Mar 26, 2024 - News

D.C.'s average air quality worsened last year

Average air quality in major U.S. cities, 2023
Data: IQAir. Note: Among cities with at least 500k metro-area residents. Chart: Kavya Beheraj/Axios

D.C.'s average air quality last year had particle pollution levels two to three times higher than what the World Health Organization (WHO) recommends, says a new report.

Why it matters: Air pollution is the world's leading environmental health threat, causing 6.7 million premature deaths every year, according to WHO estimates.

The big picture: Last year, D.C. saw the worst recorded air quality levels in years due to smoke from Canadian wildfires, causing the Metropolitan Washington Council of Governments (COG) to declare a rare Code Purple advisory.

By the numbers: D.C.'s average concentration of fine particulate pollution was 11.7 micrograms per cubic meter last year, up from 9.8 in 2022 and 9.1 in 2021.

  • Columbus, Ohio, which had the country's worst air quality last year out of cities with at least 500,000 residents, clocked in at 13.9.

How it works: The report is from IQAir, a Swiss air quality technology company that maintains a global air quality system that continuously measures contaminants in thousands of cities across the world.

  • The report examines the average level of fine particles less than 2.5 microns (PM2.5) in diameter — a particularly dangerous form of air pollution because the solid and liquid specks can penetrate deep into lung passageways.
  • Inhalation of PM2.5 can exacerbate pre-existing lung and heart conditions. Evidence suggests it can also have neurological effects.
  • Much of the fine particulate matter pollution in the U.S. and around the world is a byproduct of fossil fuel combustion and industrial activity, such as from car engines or concrete plants. Other drivers can include everything from dust storms to volcanoes, cigarettes, and air fryers.
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