California US Rank Clean Cities

People at Risk In 25 U.S. Cities Most Polluted by Year-Round Particle Pollution (Annual PM2.5)
2016 Total

1 Bakersfield
2 Visalia–Porterville–Hanford
3 Fresno–Madera
4 Los Angeles–Long Beach
5 El Centro
6 Modesto-Merced
6 San Jose–San Francisco–Oakland
16 San Luis Obispo–Paso Robles–Arroyo Grande

People at Risk In 25 Counties Most Polluted by Year-Round Particle Pollution (Annual PM2.5) PM2.5 Annual, 2016
Rank County Grade
1 Kern Fail
2 Tulare Fail
3 Kings Fail
4 Madera Fail
5 Fresno Fail
6 Riverside Fail
7 Imperial Fail
8 Plumas Fail
9 Stanislaus Fail
9 San Joaquin Fail
13 San Bernardino Fail
16 Los Angeles Fail



People at Risk in 25 Counties Most Polluted by Short-Term Particle Pollution (24-hour PM2.5) High PM2.5 Days in Unhealthy Ranges,
Rank | Grade
1 Kern F
2 Fresno F
3 Kings F
4 Stanislaus F
6 Madera F
11 San Joaquin F
12 Merced F
15 Tulare F
17 Riverside F
18 Santa Cruz CA F
22 Plumas F


People at Risk In 25 U.S. Cities Most Polluted by Short-Term Particle Pollution (24-hour PM2.5)
2016 Total
1 Bakersfield
2 Fresno–Madera
3 Visalia–Porterville–Hanford
4 Modesto–Merced
8 San Jose–San Francisco–Oakland
9 Los Angeles–Long Beach
13 El Centro
1 7 Sacramento-Roseville


People at Risk In 25 Most Ozone-Polluted Cities
Rank1 Metropolitan Statistical Areas
1 Los Angeles–Long Beach,
2 Bakersfield
3 Visalia–Porterville–Hanford
4 Fresno–Madera
6 Sacramento–Rosevill
7 Modesto–Merced
12 El Centro
13 San Diego–Carlsbad
16 San Jose–San Francisco–Oakland
23 San Luis Obispo–Paso Robles–Arroyo Grande


People at Risk in 25 Most Ozone-Polluted Counties
High Ozone Days in Unhealthy Ranges, 2016 Total
1 San Bernardino F
2 Riverside F
3 Kern F
4 Los Angeles F
5 Tulare F
6 Fresno F
7 Madera F
8 Kings F
10 El Dorado F
11 Stanislaus F
12 Sacramento F
17 Merced F
19 Mariposa F
20 Imperial F
21 San Diego F
23 Placer F
25 Nevada F


Particle pollution is produced through two separate processes—mechanical and
chemical.