Report on Air Quality in Nonattainment Areas 

For 2003-2005 Covering Ozone, Particulate Matter, 

Carbon Monoxide, Sulfur Dioxide, Nitrogen Dioxide, 

and Lead 

Technical Summary 

November 2006 

(Revised 2/14/07)

U.S. Environmental Protection Agency 

Office of Air Quality Planning and Standards 

Air Quality Assessment Division 

Air Quality Analysis Group 

Research Triangle Park, NC 27701 
TABLE OF CONTENTS 

Page 

INTRODUCTION ...............................................................................................................1 

SUMMARY.........................................................................................................................1 

BACKGROUND INFORMATION ....................................................................................2 

AIR QUALITY DESIGNATIONS AND CLASSIFICATIONS ........................................3 

CRITERIA POLLUTANTS ................................................................................................4 

Ozone .............................................................................................................................. 4 

8-Hour Ozone.............................................................................................................. 5 

Early Action Compacts ............................................................................................. 13 

Particulate Matter.......................................................................................................... 13 

PM2.5 ......................................................................................................................... 14 

PM10 .......................................................................................................................... 18 

Carbon Monoxide ......................................................................................................... 22 

Sulfur Dioxide............................................................................................................... 23

Nitrogen Dioxide .......................................................................................................... 24 

Lead............................................................................................................................... 24 

LIST OF APPENDICES 

Page 

A Additional Information on Area Classifications for the 8-Hour Ozone Standard A1 

B Interpretation of the 8-Hour Primary and Secondary National Ambient Air 

Quality Standards for Ozone.................................................................................B1 

C Interpretation of the National Ambient Air Quality Standards for PM2.5 .............C1 

D Interpretation of the National Ambient Air Quality Standards for PM ................D1 

LIST OF TABLES 

Page 

1 National Ambient Air Quality Standards for Criteria Pollutants.............................3 

2 Areas Designated Nonattainment in June 2004 and Classifications for the 8-Hour 

Ozone NAAQS ........................................................................................................6 

3 Trends in Design Values for the 8-Hour Ozone NAAQS 2001-2005 for 

Designated Nonattainment Areas ............................................................................7 

4 20 Areas Measuring Highest 8-Hour Ozone Design Values Above the NAAQS: 

2003-2005 ..............................................................................................................12 

5 Current Designated Nonattainment Areas (Jan 2005) and Design Values for the 

PM2.5 NAAQS........................................................................................................15 

6 20 Areas Measuring Highest Annual PM2.5 Design Values Above the NAAQS: 

2003-2005 ..............................................................................................................17 

7 Areas Newly Violating the PM2.5 NAAQS: 2003-2005 .......................................18 

8 Area Designations and Classifications for the PM10 NAAQS...............................18 

i 
9 Current Designated Nonattainment Areas and Design Values for the PM10 

NAAQS: 2001-2003 through 2003-2005..............................................................20 

10 Areas Newly Violating the PM10 NAAQS: 2003-2005........................................22 

11 Current Designated Nonattainment Areas and Design Values for the 8-Hour CO 

NAAQS: 2002-2003 through 2004-2005..............................................................23 

12 Area Newly Violating the CO NAAQS: 2003-2005 ............................................23 

13 Areas Currently Designated Nonattainment for the Lead NAAQS or Designated 

Attainment But Not Meeting the Lead NAAQS....................................................26 

LIST OF FIGURES 

Page 

1 Original 8-Hour Ozone Nonattainment Areas with 2001-2003 Data and Areas 

Remaining Above the NAAQS with 2003-2005 Data...........................................10 

2 20 Areas Measuring Highest 8-Hour Ozone Design Values Above the NAAQS: 

2003-2005 ..............................................................................................................12 

3 PM2.5 Nonattainment Areas with 2001-2003 Data and Areas Above the NAAQS 

with 2003-2005 Data..............................................................................................16 

ii 
INTRODUCTION 

This report presents information on outdoor air quality based on monitoring data 

collected throughout the country during 2003-2005. It focuses on areas where air quality 

was previously determined by the U.S. Environmental Protection Agency (EPA or 

agency) to be unhealthy and designated as nonattainment for one or more of the six 

principal outdoor air pollutants referred to as criteria pollutants. The criteria pollutants 

are ozone, particulate matter (PM), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen 

dioxide (NO2) and lead. Each year the EPA looks at the levels of these pollutants in the 

air measured at monitors located across the country to evaluate how air quality has 

changed over time and summarizes the current status of air quality in designated 

nonattainment areas. Background information on the pollutants is included to set the 

context for readers. 

SUMMARY 

• Ozone 

o Ozone design values in designated nonattainment areas are improving. 

o An increasing number of designated nonattainment areas are attaining the 

ozone National Ambient Air Quality Standards (NAAQS or standards). 

o There are no areas newly violating the ozone NAAQS. 

• PM2.5 

o PM2.5 design values in designated nonattainment areas are improving. 

o One designated nonattainment area is measuring attainment with 

monitoring data collected during 2003-2005. 

o There are five areas newly violating the PM2.5 NAAQS. 

• PM10 

o There are 46 designated nonattainment areas for the PM10 NAAQS. Air 

quality in 29 of these areas is measuring attainment. 

o There are 21 areas newly violating the PM10 NAAQS. 

o There are three maintenance areas violating the PM10 NAAQS. 

• CO 

o All of the designated nonattainment areas have air quality monitoring data 

measuring attainment of the CO NAAQS. 

o There is one area newly violating the CO NAAQS. 

• SO2 

o All of the designated nonattainment areas have air quality monitoring data 

measuring attainment of the SO2 NAAQS. 

o There is one area newly violating both the 24-hour and 3-hour secondary 

SO2 NAAQS. 

• NO2 

o There are no designated NO2 nonattainment areas. 

o All areas are meeting the NO2 NAAQS. 

• Lead 

1 
o There are two areas designated as nonattainment for the lead NAAQS. 

Air quality monitoring is no longer conducted in one area and air quality 

in the second area is violating the NAAQS. 

o There is one area that is designated as attainment with a monitor that is 

violating the lead NAAQS. 

BACKGROUND INFORMATION 

The Clean Act (CAA) requires EPA to set NAAQS for ‘criteria pollutants.’ 

Currently, lead and five other major pollutants are listed as criteria pollutants. 

(The others are ozone, nitrogen oxides, carbon monoxide, sulfur dioxide, and 

particulate matter.) The law also requires EPA to periodically review the 

standards to ensure that they provide adequate health and environmental 

protection, and to update those standards as necessary. The CAA requires two 

types of national air quality standards. Primary standards set limits to protect 

public health, including the health of "sensitive" populations such as asthmatics, 

children, and the elderly. Secondary standards set limits to protect public welfare, 

including protection against visibility impairment, damage to animals, crops, 

vegetation, and buildings. The NAAQS for criteria pollutants are shown in Table 

1. It is followed by a discussion of terms or names that are applied to an area 

based on how air quality compares to the NAAQS. 

2
------- 

------- 

------- 

Table 1. National Ambient Air Quality Standards for Criteria Pollutants 

Pollutant Primary Stds. Averaging Times Secondary Stds. 

Carbon Monoxide 9 ppm (10 mg/m3) 8-hour1 None 

35 ppm (40 mg/m3

) 1-hour1 None 

Lead 1.5 μg/m3 Quarterly Average Same as Primary 

Nitrogen Dioxide 0.053 ppm (100 μg/m3) Annual (Arithmetic Mean) Same as Primary 

Particulate Matter 

(PM10) 

Revoked2 Annual (Arith. Mean) Same as Primary 

150 μg/m3

 24-hour3 

Particulate Matter 

(PM2.5) 

15.0 μg/m3 Annual4 (Arith. Mean) Same as Primary 

35 μg/m3

 24-hour5 

Ozone 0.12 ppm 1-hour6 Applies only in 

limited areas 

Same as Primary 

0.08 ppm 8-hour7 Same as Primary 

Sulfur Oxides 0.03 ppm Annual (Arith. Mean) 

0.14 ppm 24-hour1 

3-hour1 0.5 ppm (1300 μg/m3

) 

Units of measure for the standards are parts per million (ppm) by volume, milligrams per cubic meter of air 

(mg/m3), and micrograms per cubic meter of air (μg/m3). 

1

 Not to be exceeded more than once per year. 

2

 Due to a lack of evidence linking health problems to long-term exposure to coarse particle pollution, the 

agency revoked the annual PM10 standard in 2006. 3 Not to be exceeded more than once per year on average over 3 years. 4

 To attain this standard, the 3-year average of the weighted annual mean PM2.5 concentrations from single or 

multiple community-oriented monitors must not exceed 15.0 μg/m3 

. 5

 To attain this standard, the 3-year average of the 98th percentile of 24-hour concentrations at each 

population-oriented monitor within an area must not exceed 35 μg/m3 

6 (a) This standard is attained when the expected number of days per calendar year with maximum hourly 

average concentrations above 0.12 ppm (235 μg/m3

) is equal to or less than 1. 

(b) As of June 15, 2005, the agency revoked the 1-hour ozone standard in all areas except the fourteen 8-hour 

ozone nonattainment Early Action Compact Areas. 

7

 To attain this standard, the 3-year average of the fourth-highest daily maximum 8-hour average ozone 

concentrations measured at each monitor within an area over each year must not exceed 0.08 ppm. 

AIR QUALITY DESIGNATIONS AND CLASSIFICATIONS 

A designation is the term EPA uses to describe how the air quality status in a 

given area compares to the NAAQS for any of the six criteria pollutants. To determine 

the correct designation, air quality data is collected at each monitoring site and used to 

calculate a design value. The design value is the pollutant concentration that describes 

whether a site is at, above, or below the level of the NAAQS. Design values are 

especially helpful when the standard is exceedance-based because they are expressed as a 

concentration instead of an exceedance count, thereby allowing a direct comparison to 

the level of the standard. Information on how design values are determined for selected 

pollutants is included in the Appendix. 

3 
EPA designates areas as nonattainment, unclassifiable/attainment, or 

unclassifiable. When air quality in an area exceeds the NAAQS for one of the criteria 

pollutants or contributes to a nearby area that exceeds the NAAQS, EPA designates that 

area as nonattainment. Under certain conditions, a designated nonattainment area may 

consist of a full or partial county or counties within an urbanized area or a rural area. 

Where data show that air quality in an area meets the NAAQS, that is, the pollution 

concentration is at or below the level of the NAAQS, the area may be designated as 

unclassifiable/attainment. If an area cannot be determined on the basis of available 

information as meeting or not meeting the NAAQS, EPA may designate the area 

unclassifiable. A nonattainment or unclassifiable area may be eligible for redesignation to 

attainment when air quality data show that the NAAQS and other requirements for 

redesignation are met. In addition to a nonattainment designation, EPA classifies O3, 

CO, and some PM nonattainment areas, based on the area’s design value, for the purpose 

of applying an attainment date or to specify the requirements to which it will be subject. 

For example, an area’s ozone classification may be marginal, moderate, serious, severe, 

or extreme. Subpart 1 is not a classification but is a term used in connection with certain 

areas to indicate the section of the CAA containing basic requirements that must be met 

to improve air quality. The technical details underlying classifications are contained in 

Title I of the CAA, Sections 172 and 181 and in the Title 40 of the Code of Federal 

Regulations (CFR) Part 51 Subpart X. General information on classifications is provided 

in the Appendix. The following discussion provides information on each of the criteria 

pollutants. 

CRITERIA POLLUTANTS 

Ozone 

Ozone is a photochemical oxidant that is the prime ingredient of smog in cities 

and other areas of the country. While ozone in the upper atmosphere is beneficial to life 

by shielding the earth from harmful ultraviolet radiation from the sun, high 

concentrations of ozone at ground level are a major health and environmental concern. 

Ozone is not emitted directly into the air but is formed through complex chemical 

reactions between precursor emissions of volatile organic compounds (VOCs) and oxides 

of nitrogen (NOx) in the presence of sunlight. These reactions are stimulated by sunlight 

and temperature so that peak ozone levels occur typically during the warmer times of the 

year. Both VOCs and NOx are emitted by human activity such as transportation and 

industrial processes. VOCs are emitted from sources as diverse as autos, chemical 

manufacturing, dry cleaners, paint shops and other sources using solvents. NOx is 

emitted as a byproduct of most combustion processes. Changing weather patterns 

contribute to yearly differences in ozone concentrations from city to city. Also, ozone and 

the pollutants that cause ozone can be carried to an area from pollution sources located 

hundreds of miles upwind. 

The reactivity of ozone causes health problems because it damages lung tissue, 

reduces lung function and sensitizes the lungs to other irritants. Ozone can irritate your 

respiratory system, causing coughing, irritation in your throat or a burning sensation in 

4
your airways. It can reduce lung function, so that you may have feelings of chest 

tightness, wheezing, or shortness of breath. Ozone can aggravate asthma and trigger 

asthma attacks. People at greater risk from ground-level ozone are people with lung 

diseases, such as asthma, and children and adults who are active outdoors. Damage to 

lung tissue may be caused by repeated exposures to ozone -- something like repeated 

sunburns of the lungs -- and this could result in a reduced quality of life as people age. 

Ground-level ozone interferes with the ability of plants to produce and store food, 

so that growth, reproduction and overall plant health are compromised. By weakening 

sensitive vegetation, ozone makes plants more susceptible to disease, pests, and 

environmental stresses. Ground-level ozone has been shown to reduce agricultural yields 

for many economically important crops (e.g., soybeans, kidney beans, wheat, cotton). 

The effects of ground-level ozone on long-lived species such as trees are believed to add 

up over many years so that whole forests or ecosystems can be affected. For example, 

ozone can adversely impact ecological functions such as water movement, mineral 

nutrient cycling, and habitats for various animal and plant species. Ground-level ozone 

can kill or damage leaves so that they fall off the plants too soon or become spotted or 

brown. These effects can significantly decrease the natural beauty of an area, such as in 

national parks and recreation areas. One of the key components of ozone, nitrogen 

oxides, contributes to fish kills and algae blooms in sensitive waterways, such as the 

Chesapeake Bay. 

 8-Hour Ozone 

In June 2004, EPA designated and classified 126 areas in the U.S. as 

nonattainment for the 8-hour ozone NAAQS based on air quality data exceeding the 

NAAQS collected primarily in 2001-2003. These areas included 462 whole and part 

counties and the District of Columbia. Approximately 159 million people were living in 

areas designated as not meeting the standard (2000 census). The area names and 

classifications are shown in Table 2. Table 3 shows the design values for 2001-2003 at 

designation, 2002-2004, and 2003-2005, and if the area’s design value meets the 8-hour 

ozone NAAQS based on the most recent data collected during 2003-2005. Fourteen of 

these areas had the effective date of their nonattainment designation date delayed. These 

areas have entered into an Early Action Compact (EAC or compact) with EPA as 

discussed below. The remaining areas were designated as unclassifiable/attainment or 

unclassifiable. At designation, design values of the nonattainment areas ranged from 

0.085 to 0.131 ppm. The average value was 0.092 ppm. 

5 
 Table 2. Areas Designated Nonattainment in June 2004 and Classifications for the 8-Hour Ozone NAAQS 

Table 2 

State Area Classification State Area Classification 

NY MI 

MI Allegan County MD Kent and Queen Anne's Counties 

PA CA ) 

PA Altoona WI Kewaunee County 

CA Subpart 1 TN Knoxville Subpart 1 

GA Atlanta IN 

MD Moderate PA Lancaster Marginal 

LA Baton Rouge MI 

NV 

MI OH 

Benzie County CA 

WV CA ) 

AL Louisville 

MA ) GA 

NH ) VA (

NY WI 

OH CA (

MI Cass County MI 

NC-SC Charlotte-Gastonia-Rock Hill WI 

Chattanooga 

GA 

(

CA Chico 

TN Nashville 

Clarksville-Hopkinsville CA ) Subpart 1 

PA CT 

OH VA (HR) 

SC 

OH 

PA-NJModerate 

TX AZ 

OH PA Pittsburgh-Beaver Valley Subpart 1 

CO ME Portland 

NY 

WI RI ) 

PA Erie NC Subpart 1 

NY PA Reading 

IN Evansville VA Marginal 

NC-SC Fayetteville CA ) 

Flint VA Roanoke 

IN Fort Wayne NY Rochester 

PA NC 

VA CA 

VA San Antonio 

MI CA San Diego 

CT CA 

PA CA San Joaquin Valley 

PA 

NC-SC WI 

Albany-Schenectady-Troy Subpart 1 Kalamazoo-Battle Creek Subpart 1 

Subpart 1 Marginal 

Allentown-Bethlehem-Easton Subpart 1 Kern County (Eastern Kern Subpart 1 

Subpart 1 Subpart 1 

Amador and Calaveras Counties (Central Mtn) 

Marginal La Porte Marginal 

Baltimore 

Marginal Lansing-East Lansing Subpart 1 

TX Beaumont-Port Arthur Marginal Las Vegas Subpart 1 

Benton Harbor Subpart 1 Lima Subpart 1 

MI Subpart 1 Los Angeles South Coast Air Basin Severe 17 

Berkeley and Jefferson Counties Subpart 1 

Los Angeles-San Bernardino Counties 

(W Mojave Moderate 

Birmingham Subpart 1 KY-IN Subpart 1 

Boston-Lawrence-Worcester (E. MA Moderate Macon Subpart 1 

Boston-Manchester-Portsmouth (SE Moderate 

Madison and Page Counties 

Shenandoah NP) Subpart 1 

Buffalo-Niagara Falls Subpart 1 Manitowoc County Subpart 1 

Canton-Massillon Subpart 1 

Mariposa and Tuolumne Counties 

Southern Mtn) Subpart 1 

Marginal Mason Co Subpart 1 

WV Charleston Subpart 1 TN-AR Memphis Marginal 

Moderate Milwaukee-Racine Moderate 

TN-GA Subpart 1 IN Muncie Subpart 1 

IL-IN Chicago-Gary-Lake County Moderate 

Murray Co Chattahoochee National 

Forest) Subpart 1 

Subpart 1 MI Muskegon Marginal 

OH-KY-IN Cincinnati-Hamilton Subpart 1 Subpart 1 

TN-KY Subpart 1 Nevada County (Western Part

Clearfield and Indiana Counties Subpart 1 

NY-NJNew York-N. New Jersey-Long Island Moderate 

Cleveland-Akron-Lorain Moderate 

Norfolk-Virginia Beach-Newport News 

Marginal 

Columbia Subpart 1 WV-OH Parkersburg-Marietta Subpart 1 

Columbus Subpart 1 MD-DE Philadelphia-Wilmington-Atlantic City 

Dallas-Fort Worth Moderate Phoenix-Mesa Subpart 1 

Dayton-Springfield Subpart 1 

Denver-Boulder-Greeley-Ft Collins-Loveland Subpart 1 Marginal 

MI Detroit-Ann Arbor Marginal Poughkeepsie Moderate 

Door County Subpart 1 Providence (All RI Moderate 

Subpart 1 Raleigh-Durham-Chapel Hill 

Essex County (Whiteface Mtn) Subpart 1 Subpart 1 

Subpart 1 Richmond-Petersburg 

Subpart 1 Riverside County (Coachella Valley Serious 

MI Subpart 1 Subpart 1 

Subpart 1 Subpart 1 

Franklin County Subpart 1 Rocky Mount Subpart 1 

Frederick County Subpart 1 Sacramento Metro Serious 

Fredericksburg Moderate TX Subpart 1 

Grand Rapids Subpart 1 Subpart 1 

Greater Connecticut Moderate San Francisco Bay Area Marginal 

Greene County Subpart 1 Serious 

IN Greene County Subpart 1 Scranton-Wilkes-Barre Subpart 1 

Greensboro-Winston Salem-High Point Marginal Sheboygan Moderate 

6
Table 2 

State Area Classification State Area Classification 

SC IN Subpart 1 

ME MA ) 

PA 

NC NP) PA State College 

NC 

TX CA (

MI PA 

CA OH 

IN CA 

VA 

NY MD 

NY 

TN PA York 

PA 

Greenville-Spartanburg-Anderson Subpart 1 South Bend-Elkhart 

Hancock, Knox, Lincoln & Waldo Counties Subpart 1 Springfield (Western MA Moderate 

Harrisburg-Lebanon-Carlisle Subpart 1 MO-IL St Louis Moderate 

Haywood and Swain Counties (Great Smoky 

Subpart 1 Subpart 1 

Hickory-Morganton-Lenoir Subpart 1 OH-WV Steubenville-Weirton Subpart 1 

Houston-Galveston-Brazoria Moderate Sutter County Sutter Buttes) Subpart 1 

WV-KY Huntington-Ashland Subpart 1 IN Terre Haute Subpart 1 

Huron County Subpart 1 Tioga County Subpart 1 

Imperial County Marginal Toledo Subpart 1 

Indianapolis Subpart 1 Ventura County Moderate 

IN Jackson County Subpart 1 

DC-MDWashington Subpart 1 

Jamestown Subpart 1 Washington County (Hagerstown) Moderate 

Jefferson County Moderate WV-OH Wheeling Subpart 1 

Johnson City-Kingsport-Bristol Subpart 1 Subpart 1 

Johnstown Subpart 1 OH-PA Youngstown-Warren-Sharon Subpart 1 

Table 3. Trends in Design Values for the 8-Hour Ozone NAAQS 2001-2005 for Designated 

Nonattainment Areas 

Design Value 

Table 3 

State Area 

2001­

2003 

) 

2002­

2004 

) 

2003­

2005 

) 

2005 

NY Yes 

MI Allegan County No 

PA No 

PA Altoona Yes 

CA No 

GA Atlanta No 

MD No 

LA Baton Rouge No 

TX No 

MI Yes 

MI Benzie County Yes 

WV Yes 

AL Yes 

MA ) No 

NH ) Yes 

NY No 

OH Yes 

MI Cass County ** 

WV Yes 

NC-SC Charlotte-Gastonia-Rock Hill No 

Yes 

No 

CA Chico Yes 

No 

Clarksville-Hopkinsville* Yes 

PA Yes 

OH No 

SC Yes 

OH No 

TX No 

OH ** 

CO Yes 

(ppm (ppm (ppm

Meets NAAQS 2003­

Albany-Schenectady-Troy 0.087 0.086 0.082 

0.097 0.093 0.089 

Allentown-Bethlehem-Easton 0.091 0.088 0.087 

0.085 0.081 0.077 

Amador and Calaveras Counties (Central Mtn) 0.091 0.09 0.091 

0.091 0.093 0.09 

Baltimore 0.103 0.094 0.091 

0.086 0.089 0.096 

Beaumont-Port Arthur 0.091 0.092 0.088 

Benton Harbor 0.091 0.086 0.084 

0.088 0.083 0.083 

Berkeley and Jefferson Counties (EAC area) 0.086 0.08 0.076 

Birmingham* 0.087 0.085 0.084 

Boston-Lawrence-Worcester (E. MA 0.095 0.091 0.086 

Boston-Manchester-Portsmouth (SE 0.087 0.084 0.08 

Buffalo-Niagara Falls 0.099 0.091 0.086 

Canton-Massillon 0.09 0.086 0.082 

0.093 0.089 Incomplete Data 

Charleston* 0.086 0.081 0.078 

0.1 0.094 0.088 

TN-GA Chattanooga (EAC area) 0.088 0.086 0.08 

IL-IN Chicago-Gary-Lake County 0.101 0.094 0.086 

0.089 0.088 0.083 

OH-KY-IN Cincinnati-Hamilton 0.096 0.091 0.089 

TN-KY 0.085 0.082 0.077 

Clearfield and Indiana Counties 0.09 0.085 0.082 

Cleveland-Akron-Lorain 0.103 0.095 0.091 

Columbia (EAC area) 0.089 0.086 0.083 

Columbus 0.095 0.091 0.088 

Dallas-Fort Worth 0.1 0.098 0.095 

Dayton-Springfield 0.09 0.087 Incomplete Data 

Denver-Boulder-Greeley-Ft Collins-Loveland (EAC 0.087 0.084 0.084 

7 
Design Value 

Table 3 

State Area 

2001­

2003 

) 

2002­

2004 

) 

2003­

2005 

) 

2005 

area) 

MI No 

WI No 

PA Erie Yes 

NY ** 

IN Evansville* Yes 

NC-SC Yes 

MI Flint Yes 

IN Fort Wayne Yes 

PA Yes 

VA Yes 

VA Yes 

MI Yes 

CT No 

IN Yes 

PA Yes 

NC-SC ) Yes 

SC ) Yes 

ME Yes 

PA Yes 

NC Yes 

NC Yes 

TX No 

Yes 

MI Yes 

CA Yes 

IN No 

IN Yes 

NY No 

NY Yes 

TN Yes 

PA Yes 

MI Yes 

MD Kent and Queen Anne's Counties Yes 

CA ) No 

WI Kewaunee County No 

TN Knoxville No 

IN ** 

PA Lancaster Yes 

MI Yes 

NV Las Vegas No 

OH Yes 

CA No 

CA No 

Louisville Yes 

GA Yes 

VA ** 

WI Manitowoc Co No 

CA No 

MI Yes 

TN-AR No 

WI No 

IN Yes 

GA ( Yes 

MI Yes 

TN Yes 

(ppm (ppm (ppm

Meets NAAQS 2003­

Detroit-Ann Arbor 0.097 0.092 0.09 

Door County 0.094 0.088 0.09 

0.092 0.087 0.083 

Essex County (Whiteface Mtn) 0.091 0.083 Incomplete Data 

0.085 0.083 0.077 

Fayetteville (EAC area) 0.087 0.084 0.083 

0.09 0.085 0.082 

0.088 0.085 0.083 

Franklin County 0.093 0.085 0.075 

Frederick County (EAC area) 0.085 0.078 0.073 

Fredericksburg* 0.088 0.084 0.079 

Grand Rapids 0.089 0.084 0.082 

Greater Connecticut 0.095 0.089 0.087 

Greene County* 0.088 0.084 0.08 

Greene County 0.089 0.084 0.081 

Greensboro-Winston Salem-High Point (EAC area 0.093 0.087 0.082 

Greenville-Spartanburg-Anderson (EAC area 0.087 0.084 0.081 

Hancock, Knox, Lincoln & Waldo Counties 0.094 0.088 0.082 

Harrisburg-Lebanon-Carlisle 0.088 0.082 0.078 

Haywood and Swain Counties (Great Smoky NP) 0.085 0.082 0.078 

Hickory-Morganton-Lenoir (EAC area) 0.088 0.082 0.077 

Houston-Galveston-Brazoria 0.102 0.101 0.103 

WV-KY Huntington-Ashland 0.091 0.086 0.079 

Huron County 0.087 0.08 0.077 

Imperial County 0.087 0.085 0.084 

Indianapolis 0.096 0.092 0.087 

Jackson County* 0.085 0.08 0.075 

Jamestown 0.094 0.093 0.089 

Jefferson County 0.097 0.086 0.081 

Johnson City-Kingsport-Bristol (EAC area) 0.086 0.084 0.079 

Johnstown 0.087 0.08 0.077 

Kalamazoo-Battle Creek 0.086 0.081 0.078 

0.095 0.089 0.082 

Kern County (Eastern Kern 0.098 0.092 0.09 

0.093 0.087 0.086 

0.092 0.091 0.086 

La Porte 0.093 0.086 Incomplete Data 

0.092 0.087 0.083 

Lansing-East Lansing 0.086 0.08 0.078 

0.086 0.085 0.085 

Lima 0.089 0.087 0.081 

Los Angeles South Coast Air Basin 0.131 0.127 0.127 

Los Angeles-San Bernardino Counties (W. Mojave) 0.106 0.107 0.105 

KY-IN 0.092 0.088 0.082 

Macon 0.086 0.086 0.083 

Madison and Page Counties (Shenandoah NP)* 0.087 0.082 Incomplete Data 

0.09 0.083 0.087 

Mariposa and Tuolumne Counties (Southern Mtn) 0.091 0.09 0.088 

Mason Co 0.089 0.082 0.081 

Memphis 0.092 0.087 0.086 

Milwaukee-Racine 0.101 0.094 0.088 

Muncie* 0.088 0.083 0.078 

Murray Co Chattahoochee National Forest) 0.085 0.083 0.079 

Muskegon 0.095 0.086 0.084 

Nashville (EAC area) 0.086 0.083 0.082 

8
Design Value 

Table 3 

State Area 

2001­

2003 

) 

2002­

2004 

) 

2003­

2005 

) 

2005 

CA ) No 

No 

VA ) Yes 

Yes 

DE 

No 

AZ Yes 

PA Pittsburgh-Beaver Valley Yes 

ME Portland Yes 

NY No 

RI ) No 

NC No 

PA Reading Yes 

VA Yes 

CA ) No 

VA Yes 

NY Rochester Yes 

NC Yes 

CA No 

TX No 

CA San Diego No 

CA Yes 

CA San Joaquin Valley No 

PA Yes 

WI No 

IN Yes 

MA ) Yes 

No 

PA State College Yes 

Yes 

CA ( Yes 

IC Yes 

PA Yes 

OH No 

CA No 

MD ( Yes 

No 

Yes 

PA York Yes 

OH-PA No 

(ppm (ppm (ppm

Meets NAAQS 2003­

Nevada County (Western Part 0.098 0.097 0.098 

NY-NJ-CT New York-N. New Jersey-Long Island 0.102 0.095 0.091 

Norfolk-Virginia Beach-Newport News (HR 0.09 0.086 0.078 

WV-OH Parkersburg-Marietta 0.087 0.084 0.081 

PA-NJ-MD- Philadelphia-Wilmington-Atlantic City 0.106 0.099 0.094 

Phoenix-Mesa 0.087 0.085 0.084 

0.094 0.09 0.084 

0.091 0.084 0.077 

Poughkeepsie 0.094 0.089 0.086 

Providence (All RI 0.095 0.09 0.089 

Raleigh-Durham-Chapel Hill 0.094 0.089 0.085 

0.091 0.083 0.08 

Richmond-Petersburg 0.094 0.09 0.082 

Riverside County (Coachella Valley 0.108 0.104 0.104 

Roanoke (EAC area) 0.085 0.079 0.074 

0.088 0.081 0.073 

Rocky Mount 0.089 0.085 0.079 

Sacramento Metro 0.107 0.102 0.097 

San Antonio (EAC area) 0.089 0.091 0.086 

0.093 0.089 0.086 

San Francisco Bay Area 0.086 0.084 0.078 

0.115 0.116 0.113 

Scranton-Wilkes-Barre 0.086 0.081 0.077 

Sheboygan 0.1 0.092 0.089 

South Bend-Elkhart 0.093 0.088 0.083 

Springfield (Western MA 0.094 0.09 0.084 

MO-IL St Louis 0.092 0.089 0.086 

0.088 0.084 0.079 

OH-WV Steubenville-Weirton 0.086 0.083 0.077 

Sutter County Sutter Buttes) 0.088 0.09 0.083 

Terre Haute* 0.087 0.083 0.076 

Tioga County 0.086 0.085 0.081 

Toledo 0.093 0.089 0.086 

Ventura County 0.095 0.094 0.091 

Washington County (Hagerstown) EAC area) 0.086 0.083 0.078 

DC-MD-VA Washington 0.099 0.096 0.091 

WV-OH Wheeling 0.087 0.078 0.076 

0.089 0.086 0.082 

Youngstown-Warren-Sharon 0.095 0.091 0.086 

*This area was originally designated as nonattainment for the ozone NAAQS; however, based on later air quality data, it has been 

redesignated to attainment. 

**A determination of whether this area meets the NAAQS cannot be made due to incomplete data. 

Source: AQS July 10, 2006 

Table 3 demonstrates that ozone air quality is improving in designated 

nonattainment areas. Ozone air quality in 73 of the original 126 O3 areas is meeting the 

NAAQS based on data collect during 2003-2005; thus, satisfying one of several criteria 

that must be met prior to redesignation to attainment. Table 3 further shows that 10 of 

the original areas have effective redesignations to attainment. These redesignations were 

based on earlier data collected during 2002-2004 or 2003-2005 showing attainment of the 

NAAQS and other criteria needed to assure that the area will remain in attainment. 

Based on the redesignations, there are now 116 areas with 157 million people living in 

areas designated as nonattainment for the 8-hour ozone NAAQS (2000 census). 

9 
Figure 1 displays designated ozone nonattainment areas. The map on the left 

shows areas designated as nonattainment for the 8-hour ozone NAAQS in 2004 based on 

air quality data collected during 2001-2003. The map on the right shows 48 remaining 

areas with air quality above the NAAQS based on data collected during 2003-2005. 

Included on the map are four additional areas with incomplete data for 2003-2005 (Cass 

County, Michigan; Dayton-Springfield, Ohio; Essex County (Whiteface Mountain), New 

York; and, La Porte, Indiana). Not included on the map is one area with incomplete data 

2003-2005 that is redesignated to attainment based on earlier data (Madison and Page 

Counties (Shenandoah National Park), Virginia. These areas do not have complete data 

as of this writing; therefore, a determination of whether the areas are attaining or not 

attaining cannot be made at this time. Only one area, Mariposa and Tuolumne Counties in 

California with air quality monitoring data measuring attainment of the standard during 

the 2002-2004 time period, went back into nonattainment based on their monitoring data 

collected during 2003-2005. Twenty-two areas not attaining in 2002-2004 are now 

attaining based on 2003-2005 data. In 2005, there were no new areas monitoring air 

quality in violation of the ozone NAAQS. 

Figure 1. Ozone Nonattainment Areas with 2001-2003 Data and Areas Above the NAAQS 

with 2003-2005 Data 

During 2002-2004, design values of the original nonattainment areas ranged from 

0.078 ppm to 0.127 ppm. The average was 0.088 ppm. Air quality improved in all but 

four areas. In the four areas, air quality in Amador and Calaveras Counties and Nevada 

County, California remained the same while ozone design values in Baton Rouge, 

Louisiana and Houston, Texas increased from 0.086 to 0.096 ppm and 0.102 to 0.103 

ppm, respectively. 

During 2003-2005, design values of the original nonattainment areas ranged from 

0.073 ppm to 0.127 ppm. The average was 0.084 ppm. Reflecting the lower ozone 

pollution, all but eight areas show lower design values than those measured during the 

2002 through 2004 time period. The improvements range from about 1 percent to 12 

percent. There are 44 areas with five percent or more improvement. The areas are: 

10
- California: Chico, San Francisco Bay Area, and Sutter County (Sutter Buttes); 

- District of Columbia-Maryland-Virginia: Washington; 

- Illinois-Indiana: Chicago-Gary-Lake County; 

- Indiana: Evansville, Indianapolis, Jackson County, Muncie, South BendElkhart, and Terre Haute; 

- Kentucky-Indiana; Louisville; 

- Maine: Hancock, Knox, Lincoln & Waldo Counties; and Portland; 

- Maryland: Kent and Queen Anne’s Counties, and Washington County 

(Hagerstown); 

- Massachusetts: Boston-Lawrence-Worcester (Eastern. MA), and Springfield 

(Western MA); 

- Michigan: Grand Rapids; 

- New York: Buffalo-Niagara Falls, Jefferson County, and Rochester; 

- North Carolina: Greensboro-Winston Salem-High Point, Hickory-MorgantonLenoir, and Rocky Mount; 

- North Carolina-South Carolina: Charlotte-Gastonia-Rock Hill; 

- Ohio: Lima; 

- Ohio-Pennsylvania: Youngstown-Warren-Sharon; 

- Ohio-West Virginia: Steubenville-Weirton; 

- Pennsylvania: Franklin County, Pittsburgh-Beaver Valley, and State College; 

- Pennsylvania-New Jersey-Maryland-Delaware: Philadelphia-WilmingtonAtlantic City; 

- Tennessee: Johnson City-Kingsport-Bristol, and Knoxville; 

- Tennessee-Georgia: Chattanooga; 

- Tennessee-Kentucky: Clarksville-Hopkinsville; 

- Texas: San Antonio; 

- Virginia: Frederick County, Norfolk-Virginia Beach-Newport News (HR), 

Richmond-Petersburg, and Roanoke; 

- West Virginia: Berkeley and Jefferson Counties; 

- West Virginia-Kentucky: Huntington-Ashland; and, 

- Wisconsin: Milwaukee-Racine. 

In the same time period, air quality in six areas worsened from about 1 percent to 

8 percent. The areas are: 

- Louisiana: Baton Rouge, from 0.089 ppm to 0.096 ppm;

- Texas: Houston-Galveston-Brazoria, from 0.101 ppm to 0.103 ppm;

- Wisconsin: Manitowoc County, from 0.083 ppm to 0.087 ppm;

- Wisconsin: Door County, from 0.088 ppm to 0.090 ppm;

- California: Amador and Calaveras Counties (Central Mtn), from 0.090 ppm 

to 0.091 ppm; and, 

- California: Nevada County (Western Part), from 97 ppm to 98 ppm. 

Table 4 and Figure 2 show the top 20 areas with ozone air quality problems in the 

U.S. along with their design values for data collected in 2003-2005. Although these areas 

have the highest ozone design values, air quality has improved since 2001-2003 in all 

11
areas except Baton Rouge, Louisiana, and Houston-Galveston-Brazoria, Texas, where it 

has worsened as noted above and several areas where it has remained stable. 

Table 4. 20 Areas Measuring Highest 8-Hour Ozone Design Values Above the NAAQS: 

2003-2005 

Table 4 

State ) 

CA 

CA San Joaquin Valley 

CA 

CA ) 

CA ) 

CA 

LA Baton Rouge 

CA 

MD 

OH 

CA 

GA Atlanta 

MI 

CA ) 

Area 

Design Value 

(ppm

Los Angeles South Coast Air Basin 0.127 

0.113 

Los Angeles-San Bernardino Counties (W Mojave) 0.105 

Riverside County (Coachella Valley 0.104 

TX Houston-Galveston-Brazoria 0.103 

Nevada County (Western Part 0.098 

Sacramento Metro 0.097 

0.096 

TX Dallas-Fort Worth 0.095 

PA-NJ-MD-DE Philadelphia-Wilmington-Atlantic City 0.094 

Amador and Calaveras Counties (Central Mtn) 0.091 

Baltimore 0.091 

Cleveland-Akron-Lorain 0.091 

NY-NJ-CT New York-N. New Jersey-Long Island 0.091 

Ventura County 0.091 

DC-MD-VA Washington 0.091 

0.090 

Detroit-Ann Arbor 0.090 

WI Door County 0.090 

Kern County (Eastern Kern 0.090 

Source: AQS July 10, 2006 

Figure 2. 20 Areas Measuring Highest 8-Hour Ozone Design Values 

Above the NAAQS: 2003-2005 

12
 Early Action Compacts 

Several communities around the country are working with EPA to achieve clean 

air as soon as possible. The communities are: 

- Berkeley and Jefferson Counties, West 

Virginia; 

- Chattanooga, Tennessee-Georgia; 

- Columbia, South Carolina; 

- Denver-Boulder-Greeley-Fort CollinsLoveland, Colorado; 

- Fayetteville, North Carolina-South 

Carolina; 

- Frederick County, Virginia; 

- Greensboro-Winston-Salem-Highpoint, 

North Carolina-South Carolina; 

- Greenville-Spartanburg-Anderson, 

South Carolina; 

- Hickory-Morganton-Lenoir, North 

Carolina; 

- Johnson City-Kingsport-Bristol, 

Tennessee; 

- Nashville, Tennessee; 

- Roanoke, Virginia; 

- San Antonio, Texas; and 

- Washington County (Hagerstown), 

Maryland. 

Together with EPA, these communities entered into Early Action Compacts (EACs). The 

goal of EACs is to reduce ground-level ozone as quickly as possible. Communities with 

EACs started reducing air pollution about two years sooner than required by the CAA. 

For example, states with communities participating in the EACs submitted plans for 

meeting the national 8-hour ozone standard in December 2004, rather than waiting until 

2007 -- the deadline for other areas not meeting the 8-hour ozone standard. By reducing 

pollution ahead of schedule, these communities will bring substantial, sustainable health 

and environmental improvements to their residents sooner than would have been 

achieved without these agreements. 

These areas are listed in Table 2 as nonattainment areas for the 8-hour standard. 

However, EPA has deferred the effective date of the nonattainment designation for as 

long as areas meet agreed upon milestones. This means that the impact of nonattainment 

designation for the 8-hour ozone standard will be deferred, i.e., certain CAA 

requirements, such as controls on new sources, will not apply. Air quality in all of the 

EAC areas is meeting the 8-hour ozone NAAQS during the 2003-2005 time period except 

San Antonio where the design value of 0.086 ppm is slightly above the NAAQS. The 1­

hour NAAQS applies to these areas until one year after the effective date of the 

designation of that area for the 8-hour ozone NAAQS. All of the areas are in attainment 

for the 1-hour O3 NAAQS. 

Particulate Matter 

Particulate matter, also known as particle pollution, is a complex mixture of 

extremely small particles and liquid droplets. Particle pollution is made up of a number of 

components, including acids and their neutralized precipitates such as nitrates and 

sulfates, organic chemicals, metals, and soil or dust particles. They are directly emitted 

into the air by sources such as factories, power plants, cars and trucks, construction 

13
activity, fires and natural windblown dust. Particles formed in the atmosphere by 

condensation or the transformation of emitted gases such as SO2, NOx, and VOCs are also 

considered particulate matter. 

Based on studies of human populations exposed to high concentrations of 

particles and laboratory studies of animals and humans, there are major effects of concern 

for human health. These include effects on breathing and respiratory symptoms, 

aggravation of existing respiratory and cardiovascular disease, alterations in the body's 

defense systems against foreign materials, damage to lung tissue, carcinogenesis and 

premature death. Even if you are healthy, you may experience temporary symptoms from 

exposure to elevated levels of particles. Symptoms may include irritation of the eyes, 

nose and throat; coughing; phlegm, chest tightness; and shortness of breath. The major 

subgroups of the population that appear to be most sensitive to the effects of PM include 

individuals with chronic obstructive pulmonary or cardiovascular disease or influenza, 

asthmatics, the elderly and children. Particulate matter also soils and damages materials, 

and is a major cause of visibility impairment in the United States. 

EPA established a set of standards to PM in 1997 covering particle size up to 2.5 microns 

in diameter and also particle size up to 10 microns in diameter. To be in attainment, the 

3-year average of the weighted annual mean PM2.5 concentrations from single or multiple 

community-oriented monitors must not exceed 15.0 μg/m3

 and the 3-year average of the 

98th percentile of 24-hour concentrations at each population-oriented monitor within an 

area must not exceed 65 μg/m3

. For PM10, an area may not exceed the daily standard of 

150 μg/m3

 more than once per year on average over 3 years and the 3-year average 

weighted annual arithmetic mean of 50 μg/m3

 at each monitor. On September 21, 2006, 

EPA completed a review of the particle pollution NAAQS. In the final rule, EPA 

retained the annual PM2.5 standard and lowered the 24-hour PM 2.5 standard. The revision 

is effective December 18, 2006. 

PM2.5 

In January 2005, EPA designated 39 areas in the U.S. as nonattainment for the 

PM2.5 NAAQS based on air quality data exceeding the NAAQS collected during 2001­

2003. These areas include a combination of 208 whole and part counties including the 

District of Columbia. This means that approximately 89,000 people are living in areas 

designated as not meeting the standard (2000 census). Greenville, South Carolina was 

designated as unclassifiable. The remaining areas were designated as 

unclassifiable/attainment. Table 5 shows the areas designated as nonattainment, the 

design value for 2001-2003 at designation, the design value for 2002-2004 and 2003­

2005, and if the area’s design value meets the PM2.5 NAAQS based on the most recent 

data collected during 2003-2005. At designation, annual design values of the 

nonattainment areas ranged from 15.2 μg/m3

 to 27.8 μg/m3. 

14
PM

Table 5. Current Designated Nonattainment Areas (Jan 2005) and Design Values for the 

2.5 NAAQS 

(μg/m3) 

State Area 

Annual 

2001­

2003 

2001­

2003 

Annual 

2002­

2004 

2002­

2004 

Annual 

2003­

2005 

2003­

2005 

Meets 

2003­

2005 

GA Atlanta 18 39 39 38 No 

MD 42 41 41 No 

AL 1 40 40 44 No 

OH 40 37 * No 

40 36 36 No 

Chattanooga 37 35 36 No 

County 40 39 46 No 

42 41 40 No 

OH 46 45 46 No 

OH 40 38 16 40 No 

OH 39 37 40 No 

MI 44 43 45 No 

IN Evansville 16.2 40 15.5 37 15.7 37 No 

NC 35 33 32 No 

PA Carlisle 43 41 40 No 

NC 34 34 36 No 

OH 41 37 35 No 

IN 39 16 38 38 No 

PA 41 40 39 No 

TN Knoxville 35 34 33 No 

PA 17 45 42 44 No 

MT 45 42 * No 

PA 63 65 68 No 

CA Air Basin 72 67 65 No 

KY-IN Louisville 42 15.9 38 16.5 37 No 

GA 33 34 34 No 

MD 40 39 36 No 

48 50 17 46 No 

16 37 35 34 No 

43 39 37 No 

PA 16.9 45 16.5 45 16.6 43 No 

PA Reading 46 42 39 No 

GA 36 35 36 No 

CA San Joaquin Valley 76 62 19 60 No 

40 40 17 40 No 

46 17 47 45 No 

44 42 37 Yes 

37 36 33 No 

PA 17 45 43 41 No 1

Note: 

Table 5 Design Value 

24-Hour 24-Hour 24-Hour NAAQS 

17.5 17.4 

Baltimore 16.6 16.3 16.6 

Birmingham 17.3 16.8 17.4 

Canton-Masillon 17.3 16.5 16.7 

WV Charleston 17.1 16.4 16.6 

TN-GA-AL 16.1 15.7 16.1 

IL-IN 

Chicago-Gary-Lake 

17.7 17.2 16.1 

OH-KY-IN Cincinnati-Hamilton 17.8 16.9 17.9 

Cleveland-Akron-Lorain 18.3 17.6 18.1 

Columbus 16.7 15.7 

Dayton-Springfield 15.2 15.5 15.9 

Detroit-Ann Arbor 19.5 18.6 18.2 

Greensboro-Winston 

Salem-High Point 15.8 15.4 15.2 

Harrisburg-Lebanon15.7 15.4 15.8 

Hickory-MorgantonLenoir 15.5 15.1 15.3 

WV-KYHuntington-Ashland 17.2 15.8 16.3 

Indianapolis 16.7 16.4 

Johnstown 15.8 15.3 15.6 

16.4 15.7 15.6 

Lancaster 16.8 17.5 

Libby 16.2 15.2 15.1 

Liberty-Clairton 21.2 20.4 20.8 

Los Angeles-South Coast 

27.8 24.8 22.6 

16.9 

Macon 15.2 15.5 16.1 

Martinsburg, WVHagerstown 16.3 16.1 16.2 

NY-NJ-CT 

New York-N. New 

Jersey-Long Island 17.7 16.8 

WV-OH Parkersburg-Marietta 15.2 15.4 

PA-NJ-DE Philadelphia-Wilmington 16.2 15.4 15.7 

Pittsburgh-Beaver Valley 

16.4 16.1 16.2 

Rome 15.6 15.5 16.2 

21.8 20.6 

MO-IL St. Louis 17.5 16.9 

OH-WV Steubenville-Weirton 17.8 17.2 

DC-MD-VA Washington 15.8 15.1 14.8 

WV-OH Wheeling 15.7 15.1 15.3 

York 16.9 17.3 

Two sites in Jefferson County, AL are encompassed in a Community Monitoring Zone (i.e. utilize spatial averaging); the spatially 

averaged design value for the CMZ is 17.4, which is the maximum for the county. 

*The 24-hour PM 2.5 design value cannot be determined due to incomplete data. 

Data that have been flagged for natural and exceptional events, for which documentation has been submitted and approved by 

the EPA (AQS concurrence field set to ‘Y’), were excluded from the design value calculations. 

Source: AQS July 10, 2006 

15
Table 5 shows that PM2.5 air quality in designated nonattainment areas is 

improving. The range of annual design values of the nonattainment areas during 2002­

2004 dropped to 15.1 μg/m3

 to 24.8 μg/m3 and during 2003-2005 the range dropped to 

14.8 μg.m3 to 22.6 μg/m3. Reflecting the lower PM2.5 pollution, all but ten areas show an 

air quality improvement over that monitored during 2001-2003. Most improved although 

still in violation of the PM2.5 NAAQS are the Los Angeles-South Coast Air Basin and San 

Joaquin Valley areas in California whose design values went from 27.8 to 22.6 μg/m3

 and 

21.8 to 19.0 μg/m3

, respectively. One of the areas, Washington, DC-MD-VA, is now 

meeting the NAAQS, thus satisfying one of several criteria that must be met prior to 

redesignation to attainment. Of the remaining areas, eight show a degradation in air 

quality over the 2001-2003 time period and two have no change. The degradation 

concentrations range from 0.1 to 0.9 μg/m3

 or 0.6 percent to 5.9 percent. The areas 

showing poorer air quality are: Birmingham, Alabama; Cincinnati-Hamilton, OhioKentucky-Indiana; Dayton-Springfield, Ohio; Harrisburg-Lebanon-Carlisle, 

Pennsylvania; Lancaster, Pennsylvania; Macon, Georgia; Reading, Pennsylvania; and, 

York, Pennsylvania. No areas have been redesignated to attainment. 

In the 2001-2003 time period, two areas, the Los Angeles-South Coast Air Basin 

and the San Joaquin Valley in California, were violating the 24-hour PM2.5 NAAQS 

whereas only the Liberty-Clairton area in Pennsylvania is violating the 24-hour PM2.5 

NAAQS during 2003-2005. Most improved is the San Joaquin Valley with a 21 percent 

decrease in 24-hour design values from 76 μg/m3

 during 2001-2003 to 60 μg/m3 during 

2003-2005. 

Figure 3 displays designated PM2.5 nonattainment areas. The map on the left 

shows areas designated as nonattainment in 2005 based on air quality data collected 

during 2001-2003. The map on the right shows the remaining areas with air quality 

above the NAAQS based on data collected during 2003-2005. 

Figure 3. PM2.5 Nonattainment Areas with 2001-2003 Data and Areas Above the NAAQS with 2003­

2005 Data 

16
Table 6 shows the top 20 areas with PM2.5 quality problems in the U.S. along with 

their design values during 2003-2005. Although these areas have the highest PM2.5 

design values, since 2001-2003 air quality has improved with decreases in design values 

ranging from 0.3 μg/m3

 in Pittsburg-Beaver Valley, Pennsylvania, and Indianapolis, 

Indiana, to 5.2 μg/m3

 in the Los Angeles-South Coast Air Basin area in California. Most 

improved is the Los Angeles-South Coast Valley area with a 19 percent decrease in 

annual design values from 27.8 μg/m3

 during 2001-2003 to 22.6 μg/m3 during 2003­

2005. Lastly, there are five areas newly violating the annual PM2.5 NAAQS. They are 

shown in Table 7. 

Table 6. 20 Areas Measuring Highest Annual PM2.5 Design Values Above the NAAQS: 

2003-2005 

Table 6 Area Design Value 3) 

CA 

PA 

CA San Joaquin Valley 

MI 

OH 

PA 

GA Atlanta 

AL

PA York 

OH-WV 17.2 

OH 

WV 

PA 16.6 

Louisville 

 (μg/m

Los Angeles-South Coast Air Basin 22.6 

Liberty-Clairton 20.8 

19.0 

Detroit-Ann Arbor 18.2 

Cleveland-Akron-Lorain 18.1 

OH-KY-IN Cincinnati-Hamilton 17.9 

Lancaster 17.5 

17.4 

 Birmingham 17.4 

17.3 

Steubenville-Weirton 

NY-NJ-CT New York-N.New Jersey-Long Island 17.0 

MO-IL St. Louis 17.0 

Canton-Masillon 16.7 

MD Baltimore 16.6 

Charleston 16.6 

Pittsburgh-Beaver Valley 

KY-IN 16.5 

IN Indianapolis 16.4 

WV-KY-OH Huntington-Ashland 16.3 

Source: AQS July 10, 2006 

17
Table 7. Areas Newly Violating the PM2.5 NAAQS: 2003-2005 

Table 7 Design Value (μg/m3) 

State Area Annual 24-hr 1 37 

GA ( 33 

KY 31 

NC ( 32 

AL-GA Columbus-Phenix City 15.2 

Richmond County Augusta) 15.5 

Fayette County (Lexington) 15.1 

Mecklenburg County Charlotte) 15.3 

OH Mahoning County (Youngstown) 15.5 38 

1

Two sites in the Columbus-Phenix City, Al-GA metropolitan area have opted to use spatial averaging. The 

spatially averaged design value is 15.2 μg/m3 which is the maximum for the area (Community Monitoring Zone.) 

Note: Data that have been flagged for natural and exceptional events, for which documentation has been submitted 

and approved by the EPA (AQS concurrence field set to ‘Y’), were excluded from the design value calculations. 

Source: AQS July 10, 2006 

 PM10 

Following the amendments to the Clean Air Act in 1990, 73 areas were 

designated as nonattainment by law and 13 additional areas through other redesignation 

actions were designated as nonattainment for the PM10 NAAQS. The names and 

classifications are shown in Table 8. Since that time, air quality in 40 areas attained the 

PM10 NAAQS and the areas have an effective redesignation to attainment leaving 46 

areas currently designated as nonattainment. As a result of this progress, approximately 

seven million additional people are now living in areas that are meeting the PM10 

NAAQS (2000 census). Table 9 shows the areas that are currently designated as 

nonattainment, the design value for 2001-2003, 2002-2004, and 2003-2005, and if the 

area meets the NAAQS based on the most recent data collected during 2003-2005. On 

September 21, 2006, EPA completed a review of the particle pollution NAAQS. In the 

final rule, EPA retained the 24-hour PM10 standard but revoked the annual PM10 

standard. Design values for the annual PM10 NAAQS in 2003-2005 are shown because 

the revocation did not become effective until December 18, 2006. 

Table 8. Area Designations and Classifications for the PM10 NAAQS 

Table 8 

State 

Area 

AZ Ajo 

NM Anthony 

CO Aspen* 

ID Boise* 

AZ Bullhead City* 

MT Butte 

CO 

PA 

IN Clinton Township* 

CA 

MT 

CA 

OH 

CO 

MI Detroit* 

Classification 

Moderate 

Moderate 

Moderate 

Moderate 

Moderate 

Moderate 

Canon City* Moderate 

Clairton & 4 Boroughs* Moderate 

Moderate 

Coachella Valley Serious 

Columbia Falls and vicinity Moderate 

Coso Junction Moderate 

Cuyahoga County* Moderate 

Denver Metro* Moderate 

Moderate 

18 
Table 8 

State 

Area 

AZ Douglas/Paul Spur 

AK 

IN )* 

TX El Paso 

OR 

WV Follansbee* 

ID Fort Hall 

IL 

OR Grants Pass* 

PR 

AZ 

CA 

CA 

AK Juneau 

MT Kalispell 

WA Kent* 

OR 

OR 

OR 

CO 

MT 

NV Las Vegas 

MT 

IL 

CA 

OR 

OH 

MT 

CA 

CT New Haven* 

NY 

AZ Nogales 

OR 

UT Ogden 

IL Oglesby* 

WA 

CA 

CO 

AZ 

AZ Phoenix 

ID 

MT Polson 

ID 

ME 

NV Reno 

AZ Rillito 

MN Rochester* 

MT Ronan 

CA 

MN Saint Paul* 

UT 

CA 

CA San Joaquin Valley 

ID ) 

WA Seattle* 

WY Sheridan 

ID 

Classification 

Moderate 

Eagle River Moderate 

East Chicago (Lake County Moderate 

Moderate 

Eugene-Springfield Moderate 

Moderate 

Moderate 

Granite City, Nameoki 

Township* 

Moderate 

Moderate 

Guaynabo County Moderate 

Hayden/Miami Moderate 

Imperial Valley Serious 

Indian Wells* Moderate 

Moderate 

Moderate 

Moderate 

Klamath Falls* Moderate 

LaGrande* Moderate 

Lakeview* Moderate 

Lamar* Moderate 

Lame Deer Moderate 

Serious 

Libby Moderate 

Lyons Township* Moderate 

Mammoth Lakes Moderate 

Medford-Ashland* Moderate 

Mingo Junction* Moderate 

Missoula Moderate 

Mono Basin Moderate 

Moderate 

New York County Moderate 

Moderate 

Oakridge Moderate 

Moderate 

Moderate 

Olympia, Tumwater, Lacey* Moderate 

Owens Valley Serious 

Pagosa Springs* Moderate 

Payson* Moderate 

Serious 

Pinehurst Moderate 

Moderate 

Portneuf Valley* Moderate 

Presque Isle* Moderate 

Moderate 

Moderate 

Moderate 

Moderate 

Sacramento County Moderate 

Moderate 

Salt Lake County Moderate 

San Bernardino Moderate 

Serious 

Sandpoint (Bonner County Moderate 

Moderate 

Moderate 

Shoshone County Moderate 

19
Table 8 

State 

Area 

CA 

IL Southeast Chicago* 

WA Spokane* 

CO 

WA 

CO 

MT 

CA 

UT Utah County 

WA Wallula* 

WV 

MT 

County) 

WA 

AZ 

10

Classification 

South Coast Air Basin Serious 

Moderate 

Moderate 

Steamboat Springs* Moderate 

Tacoma* Moderate 

Telluride* Moderate 

Thompson Falls and vicinity Moderate 

Trona Moderate 

Moderate 

Serious 

Weirton* Moderate 

Whitefish and vicinity (Flathead Moderate 

Yakima* Moderate 

Yuma Moderate 

*Since designation as a nonattainment area for the PM NAAQS, 

this area has been redesignated to attainment. 

Table 9. Current Designated Nonattainment Areas and Design Values for the PM10 NAAQS: 

2001-2003 through 2003-2005

Table 9 3) 

Annual 

2001­

2003 

2001­

2003 

Annual 

2002­

2004 

2002­

2004 

Annual 

2003­

2005 

Expected 

Exceedances 

2003­

2005 

Meets 

State Area 

AZ Ajo 18 139 20 139 22 0 139 Yes 

NM Anthony 34 394 31 333 30 148 Yes 

MT Butte 16 66 17 60 19 0 69 Yes 

CA 53 309 50 276 47 4 227 No 

MT 19 125 22 123 22 0 125 Yes 

CA 17 175 18 483 18 118 No 

AZ Douglas/Paul Spur 30 137 30 127 30 207 No 

AK 23 590 20 92 18 0 90 Yes 

TX 47 589 54 533 49 504 No 

OR 19 65 18 63 18 0 50 Yes 

ID Fort Hall 29 214 24 214 24 134 Yes 

PR 35 117 34 95 35 0 115 Yes 

AZ 34 141 33 128 31 0 128 Yes 

CA 81 647 74 373 63 211 No 

AK Juneau 7 29 7 34 10 0 42 data 

MT Kalispell 21 117 22 117 24 0 105 Yes 

MT 29 169 26 169 24 117 data 

NV 46 274 46 358 42 274 No 

MT 24 110 25 110 27 0 103 Yes 

CA 13 134 22 129 22 0 86 data 

MT 13 116 20 110 22 0 110 Yes 

CA 54 5283 78 5745 70 5283 No 

NY 4 77 No data No data No data No data No data No data 

AZ Nogales 49 213 44 188 46 280 No 

OR 18 89 19 80 18 0 76 Yes 

UT Ogden 27 163 31 136 27 111 Yes 

CA 189 120 7071 89 4125 No 

AZ Phoenix 63 280 61 248 62 240 No 

Design Value (μg/m

24-Hour 24-Hour Number of 24-Hour 

NAAQS 

2003-2005 

0.7 

Coachella Valley 

Columbia Falls and vicinity 

Coso Junction 1.2 

2.1 

Eagle River 

El Paso County 10.3 

Eugene-Springfield 

0.8 

Guaynabo County 

Hayden/Miami 

Imperial Valley 11.1 

Incomplete 

Lame Deer 0.7 Incomplete 

Las Vegas 3.8 

Libby 

Mammoth Lakes Incomplete 

Missoula 

Mono Basin 22.2 

New York County 

10.2 

Oakridge 

0.7 

Owens Valley 12160 23.5 

4.6 

20
ID 2 39 19 78 20 0 85 Yes 

Polson 20 108 20 105 20 0 105 Yes 

NV Reno 41 113 41 126 42 153 Yes 

AZ Rillito 37 118 36 118 37 0 118 Yes 

MT Ronan 17 58 19 58 17 0 61 Yes 

CA 25 144 27 144 26 0 110 Yes 

UT 42 421 41 169 40 421 No 

CA 31 172 31 198 29 162 No 

CA San Joaquin Valley 52 212 51 217 46 150 Yes 

ID ) 12 96 17 67 17 0 71 Yes 

WY Sheridan 30 137 30 137 31 0 137 Yes 

ID 19 68 19 78 20 0 85 Yes 

CA 59 166 57 159 54 149 No 

MT 16 69 16 69 13 0 48 Yes 

CA 20 186 24 186 19 136 Yes 

UT Utah County 31 111 29 118 27 111 Yes 

MT ( ) 17 109 26 100 25 0 104 Yes 

AZ 39 154 42 127 38 0 127 Yes 

(

(

. 

Pinehurst 

MT 

0.3 

Sacramento County 

Salt Lake County 2.1 

San Bernardino 1.3 

0.3 

Sandpoint (Bonner County

Shoshone County 

South Coast Air Basin 1.1 

Thompson Falls and vicinity 

Trona 0.5 

0.3 

Whitefish and vicinity 

Flathead County

Yuma 

Table 9 Notes: 1. Underlined values are based on incomplete data and are generally not valid for regulatory usage. Either there are no other sites in the area 

with complete data for this 3-year period or a complete site or sites are located in the area but have an expected estimated exceedance value of zero and an 

incomplete site in the area registered the non-zero value shown. 

2. Data that have been flagged for natural and exceptional events, for which documentation has been submitted and approved by the EPA AQS concurrence 

field set to “Y”), were excluded from the design value calculations. 

3. Some valid values are based on sites that did not meet the minimum 75 percent data capture requirements per quarter for all 12 quarters). These values are 

considered valid for regulatory usage per 40 CFR Part 50 Appendix K or the Guideline on Exceptions to Data Requirements for Determining Attainment of 

Particulate Matter Standards An incomplete, potentially violating annual standard design value is valid if by substituting one half the minimum detectable 

concentration values for missing values in deficient quarters, i.e., those with less than 75 percent data capture, the recalculated 3-year metric still exceeds 50. 

Incomplete, potentially ‘meeting’ values for expected numbers of exceedances and annual standard design value are valid if same-site maximum quarterly 

values for the 3-years period are substituted for missing data and both recalculated 3-year metrics still meet the NAAQS. See substitution requirements and 

computation detail in stated references. 

Source: AQS October 6, 2006 

In 29 of the remaining 46 nonattainment areas, air quality is now attaining the PM10 

NAAQS based on monitoring data collected during 2003-2005. About 28 million people 

live in these 46 areas (2000 census). Of the 17 remaining nonattainment areas, four areas 

have incomplete or no data on which to make a determination of attainment or 

nonattainment. Also, three maintenance areas have air quality data during 2003-2005 

that does not meet the PM10 NAAQS. Maintenance areas are previously designated 

nonattainment areas that have been redesignated to attainment with a plan to maintain 

clean air quality. The areas are Detroit, Michigan; East Chicago (Lake County), Indiana; 

and, Indian Wells Valley, California. A total of 16 of the 86 areas previously designated 

as nonattainment for the PM10 NAAQS failed to meet the standards based on 2003-2005 

air quality data. Lastly, there are 21areas (counties) newly violating the PM10 standard. 

These areas are listed in Table 10. 

21
Table 10. Areas Newly Violating the PM10 NAAQS: 2003-2005 

(μg/m3

)

 1 (μg/m3

)

 1 

State County 

30 159 

WY 24 167 

NM 2 42 205 

SC 26 157 

MT Glacier 18 195 

MO Jasper 32 152 

AL 53 179 

MN 37 209 

23 221 

AZ 2 54 158 

CO Mesa 31 198 

WY 19 194 

NV Nye 37 252 

AZ Pinal2 44 289 

CA 30 155 

NM Sandoval 27 165 

OH Scioto 20 210 

MO ) 50 191 

Sweetwater 24 306 

TN Union 39 148 

CA Yolo 26 169 

1

(

2 10

Table 10 

 Design Value Design Value 

Annual 2003-2005 

Expected Number 

of Exceedances 

24-Hour 2003-2005 

WY Campbell 1.1 

Carbon 7.4 

Dona Ana 6.1 

Georgetown 1.2 

 2.0 

1.1 

 Jefferson 3.1 

Kandiyohi 6.1 

WY Lincoln 4.4 

Maricopa 3.2 

 4.0 

Natrona 2.1 

 4.9 

8.1 

San Diego 3.1 

2.9 

2.8 

St. Louis (city 7.7 

WY 2.9 

1.1 

2.0 

Underlined annual design values are based on incomplete data. The corresponding expected number of exceedances are valid per data 

substitution protocol. See endnote for Table 9. 

Data that have been flagged for natural and exceptional events, for which documentation has been submitted and approved by the EPA 

AQS concurrence field set to “Y”), were excluded from the design value calculations. 

These counties are near or, in some cases, overlap or totally contain previously designated PM nonattainment areas. However, the 

monitoring sites from which these design values are derived are located outside the boundaries of the nonattainment area. Therefore, 

these counties are listed here as new areas. 

Source: AQS October 6, 2006 

Carbon Monoxide 

CO is a colorless, odorless and poisonous gas produced by incomplete burning of 

carbon in fuels. When CO enters the bloodstream, it reduces the delivery of oxygen to the 

body's organs and tissues. Health threats are most serious for those who suffer from 

cardiovascular disease, particularly those with angina or peripheral vascular disease. 

Exposure to elevated CO levels can cause impairment of visual perception, manual 

dexterity, learning ability and performance of complex tasks. 

Seventy-seven percent of the nationwide CO emissions are from transportation 

sources. The largest emissions contribution comes from highway motor vehicles. Thus, 

the focus of CO monitoring has been on traffic oriented sites in urban areas where the 

main source of CO is motor vehicle exhaust. Other major CO sources are wood-burning 

stoves, incinerators and industrial sources. 

There are six areas designated as nonattainment for the 8-hour CO NAAQS 

consisting of all or parts of 10 counties. About 15 million people live in these areas 

(2000 census). All designated nonattainment areas meet the CO NAAQS based on 2004­

2005 data. Table 11 shows the areas designated as nonattainment, the design value for 

22
2002-2003, 2003-2004, and 2004-2005. There is one area newly violating the 8-hour CO 

standard. The area and design values are shown in Table 12. All areas met the 1-hour 

NAAQS based on 2004-2005 data. 

Table 11. Current Designated Nonattainment Areas and Design Values for the 8-Hour CO 

NAAQS: 2002-2003 through 2004-2005 

Table 11 ) 

State Area 

2002­

2003 

2003­

2004 

2004­

2005 

Meets 

TX El Paso Yes 

NV Las Vegas Yes 

CA Coast Air Basin Yes 

MT Yes 

NV Reno Yes 

OR Not Classified Yes 

8-Hour (ppm

Classification 

NAAQS 

2004-2005 

Moderate 6.8 6.4 6.4 

Serious 5.8 5.3 5.2 

Los Angeles South 

Serious 8.5 7.2 6.1 

Missoula Moderate 3.6 3.6 3.6 

Moderate 4.4 3.9 3.9 

Salem 5.2 4.9 3.8 

Source: AQS October 28, 2006 

Table 12. Area Newly Violating the CO NAAQS: 2004-2005 

Table 12 ) 

State Area 

2002­

2003 

2003­

2004 

2004­

2005 

Meets 

WV Hancock County No 

8-Hour (ppm

NAAQS 

2004-2005 

12.1 12.0 12.0 

Source: AQS October 28, 2006 

Sulfur Dioxide 

High concentrations of SO2 affect breathing and may aggravate existing 

respiratory and cardiovascular disease. Sensitive populations include asthmatics, 

individuals with bronchitis or emphysema, children and the elderly. SO2 is also a primary 

contributor to acid deposition, or acid rain, which causes acidification of lakes and 

streams and can damage trees, crops, historic buildings and statues. In addition, sulfur 

compounds in the air contribute to visibility impairment in large parts of the country. 

This is especially noticeable in national parks. SO2 also contributes to the formation of 

PM2.5. 

Ambient SO2 results largely from stationary sources such as coal and oil 

combustion, steel mills, refineries, pulp and paper mills and from nonferrous smelters. 

There are 11 areas designated as nonattainment for the SO2 NAAQS consisting of 

all or parts of ten counties. The areas are 

Pennsylvania: Armstrong County; 

Montana: East Helena and Laurel Areas; 

Arizona: Hayden, Miami, and San Manual; 

Guam: Piti and Tanguisson; 

Utah: Salt Lake and Tooele Counties; and, 

23 
New Jersey: Warren County. 

About 1 million people are living in these areas (2000 census). All of the areas 

meet the SO2 NAAQS based on air monitoring data collected during 2004-2005. 

However, there is one newly violating area, Volcanoes National Park in Hawaii, with air 

quality monitoring data that is not meeting both the 3-hour standard and the 24-hour 

standard in 2004-2005. The area’s design value is 0.19 ppm and 0.6 ppm for the 24-hour 

and 3-hour NAAQS, respectively. 

Nitrogen Dioxide 

NO2 is a brownish, highly reactive gas that is present in all urban atmospheres. 

Nitrogen dioxide can irritate the lungs, cause bronchitis and pneumonia, and lower 

resistance to respiratory infections. Nitrogen oxides are an important precursor both to O3 

and acid rain, and may affect both terrestrial and aquatic ecosystems. The major 

mechanism for the formation of NO2 in the atmosphere is the oxidation of the primary air 

pollutant nitric oxide (NO). NOx plays a major role, together with VOCs, in the 

atmospheric reactions that produce O3. NOx forms when fuel is burned at high 

temperatures. The two major emissions sources are transportation and stationary fuel 

combustion sources such as electric utility and industrial boilers. There are no designated 

nonattainment areas for NO2. There are no newly violating areas based on 2004-2005 

data. 

Lead 

Exposure to lead can occur through multiple pathways, including inhalation of air 

and ingestion of lead in food, water, soil or dust. Excessive lead exposure can cause 

seizures, mental retardation and/or behavioral disorders. A recent National Health and 

Nutrition Examination Survey reported a 78 percent decrease in blood lead levels from 

12.8 to 2.8 μg/dL between 1976 and 1980 and from 1988 to 1991. This dramatic decline 

can be attributed to the reduction of leaded gasoline and to the removal of lead from 

soldered cans. Although this study shows great progress, infants and young children are 

especially susceptible to low doses of lead, and this age group still shows the highest 

levels. Low doses of lead can lead to central nervous system damage. Recent studies have 

also shown that lead may be a factor in high blood pressure and in subsequent heart 

disease in middle-aged males. 

Lead gasoline additives, non-ferrous smelters, and battery plants are the most 

significant contributors to atmospheric lead emissions. In 1993 transportation sources 

contributed 33 percent of the annual emissions, down substantially from 81 percent in 

1985. Total lead emissions from all sources dropped from 20,100 tons in 1985 to 4,900 

tons in 1993. The decrease in lead emissions from highway vehicles accounts for 

essentially all of this decline. The reasons for the decrease are noted below. 

Two air pollution control programs implemented by EPA before promulgation of 

the lead standard in October 1978 have resulted in lower ambient lead levels. First, 

regulations issued in the early 1970's required gradual reduction of the lead content of all 

24
gasoline over a period of many years. The lead content of the leaded gasoline pool was 

reduced from an average of 12.0 gram/gallon, to 0.5 gram/gallon on July 1, 1985, and 

still further to 0.1 gram/gallon on January 1, 1986. Second, as part of the EPA's overall 

automotive emission control program, unleaded gasoline was introduced in 1975 for 

automobiles equipped with catalytic control devices. These devices reduce emissions of 

CO, VOCs and NOx. In 1993, unleaded gasoline sales accounted for 99 percent of the 

total gasoline market. In contrast, the unleaded share of the gasoline market in 1984 was 

approximately 60 percent. These programs have essentially eliminated violations of the 

lead standard in urban areas except those areas with lead point sources. 

Programs are also in place to control lead emissions from stationary point sources. 

Lead emissions from stationary sources have been substantially reduced by control 

programs oriented toward attainment of the PM10 and lead ambient standards. However, 

significant and ambient problems still remain around some lead point sources, which are 

now the focus of new monitoring initiatives. Lead emissions in 1993 from industrial 

sources, e.g., primary and secondary lead smelters, dropped by about 91 percent from 

levels reported in 1970. Emissions of lead from solid waste disposal are down about 76 

percent since 1970. In 1993, emissions from solid waste disposal, industrial processes 

and transportation were: 500, 2,300 and 1,600 short tons, respectively. The overall effect 

of the control programs for these three categories has been a major reduction in the 

amount of lead in the ambient air. 

There are two areas currently designated as nonattainment for the lead NAAQS. 

They are East Helena Area portion of Lewis and Clark Counties, Montana; and the area 

within the city limits of Herculaneum in Jefferson County, Missouri. That means that 

about 4600 people are living in areas designated as nonattainment for the standard (2000 

census). Air quality monitoring in the East Helena Nonattainment Area has been 

discontinued and the lead source has closed. Air quality in Herculaneum is violating the 

NAAQS as shown in Table 13. There is one area, Delaware County, Indiana, with newly 

violating air quality monitoring data for the lead NAAQS. Table 13 shows lead design 

values for these areas for 2003-2004 and 2004-2005 and if the areas’ design values meet 

the NAAQS based on the most recent data collected during 2004-2005. 

25
Table 13. Areas Currently Designated Nonattainment for the Lead NAAQS or Designated 

Attainment But Not Meeting the Lead NAAQS: 2003-2004 through 2004-2005 

Table 13 Design Value (μg/m3) 

State Area 2003-2004 2004-2005 Meets NAAQS 

2004-2005 

MT E. Helena Source closed, site remediated, monitoring 

discontinued 

MO Herculaneum 1.49 1.93 No

IN Delaware County 4.09 4.09 No 

Source: AQS November 2, 2006 

Additional air quality information for all ozone and particulate matter monitors 

can be found at http://www.epa.gov/air/airtrends/. Sstatistics and capability for the user 

to create maps, graphs, and data tables is located at http://www.epa.gov/airexplorer/. 

Daily and forecast air quality information is available at http://airnow.gov/. 

EPA’s tracking system for all criteria pollutant designated nonattainment and 

maintenance areas is located at http://www.epa.gov/oar/oaqps/greenbk/index.html. 

26
List of Appendices 

Appendix A Page A1 

Additional Information on Area Classifications for the 8-Hour Ozone Standard 

Appendix B Page B1 

Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality 

Standards for Ozone 

Appendix C Page C1 

Interpretation of the National Ambient Air Quality Standards for Particulate Matter2.5 

Appendix D Page D1 

Interpretation of National Ambient Air Quality Standards for Particulate Matter10 

27
Appendix A 

Additional Information on Area Classifications for the 8-Hour Ozone Standard 

40 CFR Part 51.902 

Sec. 51.902 Which classification and nonattainment area planning provisions of the 

CAA shall apply to areas designated nonattainment for the 8-hour NAAQS? 

(a) Classification under subpart 2. An area designated nonattainment for the 8-hour 

NAAQS with a 1-hour ozone design value equal to or greater than 0.121 ppm at the time 

the Administrator signs a final rule designating or redesignating the area as nonattainment 

for the 8-hour NAAQS will be classified in accordance with section 181 of the CAA, as 

interpreted in §51.903(a), for purposes of the 8-hour NAAQS, and will be subject to the 

requirements of subpart 2 that apply for that classification. 

(b) Covered under subpart 1. An area designated nonattainment for the 8-hour ozone 

NAAQS with a 1-hour design value less than 0.121 ppm at the time the Administrator 

signs a final rule designating or redesignating the area as nonattainment for the 8-hour 

NAAQS will be covered under section 172(a)(1) of the CAA and will be subject to the 

requirements of subpart 1. 

Sec. 51.903 How do the classification and attainment date provisions in section 181 

of subpart 2 of the CAA apply to areas subject to section 51.902(a)? 

(a) In accordance with section 181(a)(1) of the CAA, each area subject to §51.902(a) 

shall be classified by operation of law at the time of designation. However, the 

classification shall be based on the 8-hour design value for the area, in accordance with 

Table 1 below, or such higher or lower classification as the State may request as provided 

in paragraphs (b) and (c) of this section. The 8-hour design value for the area shall be 

calculated using the three most recent years of air quality data. For each area classified 

under this section, the primary NAAQS attainment date for the 8-hour NAAQS shall be 

as expeditious as practicable but not later than the date provided in the following Table. 

A 1 
CLASSIFICATION FOR 8-HOUR OZONE NAAQS 

FOR AREAS SUBJECT TO SECTION 51.902(a) 

Area class 8-hour design value 

(ppm ozone) 

Maximum Period for Attainment 

Dates in State Plans 

(years after effective date of 

nonattainment designation for 8­

hour NAAQS) 

Marginal from 0.085 3 

up to* 0.092 

Moderate from 0.092 6 

up to* 0.107 

Serious from 0.107 9 

up to* 0.120 

Severe-15 from 0.120 15 

up to* 0.127 

Severe-17 from 0.127 17 

up to* 0.187 

Extreme equal to or 

above 

0.187 20 

* but not including 

(b) A State may request a higher classification for any reason in accordance with section 

181(b)(3) of the CAA. 

(c) A State may request a lower classification in accordance with section 181(a)(4) of the 

CAA. 

A 2 
Appendix B 

Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality 

Standards for O3 

40 CFR Part 50 Appendix I 

1. General. 

 This appendix explains the data handling conventions and computations necessary for 

determining whether the national 8-hour primary and secondary ambient air quality 

standards for ozone specified in Sec. 50.10 are met at an ambient ozone air quality 

monitoring site. Ozone is measured in the ambient air by a reference method based on 

appendix D of this part. Data reporting, data handling, and computation procedures to be 

used in making comparisons between reported ozone concentrations and the level of the 

ozone standard are specified in the following sections. Whether to exclude, retain, or 

make adjustments to the data affected by stratospheric ozone intrusion or other natural 

events is subject to the approval of the appropriate Regional Administrator. 

2. Primary and Secondary Ambient Air Quality Standards for Ozone. 

2.1 Data Reporting and Handling Conventions. 

2.1.1 Computing 8-hour averages. Hourly average concentrations shall be reported in 

parts per million (ppm) to the third decimal place, with additional digits to the right being 

truncated. Running 8-hour averages shall be computed from the hourly ozone 

concentration data for each hour of the year and the result shall be stored in the first, or 

start, hour of the 8-hour period. An 8-hour average shall be considered valid if at least 75 

percent of the hourly averages for the 8-hour period are available. In the event that only 6 

(or 7) hourly averages are available, the 8-hour average shall be computed on the basis of 

the hours available using 6 (or 7) as the divisor. (8-hour periods with three or more 

missing hours shall not be ignored if, after substituting one-half the minimum detectable 

limit for the missing hourly concentrations, the 8-hour average concentration is greater 

than the level of the standard.) The computed 8-hour average ozone concentrations shall 

be reported to three decimal places (the insignificant digits to the right of the third 

decimal place are truncated, consistent with the data handling procedures for the reported 

data.) 

2.1.2 Daily maximum 8-hour average concentrations. (a) There are 24 possible running 

8-hour average ozone concentrations for each calendar day during the ozone monitoring 

season. (Ozone monitoring seasons vary by geographic location as designated in part 58, 

appendix D to this chapter.) The daily maximum 8-hour concentration for a given 

calendar day is the highest of the 24 possible 8-hour average concentrations computed for 

that day. This process is repeated, yielding a daily maximum 8-hour average ozone 

concentration for each calendar day with ambient ozone monitoring data. Because the 8­

hour averages are recorded in the start hour, the daily maximum 8-hour concentrations 

B 1 
from two consecutive days may have some hourly concentrations in common. Generally, 

overlapping daily maximum 8-hour averages are not likely, except in those non-urban 

monitoring locations with less pronounced diurnal variation in hourly concentrations. 

(b) An ozone monitoring day shall be counted as a valid day if valid 8-hour averages 

are available for at least 75percent of possible hours in the day (i.e., at least 18 of the 24 

averages). In the event that less than 75 percent of the 8-hour averages are available, a 

day shall also be counted as a valid day if the daily maximum 8-hour average 

concentration for that day is greater than the level of the ambient standard.

 2.2 Primary and Secondary Standard-related Summary Statistic. The standard-related 

summary statistic is the annual fourth-highest daily maximum 8-hour ozone 

concentration, expressed in parts per million, averaged over three years. The 3-year 

average shall be computed using the three most recent, consecutive calendar years of 

monitoring data meeting the data completeness requirements described in this appendix. 

The computed 3-year average of the annual fourth-highest daily maximum 8-hour 

average ozone concentrations shall be expressed to three decimal places (the remaining 

digits to the right are truncated.)

 2.3 Comparisons with the Primary and Secondary Ozone Standards. (a) The primary 

and secondary ozone ambient air quality standards are met at an ambient air quality 

monitoring site when the 3-year average of the annual fourth-highest daily maximum 8­

hour average ozone concentration is less than or equal to 0.08 ppm. The number of 

significant Figures in the level of the standard dictates the rounding convention for 

comparing the computed 3-year average annual fourth-highest daily maximum 8-hour 

average ozone concentration with the level of the standard. The third decimal place of the 

computed value is rounded, with values equal to or greater than 5 rounding up. Thus, a 

computed 3-year average ozone concentration of 0.085 ppm is the smallest value that is 

greater than 0.08 ppm.

 (b) This comparison shall be based on three consecutive, complete calendar years of air 

quality monitoring data. This requirement is met for the three year period at a monitoring 

site if daily maximum 8-hour average concentrations are available for at least 90 percent, 

on average, of the days during the designated ozone monitoring season, with a minimum 

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

When computing whether the minimum data completeness requirements have been met, 

meteorological or ambient data may be sufficient to demonstrate that meteorological 

conditions on missing days were not conducive to concentrations above the level of the 

standard. Missing days assumed less than the level of the standard are counted for the 

purpose of meeting the data completeness requirement, subject to the approval of the 

appropriate Regional Administrator. 

(c) Years with concentrations greater than the level of the standard shall not be ignored 

on the ground that they have less than complete data. Thus, in computing the 3-year 

average fourth maximum concentration, calendar years with less than 75 percent data 

B 2 
------------------------------------------------------------------------------------------------------------ 

------------------------------------------------------------------------------------------------------------ 

------------------------------------------------------------------------------------------------------------ 

completeness shall be included in the computation if the average annual fourth maximum 

8-hour concentration is greater than the level of the standard. 

(d) Comparisons with the primary and secondary ozone standards are demonstrated by 

examples 1 and 2 in paragraphs (d)(1) and (d) (2) respectively as follows: 

(1) As shown in example 1, the primary and secondary standards are met at this 

monitoring site because the 3-year average of the annual fourth-highest daily maximum 

8-hour average ozone concentrations (i.e., 0.084 ppm) is less than or equal to 0.08 ppm. 

The data completeness requirement is also met because the average percent of days with 

valid ambient monitoring data is greater than 90 percent, and no single year has less than 

75 percent data completeness. 

 Example 1. Ambient monitoring site attaining the primary and secondary ozone 

standards 

 1st Highest 2nd Highest 3rd Highest 4th Highest 5th Highest 

Percent Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8- 

Year Valid Days hour Conc. hour Conc. hour Conc. hour Conc. hour Conc. 

(ppm) (ppm) (ppm) (ppm) (ppm) 

1993 100% 0.092 0.091 0.090 0.088 0.085 

1994 96% 0.090 0.089 0.086 0.084 0.080 

1995 98% 0.087 0.085 0.083 0.080 0.075 

=================================== 

Average 98 % 

(2) As shown in example 2, the primary and secondary standards are not met at this 

monitoring site because the 3-year average of the fourth-highest daily maximum 8-hour 

average ozone concentrations (i.e., 0.093 ppm) is greater than 0.08 ppm. Note that the 

ozone concentration data for 1994 is used in these computations, even though the data 

capture is less than 75 percent, because the average fourth-highest daily maximum 8-hour 

average concentration is greater than 0.08 ppm.

 Example 2. Ambient monitoring site failing to meet the primary and secondary 

ozone standards 

 1st Highest 2nd Highest 3rd Highest 4th Highest 5th Highest 

Percent Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8- 

Year Valid Days hour Conc. hour Conc. hour Conc. hour Conc. hour Conc. 

(ppm) (ppm) (ppm) (ppm) (ppm) 

B 3 
------------------------------------------------------------------------------------------------------------ 

------------------------------------------------------------------------------------------------------------ 

1993 96% 0.105 0.103 0.103 0.102 0.102 

1994 74% 0.090 0.085 0.082 0.080 0.078 

1995 98% 0.103 0.101 0.101 0.097 0.095 

=================================== 

Average 89 % 

3. Design Values for Primary and Secondary Ambient Air Quality Standards for 

Ozone. The air quality design value at a monitoring site is defined as that concentration 

that when reduced to the level of the standard ensures that the site meets the standard. For 

a concentration-based standard, the air quality design value is simply the standard-related 

test statistic. Thus, for the primary and secondary ozone standards, the 3-year average 

annual fourth-highest daily maximum 8-hour average ozone concentration is also the air 

quality design value for the site. 

[62 FR 38895, July 18, 1997] 

B 4 
Appendix C 

Interpretation of the National Ambient Air Quality Standards for PM2.5 

40 CFR Part 50 Appendix N 

1. General. 

(a) This appendix explains the data handling conventions and computations 

necessary for determining when the annual and 24-hour primary and secondary national 

ambient air quality standards (NAAQS) for PM2.5 specified in §50.7 and §50.13 of this 

part are met. PM2.5, defined as particles with an aerodynamic diameter less than or equal 

to a nominal 2.5 micrometers, is measured in the ambient air by a Federal reference 

method (FRM) based on appendix L of this part, as applicable, and designated in 

accordance with part 53 of this chapter, or by a Federal equivalent method (FEM) 

designated in accordance with part 53 of this chapter, or by an Approved Regional 

Method (ARM) designated in accordance with part 58 of this chapter. Data handling and 

computation procedures to be used in making comparisons between reported PM2.5 

concentrations and the levels of the PM2.5 NAAQS are specified in the following 

sections. 

(b) Data resulting from exceptional events, for example structural fires or high 

winds, may be given special consideration. In some cases, it may be appropriate to 

exclude these data in whole or part because they could result in inappropriate values to 

compare with the levels of the PM2.5 NAAQS. In other cases, it may be more appropriate 

to retain the data for comparison with the levels of the PM2.5 NAAQS and then for EPA 

to formulate the appropriate regulatory response. 

(c) The terms used in this appendix are defined as follows: 

 Annual mean refers to a weighted arithmetic mean, based on quarterly means, as 

defined in section 4.4 of this appendix. 

 Creditable samples are samples that are given credit for data completeness. They 

include valid samples collected on required sampling days and valid “make-up” samples 

taken for missed or invalidated samples on required sampling days. 

 Daily values for PM2.5 refers to the 24-hour average concentrations of PM2.5 

calculated (averaged from hourly measurements) or measured from midnight to midnight 

(local standard time) that are used in NAAQS computations. 

 Designated monitors are those monitoring sites designated in a State or local 

agency PM Monitoring Network Description in accordance with part 58 of this chapter. 

 Design values are the metrics (i.e., statistics) that are compared to the NAAQS 

levels to determine compliance, calculated as shown in section 4 of this appendix: 

C 1 
(1) The 3-year average of annual means for a single monitoring site or a group of 

monitoring sites (referred to as the “annual standard design value”). If spatial averaging 

has been approved by EPA for a group of sites which meet the criteria specified in 

section 2(b) of this appendix and section 4.7.5 of appendix D of 40 CFR part 58, then 3 

years of spatially averaged annual means will be averaged to derive the annual standard 

design value for that group of sites (further referred to as the “spatially averaged annual 

standard design value”). Otherwise, the annual standard design value will represent the 3­

year average of annual means for a single site (further referred to as the “single site 

annual standard design value”). 

(2) The 3-year average of annual 98th percentile 24-hour average values recorded 

at each monitoring site (referred to as the “24-hour standard design value”). 

 Extra samples are non-creditable samples. They are daily values that do not occur 

on scheduled sampling days and that can not be used as make-ups for missed or 

invalidated scheduled samples. Extra samples are used in mean calculations and are 

subject to selection as a 98th percentile. 

 Make-up samples are samples taken to supplant missed or invalidated required 

scheduled samples. Make-ups can be made by either the primary or the collocated 

instruments. Make-up samples are either taken before the next required sampling day or 

exactly one week after the missed (or voided) sampling day. Also, to be considered a 

valid make-up, the sampling must be administered according to EPA guidance. 

98th percentile is the daily value out of a year of PM2.5 monitoring data below 

which 98 percent of all daily values fall. 

Year refers to a calendar year. 

2.0 Monitoring Considerations. 

(a) Section 58.30 of this chapter specifies which monitoring locations are eligible 

for making comparisons with the PM2.5 standards. 

(b) To qualify for spatial averaging, monitoring sites must meet the criterion 

specified in section 4.7.5 of appendix D of 40 CFR part 58 as well as the following 

requirements: 

(1) The annual mean concentration at each site shall be within 10 percent of the 

spatially averaged annual mean. 

(2) The daily values for each site pair among the 3-year period shall yield a 

correlation coefficient of at least 0.9 for each calendar quarter. 

C 2 
(3) All of the monitoring sites should principally be affected by the same major 

emission sources of PM2.5. For example, this could be demonstrated by site-specific 

chemical speciation profiles confirming all major component concentration averages to 

be within 10 percent for each calendar quarter. 

(4) The requirements in paragraphs (b)(1) through (3) of this section shall be met 

for 3 consecutive years in order to produce a valid spatially averaged annual standard 

design value. Otherwise, the individual (single) site annual standard design values shall 

be compared directly to the level of the annual NAAQS. 

(c) Section 58.12 of this chapter specifies the required minimum frequency of 

sampling for PM2.5. Exceptions to the specified sampling frequencies, such as a reduced 

frequency during a season of expected low concentrations (i.e., “seasonal sampling”), are 

subject to the approval of EPA. Annual 98th percentile values are to be calculated 

according to equation 6 in section 4.5 of this appendix when a site operates on a 

“seasonal sampling” schedule. 

3.0 Requirements for Data Used for Comparisons with the PM2.5 NAAQS and Data 

Reporting Considerations. 

(a) Except as otherwise provided in this appendix, only valid FRM/FEM/ARM 

PM2.5 data required to be submitted to EPA’s Air Quality System (AQS) shall be used in 

the design value calculations. 

(b) PM2.5 measurement data (typically hourly for continuous instruments and 

daily for filter-based instruments) shall be reported to AQS in micrograms per cubic 

meter (μg/m3

) to one decimal place, with additional digits to the right being truncated. 

(c) Block 24-hour averages shall be computed from available hourly PM2.5 

concentration data for each corresponding day of the year and the result shall be stored in 

the first, or start, hour (i.e., midnight, hour ‘0’) of the 24-hour period. A 24-hour average 

shall be considered valid if at least 75 percent (i.e., 18) of the hourly averages for the 24­

hour period are available. In the event that less than all 24 hourly averages are available 

(i.e., less than 24, but at least 18), the 24-hour average shall be computed on the basis of 

the hours available using the number of available hours as the divisor (e.g., 19). 24-hour 

periods with seven or more missing hours shall be considered valid if, after substituting 

zero for all missing hourly concentrations, the 24-hour average concentration is greater 

than the level of the standard. The computed 24-hour average PM2.5 concentrations shall 

be reported to one decimal place (the additional digits to the right of the first decimal 

place are truncated, consistent with the data handling procedures for the reported data). 

(d) Except for calculation of spatially averaged annual means and spatially 

averaged annual standard design values, all other calculations shown in this appendix 

shall be implemented on a site-level basis. Site level data shall be processed as follows: 

C 3 
(1) The default dataset for a site shall consist of the measured concentrations 

recorded from the designated primary FRM/FEM/ARM monitor. The primary monitor 

shall be designated in the appropriate State or local agency PM Monitoring Network 

Description. All daily values produced by the primary sampler are considered part of the 

site record (i.e., that site’s daily value); this includes all creditable samples and all extra 

samples. 

(2) Data for the primary monitor shall be augmented as much as possible with 

data from collocated FRM/FEM/ARM monitors. If a valid 24-hour measurement is not 

produced from the primary monitor for a particular day (scheduled or otherwise), but a 

valid sample is generated by a collocated FRM/FEM/ARM instrument (and recorded in 

AQS), then that collocated value shall be considered part of the site data record (i.e., that 

site’s daily value). If more than one valid collocated FRM/FEM/ARM value is available, 

the average of those valid collocated values shall be used as the daily value. 

(e) All daily values in the composite site record are used in annual mean and 98th 

percentile calculations, however, not all daily values are give credit towards data 

completeness requirements. Only “creditable” samples are given credit for data 

completeness. Creditable samples include valid samples on scheduled sampling days and 

valid make-up samples. All other types of daily values are referred to as “extra” samples. 

4.0 Comparisons with the PM2.5 NAAQS. 

4.1 Annual PM2.5 NAAQS. 

(a) The annual PM2.5 NAAQS is met when the annual standard design value is 

less than or equal to 15.0 micrograms per cubic meter (μg/m3

). 

(b) For single site comparisons, 3 years of valid annual means are required to 

produce a valid annual standard design value. In the case of spatial averaging, 3 years of 

valid spatially averaged annual means are required to produce a valid annual standard 

design value. Designated sites with less than 3 years of data shall be included in annual 

spatial averages for those years that data completeness requirements are met. A year 

meets data completeness requirements when at least 75 percent of the scheduled sampling 

days for each quarter have valid data. [Quarterly data capture rates (expressed as a 

percentage) are specifically calculated as the number of creditable samples for the quarter 

divided by the number of scheduled samples for the quarter, the result then multiplied by 

100 and rounded to the nearest integer.] However, years with at least 11 samples in each 

quarter shall be considered valid, notwithstanding quarters with less than complete data, 

if the resulting annual mean, spatially averaged annual mean concentration, or resulting 

annual standard design value concentration (rounded according to the conventions of 

section 4.3 of this appendix) is greater than the level of the standard. Furthermore, where 

the explicit 11 sample per quarter requirement is not met, the site annual mean shall still 

be considered valid if, by substituting a low value (described below) for the missing data 

in the deficient quarters (substituting enough to meet the 11 sample minimum), the 

computation still yields a recalculated annual mean, spatially averaged annual mean 

C 4 
concentration, or annual standard design value concentration over the level of the 

standard. The low value used for this substitution test shall be the lowest reported daily 

value in the site data record for that calendar quarter over the most recent 3-year period. 

If an annual mean is deemed complete using this test, the original annual mean (without 

substituted low values) shall be considered the official mean value for this site, not the 

result of the recalculated test using the low values. 

(c) The use of less than complete data is subject to the approval of EPA, which 

may consider factors such as monitoring site closures/moves, monitoring diligence, and 

nearby concentrations in determining whether to use such data. 

(d) The equations for calculating the annual standard design values are given in 

section 4.4 of this appendix. 

4.2 24-Hour PM2.5 NAAQS. 

(a) The 24-hour PM2.5 NAAQS is met when the 24-hour standard design value at 

each monitoring site is less than or equal to 35 μg/m3. This comparison shall be based on 

3 consecutive, complete years of air quality data. A year meets data completeness 

requirements when at least 75 percent of the scheduled sampling days for each quarter 

have valid data. However, years shall be considered valid, notwithstanding quarters with 

less than complete data (even quarters with less than 11 samples), if the resulting annual 

98th percentile value or resulting 24-hour standard design value (rounded according to the 

conventions of section 4.3 of this appendix) is greater than the level of the standard. 

(b) The use of less than complete data is subject to the approval of EPA which 

may consider factors such as monitoring site closures/moves, monitoring diligence, and 

nearby concentrations in determining whether to use such data for comparisons to the 

NAAQS. 

(c) The equations for calculating the 24-hour standard design values are given in 

section 4.5 of this appendix. 

4.3 Rounding Conventions. For the purposes of comparing calculated values to 

the applicable level of the standard, it is necessary to round the final results of the 

calculations described in sections 4.4 and 4.5 of this appendix. Results for all 

intermediate calculations shall not be rounded. 

(a) Annual PM2.5 standard design values shall be rounded to the nearest 0.1 

μg/m3

 (decimals 0.05 and greater are rounded up to the next 0.1, and any decimal lower 

than 0.05 is rounded down to the nearest 0.1). 

(b) 24-hour PM2.5 standard design values shall be rounded to the nearest 1 μg/m3 

(decimals 0.5 and greater are rounded up to the nearest whole number, and any decimal 

lower than 0.5 is rounded down to the nearest whole number). 

C 5 
4.4 Equations for the Annual PM2.5 NAAQS. 

(a) An annual mean value for PM2.5 is determined by first averaging the daily 

values of a calendar quarter using equation 1 of this appendix: 

Equation 1 

n q 1 

n 

X s,y,q = ∑ X s,y,q,i 

q i =1 Where: 

– 

x

n

Xq,y,s = the mean for quarter q of the year y for site s; 

q = the number of daily values in the quarter; and 

i q,y,s = the ith value in quarter q for year y for site s. 

(b) Equation 2 of this appendix is then used to calculate the site annual mean: 

Equation 2 

4 1 

4

X s,y = ∑ X s,y,q 

q = 1 

Where: 

–

Xy,s = the annual mean concentration for year y (y = 1, 2, or 3) and for site s; and 

– 

Xq,y,s = the mean for quarter q of year y for site s. 

(c) If spatial averaging is utilized, the site-based annual means will then be 

averaged together to derive the spatially averaged annual mean using equation 3 of this 

appendix. Otherwise (i.e., for single site comparisons), skip to equation 4.B of this 

appendix. 

Equation 3 

ns 1 

n 

xy = ∑ x s,y 

s s =1 

Where: 

– = the spatially averaged mean for year y, xy 

C 6 
– the annual mean for year y and site s for sites designated to be averaged that = 

n

xy,s meet completeness criteria , and 

s = the number of sites designated to be averaged that meet completeness 

criteria 

(d) The annual standard design value is calculated using equation 4A of this 

appendix when spatial averaging and equation 4B of this appendix when not spatial 

averaging: 

Equation 4A Equation 4B 

When spatial averaging When not spatial averaging 

3 3 1 

3

x = ∑ xy x = 1 ∑ x s,y 

y = 1 3 y = 1 

Where: 

– = the annual standard design value (the spatially averaged annual standard x 

design value for equation 4A of this appendix and the single site annual 

standard design value for equation 4B of this appendix); and 

– = the spatially averaged annual mean for year y (result of equation 3 of this xy appendix) when spatial averaging is used, or 

– = the annual mean for year y and site s (result of equation 2 of this appendix) xy,s when spatial averaging is not used. 

(e) The annual standard design value is rounded according to the conventions in 

section 4.3 of this appendix before a comparison with the standard is made. 

4.5 Equations for the 24-Hour PM2.5 NAAQS. 

(a) When the data for a particular site and year meet the data completeness 

requirements in section 4.2 of this appendix, calculation of the 98th percentile is 

accomplished by the steps provided in this subsection. Equation 5 of this appendix shall 

be used to compute annual 98th percentile values, except that where a site operates on an 

approved seasonal sampling schedule, equation 6 of this appendix shall be used instead. 

(1) Regular formula for computing annual 98th percentile values. Calculation 

of annual 98th percentile values using the regular formula (equation 5) will be based on 

the creditable number of samples (as described below), rather than on the actual number 

of samples. Credit will not be granted for extra (non-creditable) samples. Extra samples, 

however, are candidates for selection as the annual 98th percentile. [The creditable 

number of samples will determine how deep to go into the data distribution, but all 

samples (creditable and extra) will be considered when making the percentile 

assignment.] The annual creditable number of samples is the sum of the four quarterly 

creditable number of samples. Sort all the daily values from a particular site and year by 

C 7 
i 

ascending value. (For example: (x[1], x[2], x[3], ..., x[n]). In this case, x[1] is the smallest 

number and x[n] is the largest value.) The 98th percentile is determined from this sorted 

series of daily values which is ordered from the lowest to the highest number. Compute 

98

(0.98) x (cn) as the number “i.d,” where ‘cn’ is the annual creditable number of samples, 

“i” is the integer part of the result, and “d” is the decimal part of the result. The 

th percentile value for year y, P0.98, y, is calculated using equation 5 of this appendix: 

Equation 5 

P y,98.0 = X[ +1 i ]

x

Where: 

P0.98, y = 98th percentile for year y; 

[i+1] = the (i+1)th number in the ordered series of numbers; 

= the integer part of the product of 0.98 and cn. 

(2) Formula for computing annual 98th percentile values when sampling 

frequencies are seasonal. Calculate the annual 98th percentiles by determining the 

smallest measured concentration, x, that makes W(x) greater than 0.98 using equation 6 

of this appendix: 

Equation 6 

W( ) = dHigh x + x

d d

x 

High + dLow 

FHigh ( ) dLow FLow ( )

High + dLow 

Where: 

dHigh = number of calendar days in the "High" season; 

dLow = number of calendar days in the "Low" season; 

dHigh + days in a year; and = dLow 

are that a season in values daily of number ≤ x 

Fa(x) = a season in values daily of number 

Such that “a” can be either “High” or “Low”; “x” is the measured concentration; and 

“dHigh/(dHigh + dLow) and dLow /(dHigh + dLow)” are constant and are called seasonal 

“weights.” 

(b) The 24-hour standard design value is then calculated by averaging the 

annual 98th percentiles using equation 7 of this appendix: 

Equation 7 

C 8 
3 

∑ P 

.0 98 y,

= y = 1 P .0 98 3 

(c) The 24-hour standard design value (3-year average 98th percentile) is rounded 

according to the conventions in section 4.3 of this appendix before a comparison with the 

standard is made. 

C 9 
Appendix D 

Interpretation of the National Ambient Air Quality Standards for PM 

40 CFR Part 50 Appendix K 

1.0 General. 

(a) This appendix explains the computations necessary for analyzing particulate matter 

data to determine attainment of the 24-hour standards specified in 40 CFR 50.6. For the 

primary and secondary standards, particulate matter is measured in the ambient air as 

PM10 (particles with an aerodynamic diameter less than or equal to a nominal 10 

micrometers) by a reference method based on appendix J of this part and designated in 

accordance with part 53 of this chapter, or by an equivalent method designated in 

accordance with part 53 of this chapter. The required frequency of measurements is 

specified in part 58 of this chapter. 

(b) The terms used in this appendix are defined as follows: 

Average refers to the arithmetic mean of the estimated number of exceedances per year, 

as per Section 3.1. 

Daily value for PM10 refers to the 24-hour average concentration of PM10 calculated or 

measured from midnight to midnight (local time). 

Exceedance means a daily value that is above the level of the 24-hour standard after 

rounding to the nearest 10 μg/m3

 (i.e., values ending in 5 or greater are to be rounded up). 

Expected annual value is the number approached when the annual values from an 

increasing number of years are averaged, in the absence of long-term trends in emissions 

or meteorological conditions. 

Year refers to a calendar year. 

(c) Although the discussion in this appendix focuses on monitored data, the same 

principles apply to modeling data, subject to EPA modeling guidelines. 

2.0 Attainment Determinations. 

2.1 24-Hour Primary and Secondary Standards. 

(a) Under 40 CFR 50.6(a) the 24-hour primary and secondary standards are attained when 

the expected number of exceedances per year at each monitoring site is less than or equal 

to one. In the simplest case, the number of expected exceedances at a site is determined 

by recording the number of exceedances in each calendar year and then averaging them 

over the past 3 calendar years. Situations in which 3 years of data are not available and 

D 1 
possible adjustments for unusual events or trends are discussed in sections 2.3 and 2.4 of 

this appendix. Further, when data for a year are incomplete, it is necessary to compute an 

estimated number of exceedances for that year by adjusting the observed number of 

exceedances. This procedure, performed by calendar quarter, is described in section 3.0 

of this appendix. The expected number of exceedances is then estimated by averaging the 

individual annual estimates for the past 3 years. 

(b) The comparison with the allowable expected exceedance rate of one per year is made 

in terms of a number rounded to the nearest tenth (fractional values equal to or greater 

than 0.05 are to be rounded up; e.g., an exceedance rate of 1.05 would be rounded to 1.1, 

which is the lowest rate for nonattainment). 

2.2 Reserved 

2.3 Data Requirements. 

(a) 40 CFR 58.12 specifies the required minimum frequency of sampling for PM10. For 

the purposes of making comparisons with the particulate matter standards, all data 

produced by State and Local Air Monitoring Stations (SLAMS) and other sites submitted 

to EPA in accordance with the part 58 requirements must be used, and a minimum of 75 

percent of the scheduled PM10 samples per quarter are required. 

(b) To demonstrate attainment of the 24-hour standards at a monitoring site, the monitor 

must provide sufficient data to perform the required calculations of sections 3.0 and 4.0 

of this appendix. The amount of data required varies with the sampling frequency, data 

capture rate and the number of years of record. In all cases, 3 years of representative 

monitoring data that meet the 75 percent criterion of the previous paragraph should be 

utilized, if available, and would suffice. More than 3 years may be considered, if all 

additional representative years of data meeting the 75 percent criterion are utilized. Data 

not meeting these criteria may also suffice to show attainment; however, such exceptions 

will have to be approved by the appropriate Regional Administrator in accordance with 

EPA guidance. 

(c) There are less stringent data requirements for showing that a monitor has failed an 

attainment test and thus has recorded a violation of the particulate matter standards. 

Although it is generally necessary to meet the minimum 75 percent data capture 

requirement per quarter to use the computational equations described in section 3.0 of 

this appendix, this criterion does not apply when less data is sufficient to unambiguously 

establish nonattainment. The following examples illustrate how nonattainment can be 

demonstrated when a site fails to meet the completeness criteria. Nonattainment of the 

24-hour primary standards can be established by the observed annual number of 

exceedances (e.g., four observed exceedances in a single year), or by the estimated 

number of exceedances derived from the observed number of exceedances and the 

required number of scheduled samples (e.g., two observed exceedances with every other 

day sampling). In both cases, expected annual values must exceed the levels allowed by 

the standards. 

D 2 
2.4 Adjustment for Exceptional Events and Trends. 

(a) An exceptional event is an uncontrollable event caused by natural sources of 

particulate matter or an event that is not expected to recur at a given location. Inclusion of 

such a value in the computation of exceedances or averages could result in inappropriate 

estimates of their respective expected annual values. To reduce the effect of unusual 

events, more than 3 years of representative data may be used. Alternatively, other 

techniques, such as the use of statistical models or the use of historical data could be 

considered so that the event may be discounted or weighted according to the likelihood 

that it will recur. The use of such techniques is subject to the approval of the appropriate 

Regional Administrator in accordance with EPA guidance. 

(b) In cases where long-term trends in emissions and air quality are evident, mathematical 

techniques should be applied to account for the trends to ensure that the expected annual 

values are not inappropriately biased by unrepresentative data. In the simplest case, if 3 

years of data are available under stable emission conditions, this data should be used. In 

the event of a trend or shift in emission patterns, either the most recent representative 

year(s) could be used or statistical techniques or models could be used in conjunction 

with previous years of data to adjust for trends. The use of less than 3 years of data, and 

any adjustments are subject to the approval of the appropriate Regional Administrator in 

accordance with EPA guidance. 

3.0 Computational Equations for the 24-hour Standards. 

3.1 Estimating Exceedances for a Year. 

(a) If PM10 sampling is scheduled less frequently than every day, or if some scheduled 

samples are missed, a PM10 value will not be available for each day of the year. To 

account for the possible effect of incomplete data, an adjustment must be made to the 

data collected at each monitoring location to estimate the number of exceedances in a 

calendar year. In this adjustment, the assumption is made that the fraction of missing 

values that would have exceeded the standard level is identical to the fraction of 

measured values above this level. This computation is to be made for all sites that are 

scheduled to monitor throughout the entire year and meet the minimum data requirements 

of section 2.3 of this appendix. Because of possible seasonal imbalance, this adjustment 

shall be applied on a quarterly basis. The estimate of the expected number of exceedances 

for the quarter is equal to the observed number of exceedances plus an increment 

associated with the missing data. The following equation must be used for these 

computations: 

Equation 1 

⎛

⎜

⎜

Nq ⎞

⎟

⎟ eq = vq

×

⎝ nq ⎠

D 3 
where: 

eq = the estimated number of exceedances for calendar quarter q; 

vq = the observed number of exceedances for calendar quarter q; 

Nq = the number of days in calendar quarter q; 

nq = the number of days in calendar quarter q with PM10 data; and 

q = the index for calendar quarter, q=1, 2, 3 or 4. 

(b) The estimated number of exceedances for a calendar quarter must be rounded to the 

nearest hundredth (fractional values equal to or greater than 0.005 must be rounded up). 

(c) The estimated number of exceedances for the year, e, is the sum of the estimates for 

each calendar quarter. 

Equation 2 

4 

e =∑eq 

=1 q 

(d) The estimated number of exceedances for a single year must be rounded to one 

decimal place (fractional values equal to or greater than 0.05 are to be rounded up). The 

expected number of exceedances is then estimated by averaging the individual annual 

estimates for the most recent 3 or more representative years of data. The expected 

number of exceedances must be rounded to one decimal place (fractional values equal to 

or greater than 0.05 are to be rounded up). 

(e) The adjustment for incomplete data will not be necessary for monitoring or modeling 

data which constitutes a complete record, i.e., 365 days per year. 

(f) To reduce the potential for overestimating the number of expected exceedances, the 

correction for missing data will not be required for a calendar quarter in which the first 

observed exceedance has occurred if: 

(1) There was only one exceedance in the calendar quarter; 

(2) Everyday sampling is subsequently initiated and maintained for 4 calendar quarters in 

accordance with 40 CFR 58.12; and 

(3) Data capture of 75 percent is achieved during the required period of everyday 

sampling. In addition, if the first exceedance is observed in a calendar quarter in which 

D 4 
the monitor is already sampling every day, no adjustment for missing data will be made 

to the first exceedance if a 75 percent data capture rate was achieved in the quarter in 

which it was observed. 

Example 1 

a. During a particular calendar quarter, 39 out of a possible 92 samples were recorded, 

with one observed exceedance of the 24-hour standard. Using Equation 1, the estimated 

number of exceedances for the quarter is: 

eq=1×92/39=2.359 or 2.36. 

b. If the estimated exceedances for the other 3 calendar quarters in the year were 2.30, 0.0 

and 0.0, then, using Equation 2, the estimated number of exceedances for the year is 

2.36+2.30+0.0+0.0 which equals 4.66 or 4.7. If no exceedances were observed for the 2 

previous years, then the expected number of exceedances is estimated by: 

(1/3)×(4.7+0+0)=1.57 or 1.6. Since 1.6 exceeds the allowable number of expected 

exceedances, this monitoring site would fail the attainment test. 

Example 2 

In this example, everyday sampling was initiated following the first observed exceedance 

as required by 40 CFR 58.12. Accordingly, the first observed exceedance would not be 

adjusted for incomplete sampling. During the next three quarters, 1.2 exceedances were 

estimated. In this case, the estimated exceedances for the year would be 1.0+1.2+0.0+0.0 

which equals 2.2. If, as before, no exceedances were observed for the two previous years, 

then the estimated exceedances for the 3-year period would then be 

(1/3)×(2.2+0.0+0.0)=0.7, and the monitoring site would not fail the attainment test. 

3.2 Adjustments for Non-Scheduled Sampling Days. 

(a) If a systematic sampling schedule is used and sampling is performed on days in 

addition to the days specified by the systematic sampling schedule, e.g., during episodes 

of high pollution, then an adjustment must be made in the equation for the estimation of 

exceedances. Such an adjustment is needed to eliminate the bias in the estimate of the 

quarterly and annual number of exceedances that would occur if the chance of an 

exceedance is different for scheduled than for non-scheduled days, as would be the case 

with episode sampling. 

(b) The required adjustment treats the systematic sampling schedule as a stratified 

sampling plan. If the period from one scheduled sample until the day preceding the next 

scheduled sample is defined as a sampling stratum, then there is one stratum for each 

scheduled sampling day. An average number of observed exceedances is computed for 

each of these sampling strata. With nonscheduled sampling days, the estimated number of 

exceedances is defined as: 

D 5 
Equation 3 

e = ⎜

⎛ N ⎞ mq ⎛ vj ⎞ q ⎟ ⎜ ⎟

q ⎜ ⎟ ×∑⎜ ⎝ mq ⎠ j=1 ⎝ k j ⎠

⎟

where: 

eq = the estimated number of exceedances for the quarter; 

Nq = the number of days in the quarter; 

mq = the number of strata with samples during the quarter; 

vj = the number of observed exceedances in stratum j; and 

kj = the number of actual samples in stratum j. 

(c) Note that if only one sample value is recorded in each stratum, then Equation 3 

reduces to Equation 1. 

Example 3 

A monitoring site samples according to a systematic sampling schedule of one sample 

every 6 days, for a total of 15 scheduled samples in a quarter out of a total of 92 possible 

samples. During one 6-day period, potential episode levels of PM10 were suspected, so 5 

additional samples were taken. One of the regular scheduled samples was missed, so a 

total of 19 samples in 14 sampling strata were measured. The one 6-day sampling stratum 

with 6 samples recorded 2 exceedances. The remainder of the quarter with one sample 

per stratum recorded zero exceedances. Using Equation 3, the estimated number of 

exceedances for the quarter is: 

Eq = (92/14)×(2/6+0+. . .+0)=2.19. 

D 6