Philadelphia's air quality worsened in 2023
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Philadelphia's average air quality got worse in 2023, according to the World Health Organization (WHO)'s 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.
How it works: The report from IQAir, a Swiss air quality technology company, 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 preexisting lung and heart conditions. Evidence suggests it can also have neurological effects.
By the numbers: Philly's PM2.5 levels averaged 11.9 in 2023, two to three times higher than the WHO recommends and up from 9.1 in 2022.
- The city saw its worst levels in June last year (29.4) — five to seven times higher than WHO's recommendations — when smoke from Canadian wildfires brought hazy and hazardous air quality conditions to the region.
Zoom in: Philly's PM2.5 levels have fluctuated over the years, averaging 11.5 in 2021 and 9.5 in 2020.
Zoom out: Columbus, Ohio, had the worst air quality in 2023 in U.S. cities with at least 500,000 residents (13.9), followed by the Lancaster, Pennsylvania metro area (13.6).
The big picture: Most American cities had levels two to three times higher than the WHO's guidelines.