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Air Quality Standards and Attainment Status
View state and federal standards for 11 air pollutants and see the Bay Area’s attainment status for each pollutant.
Background
The National Ambient Air Quality Standards (NAAQS) and the California Ambient Air Quality Standards (CAAQS) are set to protect public health. Primary NAAQS are set to protect public health with an adequate margin of safety and secondary NAAQS are set to protect public welfare against adverse effects caused by air pollution, including detrimental impacts to ecosystems, visibility, crops, and buildings. Detailed information on the current form of the NAAQS are available on the U.S. EPA’s website, and information on the CAAQS are available on the California Air Resource Board’s website.
Classifications
Continuous air monitoring ensures that the NAAQS and CAAQS are met and maintained. For the NAAQS, areas with air quality meeting the standard are designated “attainment/unclassifiable”, or “nonattainment” if the standard is not met. For the CAAQS, an area is designated as “attainment” if it meets the standard, “nonattainment” if it does not meet the standard, or “unclassified” if there is insufficient data to determine if the standard is met. Updated information regarding nationwide statuses can be found for the NAAQS on the U.S. EPA's website. For updated information on CAAQS, visit the California Air Resource Board’s website.
Air Quality Standards and Designation Status for the San Francisco Bay Area Air Basin
| Pollutant | Standard | Averaging Time | Level | Designation |
|---|---|---|---|---|
| Ozone (O3) | NAAQS | 8 Hour (primary and secondary) | 0.070 ppm | Nonattainment (Marginal) |
| CAAQS | 8 Hour | 0.070 ppm | Nonattainment-Transitional |
|
| Annual | 0.09 ppm | |||
| Particulate Matter (PM10) | NAAQS | 24 Hour (primary and secondary) | 150 µg/m3 | Attainment/Unclassifiable |
| CAAQS | 24 Hour | 50 µg/m3 | Nonattainment | |
| 1 Year | 20 µg/m3 | Nonattainment | ||
| Particulate Matter (PM2.5) | NAAQS | 24 Hour (primary and secondary) | 35 µg/m3 | Nonattainment (Moderate) |
| 1 Year (primary; 2012) | 12.0 µg/m3 | Attainment/Unclassifiable1 | ||
| 1 Year (primary; 2024) | 9.0 µg/m3 | TBD1 | ||
| 1 Year (secondary) | 15.0 µg/m3 | Attainment/Unclassifiable | ||
| CAAQS | 1 Year | 12 µg/m3 | Attainment | |
| Carbon Monoxide (CO) | NAAQS | 8 Hour (primary) | 9 ppm | Attainment/Unclassifiable |
| Annual (primary) | 35 ppm | Attainment/Unclassifiable | ||
| CAAQS | 8 Hour | 9.0 ppm | Attainment | |
| Annual | 20 ppm | |||
| Lead (Pb) | NAAQS | Rolling 3-month average (primary and secondary) | 0.15 µg/m3 | Attainment/Unclassifiable |
| CAAQS | 30-day average | 1.5 µg/m3 | Attainment | |
| Nitrogen Dioxide (NO2) | NAAQS | Annual (primary) | 100 ppb | Attainment/Unclassifiable |
| 1 Year (primary and secondary) | 53 ppb | Attainment/Unclassifiable | ||
| CAAQS | Annual | 0.18 ppm | Attainment | |
| 1 Year | 0.030 ppm | |||
| Sulfur Dioxide (SO2) | NAAQS | Annual (primary) | 75 ppb | Attainment/Unclassifiable |
| 1 Year (secondary) | 10 ppb | TBD2 | ||
| CAAQS | 1 Hour | 0.25 ppm | Attainment | |
| 24 Hour | 0.04 ppm | |||
| Visibility Reducing Particles | CAAQS | 8 Hour | 0.23/km extinction coefficient | Unclassified |
| Sulfates | CAAQS | 24 Hour | 25 µg/m3 | Attainment |
| Hydrogen Sulfide | CAAQS | Annual | 0.03 ppm | Unclassified |
| Vinyl Chloride | CAAQS | 24 Hour | 0.01 ppm | N/A |
| ppm = parts per million | ppb = parts per billion | µg/m3 = micrograms per cubic meter | ||||
Notes:
- The EPA promulgated a revised NAAQS for PM2.5 on February 7, 2024, strengthening the standard from 12.0 µg/m3 to 9.0 µg/m3. While the Bay Area is currently in attainment of the 2012 PM2.5 NAAQS, the region’s designation may change as a result of the revised standard. Based on a 2-year initial area designations schedule, EPA is expected to promulgate final 2024 PM2.5 NAAQS area designations in 2026.
- The EPA revised the secondary NAAQS for SO2 in December 2024, adding a new 10 ppb standard for 1 Year (secondary) concentrations while retaining the existing standards for SO2. EPA is expected to promulgate final 2025 SO2 NAAQS area designations in 2026.
Actions taken by the Bay Area Air District to address concentrations of air pollutants exceeding national and statewide standards
The Air District develops and implements Air Quality Plans to meet state and federal Clean Air Act requirements, including the CAAQS and NAAQS. For more information on the Air District’s Air Quality Plans, please visit the Air Quality Plans site.
Last Updated: 12/15/2025