Wildfire Smoke Exposure May Raise Risk for Several Cancers, New Study Finds

Long term exposure to wildfire smoke may increase the risk of developing several major cancers, according to new research presented at the American Association for Cancer Research Annual Meeting. The study found that people exposed to more wildfire-related air pollution had higher risks of lung, colorectal, breast, bladder and blood cancers, raising new concerns as wildfire seasons grow longer and more intense. 

What the Researchers Studied 

Researchers analyzed data from more than 91,000 adults across the United States and followed their cancer diagnoses for more than a decade. They focused on tiny particles in wildfire smoke called PM2.5, along with black carbon and the number of days smoke plumes covered a person’s home area. Even small increases in wildfire-related PM2.5 were linked to sharp jumps in cancer risk. Each 1 microgram per cubic meter increase was tied to a:

• 92% higher risk of lung cancer
• 131% higher risk of colorectal cancer
• 109% higher risk of breast cancer
• 249% higher risk of bladder cancer
• 63% higher risk of blood cancers

Why These Particles Matter 

Matthew Schabath, PhD

“Wildfire smoke carries a mix of toxic chemicals, including known carcinogens,” said Matthew Schabath, PhD, leader of the Cancer Epidemiology Program at Moffitt Cancer Center. “These particles can move beyond the lungs and into the bloodstream, spreading throughout the body. Smoke exposure also triggers inflammation, which may contribute to cancer development over time.”  

The goal of the study was to understand whether long term exposure to wildfire smoke could influence cancer risk in the general population. As wildfires become more frequent and severe, researchers say it is increasingly important to understand how repeated smoke exposure may affect long term health. 

Why This Matters for Florida 

Florida may not experience the massive Western wildfires seen in states like California, but it has its own wildfire seasons, especially during dry spring months. Smoke from local fires and drifting smoke from the Southeast can affect air quality for millions of Floridians. In recent years, fires in the Panhandle and Central Florida have sent smoke across major cities and triggered air quality alerts. 

“People tend to think of wildfire smoke as a West Coast issue, but Florida has had seasons with hundreds of active fires,” Schabath said. “This research suggests that even low levels of wildfire smoke, when they happen repeatedly, could have long term consequences. It’s a reminder that air quality alerts aren’t just about short term breathing problems. They may be tied to cancer risk, too.”

To conduct the study, researchers used satellite data to track wildfire smoke plumes and combined it with ground level air pollution measurements from participants’ home areas. Between 2006 and 2018, they identified thousands of cancer cases, including 1,758 lung cancers, 800 colorectal cancers, 1,739 breast cancers, 896 bladder cancers and 1,696 blood cancers. The strongest links were tied to PM2.5, the tiny particles that can travel deep into the lungs. Black carbon was associated only with breast and bladder cancer. 

What We Still Don’t Know 

The researchers noted several limitations. Satellite data were only available starting in 2006, so earlier smoke exposure could not be measured. They also assumed participants stayed in their residential areas during smoke events, which may not always be true. 

Still, the findings add to growing evidence that wildfire smoke may have long term health effects beyond the immediate breathing and heart problems many people already recognize.