Wildfire smoke exposure can be as harmful as smoking half a pack of cigarettes daily, according to pulmonologists, as hazardous air quality alerts spread across the U.S. Midwest and Northeast this week. Canadian and Minnesota wildfires have triggered widespread advisories, with Detroit recording an air quality index (AQI) of 435—the worst globally on Friday morning.

How Wildfire Smoke Affects Your Health

Breathing wildfire smoke delivers fine particulate matter deep into the lungs, with effects comparable to heavy tobacco use. At AQI levels of 100–200, exposure equals smoking a quarter to half a pack a day, says Dr. May-Lin Wilgus, a UCLA pulmonologist. The health toll is steepest for vulnerable groups: emergency room visits for asthma and COPD can double during smoke events, while cardiovascular issues and long-term risks like dementia may also rise.

Wildfire smoke is not just organic ash. As flames consume homes, vehicles, and synthetic materials, the pollution becomes a "toxic soup," warns Lisa Miller of UC Davis. This mix includes particularly harmful particles from burned plastics and fibers, elevating risks beyond typical urban pollution.

Who Is Most at Risk from Wildfire Smoke?

Certain populations face heightened dangers from smoke exposure. Children inhale more air relative to their body size, increasing their intake of pollutants. Pregnant individuals may experience higher risks of preterm birth or low birth weights. Older adults and those with preexisting heart or lung conditions are also more susceptible, as are firefighters, who face repeated heavy exposure linked to higher cancer and cardiovascular disease rates.

How to Protect Yourself from Wildfire Smoke

Experts recommend immediate action when smoke is detectable. The most effective protection is to leave the affected area entirely. If evacuation is not possible:

  • Stay indoors with windows and doors tightly sealed
  • Limit physical activity to reduce inhalation
  • Use air purifiers with HEPA filters
  • Wear a properly fitted N95 mask if outdoor exposure is unavoidable

While no level of exposure is entirely safe, reducing duration and intensity of contact—what toxicologists call "the dose"—can mitigate harm. With climate change increasing wildfire frequency and intensity, such precautions may become a recurring necessity for millions.