Breathing in California is Injurious to Health.

Air pollution threatens the health of 39.7 million people across 58 districts in California. The average PM2.5 level is 7.9 µg/m³—1.6× higher than the WHO guideline.

AboutMake Air Quality Great AgainAQLI Data

Brought to you by Amrit Sharma

Overview

Air Pollution in California

California faces significant air pollution challenges. 91% of districts exceed the WHO guideline for clean air. This is putting 39.7 million across 58 districts at risk.

The average PM2.5 over 2023 was 7.9µg/m³. That's 1.6 times the WHO guideline for clean air of 5µg/m³.

This is equivalent of everybody, including children, smoking about 131 cigarettes in a year.

Trends

Air Quality Trend

Annual PM2.5 levels from 2014 to 2023. The WHO guideline for safe air is 5 µg/m³.

Health Impact

Life Expectancy Impact

If California met the WHO guideline of 5 µg/m³, the average person would live 0.3 years longer.

That's 11.9M years of life stolen from 39.7 million people. Years of watching children grow up. Years of building a career. Years of quiet mornings and celebrations.

Lives cut short. Breathing kills.

Most Polluted

Districts with Highest Pollution

The top 10 most polluted districts in California. These areas face the greatest health burden from air pollution.

  • 1.Kern
    0.5 years lost
  • 2.San Bernardino
    0.5 years lost
  • 3.Tulare
    0.5 years lost
  • 4.Los Angeles
    0.5 years lost
  • 5.Fresno
    0.4 years lost
  • 6.Orange
    0.4 years lost
  • 7.Kings
    0.3 years lost
  • 8.Merced
    0.3 years lost
  • 9.Imperial
    0.3 years lost
  • 10.Riverside
    0.3 years lost
Exposure

Population Exposure by Pollution Level

Distribution of population across different PM2.5 pollution levels. The WHO guideline is 5 µg/m³—only populations below this threshold are breathing safe air.

< 5 µg/m³
3.4%
1.3M
5-10 µg/m³
88.8%
35.2M
10-15 µg/m³
7.8%
3.1M
15-25 µg/m³
0%
0
25-35 µg/m³
0%
0
> 35 µg/m³
0%
0
Districts

All 58 Districts in California

Complete air quality data for every district in California, sorted by population.

DistrictPopulationPM2.5 µg/m³Years Lost
Los Angeles9.9M
9.7
0.5 years
San Diego3.4M
7.5
0.2 years
Orange3.3M
8.7
0.4 years
Riverside2.3M
8.2
0.3 years
San Bernardino2.2M
10.1
0.5 years
Santa Clara2.0M
6.0
0.1 years
Alameda1.7M
5.8
0.1 years
Sacramento1.6M
6.6
0.2 years
Contra Costa1.1M
6.0
0.1 years
Fresno1.0M
9.5
0.4 years
San Francisco953K
6.2
0.1 years
Kern928K
10.2
0.5 years
Ventura831K
7.2
0.2 years
San Joaquin784K
7.0
0.2 years
San Mateo742K
5.3
0.0 years
Stanislaus548K
7.8
0.3 years
Tulare486K
9.8
0.5 years
Sonoma482K
4.7
0.0 years
Santa Barbara463K
5.8
0.1 years
Monterey444K
4.8
0.0 years
Solano435K
5.8
0.1 years
Placer421K
6.1
0.1 years
San Luis Obispo283K
4.2
0.0 years
Merced281K
8.5
0.3 years
Santa Cruz263K
5.2
0.0 years
Marin252K
5.1
0.0 years
Yolo232K
5.9
0.1 years
Butte210K
6.5
0.1 years
Imperial194K
8.4
0.3 years
Shasta184K
5.2
0.0 years
El Dorado180K
5.3
0.0 years
Madera158K
8.2
0.3 years
Kings148K
8.5
0.3 years
Napa141K
5.0
0.0 years
Humboldt134K
5.8
0.1 years
Nevada99K
5.2
0.0 years
Sutter97K
6.3
0.1 years
Mendocino89K
5.4
0.0 years
Yuba80K
6.2
0.1 years
Lake64K
4.7
0.0 years
Tehama63K
5.3
0.0 years
San Benito58K
4.6
0.0 years
Tuolumne55K
6.5
0.1 years
Siskiyou43K
6.4
0.1 years
Calaveras41K
5.8
0.1 years
Amador40K
5.5
0.0 years
Lassen34K
5.4
0.0 years
Glenn27K
6.0
0.1 years
Del Norte27K
5.7
0.1 years
Colusa22K
6.3
0.1 years
Plumas20K
6.2
0.1 years
Inyo19K
5.6
0.1 years
Mariposa16K
6.5
0.1 years
Trinity15K
5.7
0.1 years
Mono13K
7.7
0.3 years
Modoc8K
5.2
0.0 years
Sierra3K
6.7
0.2 years
Alpine1K
5.6
0.1 years

Showing 58 districts, sorted by population (largest first). PM2.5 values are for 2023. Years lost calculated against WHO guideline of 5 µg/m³.