A series of devastating wildfires in and around Los Angeles in January destroyed homes and communities, displacing tens of thousands of people and killing 29 people, according to preliminary data from the state of California. The fires rank among the deadliest and most destructive in California's history.
But beyond their immediate devastation, wildfires like these pose long-term risks to brain health for people exposed to the noxious air.
“When you see air pollution, you're seeing little pieces of dirt and soot, which we call particulate matter,” says Ray Dorsey, MD, an endowed professor of neurology at the University of Rochester in New York and co-author of the upcoming book, The Parkinson’s Plan: A New Path to Prevention and Treatment, a guide that includes a discussion of air pollution risk and Parkinson’s disease. “The larger pieces of particulate matter we cough or sneeze out. But some of the small pieces are many times smaller than the diameter of a human hair, and they can penetrate the nerve that’s responsible for the sense of smell—the olfactory nerve—and make their way back into the brain, bypassing its normal protective mechanisms.”
That fine particulate matter—known as PM2.5—often carries with it other hazards, such as toxic chemicals including heavy metals and pesticides, all of which have been found to contribute to progressive brain disorders, such as Alzheimer’s disease and Parkinson’s. In fact, recent research suggests that wildfire smoke may be even more damaging to brain health than other forms of pollution.
In a study published in JAMA Neurology in January, researchers tracked health records from 1.2 million older adults in Southern California between 2009 and 2019, using air quality monitoring to estimate people’s exposure to fine particulate matter from wildfire smoke and other causes. For each one-unit increase of wildfire fine particulate matter, the risk of a dementia diagnosis rose by 18 percent, they found. In non-wildfire fine particulate matter, however, the risk increased by just 1 percent.
“Air pollution produced by wildfires now accounts for more than 70 percent of total PM2.5 exposure on poor air quality days in California,” says Holly Elser, MD, PhD, MPH, the study’s lead author and a fourth-year neurology resident at the Hospital of the University of Pennsylvania. “This is a real problem.”
There are some possible explanations for why smoke produced by wildfire events may be uniquely hazardous, Dr. Elser says. “Wildfire PM2.5 contains higher concentrations of oxidative and pro-inflammatory compounds, has a smaller average particle size, and is generated at substantially higher temperatures.”
What can you do to protect yourself from the harmful effects of wildfire smoke and other pollutants? First, check the air quality index (AQI) where you live. Many mobile apps track local AQI reports, including AirNow from the Environmental Protection Agency (EPA). “If the number is over 100, this means the air quality in your area is unhealthy,” Dr. Elser says. “Reducing outdoor activity, wearing a KN95 or fitted N95 mask when outside, and using an in-home air filtration system are all steps individuals can take to minimize their risk.”
Staying indoors with the windows and doors closed can offer protection against the smoke. Small air purifiers for individual rooms can cost between $50 and $400, while whole-house air purifiers range from $500 to over $10,000. “These air purifiers require periodic cleaning and changes of the carbon filters that remove chemicals. Depending on the size of your home, you may want to have more than one,” Dr. Dorsey says. “For example, you could place one in your bedroom and one in your kitchen or home office.”
If you live in an area affected by wildfire smoke and have meetings or appointments scheduled, see if you can move them online. Check with your health care provider about telehealth options.
Taking steps to avoid air pollution is one of the most important things you can do to protect your brain health and your health in general, Dr. Dorsey says. “Air pollution as a whole is more disabling than high levels of blood glucose and high blood pressure,” he adds. “It's estimated that air pollution costs all of us on average three years of life.”
AirNow also offers information about how people can help keep the air clean, maps of current fires, and other guidance.
