The worst pollution in America that might harm one’s health


1.Worst (and Best) Cities for Smog

2021 marks the 51st year of America’s Clean Air Act, a law passed to improve air quality. But more than half a century later, many U.S. cities still have unhealthy levels of smog, according to the American Lung Association’s annual State of the Air rankings. Warming trends from climate change increase ozone and, along with frequent wildfires, worsen air quality.


2.No. 10: San Francisco

Think of the Bay Area as a big bowl. Winds make it easy for polluted air to move from one valley to another. Vehicles driven by the nearly 9 million residents of San Francisco, San Jose, and Oakland play a role in the area’s dirty air. During warm months, residents can get daily updates on air quality from the Bay Area Air Quality Management District’s Spare the Air campaign.