Particulate matter

When wildfires rage, the immediate threat is obvious – but smoke from the fires actually kills far more people than the flames. As fires become more frequent, that smoke is leading to a public health crisis. In a new study published in the journal Science Advances, we found that wildfire smoke likely contributed to more than 52,000 premature deaths across California alone from 2008 to 2018, with an economic impact from the deaths of more than US$430 billion. Previous studies have examined the short-term health risks from wildfire smoke, but few have assessed how exposure to wildfire smoke over years adds up to shorten human lives. Smoke from far-off wildfires turns the skies orange over San Francisco in 2020. Running in wildfire smoke carries harmful particles deep into a person’s lungs. AP Photo/Tony Avelar Wildfire risk and severity have grown as the climate has changed and as more...

Air pollution particles from coal-fired power plants are more harmful to human health than many experts realized, and it’s more than twice as likely to contribute to premature deaths as air pollution particles from other sources, new research demonstrates. In the study, published in the journal Science, colleagues and I mapped how U.S. coal power plant emissions traveled through the atmosphere, then linked each power plant’s emissions with death records of Americans over 65 years old on Medicare. Our results suggest that air pollutants released from coal power plants were associated with nearly half a million premature deaths of elderly Americans from 1999 to 2020. It’s a staggering number, but the study also has good news: Annual deaths associated with U.S. coal power plants have fallen sharply since the mid-2000s as federal regulations compelled operators to install emissions scrubbers and many utilities shut down coal plants entirely. In 1999, 55,000 death...

Kids born in 2020 worldwide will experience twice the number of wildfires during their lifetimes compared with those born in 1960. In California and other western states, frequent wildfires have become as much a part of summer and fall as popsicles and Halloween candy. Wildfires produce fine particulate matter, or PM₂.₅, that chokes the air and penetrates deep into lungs. Researchers know that short-term exposure to wildfire PM₂.₅ increases acute care visits for cardiorespiratory problems such as asthma. However, the long-term effects of repeated exposure to wildfire PM₂.₅ on chronic health conditions are unclear. One reason is that scientists have not decided how best to measure this type of intermittent yet ongoing exposure. Environmental epidemiologists and health scientists like us usually summarize long-term exposure to total PM₂.₅ – which comes from power plants, industry and transportation – as average exposure...

Smoke from more than 100 wildfires burning across Canada has been rolling into North American cities far from the flames. New York City, Denver, Chicago, Minneapolis and Detroit each made the list of the most polluted cities in the world at times in May and June 2023 because of the fires. The smoke has triggered air quality alerts in several states. We asked Chris Migliaccio, a toxicologist at the University of Montana who studies the impact of wildfire smoke on human health, about the health risks people can face when smoke blows in from distant wildfires. What’s in wildfire smoke that’s a problem? When we talk about air quality, we often talk about PM2.5. That’s particulate matter 2.5 microns or smaller – small enough that it can travel deep into the lungs. Exposure to PM2.5 from smoke or other air pollution, such as vehicle emissions, can exacerbate health conditions like asthma and reduce lung function in ways that can worsen existing respiratory pr...