California
Most Polluted California Counties 2017
The National Air Quality report released in mid-April 2017 says:
Los Angeles, CA, remains the city with the worst ozone pollution as it has for nearly the entire history of the report.
Bakersfield, CA, maintains its rank as the city with the worst short-term particle pollution.
Visalia-Porterville-Hanford, CA, moved for the first time to rank as the most-polluted city for year-round particle pollution (particle pollution can cause early death and heart attacks, strokes and emergency room visits for people with asthma, cardiovascular disease and diabetes.)
California Counties Grades Combine Averages of Ozone and Short-Term Particle Pollution with the number of moderate days receiving a factor of 1; unhealthy days 1.5; and very unhealthy days, a factor of 2
A Grade (9) : Colusa, Humboldt, Lake, Marin, Mendocino, Monterey, San Francisco, Santa Cruz, Sonoma
B Grade (4) : Glenn, Napa, San Mateo, Siskiyou
C Grade (2) : Solano, Yolo
D Grade (2) : Inyo, San Benito
F Grade (32) : Alameda, Amador, Butte, Calaveras, Contra Costa, El Dorado, Fresno, Imperial, Kern, Kings, Los Angeles, Madera, Mariposa, Merced, Nevada, Orange, Placer, Riverside, Sacramento, San Bernardino, San Diego, San Joaquin, San Luis Obispo, Santa Barbara, Santa Clara, Shasta, Stanislaus, Sutter, Tehama, Tulare, Tuolumne, Ventura
No Monitor Collecting (9) : Alpine, Del Norte, Lassen, Modoc, Mono, Plumas, Sierra, Trinity, Yuba
Scale
0 – 54 ppb Good
55 – 70 ppb Moderate
71 – 85 ppb Unhealthy for Sensitive Groups
86 – 105 ppb Unhealthy
106 – 200 ppb Very Unhealthy
Alameda Grade F 19 days moderate
Alpine - No Monitor Collecting
Amador Grade F 2 days moderate
Butte Grade F 23
moderate | 1 day unhealthy
Calaveras Grade F 23
days moderate | 1
day unhealthy
Colusa Grade A
Contra Costa Grade F 13
days moderate
Del Norte - No Monitor Collecting
El Dorado Grade F 87 day moderate | 4 days unhealthy
Fresno Grade F 215
days moderate
| 41 days unhealthy | 1 day very unhealthy!
Glenn Grade B 2 days moderate
Humboldt Grade A
Imperial Grade F 63
days moderate | 3 days unhealthy
Inyo Grade D 9
days moderate
Kern Grade F 232 days moderate
| 45 days unhealthy | 1 day very unhealthy!
Kings Grade F 120 moderate | 9 days unhealthy
Lake Grade A
Lassen - No Monitor Collecting
Los Angeles Grade F 202 moderate | 78 days unhealthy | 3 very
unhealthy days!
Madera Grade F 124 days moderate | 11 days
unhealthy
Marin Grade A
Mariposa Grade F
49 days moderate
Mendocino Grade A
Merced Grade F 94
days moderate | 4 days unhealthy
Modoc - No Monitor Collecting
Mono - No Monitor Collecting
Monterey Grade A
Napa Grade B 2
days moderate
Nevada Grade F 74 days
moderate | 2 days unhealthy
Orange Grade F 26
days moderate | 4 days unhealthy
Placer Grade F 49
days moderate | 5
days unhealthy
Plumas - No Monitor Collecting
Riverside Grade F 243 moderate | 82 days unhealthy
Sacramento Grade F 72
days moderate | 4 days unhealthy
San Benito Grade D 9
days moderate
San Bernardino Grade F 220
days moderate | 126 days
unhealthy | 9 days very
unhealthy!
San Diego Grade F 92 days moderate | 1 day unhealthy
San Francisco Grade A
San Joaquin Grade F 39
days moderate | 2 days unhealthy
San Luis Obispo Grade F
21 days moderate
San Mateo Grade B 2 days
moderate
Santa Barbara Grade F 8 days moderate | 2 days unhealthy
Santa Clara Grade F
13 days moderate
Santa Cruz Grade A
Shasta Grade F
16 days moderate
Sierra - No Monitor Collecting
Siskiyou Grade B 1 day moderate
Solano Grade C
4 days moderate
Sonoma Grade A
Stanislaus Grade F 84
days moderate | 4 days unhealthy
Sutter Grade F 19
days moderate | 1
day unhealthy
Tehama Grade F 42 days moderate | 1 day unhealthy
Trinity - No Monitor Collecting
Tulare Grade F 226 days moderate | 33 days unhealthy | 1 day very unhealthy!
Tuolumne Grade F 29 days moderate
Ventura Grade F 37
days moderate | 1 day unhealthy
Yolo Grade C
4 days moderate
Yuba - No Monitor Collecting
Air quality information was obtained from the U.S. Environmental
Protection Agency - Air Quality System (AQS). The American Lung Association
contracted others to characterize the hourly averaged ozone concentration
information and the 24-hour averaged PM2.5 concentration information for the
3-year period for 2012-2014 for each monitoring site, just like EPA uses three years of data to prevent a single year where anomalies of weather or other factors create air pollution levels inaccurately reflecting normal conditions.