The sport of running offers a myriad of health benefits, but those may be outweighed by poor air quality for runners in wildfire-prone California. Smoke during wildfire season can lead to a severe increase in fine particulate matter (PM2.5). The dangerous, inhalable pollutant can cause a variety of adverse health issues upon entering the bloodstream. Runners now face a difficult choice to protect their health: adapt or forgo the sport they love.

"From air pollution studies, we know without a doubt that the more you’re exposed to PM2.5, the shorter your life expectancy,” Stanford University researcher Mary Prunicki told the San Francisco Chronicle. "And then we know from wildfire smoke studies that when a population is exposed to wildfire smoke, there’s going to be increases in respiratory problems, cardiac problems, and neurologic problems.”

Why This Matters

Across the US, wildfires are forcing communities to adapt to a changing world. Historically, Yosemite National Park’s giant sequoias maintain resiliency and can even thrive during fire season, but recent, vicious cycles of drought and burning have left them vulnerable. Now the region is at a climate tipping point -- the forests that once served exclusively as carbon sinks are now also major emitters.

Runners aren’t alone. From surfers and MLB players to Olympians, climate change is becoming an increasingly personal issue for outdoor athletes. Still, marginalized communities feel the consequences of air pollution most. Not only are they often exposed to higher levels of PM2.5m but there is a significant economic and racial disparity in access to the outdoors, according to a recent study. Alaska, for instance, is on the front end of a potentially record-setting wildfire season, rendering Indigenous Gwich’in communities especially vulnerable.

Racing to Adapt

During exercise, people breathe in up to 20 times more air per minute, significantly increasing their exposure to harmful pollutants. So, it’s imperative for outdoor athletes -- especially runners -- to keep close tabs on air quality in order to avoid dangerous levels of PM2.5. The EPA advises people to "reduce prolonged or heavy exertion” when the Air Quality Index (AQI) is 151 or higher and avoid it completely at 201 and above.

In many areas, air quality data is inaccurate or unavailable, so making safety assessments is a difficult task. Working to overcome this information gap is the company PurpleAir, which can provide real-time data on air quality in any given location through the placement of local sensors. Air quality data for areas across the country is publicly accessible via the PurpleAir interactive map.