Wildfires: what you need to know to stay safe

This summer, wildfires have become a common occurrence on the West Coast, with fires burning in Oregon, California, and Colorado. In March, Texas experienced the largest and most destructive wildfire in state history. The Smokehouse Creek Fire burned more than one million acres of land, killing two people and more than 7,000 cattle, according to news reports. And in Greece, wildfires came close to consuming towns and villages.

In addition to deadly flames, harmful smoke from wildfires also is a threat to human lives and health. Wildfire smoke contains a mixture of fine particle pollutants that have been shown to lead to adverse health effects.

A study by researchers at the Yale School of Public Health (YSPH) confirms that harmful smoke from wildfires is capable of traveling great distances and can impact the health of people hundreds of miles away.

When smoke from a Canadian wildfire descended on New York City in 2023, Kai Chen, associate professor of epidemiology (Environmental Health Sciences), noted that the wildfire smoke “had such a high concentration of particles that it turned the sky orange, which tells you how polluted the air is during a smoke wave.”

Extreme heat could enhance the health effects of wildfire smoke, Chen added. “With a warming climate, the health burden of exposure to extreme heat and wildfire smoke is expected to increase,” said Chen, who is also co-faculty director of the Yale Center on Climate Change and Health.

Wildfire risk in the United States is highest in the West and Midwest, but regions in the South and Northeast can be at heightened risk. In 2023, more than 2.6 million acres were burned across the country from 55,571 fires, including the wildfire on the Hawaiian island of Maui. The Lahaina fire was the deadliest U.S. fire in more than 100 years.

Wildfires are often human-caused, from campfires, equipment, cigarettes, and arson. Lightning strikes can also spark flames. Climate change has been identified as a contributor to an increase in conditions that fuel wildfires, including increased temperatures and drought.

While wildfire flames can damage land and property, and be deadly for humans and wildlife, wildfire smoke is also a concern. Protecting yourself from wildfire smoke is an important step in avoiding the health effects of wildfires, as the particulates can be incredibly small, allowing them to travel to deep parts of the lungs.

The Air Quality Index (AQI) provides information about the status of air pollution. Check the AQI of your current location now at AirNow.gov.

“When it comes to wildfire preparedness, the time to act is now, said Joanne McGovern, a YSPH lecturer and affiliated faculty at the Yale Center on Climate Change and Health. “Stay informed by monitoring local news, weather, and emergency alerts for wildfire updates and evacuation orders. Create a fire break by clearing brush, dead wood, and leaves around your home. Develop an emergency plan.”

Exposure to wildfire smoke can lead to:

• Respiratory complications
  • Coughing
  • Wheezing
  • Breathing difficulties
  • Bronchitis
  • Diminished lung function
  • Exacerbated asthma and lung conditions
• Cardiovascular effects
  • Heart failure
  • Heart attack
  • Stroke
• Aggravation of kidney disease
• Cognitive decline and dementia
• Premature death

Who should be particularly careful when exposed to wildfire smoke?

• Children
• People with certain health conditions (i.e. asthma, COPD, heart disease, diabetes and chronic kidney disease)
• Pregnant people
• Older adults and people with disabilities may face challenges when evacuating from wildfires. Having a preparedness plan ahead of time is important.

When wildfire smoke is present in your area:

• Stay indoors when possible with windows and doors closed. If you need to go outside, wear a NIOSH approved respirator.
• Use a filtered HVAC system or portable air filter.
• Check the air quality in your area.
• Monitor your health symptoms.
• Pay attention to alert systems and monitor fires on AirNow.gov’s Fire and Smoke Map.
• Check on your friends and family!

• Several YSPH students and faculty co-authored a paper that identified “a non-linear association between 12-month moving average concentration of smoke PM2.5 and monthly non-accidental mortality rate.” The paper is awaiting peer review.
• In a research letter published in JAMA, YSPH researchers and a colleague discussed the relationship between wildfire smoke and asthma-related emergency department visits.The research letter was authored by Kai Chen, associate professor of epidemiology (Environmental Health Sciences), Yiqun Ma, pre-doctoral fellow, Climate Change and Health, Michelle Bell, Mary E. Pinchot Professor at the Yale School of the Environment, and Wan Yang, assistant professor of epidemiology at Columbia Mailman School of Public Health. Elizabeth Ziying Lin, a postdoctoral associate in the Pollitt Lab, wrote about the research in an article for the YSPH News.
• Kai Chen recently wrote about heatwaves and wildfire smoke in the Spring 2024 Focus publication, A Climate Change Handbook.

For more information on wildfire smoke and your health, check out resources provided by the CDC.