US scientists from the University of Washington have found a link between fine particulate matter (PM2.5) air pollution from wildfires and an increased risk of dementia. The study was published in the scientific journal JAMA Neurology. Specialists analyzed the medical records of 1.2 million California residents aged 60 years and older from 2008 to 2019. The researchers found that for every 1 microgram per cubic meter (µg/m3) increase in the three-year average concentration of PM2.5 in a wildfire area, the likelihood of being diagnosed with dementia increased by 18%. Exposure to PM2.5 not associated with wildfires also affected the risk of dementia, but to a much lesser extent. According to Joan Casey, lead author of the research paper and associate professor of environmental and occupational health and safety at the University of Washington, previous studies have linked total PM2.5 to the risk of dementia. However, no one had previously specifically looked at exposure to microparticles from wildfires, even though their smoke is much more pungent than other sources of PM2.5.