Air Quality Information
For information on ground-level ozone or particulate matter pollution in your county, please contact the appropriate air district:
Air Quality 101
The Sacramento region is designated as a serious non-attainment area for the federal 8-hour ozone standard with an attainment deadline of June 2013. This non-attainment area includes all of Sacramento and Yolo counties and portions of El Dorado, Placer, Sutter and Solano counties (see map below).

In July 1997, the U. S. Environmental Protection Agency (EPA) promulgated a new 8-hour standard for ozone. This change lowered the standard for ambient ozone from 0.12 parts per million of ozone averaged over one hour to 0.08 parts per million of ozone averaged over eight hours. In general, the 8-hour standard is more protective of public health and more stringent than the previous federal 1-hour standard that was revoked in 2005.

Ground-level ozone forms readily in the atmosphere during hot summer weather, but it is not emitted directly into the air. It is formed by a photochemical reaction when Volatile Organic Compounds (VOCs) and Oxides of Nitrogen (NOx) react with ultraviolet rays from the sun. VOCs come from things that evaporate like gasoline, paint fumes, lighter fluid and consumer products. NOx is emitted from vehicles, power plants and other sources of combustion like gas-powered lawn and garden equipment.

Because the Sacramento Valley is shaped like a bowl, pollution presents a critical problem when an inversion layer traps pollutants close to the ground, causing unhealthy air quality levels. Vehicles and other mobile sources, including trucks, locomotives, buses, motorcycles, agricultural equipment and construction equipment cause approximately 70 percent of our region’s air pollution problem.

Sacramento Federal Non-attainment Area Map
The Sacramento region ozone non-attainment area
Monitoring Sites
There are 18 official monitoring sites throughout the ozone non-attainment area.
Monitoring Sites Operated
By Local Air Districts
1. Woodland GP
2. Vacaville-Elmira G
3. Auburn GP
4. Colfax GPM
5. Folsom GMP
6. North Highlands GP
7. Elk Grove-Bruceville GPM
8. Del Paso Manor GPM
9. El Camino & Watt GP
10. Stockton Blvd. P
11. Sloughhouse GM
12. Airport Rd. GPM
Monitoring Sites
Operated By ARB
13. Walnut Grove GM
14. Davis GPM
15. Roseville GPTM
16. Cool GM
17. Placerville GPM
18. Downtown Sacramento
13th and T		 GPAM
Legend
G Gaseous Monitoring
P Particulate Monitoring
T Toxics Sampling
A Acid Deposition Sampling
M Meteorological Monitoring


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