Worsening wildfires cause harmful pollutant overlap
The role of air pollutants in cardiovascular and respiratory illnesses and deaths, including COVID-19, is well known.
But a new study in the journal Science Advances suggests climate change and rampant wildfires may be redoubling those effects in the western U.S.
“We're seeing these pollutant co-occurrences happening more often. We're seeing them happening more persistently — to where, when they happen, they actually last longer as far as consecutive days. And we're seeing them happening over larger areas,” said lead author Dmitri Kalashnikov of Washington State University Vancouver.
Pollution from microscopic particles called PM2.5s formerly peaked in the winter, when cool, stagnant air let them build up in western valleys. Surface ozone peaked during summer, when the chemical reactions that produce the molecules are more active.
But from 2001 to 2020, smoke from longer, more intense wildfire seasons pumped out so much PM2.5 that the two pollutants overlapped — frequently, persistently and over large areas.
What's more, persistent summer high pressure zones amplified the effect.
"These patterns are kind of a perfect storm, because they're hot and because they're dry. And, because they're calm, they let heat build up; they let pollution build up. And because it's so hot and dry, that's also the kind of pattern which lets wildfires keep burning and keep spreading."
That's bad news for human health.
"It's been shown in some studies that there are worse health impacts if the human body is exposed to both pollutants, as opposed to just one or the other," said Kalashnikov.
The research suggests continued climate change will worsen the trend.