A firefighter looks at the aftermath of a fire on a hillside near Pepperdine University during the Franklin Fire in Malibu, California, December 10, 2024. (Image credit: Bloomberg/Contributor via Getty Images)
Wildfires are becoming more frequent, intense and destructive in the United States, especially in western regions such as California.
California has experienced longer, more intense fire seasons in recent years—in 2023, the state saw more than 7,000 wildfires, and the California Department of Forestry and Fire Protection had to respond to approximately 590,000 related emergencies. In January 2025, a devastating fire swept through Los Angeles County, burning nearly 40,000 acres (16,000 hectares) in the first nine days. The event was the second-deadliest wildfire in California history, killing 30 people.
Large wildfires leave behind terrible destruction, putting lives at risk and forcing people to quickly flee their homes and businesses. Climate change is a major contributor to these disasters and is expected to continue to worsen the situation in the coming years.
One of the major health risks associated with wildfires is the smoke they produce. Wildfire smoke can have a variety of harmful effects on the body, including the lungs, heart, and brain. Fortunately, there are steps people can take to protect themselves, experts tell Live Science.
How does smoke from forest fires affect the body?
Sarah Adar, a professor of epidemiology at the University of Michigan, told Live Science that smoke from wildfires contains many different chemicals that are produced during the combustion process.
Among the most concerning substances are the smallest particles known as particulate matter 2.5 (PM2.5). These particles are smaller than 2.5 micrometers in size — about 28 times smaller than the width of a human hair — and can linger in the mucous membranes of the nose, mouth, and eyes.
In the short term, it causes irritation and various symptoms such as burning eyes, runny nose or coughing that may occur immediately after exposure. People with skin conditions such as eczema may also be more likely to experience flare-ups of their condition due to short-term exposure to PM2.5 during a bushfire.
Over the longer term, these particles are small enough to be inhaled into the lungs and cause additional harm to the body, especially when they enter the bloodstream. For example, they can cause inflammation that can worsen respiratory conditions like asthma or chronic obstructive pulmonary disease (COPD). This can happen immediately or within a day or two of exposure to wildfire smoke, Dr. Stephanie Lovinsky-Desir, an assistant professor of pediatrics and environmental health sciences at Columbia University in New York City, told Live Science.
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Sourse: www.livescience.com
