Wildfires are becoming more common in many parts of the world, and their smoke can travel long distances, affecting people far from the flames.
A new study has found that long-term exposure to wildfire smoke may increase the risk of several types of cancer.
These findings were presented at the American Association for Cancer Research Annual Meeting 2026.
Wildfire smoke contains tiny particles and harmful chemicals that people breathe in. These include substances known to cause cancer. While it is already known that smoke can harm the lungs and heart, scientists are now learning that its effects may go much further.
Researchers from the University of New Mexico Comprehensive Cancer Center studied how long-term exposure to wildfire smoke affects cancer risk. They used data from a large U.S. study that followed thousands of adults over many years. The participants had no history of certain cancers when the study began.
To measure exposure, the scientists used air pollution data and satellite images. They looked at fine particles in the air and tracked how often people were exposed to smoke over time. They then compared this information with the number of people who later developed cancer.
The results showed that higher exposure to wildfire smoke was linked to a greater risk of several cancers. These included lung, colorectal, breast, bladder, and blood cancers. The risk increased steadily as exposure increased, meaning that even small rises in smoke levels could matter.
For example, for every increase in smoke-related particles, the risk of lung cancer rose sharply. Other cancers also showed large increases. This suggests that wildfire smoke may affect the whole body, not just the lungs.
Scientists believe this happens because harmful chemicals in the smoke enter the bloodstream and spread through the body. The smoke also causes inflammation, which may help cancer develop over time.
The study is important because it shows that wildfire smoke is not just a short-term problem. It may have long-term health effects that are not immediately visible.
However, the research also has limits. It assumes people stayed in the same place during exposure and does not fully account for indoor protection. Also, cancer can take many years to develop, so more long-term studies are needed.
Overall, the findings suggest that wildfire smoke could be a serious public health risk. More research is needed, but people should take steps to reduce exposure when possible.
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