On Aug. 24, 2020, 68% of the western United States experienced extreme levels of air pollution caused by wildfire smoke and rising heat, according to a newly published study from Washington State University researchers that sheds light on the broad health impacts of fires and heat.
The presence of harmful particles called particulate matter, or PM 2.5, and ozone can make air unhealthy to breathe, and a WSU researcher discovered that the frequency, intensity and unhealthy level of pollution from both particles has increased dramatically, especially in the past decade.
Air pollution is made up of particles that can be harmful, especially at extreme levels. PM 2.5 is emitted by wildfire smoke, as is ozone, to some degree. Ozone also naturally increases in hot and dry conditions, making it more common in summertime.
The increase in pollution is due to two culprits: wildfires and heat, the WSU research published in Science Advances, says.
Dmitri Kalashnikov, doctoral candidate at WSU Vancouver, used pollution data from the Environmental Protection Agency as well as weather, temperature and pressure data from European Centre for Medium-Range Weather Forecasts, to analyze the past 20 years’ worth of pollution levels, paying attention to the co-occurrence of PM2.5 and ozone.
While Kalashnikov expected to see an increase in air pollution due to the recent extreme fire seasons and climate change, the results surprised him.
That’s because every variable appeared to be headed in the wrong direction.
Not only are there more instances of air pollution involving both PM 2.5 and ozone, but it was affecting more people over more days at the same time ridging weather patterns, like heat domes, were becoming more common.
“I was still surprised at how striking these increasing trends are sort of across the board with co-occurrences, increases in ridging weather patterns and population exposure, all of those trends are very striking in the past decade or so,” Kalashnikov said.
While analyzing weather data over two decades can come with some variability, he said that the 2010s were a lot worse than the 2000s when it comes to co-occurring air pollution.
“The sort of high-level answer would be: We’re seeing more of the kinds of large-scale weather patterns that are favorable for hot, dry weather and wildfires,” Kalashnikov said.
The 2010s were marked by some extreme fire seasons, and California fires led to the record-breaking air pollution day in August 2020, notably even before more wildfires ignited in the Pacific Northwest that September.
Climate change means temperatures are increasing, and extreme weather events like last year’s heat dome in Washington state, which wasn’t included in the WSU study, are expected to become more common in the future, experts say.
When the jet stream, which pushes air west to east over the western United States, moves far enough north, high-pressure ridges, or heat domes, are allowed to sit and linger for days at a time.
This is what happened in July 2021, when temperatures in the Inland Northwest shattered records and lingered for several days. To date, the heat dome resulted in 157 deaths statewide, an explosive increase from the previous year, when seven people died from heat-related causes.
Locally, 20 Spokane County residents died last summer of environmental heat exposure, either directly or a contributing factor to their deaths, according to data from the medical examiner’s office. These people ranged in age from 26 to 84.
Heat patterns are becoming more frequent and lasting longer, and because that brings with it an increased wildfire risk, threats to health are exacerbated.
“It’s not just that it’s warmer temperatures, it’s also the air quality, which impacts your heart and other bodily functions,” Kalashnikov said.
Heat waves are particularly dangerous for older adults, as well as those whose exposure to extreme heat is prolonged without opportunities to cool the body down.
In 2020, Spokane’s air quality peaked at hazardous levels due to the wildfires, and health officials and pulmonologists warned people to stay indoors and seek clean air. That’s because wildfire smoke can harm a person’s lungs and airways significantly.
Studies like Kalashnikov’s point to a future with more air pollution, longer heat waves and the potential for adverse health consequences from both extreme heat and bad air. Awareness, he said, is important to prepare for that future.
“I still see people doing all sorts of outdoor activities when it’s smoky conditions, when in reality, they shouldn’t go for a run because they are breathing much, much unhealthier air compared to normal,” Kalashnikov said.
He hopes that awareness of how bad smoke, air pollution and extreme heat are for people’s health will help lead to policy changes, especially to protect people who have to work outside like agricultural and construction workers.
“I am sure there are some policy solutions we can think about to protect those people,” he said.