National Ambient Air Quality Standards for Criteria Air Pollutants, 1997
Pollutant | Primary Standards* |
---|---|
Ozone | |
1-h average | 0.12 ppm (235 μg/m3) |
8-h average | 0.08 ppm (157 μg/m3) |
PM10 | |
Annual arithmetic mean | 50 μg/m3 |
24-h average | 150 μg/m3 |
PM2.5 | |
Annual arithmetic mean | 15 μg/m3 |
24-h average | 65 μg/m3 |
Sulfur dioxide | |
Annual arithmetic mean | 0.03 ppm (80 μg/m3) |
24-h average | 0.14 ppm (365 μg/m3) |
Nitrogen dioxide | |
Annual arithmetic mean | 0.053 ppm (100 μg/m3) |
Carbon monoxide | |
8-h average | 9 ppm (10 mg/m3) |
1-h average | 35 ppm (40 mg/m3) |
Lead | |
Quarterly average | 1.5 μg/m3 |
Additional information on air quality standards are available at www.epa.gov/air/criteria.html.
↵* People residing in regions with pollutant concentrations above the primary standard may experience adverse health effects from poor air quality.