On June 7, 2023, smoke from Quebec's wildfires turned Manhattan's sky orange and made New York the most polluted major city on Earth for a day. Wildfire smoke is now America's fastest-growing source of fine-particle pollution and has erased a meaningful share of Clean Air Act gains. Under the law's exceptional events rule, smoke is effectively nobody's externality.
Who's who
- Marshall Burke+2 more episodesStanford economist; senior author of the 2023 Nature study on smoke
- Marissa ChildsBuilt the daily wildfire-smoke PM2.5 dataset behind the national accounting
- Minghao Qiu+2 more episodesLead author of a 2025 Nature projection of smoke mortality
- Rosana AguileraCo-author of a study finding wildfire PM2.5 far more harmful to breathing
- Michael JerrettUCLA environmental health scientist who called the national estimates reasonable
- James InhofeSenator who pushed the exceptional-events exclusion after 1998 smoke
Where it happens
- New York City, New York+3 more episodesAir quality index passed 480 on June 7, 2023
- Quebec, CanadaSource of the 2023 smoke; record fire season
- Paradise, California+1 more episode2018 Camp Fire killed 85 and smothered the Bay Area in smoke
- Los Angeles, California+13 more episodesJanuary 2025 Palisades and Eaton fires burned into the city
Timeline
- 2007EPA finalizes the Exceptional Events Rule, later revised in 2016.
- June 7, 2023Quebec smoke pushes New York's air quality index past 480.
- September 2023A Nature study finds smoke eroding about a quarter of prior particle-pollution progress.
- February 2024EPA tightens the annual PM2.5 standard from 12 to 9 micrograms per cubic meter.
- January 2025The Palisades and Eaton fires burn into Los Angeles.
Still debated
Whether wildfire smoke is more toxic than ordinary urban PM2.5 is still researched, and the death tolls are modeled estimates with wide ranges. Experts also disagree on whether climate or accumulated fuel matters more, and on whether the exceptional events rule is a loophole or a necessity.
