Effective May 6, 2024, the National Ambient Air Quality Standard (NAAQS) for PM2.5 was lowered from 12.0 to 9.0 µg/m3.
EPA expects to finalize the attainment designations for the lower standard by February 2026. Based on prior monitoring data, Santa Barbara County is expected to be in attainment. More information on the revised PM2.5 standard can be found here: www.epa.gov/particle-pollution-designations
Air quality standards define clean air. They tell us how much of a substance can be in the air without causing harm, based on proven scientific and medical research. Air quality standards have been set by both the federal Environmental Protection Agency (EPA) and the California Air Resources Board (CARB). In most cases, California’s standards are more health-protective than the national standards.
National standards have been established by the EPA for seven pollutants:
- Ozone,
- Nitrogen Dioxide,
- Sulfur Dioxide,
- Carbon Monoxide,
- Particulate Matter less than 10 microns in diameter (PM10),
- Particulate Matter less than 2.5 microns in diameter (PM2.5), and
- Lead.
California standards exist for all of the pollutants above, plus four more:
- Sulfates,
- Hydrogen Sulfide,
- Vinyl Chloride (chloroethene), and
- Visibility Reducing Particles.
These are the only pollutants – out of hundreds in our air – for which ambient air quality standards have been set. These pollutants were chosen because they are commonly emitted from numerous sources and they are considered harmful to both human health and the environment.
The Attainment Designation tells us whether our air meets the health-based standards. Santa Barbara County is attainment for all federal ambient air quality standards. However, the County is currently nonattainment-transitional for the state ozone standard and nonattainment for the state PM10. See the Table below for a full listing of the standards and attainment status for each pollutant.
Other Resources:
- View the California Air Resources Board webpages on the California AAQS and the National AAQS.
- View Santa Barbara County Exceedances of the Ozone and PM Standards.
- View historical statistics on ozone and particle pollution using the California Air Resources Board database.
- View information on other air pollutants that have health effects through the District’s Air Toxics Program.
Santa Barbara County Attainment & Nonattainment Designations
Pollutant | Averaging Time | California Standards | National Standards | ||
| Pollutant Concentration | Attainment Designation | Pollutant Concentration | Attainment Designation | ||
Ozone | 8 hour | 0.070 ppm | NA-T | 0.070 ppm | A/U |
| 1 hour | 0.09 ppm | Revoked | — | ||
Nitrogen Dioxide | annual arithmetic mean | 0.030 ppm (56 µg/m3) | A | 0.053 ppm (100 µg/m3) | A/U |
| 1 hour | 0.18 ppm (338 µg/m3) | 0.10 ppm (188 µg/m3) | A/U | ||
Sulfur Dioxide | 24 hour | 0.04 ppm (105 µg/m3) | A | Revoked | — |
| 1 hour | 0.25 ppm (655 µg/m3) | 0.075 ppm (196 µg/m3) | A/U | ||
Carbon Monoxide | 8 hour | 9.0 ppm (10 mg/m3) | A | 9 ppm (10 mg/m3) | A/U |
| 1 hour | 20 ppm (23 mg/m3) | 35 ppm (40 mg/m3) | |||
Particulate Matter (PM10) | annual arithmetic mean | 20 µg/m3 | N | Revoked | — |
| 24 hour | 50 µg/m3 | 150 µg/m3 | U | ||
Particulate Matter (PM2.5) | annual arithmetic mean | 12 µg/m3 | A | 9.0 µg/m3 | A/U |
| 24 hour | — | — | 35 µg/m3 | A/U | |
Lead | Rolling 3-month average | — | — | 0.15 µg/m3 | A/U |
| 30 day average | 1.5 µg/m3 | A | — | — | |
Sulfates | 24 hour | 25 µg/m3 | A | ||
Hydrogen Sulfide | 1 hour | 0.03 ppm (42 µg/m3) | A | ||
Vinyl Chloride (chloroethene) | 24 hour | 0.01 ppm (26 µg/m3) | — | ||
Visibility Reducing Particles | 8 hour (1000 to 1800 PST) | See Note #1 | U | ||
Legend
A = Attainment;
NA-T = Nonattainment-Transitional;
N = Nonattainment;
U = Unclassified;
A/U = Attainment/Unclassifiable;
— = No Standard
mg/m3 = milligrams per cubic meter;
µg/m3 = micrograms per cubic meter;
ppm = parts per million;
ppb = parts per billion;
Note #1: Statewide VRP Standard (except Lake Tahoe Air Basin): Particles in sufficient amount to produce an extinction coefficient of 0.23 per kilometer when the relative humidity is less than 70 percent. This standard is intended to limit the frequency and severity of visibility impairment due to regional haze and is equivalent to a 10-mile nominal visual range.
Note #2: Recent EPA federal registers have established that the “Attainment/Unclassifiable” designation is clearer than “Unclassifiable/Attainment”, and that re-ordering the terms has no regulatory consequence.
