Since the passage of the Clean Air Act, particulate pollution (PM2.5) in the United States has declined by 65 percent thanks to sustained enforcement of strong air pollution policies—expanding the average life expectancy by 1.4 years. But new evidence of the effect of even low levels of pollution on health, as reflected by the World Health Organization’s updated guideline of 5 µg/m3, reveals that almost all of the residents of the United States are still breathing unsafe air. To meet this challenge, the U.S. Environmental Protection Agency has tightened the national PM2.5 standard from 12µg/m3 to 9µg/m3. The latest data from the Air Quality Life Index shows that if this tightened standard is met across the country, 6.6 million more total life years would be saved compared to under the former standard.
People living in California and areas of the Midwest would see the greatest benefits. For example, meeting the tightened standard would save about 2.5 million additional life years in Los Angeles alone, relative to the former standard; close to 400,000 life years in Chicago’s Cook county. Though wildfires likely play an important role in California’s pollution challenge, if all counties in the state were able to comply with the new standard, residents would gain 4.5 million more total life years with this cleaner air compared to the former standard.
Post updated on February 7, 2024 to reflect the release of the final proposal by EPA.