What we know and don’t know about wildfire smoke’s health risks

Experts weigh in on smoke’s hazards and the potential risk as fires become more common

San Francisco Bay bridge smoky skyline

Water and sky take on a deep orange hue in the San Francisco Bay area on September 9 as wildfires rage in Northern California. The fires there and throughout the U.S. West have led to dense, smoky air and hazardous air quality readings.

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Acrid smoke continues to pollute skies in the western United States.