There are six criteria pollutants, that act as indicators of air quality in this country. The National Ambient Air Quality Standards (NAAQS) are the concentrations of these criteria pollutants, above which, adverse effects on human health may occur.
Areas of Pennsylvania where air pollution levels consistently stay below these standards are designated "attainment." Areas where air pollution levels persistently exceed these standards are designated "nonattainment". For the exact calculation used to determine attainment of a standard for a particular pollutant, where available, please view the footnotes on the EPA's NAAQS website. If an area was in nonattainment, but now attains the standard and has an EPA-approved plan to maintain the standard, it is designated a "maintenance" area.
EPA maintains a list of nonattainment areas for all six principal pollutants on their Green Book website. Attainment designations for all states are listed in the Code of Federal Regulations. Pennsylvania's listings are contained in Title 40, Part 81, Section 339 (PDF). For the history of these designations, see the Recommendations for Area Designations page.
States submit recommendations for designation up to one year after the promulgation of the revised NAAQS. EPA may make modifications and promulgate all or part of a state's recommendations. If EPA determines that a modification to the recommendation is necessary, EPA will notify the state no later than 120 days prior to promulgating the designation. This provides an opportunity for the state to work with EPA if the state believes EPA's decisions are not appropriate.
Ozone
The Clean Air Act required EPA to classify areas that are designated as non-attainment for the ozone standard by the severity of their pollution. These classifications, in order of severity, are: Nonattainment, Marginal, Moderate, Serious, Severe, and Extreme.
2015 8-hour Ozone Standard: 0.070 ppm
Current Attainment Status
- Nonattainment: (All are classified Marginal) Bucks, Chester, Delaware, Montgomery, and Philadelphia.
2008 8-hour Ozone Standard: 0.075 ppm
Map: Original Designations (PDF)
Current Attainment Status
- Nonattainment: (All are classified Marginal) Allegheny, Armstrong, Beaver, Berks, Bucks, Butler, Carbon, Chester, Delaware, Fayette, Lancaster, Lehigh, Montgomery, Northampton, Philadelphia, Washington and Westmoreland.
1997 8-hour Ozone Standard: 0.08 ppm
The 1997 8-hour Ozone Standard has been revoked effective April 6, 2015. For additional information about original designations and attainment status, please refer to the EPA's Green Book.
1979 1-hour Ozone Standard: 0.12 ppm
The 1-hour Ozone Standard has been revoked. For additional information about original designations and attainment status, please refer to the EPA's Green Book.
Particulate Matter (PM)
2024 PM Standard
PM2.5 24-hour Standard: 35 µg/m 3
PM2.5 Annual Standard: 9 µg/m 3
2012 PM Standard
PM2.5 24-hour Standard: 35 µg/m 3
PM2.5 Annual Standard: 12 µg/m 3
Map: Original Designations (PDF) (P - partial county)
Original Designations
- Nonattainment (All classified Moderate): Allegheny, Delaware, and Lebanon.
Current Attainment Status
- Nonattainment (Moderate): Allegheny
- Maintenance: Delaware and Lebanon.
2006 PM Standard
PM2.5 24-hour Standard: 35 µg/m 3
PM2.5 Annual Standard: 15 µg/m 3
Map: Original Designations (PDF)
Current Attainment Status (P - partial county)
- Nonattainment: (Moderate): Allegheny (Liberty-Clairton)
- Maintenance: Allegheny (remainder), Armstrong (p), Beaver, Bucks, Butler, Cambria, Chester, Cumberland, Dauphin, Delaware, Greene (p), Indiana (p), Lancaster, Lawrence (p), Lebanon, Lehigh, Montgomery, Northampton, Philadelphia, Washington, Westmoreland and York.
1997 PM Standard
PM2.5 24-hour Standard: 65 µg/m 3
PM2.5 Annual Standard: 15 µg/m 3
Map: Original Designations (PDF)
Current attainment status (P-partial county):
- Nonattainment (Moderate): Allegheny (Liberty-Clairton)
- Maintenance: Allegheny (remainder), Armstrong (p), Berks, Beaver, Bucks, Butler, Cambria, Chester, Cumberland, Dauphin, Delaware, Greene (p), Indiana (p), Lancaster, Lawrence (p), Lebanon, Montgomery, Philadelphia, Washington, Westmoreland and York.
Sulfur Dioxide (SO2)
2010 SO2 Standard
SO2 1-hour standard: 0.075ppm (75ppb)
SO2 3-hour standard: 0.5 ppm
Original Designations (no map available)
- Nonattainment: Allegheny (p), Armstrong (p), Beaver (p), Indiana (p), Warren (p)
Current Attainment Status (P - partial county)
- Nonattainment: Allegheny (p), Armstrong (p), Beaver (p), Indiana (p), Warren (p)
Carbon Monoxide (CO)
1971 CO Standards (Pre-1990)
CO 8-hour Standard: 9 ppm
CO 1-hour Standard: 35 ppm
Original Designations (no map available)
- Nonattainment: Philadelphia (p) – portions of City of Philadelphia; Allegheny (p) – portions of City of Pittsburgh
Current Attainment Status (p – partial county)
- Maintenance: Philadelphia (p) – Allegheny (p)
Nitrogen Dioxide (NO2)
2010 NO 2 Standard
1-hour NO 2 Standard: 0.10ppm (100 ppb)
Annual Primary and Secondary standard: 0.053 ppm - Retained without
revision in 2010
- Final designations were published by the EPA in the Federal Register (77 FR 9532) on Feb. 17, 2012.
- All areas in Pennsylvania designated as attainment for these standards.
Lead (Pb)
2008 Lead Standard
3 Month Rolling Average: 0.15 µg/m 3
Original Designations
- Nonattainment: Beaver (p) – Lower Beaver Valley; Berks (p) – Lyons and North Reading (see EPA Green Book for area boundaries).
Current attainment status
- Nonattainment: Beaver (p) – Lower Beaver Valley; Berks (p) – Lyons and North Reading
Revised 07/07/21