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United States

Pollution Ranking

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  Particulate Pollution (µg/m3)

  Gain in life expectancy if WHO Guideline is met

WHO Guideline: µg/m3

  National Standard

United States does not have a National Standard for PM2.5 (µg/m3)

Studying pollution in the United States tells largely a success story. Part of the United States once had levels of pollution similar to Beijing in recent years. Los Angeles had become known as the smog capital of the world, and other large metropolitan areas weren’t far behind. Pollution had become a part of everyday life for many Americans, and citizens made clear that they wouldn’t tolerate it any longer. The Clean Air Act was enacted in 1970, and since that time particulate pollution has declined by 62 percent—extending the life expectancy of the average American by 1.4 years. Twenty-seven percent of those reductions have occurred over the last twenty years.


  • For those living in the former smog capital of Los Angeles, particulate pollution has declined by nearly 60 percent since 1970, extending life expectancy for the average Angeleno by 1.4 years. In Philadelphia and Washington, DC, a reduction in pollution has extended life expectancy by 2.6 years and 3.3 years, respectively.
  • Only 10 percent of the population still lives in an area where particulate pollution exceeds the World Health Organization (WHO) guideline.
  • California remains the most polluted state in the nation. Los Angeles, San Bernardino and the lower Central Valley have consistently been exposed to particulate pollution above both the WHO guideline and the nation’s own air quality standard. In the last two decades, however, pollution has decreased in these areas. In Los Angeles, there has been a 40 percent reduction in particulate pollution and residents have gained 0.7 years in life expectancy as a result.
  • Hundreds of counties, primarily along the East Coast as well as in the Midwest and parts of Texas, have witnessed a decline of nearly 60 percent in particulate pollution since 2000—extending life expectancy in these areas by almost 6 months.

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Potential Change in Life Expectancy

10 Most Polluted Regions
10 Most Populous Regions

United States: Clean Air Act (1970)

With 66.9% less pollution, Americans are living healthier, longer lives.

Reductions in particulate air pollution alone, thanks in large part to the Clean Air Act, have added 1.3 years to the life expectancy of the average American since 1970.

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The Index

The AQLI converts air pollution concentrations into their impact on life expectancy. From this, the public and policymakers alike can determine the benefits of air pollution policies in perhaps the most important measure that exists: longer lives.

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The AQLI estimates the relationship between air pollution and life expectancy, allowing users to view the gain in life expectancy they could experience if their community met World Health Organization (WHO) guidelines, national standards or some other standard.

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