Wildfire Smoke Far More Deadly Than Previously Estimated: Study

Even short-term exposure to wildfire smoke significantly increased the risk of death, particularly from cardiovascular disease and respiratory conditions.

Data from a new international study warns that exposure to air pollution from wildfire smoke is much more harmful to the human body than exposure from other sources, like vehicle emissions.

According to findings published in The Lancet Planetary Health on August 13, past research underestimated the death risk associated with exposure to wildfire smoke particles by 93%, linking it to more than 500 deaths per year.

Wildfire smoke contains a mix of harmful pollutants, such as carbon monoxide, ozone and fine particulate matter. These particles, known as PM2.5, are smaller than 2.5 microns, roughly 30 times thinner than a human hair.

Inhaling air pollution, including PM2.5 particles, can cause various serious side effects, including asthma, heart attack and strokes.

Until now, researchers believed exposure to PM2.5 in wildfires carried the same risk to human health as exposure to PM2.5 particles in air pollution from vehicle emissions, fossil fuel production and other pollution sources. However, the new findings suggest the health impact of wildfires may be much worse.

For the new study, researchers from Barcelona Institute for Global Health (ISGlobal), led by Dr. Anna Alari, studied epidemiological data from the EARLY-ADAPT database. The data included daily death records in 654 subnational regions in 32 European countries, representing more than 541 million people.

The study also used daily estimates of PM2.5 levels, both wildfire-related and unrelated, based on atmospheric data collected between 2004 and 2022 from the System for Integrated Modeling of Atmospheric Composition.

Researchers concluded that the risk of death from wildfire-related PM2.5 has been underestimated by 93 percent. They found that particulate matter from wildfire smoke poses a 14 times greater threat to human health compared to PM2.5 from other sources.

In the seven days following exposure, increases in fire-related PM2.5 caused a similar increase in the risk of deaths from respiratory conditions, death from cardiovascular issues and an increase in the risk of death from all causes.

Using the new data, researchers found even short-term exposure to PM2.5 from wildfire smoke is responsible for an average of 535 annual deaths from all causes, 184 from cardiovascular disease, and 31 from respiratory conditions.

The old risk models showed exposure to PM2.5 was responsible for only 38 deaths per year, regardless of origin. Those rates are much lower than what humans actually experience from exposure to wildfire smoke, and underestimate the overall health impacts, the researchers indicated.

“Associations with all-cause and cause-specific mortality were larger for fire-related compared with non-fire-related PM2.5. Assuming wildfire PM2.5 has the same effect as total PM2.5 substantially underestimates the mortality burden of wildfire smoke.”

– Dr. Anna Alari, Barcelona Institute for Global Health

As a result, the research team warned that wildfire smoke poses a much more serious risk to human health than PM2.5 exposure from other types of air pollution.

Wildfire Smoke Risks

With wildfires becoming more prevalent worldwide, an increasing amount of research is focusing on the health dangers they present.

Data from a study published by Harvard Researchers earlier this year indicated exposure to air pollution from wild fires increases the risk of hospitalization for respiratory problems, including asthma, bronchitis, wheezing, clots in the lungs, infections and other health emergencies.

In addition, exposure to wildfire smoke increases the risk of suffering from heart failure, especially among women, according to data published by researchers from Emory University, who also concluded exposure to wildfires increased the risk of death by 43% for lung cancer patients.

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