Exposure to wildfire smoke increases the risk of being diagnosed with dementia more than other types of air pollution, according to a decade-long study of more than 1.2 million people in southern California. The findings, reported at the Alzheimer’s Association International Conference® suggest the brain health threat posed by wildfire smoke is higher than other forms of air pollution.
Wildfire smoke, motor vehicles and factories all emit a type of air pollution called fine particulate matter (PM2.5). This is a microscopic mixture of solid and liquid droplets in the air that are 30 times smaller than the width of an average human hair. Researchers found that the risk of dementia diagnosis due to exposure to PM2.5 in wildfire smoke was notably stronger — even with less exposure — than the risk due to the other sources of PM2.5 air pollution. Exposure to non-wildfire PM2.5 raised the risk of dementia diagnosis, but not as much as wildfire smoke.
High levels of PM2.5 also have been shown to raise the risk of heart disease, asthma and low birth weight.
“With the rising global incidence of wildfires, including in California and the western U.S., exposure to this type of air pollution is an increasing threat to brain health,” said Claire Sexton, DPhil, Alzheimer’s Association senior director of scientific programs and outreach. “These findings underscore the importance of enacting policies to prevent wildfires and investigating better methods to address them.”