Aug 6, 2025 - Energy & Climate
These U.S. regions are blanketed in wildfire smoke. Here's what to know
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Air quality alerts are in effect for swaths of the Northeast and Midwest on Wednesday because of smoke from Canadian wildfires.
Why it matters: Breathing wildfire smoke has long-lasting health ramifications, as climate change exacerbates wildfires in and around the U.S.
- Climate change contributed to about 15,000 deaths from exposure to wildfire particulate matter between 2006 and 2020, according to a May report.
State of play: As of Wednesday, air quality advisories and alerts are in effect in Wisconsin, New York, Pennsylvania, Illinois, Vermont, Massachusetts, Minnesota, Delaware, Michigan and New Hampshire.
- In the West, Colorado and southern California were also under alert.
Flashback: The 2023 wildfire season more than doubled the previous record for fire-related air pollution in the U.S.
- The average American was exposed to 66% more air pollution than in 2021, the second-most polluted year at that point.
What is wildfire smoke?
- Wildfire smoke is a mixture of gaseous pollutants, like carbon monoxide, hazardous air pollutants, water vapor and particle pollution, according to the Environmental Protection Agency.
- Particle pollution is the main public health threat from wildfire smoke. It can travel into the lungs and even enter the bloodstream.
Who is most at risk?
- People more at risk include those with cardiovascular or respiratory disease, older adults, children under 18, pregnant women and outdoor workers, the EPA says.
- Studies have shown socially vulnerably communities also face disproportionate levels of wildfire smoke.
- Smoke can also exacerbate pre-existing lung and heart conditions and can trigger asthma and heart attacks, which can be fatal.
- Some studies have found links between exposure to wildfire smoke and an increased risk for dementia, fertility treatment issues and adverse birth outcomes.
How can I protect myself?
- Visit the EPA's AirNow website to view the most recent air quality reports and forecasts.
- The air quality index (AQI) ranges from 0 to 500. A level above 150 means its unhealthy for anyone to be outside.
- Limit smoke pollution inside homes by closing doors and windows and avoiding activities like high-heat cooking, using a wood or propane stove, burning candles, or vacuuming.
- Central air systems should be set to recirculate, and portable air purifiers should be run at the highest speed.
- If leaving the home, avoid strenuous activities, wear an N95 mask and wear long sleeves and pants.
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