment by 

2015 Attainment Date 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr 

Average Value 2012- 2014 

Design 

Value 

(ppm)(1) 

Percent Complete 

2012 2013 2014 2012 2013 2014 

Allentown-Bethlehem-Easton, PA 

420958000 Northampton Pennsylvania 0.073 0.064 0.066 0.067 98 83 90 420770004 Lehigh Pennsylvania 0.075 0.068 0.068 0.070 96 100 96 420950025 Northampton Pennsylvania 0.073 0.065 0.067 0.068 99 81 98 

Baton Rouge, LA 

220470009 Iberville Louisiana 0.074 0.061 0.061 0.065 98 100 98 221210001 

West Baton Rouge Louisiana 0.070 0.060 0.066 0.065 97 100 100 

220330013 East Baton Rouge Louisiana 0.070 0.062 0.068 0.066 93 99 96 220050004 Ascension Louisiana 0.071 0.062 0.069 0.067 98 99 98 220330009 East Baton Rouge Louisiana 0.072 0.066 0.070 0.069 98 100 99 220470012 Iberville Louisiana 0.073 0.068 0.068 0.069 97 98 96 220630002 Livingston Louisiana 0.071 0.069 0.073 0.071 98 100 100 220330003 East Baton Rouge Louisiana 0.075 0.067 0.075 0.072 97 98 97 

Calaveras County, CA 

060090001 Calaveras California 0.076 0.067 0.071 0.071 98 99 98 

Charlotte-Gastonia-Rock Hill, NC-SC 

371191005 Mecklenburg 

North Carolina 0.073 0.062 0.063 0.066 99 100 100 
8 

Table 1 - Marginal 2008 8-Hour Ozone NAAQS Nonattainment Areas Qualifying for a Determination of Attainment by 

2015 Attainment Date 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr 

Average Value 2012- 2014 

Design 

Value 

(ppm)(1) 

Percent Complete 

2012 2013 2014 2012 2013 2014 

371090004 Lincoln 

North Carolina 0.076 0.064 0.064 0.068 100 100 97 

371590021 Rowan 

North Carolina 0.080 0.062 0.064 0.068 100 98 100 

371790003 Union 

North Carolina 0.075 0.062 0.067 0.068 100 94 100 

371190041 Mecklenburg 

North Carolina 0.080 0.067 0.065 0.070 99 99 100 

371191009 Mecklenburg 

North Carolina 0.085 0.066 0.068 0.073 100 100 98 

371590022 Rowan 

North Carolina 0.077 0.063 (2) 98 99 

Chico (Butte County), CA 

060070008 Butte California 0.065 0.062 0.066 0.064 96 99 98 060070007 Butte California 0.078 0.071 0.074 0.074 97 96 99 

Cincinnati, OH-KY-IN 

210150003 Boone Kentucky 0.074 0.059 0.062 0.065 100 100 100 391650007 Warren Ohio 0.080 0.067 0.071 0.072 100 99 100 390170004 Butler Ohio 0.083 0.068 0.070 0.073 100 98 99 390170018 Butler Ohio 0.084 0.068 0.069 0.073 95 100 99 390271002 Clinton Ohio 0.086 0.064 0.070 0.073 100 99 99 390610010 Hamilton Ohio 0.083 0.064 0.073 0.073 87 97 100 390610040 Hamilton Ohio 0.082 0.069 0.069 0.073 100 99 100 
9 

Table 1 - Marginal 2008 8-Hour Ozone NAAQS Nonattainment Areas Qualifying for a Determination of Attainment by 

2015 Attainment Date 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr 

Average Value 2012- 2014 

Design 

Value 

(ppm)(1) 

Percent Complete 

2012 2013 2014 2012 2013 2014 

390179991 Butler Ohio 0.085 0.069 0.069 0.074 93 94 94 210373002 Campbell Kentucky 0.084 0.072 0.071 0.075 99 100 99 390250022 Clermont Ohio 0.091 0.066 0.068 0.075 100 100 98 390610006 Hamilton Ohio 0.087 0.069 0.070 0.075 96 95 96 

Columbus, OH 

390490081 Franklin Ohio 0.076 0.065 0.068 0.069 100 99 100 390830002 Knox Ohio 0.074 0.067 0.066 0.069 100 100 100 390890005 Licking Ohio 0.077 0.065 0.066 0.069 99 100 100 390410002 Delaware Ohio 0.077 0.070 0.066 0.071 99 98 100 390970007 Madison Ohio 0.078 0.066 0.069 0.071 100 99 95 390490037 Franklin Ohio 0.081 0.070 0.069 0.073 98 100 100 390490029 Franklin Ohio 0.082 0.073 0.070 0.075 99 100 100 

Dukes County, MA 

250070001 Dukes Massachusetts 0.082 0.065 0.059 0.068 97 97 95 

Jamestown, NY 

360130006 Chautauqua New York 0.081 0.066 0.066 0.071 97 95 97 360130011 Chautauqua New York 0.081 (3) 94 

Knoxville, TN 

470090102 Blount Tennessee 0.064 0.059 0.058 0.060 99 100 99 470930021 Knox Tennessee 0.073 0.057 0.060 0.063 99 98 98 
10 

Table 1 - Marginal 2008 8-Hour Ozone NAAQS Nonattainment Areas Qualifying for a Determination of Attainment by 

2015 Attainment Date 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr 

Average Value 2012- 2014 

Design 

Value 

(ppm)(1) 

Percent Complete 

2012 2013 2014 2012 2013 2014 

470090101 Blount Tennessee 0.075 0.064 0.064 0.067 97 98 99 470931020 Knox Tennessee 0.078 0.061 0.063 0.067 100 96 98 

Lancaster, PA 

420710012 Lancaster Pennsylvania 0.079 0.063 0.063 0.068 99 100 100 420710007 Lancaster Pennsylvania 0.081 0.066 0.066 0.071 100 99 100 

Memphis, TN-MS-AR 

280330002 DeSoto Mississippi 0.075 0.065 0.067 0.069 98 100 99 471571004 Shelby Tennessee 0.084 0.063 0.065 0.070 88 98 100 050350005 Crittenden Arkansas 0.079 0.067 0.067 0.071 99 99 99 471570021 Shelby Tennessee 0.083 0.069 0.067 0.073 100 98 100 471570075 Shelby Tennessee 0.086 0.069 0.066 0.073 99 100 98 

Reading, PA 

420110006 Berks Pennsylvania 0.075 0.061 0.063 0.066 99 100 95 420110011 Berks Pennsylvania 0.078 0.068 0.068 0.071 98 99 98 

San Francisco Bay Area, CA 

060010009 Alameda California 0.040 0.046 0.057 0.047 95 98 98 060010011 Alameda California 0.046 0.045 0.051 0.047 96 95 98 060750005 San Francisco California 0.047 0.043 0.052 0.047 95 97 97 060131004 Contra Costa California 0.049 0.052 0.055 0.052 98 98 98 060410001 Marin California 0.049 0.057 0.064 0.056 98 98 98 
11 

Table 1 - Marginal 2008 8-Hour Ozone NAAQS Nonattainment Areas Qualifying for a Determination of Attainment by 

2015 Attainment Date 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr 

Average Value 2012- 2014 

Design 

Value 

(ppm)(1) 

Percent Complete 

2012 2013 2014 2012 2013 2014 

060811001 San Mateo California 0.050 0.056 0.064 0.056 97 97 98 060550003 Napa California 0.058 0.055 0.062 0.058 97 97 98 060950004 Solano California 0.056 0.055 0.064 0.058 96 99 97 060850005 Santa Clara California 0.057 0.060 0.065 0.060 95 94 96 060012001 Alameda California 0.052 0.059 0.072 0.061 100 100 100 060950005 Solano California 0.067 0.061 0.063 0.063 98 99 96 060130002 Contra Costa California 0.070 0.057 0.067 0.064 98 98 98 060851001 Santa Clara California 0.063 0.062 0.069 0.064 98 100 100 060850002 Santa Clara California 0.066 0.063 0.071 0.066 94 99 99 060131002 Contra Costa California 0.072 0.062 0.069 0.067 99 76 96 060132007 Contra Costa California 0.065 0.065 0.072 0.067 98 98 98 060852006 Santa Clara California 0.070 0.067 0.073 0.070 100 100 100 060010007 Alameda California 0.071 0.069 0.076 0.072 98 98 99 060852009 Santa Clara California 0.061 0.063 (4) 99 93 060970003 Sonoma California 0.042 0.055 (4) 98 95 060970004 Sonoma California 0.054 (5) 95 

Seaford, DE 

100051002 Sussex Delaware 0.084 0.065 0.063 0.070 100 93 100 100051003 Sussex Delaware 0.085 0.072 0.067 0.074 92 97 97 

Tuscan Buttes, CA 

061030004 Tehama California 0.077 0.072 0.076 0.075 100 98 98 
12 

Table 1 - Marginal 2008 8-Hour Ozone NAAQS Nonattainment Areas Qualifying for a Determination of Attainment by 

2015 Attainment Date 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr 

Average Value 2012- 2014 

Design 

Value 

(ppm)(1) 

Percent Complete 

2012 2013 2014 2012 2013 2014 

Upper Green River Basin, WY 

560350101 Sublette Wyoming 0.067 0.061 0.057 0.061 100 98 94 560350099 Sublette Wyoming 0.065 0.061 0.060 0.062 93 97 94 560350700 Sublette Wyoming 0.065 0.064 0.060 0.063 94 98 96 560350100 Sublette Wyoming 0.067 0.063 0.062 0.064 100 98 97 560351002 Sublette Wyoming 0.066 0.064 0.062 0.064 100 100 98 560350097 Sublette Wyoming 0.066 0.059 (6) 97 98 560359991 Sublette Wyoming 0.066 0.066 0.062 (7) 74 91 91 

(1) The level of the 2008 8-hour ozone NAAQS is 0.075 parts per million (ppm). The design value is the 3-y

annual fourth highest daily maximum 8-hour average ozone concentration. Each area’s design value is de

highest design value among monitors with valid design values. The design values shown here are comput

Reference Method or equivalent data reported by State, Tribal, and Local monitoring agencies to EPA's A(AQS) as of July 20, 2015. Individual 8-hour concentrations that were flagged by state, tribal, or local mo

having been affected by an exceptional event (e.g., wildfire, volcanic eruption) and received concurrence EPA Regional Office are not included in these calculations. 

(2) Monitor shut down prior to the end of the 2014 ozone monitoring season and did not collect sufficient da

2012-2014 design value. Monitor previously attained the NAAQS based on 2011-2013 data. The monitoapproved by EPA through the annual monitoring network plan review process (see 40 CFR 58.10). 

(3) Monitor shut down on 1/1/2013 and did not collect sufficient data to calculate a valid 2012-2014 design v

DV for the monitor recorded a violation in 2010-2012 (0.076 ppm), but the remaining site in the nonattainhad the highest DV in the area. The monitor shut down was approved by EPA through the annual monito

review process (see 40 CFR 58.10). 
13 

(4) Monitor shut down prior to the end of the 2014 ozone monitoring season and did not collect sufficient da

2012-2014 design value. Monitor previously attained the NAAQS based on 2011-2013 data. The monitoapproved by EPA through the annual monitoring network plan review process (see 40 CFR 58.10). 

(5) Monitor began operation at the beginning of the 2014 ozone monitoring season and has not yet collected 

calculate a valid 3-year design value. 

(6) Monitor shut down at the end of the 2013 ozone monitoring season and did not collect sufficient data to c

2014 design value. Monitor previously attained the NAAQS based on 2011-2013 data. The monitor was dPurpose monitor in AQS and in the Wyoming Annual Monitoring Network Plan. 40 CFR Section 58.20(f

approval from EPA is not required for discontinuance of an SPM." 

(7) CASTNET monitor started 6/1/2011, and had incomplete data in 2012 so that a valid design value for 20

calculated. Since inception in 2011, and with complete data through March 2015 with the exception of m

2012 data, the monitor has recorded no readings that have exceeded the ozone standard of 0.075 ppm. 
14 

B. EPA’s Determinations to Grant 1-Year Attainment Date Extensions to Certain 2008 

Ozone NAAQS Marginal Nonattainment Areas 

The EPA is proposing to grant 1-year attainment date extensions for eight Marginal 

nonattainment areas for the 2008 ozone NAAQS, on the basis that the state air agencies 

adequately demonstrated that they have met the requirements under Clean Air Act section 

181(a)(5) to qualify for a 1-year extension to their attainment date. CAA section 181(a)(5) and 

40 CFR 51.1107 specify that EPA may grant a 1-year extension of an area’s attainment date if 

the state has complied with all requirements and commitments pertaining to the area in the 

applicable implementation plan, and all monitors in the area have a fourth highest daily 

maximum 8-hour average of 0.075 ppm or less for the attainment year. 

With regard to CAA section 181(a)(5)(A), the states submitted requests to the EPA which certify 

that the states have complied with all requirements and commitments pertaining to the area in the 

applicable implementation plan and that all monitors in the area have a fourth highest daily 

maximum 8-hour average of 0.075 ppm or less for the attainment year. These letters, the 

signatory parties, the dates of request, and the adequacy of each letter for purposes of 

181(a)(5)(A) are provided below in Table 2, “2008 Ozone NAAQS Marginal Nonattainment 

Areas Requesting a 1-Year Extension to their Attainment Date.” The state letters are available in 

the docket for this rulemaking. 

The State of Delaware did not submit a request for a one-year extension of the attainment date 

for the Philadelphia-Wilmington-Atlantic City nonattainment area. However, the other three 

states with jurisdiction over the Philadelphia nonattainment area did request such an extension, 

and EPA interprets CAA section 181(a)(5)’s provision that the Administrator may grant an 

extension “[u]pon application by any State” (emphasis added) to mean that if any state with 

jurisdiction over the nonattainment area requests such extension, the Agency will consider 

granting the request provided that the criteria in section 181(a)(5) are met for all of the governing 

states. 

The EPA is proposing to find that the State of Delaware has complied with all requirements and 

commitments pertaining to the Philadelphia-Wilmington-Atlantic City area in the applicable 

implementation plan in accordance with CAA section 181(a)(5)(A). EPA recently proposed to 

disapprove a revision to Delaware’s New Source Review (NSR) preconstruction permitting 

program regulation, see 80 FR 30015 (May 26, 2015), but we do not believe that this proposed 

disapproval in itself prohibits EPA from granting an extension under section 181(a)(5) for the 

Philadelphia area. Despite this proposed disapproval of a SIP revision, EPA is here proposing to 

find the Delaware meets the requirements of section 181(a)(5)(A), that is, it has complied with 

all the requirements and commitments pertaining to the Philadelphia-Wilmington-Atlantic City 

area in the applicable implementation plan, because no preconstruction permits have been issued 

that are inconsistent with the EPA-approved NSR preconstruction program in Delaware’s SIP.
15 

Table 2: 2008 Ozone NAAQS Marginal Nonattainment Areas Requesting a 1-Year 

Extension to their Attainment Date 

2008 Ozone NAAQS Nonattainment Area Date of Request Signatory 

Party 

Satisfies 

CAA 

§181(a)(5) 

Criteria

Cleveland-Akron-Lorain, OH February 20, 2015 

with March 19, 2015 

(supplemental letter) 

Craig W. Butler, 

Director, Ohio 

Environmental 

Protection 

Agency (EPA); 

supplemental 

letter signed by 

Bob Hodanbosi, 

Chief, Ohio EPA, 

DAPC 

Yes 

Houston-Galveston-Brazoria, TX February 27, 2015 

with May 22, 2015 

(supplemental letter) 

Richard Hyde, 

TCEQ Executive 

Director 

Yes 

Philadelphia-Wilmington-Atlantic City, NJ June 17, 2015 Bob Martin, 

Commissioner, 

State of New 

Jersey, 

Department of 

Environmental 

Protection 

Yes 

Philadelphia-Wilmington-Atlantic City, PA July 8, 2015 John Quigley, 

Secretary, 

Department of 

Environmental 

Protection 

Yes 

Philadelphia-Wilmington-Atlantic City, MD August 3, 2015 George (Tad) S. 

Aburn, Jr., 

Director, Air and 

Radiation 

Management 

Administration, 

Maryland 

Department of the 

Environment 

Yes 

Philadelphia-Wilmington-Atlantic City, DE Not Applicable Not Applicable Yes 

Pittsburgh-Beaver Valley, PA April 20, 2015 Jayme Graham, 

Manager, Air 

quality Program, 

County of 

Allegheny 

Yes 
16 

Table 2: 2008 Ozone NAAQS Marginal Nonattainment Areas Requesting a 1-Year 

Extension to their Attainment Date 

2008 Ozone NAAQS Nonattainment Area Date of Request Signatory 

Party 

Satisfies 

CAA 

§181(a)(5) 

Criteria

San Luis Obispo County (Eastern part), CA June 1, 2015 

referencing District’s 

May 19, 2015 letter 

Richard W. 

Corey, Executive 

Director, CARB 

Yes 

Sheboygan, WI May 12, 2015 Bart Sonseller, 

Air Division 

Director, WDNR 

Yes 

St. Louis-St. Charles-Farmington, MO May 22, 2015 Kyra L. Moore, 

Director, MDNR 

Yes 

St. Louis-St. Charles-Farmington, IL May 29, 2015 Lisa Bonnett, 

Director, Illinois 

Environmental 

Protection 

Agency 

Yes 

Washington, DC May 14, 2015 Thomas Wells, 

Director, District 

Department of the 

Environment 

Yes 

Washington, MD July 14, 2015 George (Tad) S. 

Aburn, Jr., 

Director, Air and 

Radiation 

Management 

Administration, 

Maryland 

Department of the 

Environment 

Yes 

Washington, VA May 13, 2015 David K. Paylor, 

Director, 

Department of 

Environmental 

Quality 

Yes 

EPA has interpreted CAA section 181(a)(5)(B), which was written for an exceedance-based 

standard, for purposes of a violation-based standard such as the 2008 ozone NAAQS to mean 

that an area meets the requirement if all of the area’s monitors record a fourth highest daily 

maximum 8-hour average of 0.075 ppm or less for the attainment year. Because the applicable 

attainment date of July 20, 2015 is in the middle of the 2015 ozone season, the definition of 

“attainment year” as provided in 40 CFR 51.1100(h) is considered the year, and ozone season, 
17 

immediately preceding this date. Thus, the EPA has evaluated the certified air quality data for 

2014 for purposes of considering an area’s eligibility for a 1-year attainment date extension. 

Table 3, “2014 4th Highest Daily Maximum 8-hour Average Concentration for 2008 Ozone 

NAAQS Marginal Nonattainment Areas Eligible for an Extended Attainment Date to July 20, 

2016, identifies the 8 areas that were not attaining the 2008 ozone standard based on 2012-2014 

data but that meet the section 181(a)(5)(B) requirement because the 2014 fourth highest daily 

maximum 8-hour average value for each area monitor shown in Table 3 has not exceeded the 

standard. The EPA notes that some monitors in the relevant areas had data completeness issues 

for calculating a valid design value in 2014. See footnotes 2-6 to Table 3. We have evaluated 

each of those monitors and provided rationale for the data issues in the footnotes. Therefore, we 

do not believe that the missing or invalid data from these monitors undermines our proposal to 

find that the fourth highest daily maximum value for these areas was less than or equal to 0.075 

ppm. 

The EPA has evaluated the information submitted by the states for each area and the air quality 

data for the areas and has determined that the states have met the CAA section 181(a)(5) criteria. 

The EPA is therefore proposing to grant 1-year extensions of the attainment date for these areas. 

Table 3: 2014 4th Highest Daily Maximum 8-hour Average Concentration for 2008 

Ozone NAAQS Marginal Nonattainment Areas Eligible for an Extended Attainment 

Date to July 20, 2016 

AQS 

Monitoring Site 

ID 

County Name State 

2014 4th 

Highest 

Daily Max 

8-hr 

Average 

Value 

(ppm)(1) 

2012-2014 

Design 

Value 

(ppm) (1) 

Cleveland-Akron-Lorain, OH 

391530020 Summit Ohio 0.058 0.062 

391331001 Portage Ohio 0.061 0.064 

390350060 Cuyahoga Ohio 0.066 0.065 

391030004 Medina Ohio 0.064 0.067 

390350064 Cuyahoga Ohio 0.059 0.068 

390930018 Lorain Ohio 0.067 0.069 

390550004 Geauga Ohio 0.065 0.070 

390355002 Cuyahoga Ohio 0.061 0.071 

390850007 Lake Ohio 0.062 0.071 

390071001 Ashtabula Ohio 0.069 0.072 

390350034 Cuyahoga Ohio 0.071 0.075 

390850003 Lake Ohio 0.075 0.078 

Houston-Galveston-Brazoria, TX 

480391016 Brazoria Texas 0.061 0.066 

482011015 Harris Texas 0.059 0.066 
18 

Table 3: 2014 4th Highest Daily Maximum 8-hour Average Concentration for 2008 

Ozone NAAQS Marginal Nonattainment Areas Eligible for an Extended Attainment 

Date to July 20, 2016 

AQS 

Monitoring Site 

ID 

County Name State 

2014 4th 

Highest 

Daily Max 

8-hr 

Average 

Value 

(ppm)(1) 

2012-2014 

Design 

Value 

(ppm) (1) 

482010026 Harris Texas 0.064 0.067 

482011035 Harris Texas 0.058 0.068 

482010046 Harris Texas 0.062 0.069 

481671034 Galveston Texas 0.071 0.072 

482010024 Harris Texas 0.068 0.072 

482011034 Harris Texas 0.066 0.072 

482011039 Harris Texas 0.063 0.072 

482011050 Harris Texas 0.065 0.072 

482010047 Harris Texas 0.064 0.074 

482010062 Harris Texas 0.065 0.074 

482010416 Harris Texas 0.066 0.074 

482010029 Harris Texas 0.063 0.075 

482010051 Harris Texas 0.067 0.075 

482010055 Harris Texas 0.067 0.075 

482010066 Harris Texas 0.070 0.076 

483390078 Montgomery Texas 0.072 0.076 

480391004 Brazoria Texas 0.071 0.080 

482010070 Harris Texas (2) (2) 

482011017 Harris Texas 0.067 (2) 

Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE 

421010004 Philadelphia Pennsylvania 0.058 0.056 

340010006 Atlantic New Jersey 0.061 0.069 

340110007 Cumberland New Jersey 0.067 0.070 

100031007 New Castle Delaware 0.071 0.071 

100031013 New Castle Delaware 0.069 0.071 

100032004 New Castle Delaware 0.068 (3) 

420910013 Montgomery Pennsylvania 0.072 0.072 

340070002 Camden New Jersey 0.068 0.073 

340210005 Mercer New Jersey 0.071 0.073 

340219991 Mercer New Jersey 0.071 0.073 

420290100 Chester Pennsylvania 0.071 0.073 

420450002 Delaware Pennsylvania 0.073 0.074 
19 

Table 3: 2014 4th Highest Daily Maximum 8-hour Average Concentration for 2008 

Ozone NAAQS Marginal Nonattainment Areas Eligible for an Extended Attainment 

Date to July 20, 2016 

AQS 

Monitoring Site 

ID 

County Name State 

2014 4th 

Highest 

Daily Max 

8-hr 

Average 

Value 

(ppm)(1) 

2012-2014 

Design 

Value 

(ppm) (1) 

340290006 Ocean New Jersey 0.072 0.075 

420170012 Bucks Pennsylvania 0.071 0.075 

421010024 Philadelphia Pennsylvania 0.072 0.075 

340071001 Camden New Jersey 0.068 0.076 

340150002 Gloucester New Jersey 0.070 0.076 

240150003 Cecil Maryland 0.074 0.077 

100031010 New Castle Delaware 0.075 (4) 0.072 (4)

421010048 Philadelphia Pennsylvania 0.068 (5) 

421011002 Philadelphia Pennsylvania (6) 

Pittsburgh-Beaver Valley, PA 

421250005 Washington Pennsylvania 0.065 0.068 

421255001 Washington Pennsylvania 0.064 0.068 

421250200 Washington Pennsylvania 0.064 0.069 

421290008 Westmoreland Pennsylvania 0.064 0.069 

420030067 Allegheny Pennsylvania 0.065 0.070 

420070014 Beaver Pennsylvania 0.066 0.070 

420070002 Beaver Pennsylvania 0.069 0.071 

420030008 Allegheny Pennsylvania 0.065 0.073 

420050001 Armstrong Pennsylvania 0.068 0.074 

420070005 Beaver Pennsylvania 0.070 0.075 

420031008 Allegheny Pennsylvania 0.071 0.077 

420030010 Allegheny Pennsylvania (7) 

421255200 Washington Pennsylvania 0.062 (8) 

421290006 Westmoreland Pennsylvania 0.053 (7) 

San Luis Obispo County (Eastern part), CA 

060798006 San Luis Obispo California 0.068 0.070 

060798005 San Luis Obispo California 0.073 0.076 

Sheboygan, WI 

551170006 Sheboygan Wisconsin 0.072 0.081 

St. Louis-St. Charles-Farmington, MO-IL 
20 

Table 3: 2014 4th Highest Daily Maximum 8-hour Average Concentration for 2008 

Ozone NAAQS Marginal Nonattainment Areas Eligible for an Extended Attainment 

Date to July 20, 2016 

AQS 

Monitoring Site 

ID 

County Name State 

2014 4th 

Highest 

Daily Max 

8-hr 

Average 

Value 

(ppm)(1) 

2012-2014 

Design 

Value 

(ppm) (1) 

171630010 Saint Clair Illinois 0.067 0.072 

291890005 Saint Louis Missouri 0.065 0.072 

295100085 St. Louis City Missouri 0.066 0.073 

171199991 Madison Illinois 0.068 0.074 

171193007 Madison Illinois 0.070 0.075 

290990019 Jefferson Missouri 0.072 0.075 

171190008 Madison Illinois 0.072 0.076 

171191009 Madison Illinois 0.070 0.076 

291831004 Saint Charles Missouri 0.072 0.076 

291890014 Saint Louis Missouri 0.072 0.077 

291831002 Saint Charles Missouri 0.072 0.078 

Washington, DC-MD-VA 

511530009 Prince William Virginia 0.062 0.066 

511071005 Loudoun Virginia 0.063 0.067 

240313001 Montgomery Maryland 0.064 0.068 

240210037 Frederick Maryland 0.063 0.070 

240330030 Prince George's Maryland 0.065 0.070 

240170010 Charles Maryland 0.067 0.071 

510590030 Fairfax Virginia 0.065 0.072 

110010043 District of Columbia 

District Of 

Columbia 0.068 0.073 

240090011 Calvert Maryland 0.070 0.073 

510130020 Arlington Virginia 0.071 0.074 

240338003 Prince George's Maryland 0.069 0.076 

110010041 District of Columbia 

District Of 

Columbia 0.047 (7) 

110010050 District of Columbia 

District Of 

Columbia 0.069 (5) 

240339991 Prince George's Maryland 0.069 (9) 

515100009 Alexandria City Virginia (6) 
21 

(1) The level of the 2008 8-hour ozone NAAQS is 0.075 parts per million (ppm). The design 

value is the 3-year average of the annual fourth highest daily maximum 8-hour average 

ozone concentration. Each area’s design value is determined by the highest design value 

among monitors with valid design values. The design values shown here are computed 

using Federal Reference Method or equivalent data reported by State, Tribal, and Local 

monitoring agencies to EPA's Air Quality System (AQS) as of July 20, 2015. Individual 

8-hour concentrations that were flagged by State, Tribal, or Local monitoring agencies as 

having been affected by an exceptional event (e.g., wildfire, volcanic eruption) and 

received concurrence from the associated EPA Regional Office are not included in these 

calculations. 

(2) Site 482010070 monitor was moved to site 482011017 in June 2012. Therefore, neither 

site collected sufficient data to calculate a valid 2012-2014 design value. Site 482011017 

monitor has sufficient data to determine that the 2014 fourth highest daily maximum 8-

hour average value did not exceed the level of the NAAQS. 

(3) Monitor did not collect sufficient monitoring data to calculate a valid 2012-2014 design 

value, which requires an average percent of days with valid data in the designated ozone 

monitoring season of at least 90 percent. However, because other monitors in the area had 

valid 2012-2014 design values that violated the NAAQS, the 2012-2014 design value is 

not needed to determine that the area violated. The monitor did collect sufficient data 

(i.e., at least 75 percent of the designated sampling days) to determine a valid 2014 fourth 

highest daily maximum 8-hour average value adequate to determine if the area qualifies 

for a 1-year attainment date extension. 

(4) Monitor did not collect sufficient data in 2014. We substituted missing values for this site 

with the highest corresponding values from the other three New Castle County 

monitoring sites, which created a complete data set to calculate a valid 2012-2014 design 

value and a 2014 fourth highest daily maximum value (see Exhibit 2 in the Appendix to 

this TSD). 

(5) Monitor began operation after the beginning of the 2013 ozone monitoring season and 

has not yet collected sufficient data to calculate a valid 3-year design value. However, 

this monitor has sufficient data to determine a valid 2014 fourth highest daily maximum 

8-hour average value to determine if the area meets the air quality criteria pertaining to a 

1-year attainment date extension. 

(6) Monitor shut down prior to the 2014 ozone monitoring season and did not collect 

sufficient data to calculate a valid 2012-2014 design value. The monitor shut down was 

approved by EPA through the annual monitoring network plan review process (see 40 

CFR 58.10). 

(7) Monitor shut down prior to the end of the 2014 ozone monitoring season and did not 

collect sufficient data to calculate a valid 2012-2014 design value. Monitor previously 

attained the NAAQS based on 2011-2013 data. The monitor shut down was approved by 

EPA through the annual monitoring network plan review process (see 40 CFR 58.10). 

(8) Monitor began operation after the beginning of the 2012 ozone monitoring season and 

has not yet collected sufficient data to calculate a valid 3-year design value. However, 

this monitor has sufficient data to determine a valid 2014 fourth highest daily maximum 

8-hour average value to determine if the area meets the air quality criteria pertaining to a 

1-year attainment date extension. 
22 

(9) Monitor did not collect sufficient data to calculate a valid 2012-2014 design value. 

However, this monitor has sufficient data to determine a valid 2014 fourth highest daily 

maximum 8-hour average value to determine if the area meets the air quality criteria 

pertaining to a 1-year attainment date extension. 

Exhibit 1 in the Appendix to this TSD provides the data completeness of each monitor. We have 

determined that the 2014 fourth highest daily maximum 8-hour average values included in Table 

3 meet the data completeness requirements of Appendix P, with the exception of one monitoring 

site in New Castle County, DE (AQS site ID 100031010). That site had 73% data completeness 

in 2014, which does not meet the 75% requirement for annual data completeness. In this case, 

EPA performed an analysis where missing daily maximum 8-hour average ozone readings at the 

deficient site were substituted with the highest of the corresponding daily maximum 8-hour 

average values from three other monitoring sites in New Castle County, DE. This resulted in a 

2014 fourth highest value of 0.075 ppm at the deficient site, thus EPA believes that it is 

appropriate to grant a 1-year attainment date extension for the Philadelphia-Wilmington-Atlantic 

City area. For an in-depth explanation of EPA’s analysis, see Exhibit 2 in the Appendix to this 

TSD. 

C. EPA’s Determinations of Failure to Attain by the Attainment Date and to Reclassify 

Certain Nonattainment Areas to Moderate for the 2008 Ozone NAAQS 

The EPA is proposing to determine that eleven areas failed to attain the 2008 ozone NAAQS by 

the applicable attainment deadline of July 20, 2015. As shown in Table 4 below, at least one 

monitor in each of these areas had a 2012-2014 design value greater than 0.075 ppm. The EPA 

further proposes to determine that these areas did not meet the air quality requirement under 

section 181(a)(5)(B) and 40 CFR 51.1107, necessary to grant a 1-year extension of the 

attainment date, because at least one monitor in each area had a 2014 fourth highest daily 

maximum 8-hour average that was greater than 0.075 ppm. The EPA is therefore proposing to 

find that these eleven areas failed to attain the 2008 ozone NAAQS by the attainment date 

pursuant to CAA section 181(b)(2)(A), and thus the areas must be reclassified to “Moderate” by 

operation of law. 

Table 4: 2008 Ozone NAAQS Marginal Nonattainment Areas That Did Not Attain the 

2008 Ozone Standard as of July 20, 2015 Attainment Date and Requiring Reclassification 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr Avg Value 

(ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

2012 2013 2014 

Atlanta, GA 

130770002 Coweta Georgia 0.062 0.053 0.067 0.060 

132230003 Paulding Georgia 0.072 0.062 0.059 0.064 

130970004 Douglas Georgia 0.073 0.063 0.065 0.067 

130890002 DeKalb Georgia 0.085 0.062 0.070 0.072 

131350002 Gwinnett Georgia 0.080 0.069 0.068 0.072 
23 

Table 4: 2008 Ozone NAAQS Marginal Nonattainment Areas That Did Not Attain the 

2008 Ozone Standard as of July 20, 2015 Attainment Date and Requiring Reclassification 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr Avg Value 

(ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

2012 2013 2014 

131210055 Fulton Georgia 0.087 0.069 0.073 0.076 

131510002 Henry Georgia 0.088 0.070 0.075 0.077 

132470001 Rockdale Georgia 0.081 0.071 0.079 0.077 

130670003 Cobb Georgia 0.075 0.067 0.066 (2) 

Chicago-Naperville, IL-IN-WI 

171971011 Will Illinois 0.071 0.061 0.064 0.065 

181270026 Porter Indiana 0.067 0.063 0.067 0.065 

170436001 DuPage Illinois 0.074 0.063 0.064 0.067 

170890005 Kane Illinois 0.075 0.064 0.066 0.068 

170310001 Cook Illinois 0.079 0.064 0.066 0.069 

170314002 Cook Illinois 0.083 0.063 0.063 0.069 

170314007 Cook Illinois 0.073 0.067 0.069 0.069 

171110001 McHenry Illinois 0.077 0.065 0.067 0.069 

180890022 Lake Indiana 0.078 0.064 0.067 0.069 

180890030 Lake Indiana 0.081 0.062 0.065 0.069 

170310076 Cook Illinois 0.081 0.062 0.067 0.070 

170311601 Cook Illinois 0.081 0.064 0.070 0.071 

170314201 Cook Illinois 0.087 0.069 0.065 0.073 

181270024 Porter Indiana 0.081 0.069 0.071 0.073 

170310032 Cook Illinois 0.091 0.071 0.067 0.076 

170317002 Cook Illinois 0.093 0.069 0.072 0.078 

170971007 Lake Illinois 0.093 0.072 0.073 0.079 

550590019 Kenosha Wisconsin 0.092 0.075 0.076 0.081 

170310064 Cook Illinois 0.081 0.058 (2) 

170311003 Cook Illinois 0.079 0.066 0.065 (2) 

170313103 Cook Illinois 0.062 0.063 (2) 

180892008 Lake Indiana 0.077 0.063 0.067 (2) 

Denver-Boulder-Greeley-Fort Collins-Loveland, CO 

080310002 Denver Colorado 0.068 0.067 0.061 0.065 

080050006 Arapahoe Colorado 0.074 0.073 0.067 0.071 

080013001 Adams Colorado 0.077 0.077 0.067 0.073 

080590013 Jefferson Colorado 0.077 0.077 0.065 0.073 

080691004 Larimer Colorado 0.074 0.074 0.072 0.073 
24 

Table 4: 2008 Ozone NAAQS Marginal Nonattainment Areas That Did Not Attain the 

2008 Ozone Standard as of July 20, 2015 Attainment Date and Requiring Reclassification 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr Avg Value 

(ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

2012 2013 2014 

080690007 Larimer Colorado 0.079 0.074 0.069 0.074 

081230009 Weld Colorado 0.080 0.073 0.070 0.074 

080130011 Boulder Colorado 0.076 0.079 0.070 0.075 

080590005 Jefferson Colorado 0.079 0.080 0.066 0.075 

080690011 Larimer Colorado 0.080 0.082 0.074 0.078 

080590011 Jefferson Colorado 0.081 0.084 0.076 0.080 

080350004 Douglas Colorado 0.086 0.083 0.074 0.081 

080590006 Jefferson Colorado 0.084 0.085 0.077 0.082 

080050002 Arapahoe Colorado 0.080 0.079 (2) 

080310014 Denver Colorado 0.077 0.044 (2) 

080310025 Denver Colorado 0.073 (2) 

080310026 Denver Colorado 0.071 0.066 (2) 

080590002 Jefferson Colorado 0.041 (2) 

080690012 Larimer Colorado 0.071 0.066 (2) 

Greater Connecticut, CT 

090050005 Litchfield Connecticut 0.073 0.068 0.066 0.069 

090159991 Windham Connecticut 0.075 0.069 0.067 0.070 

090031003 Hartford Connecticut 0.077 0.077 0.077 0.077 

090110124 New London Connecticut 0.087 0.085 0.065 0.079 

090131001 Tolland Connecticut 0.083 0.081 0.077 0.080 

Imperial County, CA 

060254004 Imperial California 0.070 0.072 0.069 0.070 

060250005 Imperial California 0.080 0.078 0.078 0.078 

060251003 Imperial California 0.084 0.080 0.078 0.080 

060254003 Imperial California 0.069 (2) 

Kern County (Eastern Kern), CA 

60290011 Kern California 0.082 0.081 0.089 0.084 

Mariposa County, CA 

060430003 Mariposa California 0.081 0.073 0.077 0.077 

060430006 Mariposa California 0.081 0.077 0.077 0.078 

Nevada County (Western part), CA 
25 

Table 4: 2008 Ozone NAAQS Marginal Nonattainment Areas That Did Not Attain the 

2008 Ozone Standard as of July 20, 2015 Attainment Date and Requiring Reclassification 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr Avg Value 

(ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

2012 2013 2014 

060570007 Nevada California 0.084 0.065 0.078 0.075 

060570005 Nevada California 0.077 0.078 0.082 0.079 

New York-N. New Jersey-Long Island, NY-NJ-CT 

340410007 Warren New Jersey 0.069 0.061 0.060 0.063 

360610135 New York New York 0.074 0.062 0.065 0.067 

340315001 Passaic New Jersey 0.073 0.069 0.065 0.069 

360050133 Bronx New York 0.076 0.068 0.070 0.071 

361030009 Suffolk New York 0.079 0.074 0.062 0.071 

340190001 Hunterdon New Jersey 0.078 0.073 0.065 0.072 

340250005 Monmouth New Jersey 0.083 0.071 0.064 0.072 

340273001 Morris New Jersey 0.076 0.073 0.068 0.072 

360810124 Queens New York 0.082 0.071 0.063 0.072 

360870005 Rockland New York 0.079 0.069 0.068 0.072 

340130003 Essex New Jersey 0.080 0.069 0.070 0.073 

360850067 Richmond New York 0.078 0.071 0.072 0.073 

361030002 Suffolk New York 0.083 0.072 0.066 0.073 

340230011 Middlesex New Jersey 0.082 0.070 0.071 0.074 

361030004 Suffolk New York 0.083 0.078 0.064 0.075 

361192004 Westchester New York 0.079 0.072 0.074 0.075 

090090027 New Haven Connecticut 0.081 0.075 0.072 0.076 

090011123 Fairfield Connecticut 0.084 0.076 0.074 0.078 

090070007 Middlesex Connecticut 0.081 0.082 0.080 0.081 

090099002 New Haven Connecticut 0.090 0.085 0.069 0.081 

090010017 Fairfield Connecticut 0.088 0.082 0.078 0.082 

090013007 Fairfield Connecticut 0.090 0.090 0.074 0.084 

090019003 Fairfield Connecticut 0.089 0.086 0.081 0.085 

340030006 Bergen New Jersey 0.076 0.074 0.069 (2) 

340170006 Hudson New Jersey 0.074 0.066 0.072 (2) 

360050110 Bronx New York 0.068 0.071 0.071 (2) 

Phoenix-Mesa, AZ 

040134011 Maricopa Arizona 0.068 0.060 0.060 0.062 

040213001 Pinal Arizona 0.076 0.069 0.066 0.070 

040134004 Maricopa Arizona 0.074 0.070 0.070 0.071 
26 

Table 4: 2008 Ozone NAAQS Marginal Nonattainment Areas That Did Not Attain the 

2008 Ozone Standard as of July 20, 2015 Attainment Date and Requiring Reclassification 

AQS Site 

ID County Name State 

4th Highest Daily Max 8-hr Avg Value 

(ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

2012 2013 2014 

040134005 Maricopa Arizona 0.073 0.071 0.071 0.071 

040134010 Maricopa Arizona 0.073 0.074 0.070 0.072 

040139706 Maricopa Arizona 0.072 0.073 0.073 0.072 

040137024 Maricopa Arizona 0.074 0.074 0.071 0.073 

040131010 Maricopa Arizona 0.069 0.077 0.076 0.074 

040132001 Maricopa Arizona 0.078 0.074 0.071 0.074 

040133002 Maricopa Arizona 0.077 0.075 0.071 0.074 

040134008 Maricopa Arizona 0.078 0.072 0.074 0.074 

040137020 Maricopa Arizona 0.076 0.074 0.073 0.074 

040133003 Maricopa Arizona 0.080 0.074 0.072 0.075 

040134003 Maricopa Arizona 0.078 0.075 0.073 0.075 

040137022 Maricopa Arizona 0.075 0.075 0.076 0.075 

040139508 Maricopa Arizona 0.079 0.073 0.074 0.075 

040139702 Maricopa Arizona 0.077 0.075 0.074 0.075 

040137021 Maricopa Arizona 0.077 0.075 0.080 0.077 

040139997 Maricopa Arizona 0.076 0.079 0.077 0.077 

040130019 Maricopa Arizona 0.083 0.076 0.076 0.078 

040132005 Maricopa Arizona 0.079 0.077 0.080 0.078 

040131004 Maricopa Arizona 0.083 0.079 0.078 0.080 

040131003 Maricopa Arizona 0.044 0.079 0.078 (2) 

040139704 Maricopa Arizona 0.077 0.070 0.068 (2) 

San Diego County, CA 

060731011 San Diego California 0.018 0.027 (2) 

060731010 San Diego California 0.052 0.052 0.068 0.057 

060730001 San Diego California 0.065 0.059 0.063 0.062 

060731008 San Diego California 0.062 0.062 0.071 0.065 

060731016 San Diego California 0.067 0.066 0.070 0.067 

060731002 San Diego California 0.068 0.072 0.076 0.072 

060731006 San Diego California 0.080 0.078 0.080 0.079 

060730003 San Diego California 0.068 0.068 0.048 (2) 

060731001 San Diego California 0.061 0.062 0.073 (2) 

060731014 San Diego California 0.063 (2) 

060731018 San Diego California 0.064 (2) 

060732007 San Diego California 0.057 0.059 0.049 (2) 
27 

(1) The level of the 2008 8-hour ozone NAAQS is 0.075 parts per million (ppm). The design 

value is determined by the 3-year average of the annual fourth highest daily maximum 8-hour 

average ozone concentration. Each area’s design value is the highest design value among 

monitors with valid design values. The design values shown here are computed using 

Federal Reference Method or equivalent data reported by State, Tribal, and Local monitoring 

agencies to EPA's Air Quality System (AQS) as of July 20, 2015. Individual 8-hour 

concentrations flagged by State, Tribal, or Local monitoring agencies as having been affected 

by an exceptional event (e.g., wildfire, volcanic eruption) and received concurrence by the 

associated EPA Regional Office are not included in these calculations. 

(2) Monitor did not collect sufficient data to calculate a valid 2012-2014 design value. 

However, since other monitor(s) in the area had 2012-2014 design values that violated 

the NAAQS, the area qualifies for reclassification to Moderate. Also, at least one 

monitor in the area reported a 2014 fourth highest daily maximum 8-hour average value 

greater than the NAAQS; therefore the area does not qualify for a 1-year attainment date 

extension.
28 
29 

APPENDIX 

Exhibit 1:

Monitor Level Design Value Data for 2012-2014 for the 2008 8-Hour Ozone NAAQS Data C

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

Allentown-Bethlehem-Easton, PA 

420958000 Northampton Pennsylvania 0.073 0.064 0.066 0.067 98 83 420770004 Lehigh Pennsylvania 0.075 0.068 0.068 0.070 96 100 420950025 Northampton Pennsylvania 0.073 0.065 0.067 0.068 99 81 

Atlanta, GA 

130770002 Coweta Georgia 0.062 0.053 0.067 0.060 99 98 132230003 Paulding Georgia 0.072 0.062 0.059 0.064 99 98 130970004 Douglas Georgia 0.073 0.063 0.065 0.067 96 98 130890002 DeKalb Georgia 0.085 0.062 0.070 0.072 100 100 131350002 Gwinnett Georgia 0.080 0.069 0.068 0.072 99 100 131210055 Fulton Georgia 0.087 0.069 0.073 0.076 99 99 131510002 Henry Georgia 0.088 0.070 0.075 0.077 100 97 132470001 Rockdale Georgia 0.081 0.071 0.079 0.077 99 100 130670003 Cobb Georgia 0.075 0.067 0.066 (2) 100 98 

Baton Rouge, LA 

220470009 Iberville Louisiana 0.074 0.061 0.061 0.065 98 100 
30 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

221210001 

West Baton Rouge Louisiana 0.070 0.060 0.066 0.065 97 100 

220330013 

East Baton Rouge Louisiana 0.070 0.062 0.068 0.066 93 99 

220050004 Ascension Louisiana 0.071 0.062 0.069 0.067 98 99 220330009 

East Baton Rouge Louisiana 0.072 0.066 0.070 0.069 98 100 

220470012 Iberville Louisiana 0.073 0.068 0.068 0.069 97 98 220630002 Livingston Louisiana 0.071 0.069 0.073 0.071 98 100 220330003 

East Baton Rouge Louisiana 0.075 0.067 0.075 0.072 97 98 

Calaveras County, CA 

060090001 Calaveras California 0.076 0.067 0.071 0.071 98 99 

Charlotte-Gastonia-Rock Hill, NC-SC 

371191005 Mecklenburg 

North Carolina 0.073 0.062 0.063 0.066 99 100 

371090004 Lincoln 

North Carolina 0.076 0.064 0.064 0.068 100 100 

371590021 Rowan 

North Carolina 0.080 0.062 0.064 0.068 100 98 

371790003 Union 

North Carolina 0.075 0.062 0.067 0.068 100 94 

371190041 Mecklenburg 

North Carolina 0.080 0.067 0.065 0.070 99 99 
31 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

371191009 Mecklenburg 

North Carolina 0.085 0.066 0.068 0.073 100 100 

371590022 Rowan 

North Carolina 0.077 0.063 (3) 98 99 

Chicago-Naperville, IL-IN-WI 

171971011 Will Illinois 0.071 0.061 0.064 0.065 100 94 181270026 Porter Indiana 0.067 0.063 0.067 0.065 84 100 170436001 DuPage Illinois 0.074 0.063 0.064 0.067 100 87 170890005 Kane Illinois 0.075 0.064 0.066 0.068 90 90 170310001 Cook Illinois 0.079 0.064 0.066 0.069 99 91 170314002 Cook Illinois 0.083 0.063 0.063 0.069 96 98 170314007 Cook Illinois 0.073 0.067 0.069 0.069 98 99 171110001 McHenry Illinois 0.077 0.065 0.067 0.069 98 96 180890022 Lake Indiana 0.078 0.064 0.067 0.069 98 93 180890030 Lake Indiana 0.081 0.062 0.065 0.069 96 99 170310076 Cook Illinois 0.081 0.062 0.067 0.070 93 95 170311601 Cook Illinois 0.081 0.064 0.070 0.071 93 95 170314201 Cook Illinois 0.087 0.069 0.065 0.073 99 88 181270024 Porter Indiana 0.081 0.069 0.071 0.073 91 97 170310032 Cook Illinois 0.091 0.071 0.067 0.076 99 100 170317002 Cook Illinois 0.093 0.069 0.072 0.078 93 99 170971007 Lake Illinois 0.093 0.072 0.073 0.079 100 95 550590019 Kenosha Wisconsin 0.092 0.075 0.076 0.081 99 100 170310064 Cook Illinois 0.081 0.058 (2) 98 96 
32 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

170311003 Cook Illinois 0.079 0.066 0.065 (2) 88 87 170313103 Cook Illinois 0.062 0.063 (2) 88 180892008 Lake Indiana 0.077 0.063 0.067 (2) 70 98 

Chico (Butte County), CA 

060070008 Butte California 0.065 0.062 0.066 0.064 96 99 060070007 Butte California 0.078 0.071 0.074 0.074 97 96 

Cincinnati, OH-KY-IN 

210150003 Boone Kentucky 0.074 0.059 0.062 0.065 100 100 391650007 Warren Ohio 0.080 0.067 0.071 0.072 100 99 390170004 Butler Ohio 0.083 0.068 0.070 0.073 100 98 390170018 Butler Ohio 0.084 0.068 0.069 0.073 95 100 390271002 Clinton Ohio 0.086 0.064 0.070 0.073 100 99 390610010 Hamilton Ohio 0.083 0.064 0.073 0.073 87 97 390610040 Hamilton Ohio 0.082 0.069 0.069 0.073 100 99 390179991 Butler Ohio 0.085 0.069 0.069 0.074 93 94 210373002 Campbell Kentucky 0.084 0.072 0.071 0.075 99 100 390250022 Clermont Ohio 0.091 0.066 0.068 0.075 100 100 390610006 Hamilton Ohio 0.087 0.069 0.070 0.075 96 95 

Cleveland-Akron-Lorain, OH 

391530020 Summit Ohio 0.070 0.060 0.058 0.062 100 100 391331001 Portage Ohio 0.074 0.058 0.061 0.064 95 98 390350060 Cuyahoga Ohio 0.073 0.057 0.066 0.065 98 95 391030004 Medina Ohio 0.074 0.065 0.064 0.067 98 100 
33 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

390350064 Cuyahoga Ohio 0.083 0.064 0.059 0.068 98 97 390930018 Lorain Ohio 0.081 0.060 0.067 0.069 97 100 390550004 Geauga Ohio 0.082 0.065 0.065 0.070 100 100 390355002 Cuyahoga Ohio 0.087 0.065 0.061 0.071 99 99 390850007 Lake Ohio 0.083 0.068 0.062 0.071 99 100 390071001 Ashtabula Ohio 0.079 0.070 0.069 0.072 98 100 390350034 Cuyahoga Ohio 0.085 0.069 0.071 0.075 98 98 390850003 Lake Ohio 0.089 0.070 0.075 0.078 100 100 

Columbus, OH 

390490081 Franklin Ohio 0.076 0.065 0.068 0.069 100 99 390830002 Knox Ohio 0.074 0.067 0.066 0.069 100 100 390890005 Licking Ohio 0.077 0.065 0.066 0.069 99 100 390410002 Delaware Ohio 0.077 0.070 0.066 0.071 99 98 390970007 Madison Ohio 0.078 0.066 0.069 0.071 100 99 390490037 Franklin Ohio 0.081 0.070 0.069 0.073 98 100 390490029 Franklin Ohio 0.082 0.073 0.070 0.075 99 100 

Denver-Boulder-Greeley-Fort Collins-Loveland, CO 

080310002 Denver Colorado 0.068 0.067 0.061 0.065 99 98 080050006 Arapahoe Colorado 0.074 0.073 0.067 0.071 99 99 080013001 Adams Colorado 0.077 0.077 0.067 0.073 89 92 080590013 Jefferson Colorado 0.077 0.077 0.065 0.073 95 97 080691004 Larimer Colorado 0.074 0.074 0.072 0.073 93 99 080690007 Larimer Colorado 0.079 0.074 0.069 0.074 98 99 
34 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

081230009 Weld Colorado 0.080 0.073 0.070 0.074 98 89 080130011 Boulder Colorado 0.076 0.079 0.070 0.075 99 98 080590005 Jefferson Colorado 0.079 0.080 0.066 0.075 98 99 080690011 Larimer Colorado 0.080 0.082 0.074 0.078 97 99 080590011 Jefferson Colorado 0.081 0.084 0.076 0.080 99 97 080350004 Douglas Colorado 0.086 0.083 0.074 0.081 97 98 080590006 Jefferson Colorado 0.084 0.085 0.077 0.082 95 97 080050002 Arapahoe Colorado 0.080 0.079 (2) 92 97 080310014 Denver Colorado 0.077 0.044 (2) 99 0 080310025 Denver Colorado 0.073 (2) 76 080310026 Denver Colorado 0.071 0.066 (2) 95 080590002 Jefferson Colorado 0.041 (2) 0 080690012 Larimer Colorado 0.071 0.066 (2) 80 55 

Dukes County, MA 

250070001 Dukes Massachusetts 0.082 0.065 0.059 0.068 97 97 

Greater Connecticut, CT 

090050005 Litchfield Connecticut 0.073 0.068 0.066 0.069 95 92 090159991 Windham Connecticut 0.075 0.069 0.067 0.070 98 97 090031003 Hartford Connecticut 0.077 0.077 0.077 0.077 85 91 090110124 New London Connecticut 0.087 0.085 0.065 0.079 90 93 090131001 Tolland Connecticut 0.083 0.081 0.077 0.080 96 91 

Houston-Galveston-Brazoria, TX 

480391016 Brazoria Texas 0.071 0.067 0.061 0.066 95 99 
35 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

482011015 Harris Texas 0.075 0.064 0.059 0.066 98 99 482010026 Harris Texas 0.077 0.061 0.064 0.067 86 96 482011035 Harris Texas 0.081 0.067 0.058 0.068 99 98 482010046 Harris Texas 0.075 0.070 0.062 0.069 95 98 481671034 Galveston Texas 0.081 0.064 0.071 0.072 99 96 482010024 Harris Texas 0.075 0.074 0.068 0.072 98 100 482011034 Harris Texas 0.083 0.069 0.066 0.072 98 99 482011039 Harris Texas 0.085 0.069 0.063 0.072 99 99 482011050 Harris Texas 0.086 0.067 0.065 0.072 98 96 482010047 Harris Texas 0.081 0.079 0.064 0.074 98 95 482010062 Harris Texas 0.085 0.074 0.065 0.074 99 99 482010416 Harris Texas 0.077 0.079 0.066 0.074 97 97 482010029 Harris Texas 0.082 0.080 0.063 0.075 97 96 482010051 Harris Texas 0.079 0.079 0.067 0.075 99 99 482010055 Harris Texas 0.077 0.081 0.067 0.075 100 90 482010066 Harris Texas 0.081 0.077 0.070 0.076 100 98 483390078 Montgomery Texas 0.082 0.075 0.072 0.076 97 99 480391004 Brazoria Texas 0.087 0.084 0.071 0.080 90 97 482010070 Harris Texas 0.075 (4) 45 482011017 Harris Texas 0.071 0.061 0.067 (4) 55 73 

Imperial County, CA 

060254004 Imperial California 0.070 0.072 0.069 0.070 98 88 060250005 Imperial California 0.080 0.078 0.078 0.078 98 94 060251003 Imperial California 0.084 0.080 0.078 0.080 99 96 
36 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

060254003 Imperial California 0.069 (2) 94 

Jamestown, NY 

360130006 Chautauqua New York 0.081 0.066 0.066 0.071 97 95 360130011 Chautauqua New York 0.081 (5) 94 

Kern County (Eastern Kern), CA 

060290011 Kern California 0.082 0.081 0.089 0.084 99 97 

Knoxville, TN 

470090102 Blount Tennessee 0.064 0.059 0.058 0.060 99 100 470930021 Knox Tennessee 0.073 0.057 0.060 0.063 99 98 470090101 Blount Tennessee 0.075 0.064 0.064 0.067 97 98 470931020 Knox Tennessee 0.078 0.061 0.063 0.067 100 96 

Lancaster, PA 

420710012 Lancaster Pennsylvania 0.079 0.063 0.063 0.068 99 100 420710007 Lancaster Pennsylvania 0.081 0.066 0.066 0.071 100 99 

Mariposa County, CA 

060430003 Mariposa California 0.081 0.073 0.077 0.077 98 95 060430006 Mariposa California 0.081 0.077 0.077 0.078 92 92 

Memphis, TN-MS-AR 

280330002 DeSoto Mississippi 0.075 0.065 0.067 0.069 98 100 471571004 Shelby Tennessee 0.084 0.063 0.065 0.070 88 98 
37 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

050350005 Crittenden Arkansas 0.079 0.067 0.067 0.071 99 99 471570021 Shelby Tennessee 0.083 0.069 0.067 0.073 100 98 471570075 Shelby Tennessee 0.086 0.069 0.066 0.073 99 100 

Nevada County (Western part), CA 

060570007 Nevada California 0.084 0.065 0.078 0.075 99 93 060570005 Nevada California 0.077 0.078 0.082 0.079 99 99 

New York-N. New Jersey-Long Island, NY-NJ-CT 

340410007 Warren New Jersey 0.069 0.061 0.060 0.063 95 99 360610135 New York New York 0.074 0.062 0.065 0.067 95 97 340315001 Passaic New Jersey 0.073 0.069 0.065 0.069 95 94 360050133 Bronx New York 0.076 0.068 0.070 0.071 100 100 361030009 Suffolk New York 0.079 0.074 0.062 0.071 85 93 340190001 Hunterdon New Jersey 0.078 0.073 0.065 0.072 97 100 340250005 Monmouth New Jersey 0.083 0.071 0.064 0.072 93 99 340273001 Morris New Jersey 0.076 0.073 0.068 0.072 98 98 360810124 Queens New York 0.082 0.071 0.063 0.072 96 94 360870005 Rockland New York 0.079 0.069 0.068 0.072 97 98 340130003 Essex New Jersey 0.080 0.069 0.070 0.073 98 100 360850067 Richmond New York 0.078 0.071 0.072 0.073 98 100 361030002 Suffolk New York 0.083 0.072 0.066 0.073 98 99 340230011 Middlesex New Jersey 0.082 0.070 0.071 0.074 94 99 361030004 Suffolk New York 0.083 0.078 0.064 0.075 92 96 361192004 Westchester New York 0.079 0.072 0.074 0.075 100 98 
38 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

090090027 New Haven Connecticut 0.081 0.075 0.072 0.076 98 95 090011123 Fairfield Connecticut 0.084 0.076 0.074 0.078 91 92 090070007 Middlesex Connecticut 0.081 0.082 0.080 0.081 95 96 090099002 New Haven Connecticut 0.090 0.085 0.069 0.081 79 96 090010017 Fairfield Connecticut 0.088 0.082 0.078 0.082 93 98 090013007 Fairfield Connecticut 0.090 0.090 0.074 0.084 93 96 090019003 Fairfield Connecticut 0.089 0.086 0.081 0.085 98 97 340030006 Bergen New Jersey 0.076 0.074 0.069 (2) 59 99 340170006 Hudson New Jersey 0.074 0.066 0.072 (2) 95 67 360050110 Bronx New York 0.068 0.071 0.071 (2) 34 94 

Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE 

421010004 Philadelphia Pennsylvania 0.065 0.047 0.058 0.056 99 100 340010006 Atlantic New Jersey 0.076 0.070 0.061 0.069 95 95 340110007 Cumberland New Jersey 0.084 0.061 0.067 0.070 99 96 100031007 New Castle Delaware 0.082 0.062 0.071 0.071 94 95 100031013 New Castle Delaware 0.078 0.067 0.069 0.071 94 88 100032004 New Castle Delaware 0.080 0.067 0.068 (6) 96 83 420910013 Montgomery Pennsylvania 0.075 0.069 0.072 0.072 98 100 340070002 Camden New Jersey 0.086 0.065 0.068 0.073 88 100 340210005 Mercer New Jersey 0.080 0.070 0.071 0.073 99 100 340219991 Mercer New Jersey 0.081 0.069 0.071 0.073 94 92 420290100 Chester Pennsylvania 0.081 0.068 0.071 0.073 93 100 420450002 Delaware Pennsylvania 0.081 0.069 0.073 0.074 95 100 340290006 Ocean New Jersey 0.085 0.070 0.072 0.075 97 100 
39 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

420170012 Bucks Pennsylvania 0.082 0.073 0.071 0.075 98 98 421010024 Philadelphia Pennsylvania 0.085 0.068 0.072 0.075 97 98 340071001 Camden New Jersey 0.092 0.068 0.068 0.076 93 93 340150002 Gloucester New Jersey 0.087 0.073 0.070 0.076 94 98 240150003 Cecil Maryland 0.087 0.072 0.074 0.077 96 98 100031010 New Castle Delaware 0.078 0.063 0.075 (7)

0.072 

(7) 86 76 

421010048 Philadelphia Pennsylvania 0.036 0.068 (8) 6 421011002 Philadelphia Pennsylvania 0.083 0.071 (9) 87 82 

Phoenix-Mesa, AZ 

040134011 Maricopa Arizona 0.068 0.060 0.060 0.062 100 96 040213001 Pinal Arizona 0.076 0.069 0.066 0.070 97 100 040134004 Maricopa Arizona 0.074 0.070 0.070 0.071 100 100 040134005 Maricopa Arizona 0.073 0.071 0.071 0.071 100 100 040134010 Maricopa Arizona 0.073 0.074 0.070 0.072 100 99 040139706 Maricopa Arizona 0.072 0.073 0.073 0.072 97 100 040137024 Maricopa Arizona 0.074 0.074 0.071 0.073 98 98 040131010 Maricopa Arizona 0.069 0.077 0.076 0.074 100 100 040132001 Maricopa Arizona 0.078 0.074 0.071 0.074 100 100 040133002 Maricopa Arizona 0.077 0.075 0.071 0.074 100 100 040134008 Maricopa Arizona 0.078 0.072 0.074 0.074 100 100 040137020 Maricopa Arizona 0.076 0.074 0.073 0.074 85 99 040133003 Maricopa Arizona 0.080 0.074 0.072 0.075 100 100 040134003 Maricopa Arizona 0.078 0.075 0.073 0.075 98 100 
40 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

040137022 Maricopa Arizona 0.075 0.075 0.076 0.075 99 98 040139508 Maricopa Arizona 0.079 0.073 0.074 0.075 100 97 040139702 Maricopa Arizona 0.077 0.075 0.074 0.075 99 99 040137021 Maricopa Arizona 0.077 0.075 0.080 0.077 95 100 040139997 Maricopa Arizona 0.076 0.079 0.077 0.077 95 94 040130019 Maricopa Arizona 0.083 0.076 0.076 0.078 100 99 040132005 Maricopa Arizona 0.079 0.077 0.080 0.078 47 99 040131004 Maricopa Arizona 0.083 0.079 0.078 0.080 100 100 040131003 Maricopa Arizona 0.044 0.079 0.078 (2) 0 100 040139704 Maricopa Arizona 0.077 0.070 0.068 (2) 99 64 

Pittsburgh-Beaver Valley, PA 

421250005 Washington Pennsylvania 0.076 0.064 0.065 0.068 100 98 421255001 Washington Pennsylvania 0.071 0.071 0.064 0.068 100 100 421250200 Washington Pennsylvania 0.077 0.067 0.064 0.069 100 98 421290008 Westmoreland Pennsylvania 0.075 0.070 0.064 0.069 99 97 420030067 Allegheny Pennsylvania 0.080 0.066 0.065 0.070 100 99 420070014 Beaver Pennsylvania 0.079 0.066 0.066 0.070 94 89 420070002 Beaver Pennsylvania 0.074 0.072 0.069 0.071 97 98 420030008 Allegheny Pennsylvania 0.085 0.070 0.065 0.073 100 98 420050001 Armstrong Pennsylvania 0.078 0.078 0.068 0.074 100 95 420070005 Beaver Pennsylvania 0.083 0.072 0.070 0.075 99 96 420031008 Allegheny Pennsylvania 0.085 0.076 0.071 0.077 100 98 420030010 Allegheny Pennsylvania 0.077 0.075 (3) 90 100 421255200 Washington Pennsylvania 0.056 0.063 0.062 (10) 45 99 
41 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

421290006 Westmoreland Pennsylvania 0.081 0.067 0.053 (3) 100 98 

Reading, PA 

420110006 Berks Pennsylvania 0.075 0.061 0.063 0.066 99 100 420110011 Berks Pennsylvania 0.078 0.068 0.068 0.071 98 99 

San Diego County, CA 

060731010 San Diego California 0.052 0.052 0.068 0.057 96 95 060731011 San Diego California 0.018 0.027 (2) 48 060730001 San Diego California 0.065 0.059 0.063 0.062 97 97 060731008 San Diego California 0.062 0.062 0.071 0.065 96 97 060731016 San Diego California 0.067 0.066 0.070 0.067 96 96 060731002 San Diego California 0.068 0.072 0.076 0.072 88 95 060731006 San Diego California 0.080 0.078 0.080 0.079 96 95 060730003 San Diego California 0.068 0.068 0.048 (2) 94 92 060731001 San Diego California 0.061 0.062 0.073 (2) 81 73 060731014 San Diego California 0.063 (2) 060731018 San Diego California 0.064 (2) 060732007 San Diego California 0.057 0.059 0.049 (2) 93 96 

San Francisco Bay Area, CA 

060010009 Alameda California 0.040 0.046 0.057 0.047 95 98 060010011 Alameda California 0.046 0.045 0.051 0.047 96 95 060750005 San Francisco California 0.047 0.043 0.052 0.047 95 97 060131004 Contra Costa California 0.049 0.052 0.055 0.052 98 98 060410001 Marin California 0.049 0.057 0.064 0.056 98 98 
42 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

060811001 San Mateo California 0.050 0.056 0.064 0.056 97 97 060550003 Napa California 0.058 0.055 0.062 0.058 97 97 060950004 Solano California 0.056 0.055 0.064 0.058 96 99 060850005 Santa Clara California 0.057 0.060 0.065 0.060 95 94 060012001 Alameda California 0.052 0.059 0.072 0.061 100 100 060950005 Solano California 0.067 0.061 0.063 0.063 98 99 060130002 Contra Costa California 0.070 0.057 0.067 0.064 98 98 060851001 Santa Clara California 0.063 0.062 0.069 0.064 98 100 060850002 Santa Clara California 0.066 0.063 0.071 0.066 94 99 060131002 Contra Costa California 0.072 0.062 0.069 0.067 99 76 060132007 Contra Costa California 0.065 0.065 0.072 0.067 98 98 060852006 Santa Clara California 0.070 0.067 0.073 0.070 100 100 060010007 Alameda California 0.071 0.069 0.076 0.072 98 98 060852009 Santa Clara California 0.061 0.063 (3) 99 93 060970003 Sonoma California 0.042 0.055 (3) 98 95 060970004 Sonoma California 0.054 (11) 

San Luis Obispo County (Eastern part), CA 

060798006 

San Luis Obispo California 0.075 0.067 0.068 0.070 98 99 

060798005 

San Luis Obispo California 0.081 0.075 0.073 0.076 98 98 

Seaford, DE 

100051002 Sussex Delaware 0.084 0.065 0.063 0.070 100 93 100051003 Sussex Delaware 0.085 0.072 0.067 0.074 92 97 
43 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

Sheboygan, WI 

551170006 Sheboygan Wisconsin 0.093 0.078 0.072 0.081 97 100 

St. Louis-St. Charles-Farmington, MO-IL 

171630010 Saint Clair Illinois 0.083 0.066 0.067 0.072 98 97 291890005 Saint Louis Missouri 0.085 0.067 0.065 0.072 100 100 295100085 St. Louis City Missouri 0.087 0.066 0.066 0.073 100 100 171199991 Madison Illinois 0.083 0.071 0.068 0.074 83 100 171193007 Madison Illinois 0.087 0.069 0.070 0.075 99 98 290990019 Jefferson Missouri 0.085 0.069 0.072 0.075 100 100 171190008 Madison Illinois 0.084 0.072 0.072 0.076 73 99 171191009 Madison Illinois 0.084 0.075 0.070 0.076 95 98 291831004 Saint Charles Missouri 0.086 0.071 0.072 0.076 100 100 291890014 Saint Louis Missouri 0.090 0.070 0.072 0.077 100 100 291831002 Saint Charles Missouri 0.092 0.071 0.072 0.078 100 86 

Tuscan Buttes, CA 

061030004 Tehama California 0.077 0.072 0.076 0.075 100 98 

Upper Green River Basin, WY 

560350101 Sublette Wyoming 0.067 0.061 0.057 0.061 100 98 560350099 Sublette Wyoming 0.065 0.061 0.060 0.062 93 97 560350700 Sublette Wyoming 0.065 0.064 0.060 0.063 94 98 560350100 Sublette Wyoming 0.067 0.063 0.062 0.064 100 98 560351002 Sublette Wyoming 0.066 0.064 0.062 0.064 100 100 
44 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

560350097 Sublette Wyoming 0.066 0.059 (12) 97 98 560359991 Sublette Wyoming 0.066 0.066 0.062 (13) 74 91 

Washington, DC-MD-VA 

511530009 

Prince William Virginia 0.072 0.066 0.062 0.066 99 100 

511071005 Loudoun Virginia 0.073 0.066 0.063 0.067 99 100 240313001 Montgomery Maryland 0.073 0.069 0.064 0.068 98 98 240210037 Frederick Maryland 0.078 0.069 0.063 0.070 92 97 240330030 

Prince George's Maryland 0.079 0.068 0.065 0.070 100 100 

240170010 Charles Maryland 0.084 0.064 0.067 0.071 90 90 510590030 Fairfax Virginia 0.084 0.067 0.065 0.072 98 99 110010043 

District of Columbia 

District Of Columbia 0.087 0.066 0.068 0.073 100 99 

240090011 Calvert Maryland 0.082 0.067 0.070 0.073 98 99 510130020 Arlington Virginia 0.084 0.067 0.071 0.074 92 94 240338003 

Prince George's Maryland 0.090 0.069 0.069 0.076 97 100 

110010041 

District of Columbia 

District Of Columbia 0.076 0.062 0.047 (3) 98 99 

110010050 

District of Columbia 

District Of Columbia 0.066 0.069 (8) 42 

240339991 

Prince George's Maryland 0.084 0.072 0.069 (9) 88 82 
45 

AQS Site ID County Name State 

4th Highest Daily Max 8-hr Avg 

Value (ppm) 

2012-

2014 

Design 

Value 

(ppm) 

(1) 

Percent Compl

2012 2013 2014 2012 2013 

515100009 

Alexandria City Virginia 0.086 (14) 64 

(1) The level of the 2008 8-hour ozone NAAQS is 0.075 parts per million (ppm). The design value is determined by the 3-year averag

annual fourth highest daily maximum 8-hour average ozone concentration. Each area’s design value is determined by the highest desig

among monitors with valid design values. The design values shown here are computed using Federal Reference Method or equivalent 

by State, Tribal, and Local monitoring agencies to EPA's Air Quality System (AQS) as of July 20, 2015. Individual 8-hour concentrat

were flagged by State, Tribal, or Local monitoring agencies as having been affected by an exceptional event (e.g., wildfire, volcanic ereceived concurrence from the associated EPA Regional Office are not included in these calculations. (2) Monitor did not collect sufficient data to calculate a valid 2012-2014 design value. However, since other monitor(s) in the area hadesign values that violated the NAAQS, the area qualifies for reclassification to Moderate. Also, at least one monitor in the area reporfourth highest daily maximum 8-hour average value greater than the NAAQS; therefore the area does not qualify for a 1-year attainmeextension. (3) Monitor shut down prior to the end of the 2014 ozone monitoring season and did not collect sufficient data to calculate a valid 201design value. Monitor previously attained the NAAQS based on 2011-2013 data. The monitor shut down was approved by EPA throu

annual monitoring network plan review process (see 40 CFR 58.10). (4) Site 482010070 monitor was moved to site 482011017 in June, 2012. Therefore, neither site collected sufficient data to calculate a 2014 design value. Site 482011017 monitor has sufficient data to determine that the 2014 fourth highest daily maximum 8-hour averanot exceed the level of the NAAQS. (5) Monitor shut down January 1, 2013 and did not collect sufficient data to calculate a valid 2012-2014 design value. The previous D

monitor recorded a violation in 2010-2012 (0.076 ppm), but the remaining site in the nonattainment area always had the highest DV in 

The monitor shut down was approved by EPA through the annual monitoring network plan review process (see 40 CFR 58.10). 

(6) Monitor did not collect sufficient monitoring data to calculate a valid 2012-2014 design value, which requires an average percent o

valid data in the designated ozone monitoring season of at least 90 percent. However, because other monitors in the area had valid 201

design values that violated the NAAQS, the 2012-2014 design value is not needed to determine that the area violated. The monitor did 
46 

sufficient data (i.e., at least 75 percent of the designated sampling days) to determine a valid 2014 fourth highest daily maximum 8-hovalue adequate to determine if the area qualifies for a 1-year attainment date extension. (7) Monitor did not collect sufficient data in 2014. We substituted missing values for this site with the highest corresponding values fr

three New Castle County monitoring sites, which created a complete data set to calculate a valid 2012-2014 design value and a 2014 fdaily maximum value (see Exhibit 2 in the Appendix to this TSD). 

(8) Monitor began operation after the beginning of the 2013 ozone monitoring season and has not yet collected sufficient data to calcu

3-year design value. However, this monitor has sufficient data to determine a valid 2014 fourth highest daily maximum 8-hour averagdetermine if the area meets the air quality criteria pertaining to a 1-year attainment date extension.(9) Monitor did not collect sufficient data to calculate a valid 2012-2014 design value. However, this monitor has sufficient data to devalid 2014 fourth highest daily maximum 8-hour average value to determine if the area meets the air quality criteria pertaining to a 1-y

attainment date extension. (10) Monitor began operation after the beginning of the 2012 ozone monitoring season and has not yet collected sufficient data to calc

3-year design value. However, this monitor has sufficient data to determine a valid 2014 fourth highest daily maximum 8-hour averagdetermine if the area meets the air quality criteria pertaining to a 1-year attainment date extension.(11) Monitor began operation at the beginning of the 2014 ozone monitoring season and has not yet collected sufficient data to calcula

year design value.  (12) Monitor shut down at the end of the 2013 ozone monitoring season and did not collect sufficient data to calculate a valid 2012-2

value. Monitor previously attained the NAAQS based on 2011-2013 data. The monitor was designated a Special Purpose monitor in Athe Wyoming Annual Monitoring Network Plan. 40 CFR Section 58.20(f) states that “Prior approval from EPA is not required for dis

of an SPM.” (13) CASTNET monitor started 6/1/2011, and had incomplete data in 2012 so that a valid design value could not be calculated. Since 2011, and with complete data through March 2015 with the exception of missing June and July 2012 data, the monitor has recorded no that have exceeded the ozone standard of 0.075 ppm.(14) Monitor shut down prior to the 2014 ozone monitoring season and did not collect sufficient data to calculate a valid 2012-2014 d

The monitor shut down was approved by EPA through the annual monitoring network plan review process (see 40 CFR 58.10). 
47 

Exhibit 2: 

Philadelphia-Wilmington-Atlantic City Nonattainment Area (PA-NJ-MD-DE) 

1-Year Attainment Date Extension – Delaware Monitoring Data Substitution 

Introduction:

As part of its proposals for the 2008 ozone NAAQS Marginal nonattainment areas, the U.S. 

Environmental Protection Agency is proposing a 1-year attainment date extension for the 

Philadelphia-Wilmington-Atlantic City area (“Philadelphia area”). This “extension year” is 

allowed under CAA section 181(a)(5) for areas that did not attain the 2008 ozone NAAQS by the 

July 20, 2015 attainment date, but were otherwise in compliance with their SIPs and whose 

fourth highest daily maximum 8-hour average did not exceed the ozone NAAQS in the year 

preceding the extension year (i.e., 2014). For the 4-state Philadelphia area (PA-NJ-MD-DE), 

three of the four states have requested the 1-year attainment date extension, with the exception of 

the state of Delaware. In 2014, all of the four Delaware monitoring sites (in New Castle County) 

reported fourth-highest daily maximum 8-hour average ozone concentrations less than or equal 

to the 0.075 ppm standard level; however, one monitoring site (ID 100031010, or Site 1010) did 

not satisfy the EPA’s data completeness guidelines. 4 The EPA is proposing to substitute 

maximum readings from the other New Castle County monitoring sites for missing daily values 

from the deficient monitoring site to meet the data completeness guidelines for the 2014 air 

quality data. 

Discussion 

As illustrated in Table 1, all monitoring sites for the Philadelphia area reported 2014 fourthhighest daily maximum 8-hour average ozone concentrations less than the 0.075 ppm standard 

level. 

Table 1: 2014 4th Highest Daily Maximum 8-hour Average Concentrations for the 

Philadelphia Nonattainment Area 

AQS Monitoring 

Site ID County Name State 

2014 4th 

Highest Daily 

Max 8-hr 

Average Value 

(ppm) 

420170012 Bucks Pennsylvania 0.071

420290100 Chester Pennsylvania 0.071

 

4

 Note that Site ID100032004 did not collect sufficient monitoring data to calculate a valid 2012-2014 design value, 

which requires an average percent of days with valid data in the designated ozone monitoring season of at least 90 

percent. However, because other monitors in the area had valid 2012-2014 design values that violated the NAAQS, 

the 2012-2014 design value is not needed to determine that the area violated. The monitor did collect sufficient data 

(i.e., at least 75 percent of the designated sampling days) to determine a valid 2014 fourth highest daily maximum 8-

hour average value (0.068 ppm), adequate to determine if the area qualifies for a 1-year attainment date extension. 
48 

AQS Monitoring 

Site ID County Name State 

2014 4th 

Highest Daily 

Max 8-hr 

Average Value 

(ppm) 

420450002 Delaware Pennsylvania 0.073

420910013 Montgomery Pennsylvania 0.072

421010004 Philadelphia Pennsylvania 0.058

421010024 Philadelphia Pennsylvania 0.072

421010048 Philadelphia Pennsylvania 0.068

340010006 Atlantic New Jersey 0.061

340070002 Camden New Jersey 0.068

340071001 Camden New Jersey 0.068

340110007 Cumberland New Jersey 0.067

340150002 Gloucester New Jersey 0.07

340210005 Mercer New Jersey 0.071

340219991 Mercer New Jersey 0.071

340290006 Ocean New Jersey 0.072

240150003 Cecil Maryland 0.074 

100031007 New Castle Delaware 0.071

100031010 New Castle Delaware 0.074

100031013 New Castle Delaware 0.069

100032004 New Castle Delaware 0.068

The data handling and ambient air quality monitoring data completeness requirements for the 8-

hour ozone NAAQS are given in 40 CFR 50, Appendix I. Specifically, section 2.3(b) requires a 

minimum data completeness in any one year of at least 75 percent of the days in the designated 

ozone monitoring season. For the Philadelphia area, the ozone monitoring season extends from 

April 1 through October 31, for a total of 214 days. In 2014, one of the four New Castle County 

monitoring sites (ID 100031010, or Site 1010) had monitoring data for only 157 days (73 

percent) of the ozone monitoring season, which is insufficient to judge compliance with the 

standard. 

To remedy this deficiency, we propose to substitute the missing daily maximum 8-hour average 

ozone readings for Site 1010 with the highest of the corresponding daily values from the other 

three New Castle County monitoring sites.5

 This approach provides reasonable estimates of 

worst-case readings for Site 1010 where data were missing and generates sufficient data 

completeness (in this case, 100 percent). In total, we substituted 57 values for Site 1010, and 

only one of those values was needed to determine the four highest daily maximum 8-hour 

average ozone concentrations. 

 

5

 Site 1010 is located within approximately five miles of New Castle County monitoring sites 100031013 and 

100032004, and within approximately 20 miles of New Castle County monitoring site 100031007. 
49 

Table 2 illustrates how the EPA used available maximum values from other New Castle County 

monitoring sites to substitute for missing daily maximum 8-hour average ozone concentrations at 

Site 1010. For illustration purposes, the table presents the 10 days of highest values for Site 1010 

in descending order, compared with corresponding values for the other three monitoring sites. 

Within the four highest values, only one substitute reading was used (0.083 ppm from Site 1013 

and Site 2004 on July 11, 2014), resulting in a fourth-highest daily maximum 8-hour average 

ozone concentration of 0.075 ppm for Site 1010. Note that, using this approach, the fourthhighest value would remain the same, even if a higher substitute value were used for the missing 

July 11, 2014 reading. 

Table 2: Illustration of Data Substitution Used to Determine 2014 4th-highest Daily 

Maximum 8-hour Average Ozone Concentration for Delaware (New Castle County) 

Monitoring Site 1010 

Monitoring 

Date 

Daily Maximum 8-hour Average Ozone Concentration (ppm) by Monitoring Site 1

ORIGINAL WITH SUBSTITUTION 2

1007 1010 1013 2004 1007 1010 1013 2004 

7/11/2014 0.081 NO DATA 0.083 0.083 0.081 0.083 0.083 0.083 

8/27/2014 0.071 0.081 0.081 0.079 0.071 0.081 0.081 0.079 

7/8/2014 0.078 0.078 NO 

DATA 0.067 0.078 0.078 NO DATA 0.067 

7/7/2014 0.075 0.075 0.068 0.068 0.075 0.075 

(4th highest) 0.068 0.068 

8/26/2014 0.066 0.074 

(4th highest) 0.073 0.070 0.066 0.074 0.073 0.070 

6/16/2014 NO 

DATA 0.072 0.063 0.067 NO DATA 0.072 0.063 0.067 

6/17/2014 NO 

DATA 0.071 0.069 0.066 NO DATA 0.071 0.069 0.066 

5/26/2014 0.051 0.069 0.066 0.064 0.051 0.069 0.066 0.064 

5/20/2014 0.053 0.068 0.067 0.059 0.053 0.068 0.067 0.059 

6/28/2014 0.052 NO DATA 0.066 0.063 0.052 0.066 0.066 0.063 

1

 Monitoring site IDs are truncated (100031007, 100031010, 100031013, 100032004). 

2

 Data substitution not applied for Site 1007 and Site 1013, which satisfied the EPA’s data completeness guidelines 

for 2014. 

Comparing Tables 1 and 2, the fourth-highest daily maximum 8-hour average ozone 

concentration for Site 1010 changes from 0.074 ppm (based on incomplete data) to 0.075 ppm 

(based on complete data with substitution). 

Conclusions 

The four Delaware monitoring sites (in New Castle County) reported 2014 fourth-highest daily 

maximum 8-hour average ozone concentrations less than the 0.075 ppm standard level. One site 
50 

(Site 1010) did not satisfy the EPA’s data completeness guidelines. The fourth-highest daily 

maximum 8-hour average ozone concentration for Site 1010 (0.074 ppm) was therefore not 

valid. We substituted missing values for Site 1010 with the highest corresponding values from 

the other three New Castle County monitoring sites, which created a complete data set for Site 

1010. The EPA used data substitution to develop the 2014 data for Site 1010 that meets the data 

handling and ambient air quality monitoring data completeness requirements for the 8-hour 

ozone NAAQS. The fourth-highest daily maximum 8-hour average ozone concentration for Site 

1010 is 0.075 ppm in 2014.