Pollution from wildfire smoke has rolled back the U.S.’ decades of progress on clean air, and it’s particularly bad in California, Oregon, Washington, and other western states. That’s all according to a new study published in Nature.
At the core of the research is a type of particulate pollution called PM2.5, which is so small that it can infiltrate human bloodstreams and lungs, says Marshall Burke, professor of sustainability at Stanford University and the study’s lead author.
Wildfire smoke emits the pollutant, Burke explains, and when ingested, creates an inflammatory response throughout the body. Starting in the respiratory system, it can even cause heart attacks and strokes.
In the last five to six years, Burke says wildfire smoke has eroded a third of the clean air progress made since 1970, when President Nixon signed the Clean Air Act. In some states, up to 50% of the progress has been set back.
While today’s bad air pales in comparison to the 1970s, Burke points out that scientists are concerned about the harmful materials that modern wildfires are releasing.
“It's really an open question as to the exact metals and other toxic chemicals that could be in wildfire smoke. That's an ongoing area of research. Our best estimates, though, are that particulate matter from wildfires are at least as bad as the other sources we’re unfortunately more used to. So think of this as another bad source of air pollution that has negative consequences for human health.”
Burke says these extreme wildfires are a result of a warming climate and a century of fire suppression. But people can help on the local level, like by using prescribed burns that release less smoke.
“The whole idea with prescribed burns is to have low-intensity fire that doesn't burn entire trees, but burns up the leaf litter, the shrubs, the accumulated wood that are on the ground. If you burn that in a low-intensity way, you're burning less fuel and thus producing less smoke,” Burke explains. “Research has shown if you do that, it reduces the likelihood of the really extreme wildfires that burn everything and generate a lot of smoke.”
He adds that protecting one’s health during wildfires doesn’t end with staying indoors. That’s because smoke can get inside buildings, and California houses tend to not be well sealed. Thus, he advises people to filter indoor air, such as through A/C, and it helps to wear an N-95 mask.