The study found an increase in premature deaths in fire-prone areas and downwind areas. Just think back to last summer’s wildfires in the United States and Canada to see how much of an impact these fires had on the environment and human health. Two decades of wildfires have severely affected air quality in the American West, increased health risks, undoing efforts to reduce pollution, and conservatively causing an estimated 670 additional premature deaths each year.

Wildfires increase air pollution

A new study lays out the toll wildfires have taken on air quality and human health in the continental United States over two decades. The authors report that air in the western United States worsened from 2000 to 2020, primarily due to increased frequency and intensity of wildfires, resulting in 670 premature deaths per year in the region during this period. Overall, the fires have undermined federal efforts to improve air quality primarily by reducing vehicle emissions, the study's authors said.

James E. Ashton, professor and chair of the Department of Chemical and Biochemical Engineering at the University of Iowa and assistant director of the Iowa Institute of Technology, and Wang Jun (transliteration), the lead corresponding author of the study, said: "Our air should be getting cleaner and cleaner, mainly thanks to the U.S. Environmental Protection Agency (EPA) emissions regulations, but fires are limiting those air quality gains. In other words, all the EPA's efforts over the past 20 years to make our air cleaner are essentially being lost in fire-prone areas and downwind areas."

University of Iowa researchers have found that wildfires originating in the western United States and Canada have erased air quality gains made over the past two decades and led to an increase in premature deaths in fire-prone and downwind areas. The map shows areas (red) with the highest concentrations of black carbon, a fine-particle air pollutant linked to respiratory and heart disease in humans. Source: Jun Wang Laboratory, University of Iowa

Deteriorating air quality and health risks

The researchers calculated the concentration of black carbon, a fine-particle air pollutant linked to respiratory and heart disease, on a grid per kilometer (0.6 miles) across the continental United States.

In the western United States, black carbon concentrations are rising 55% annually, largely due to wildfires. Not surprisingly, the areas with the highest premature mortality rates are in the American West, the region where wildfires originate and the region hardest hit by Canadian wildfire smoke. The authors say an increase of 670 premature deaths per year is a conservative estimate because the impact of black carbon on human health is not fully understood.

"Wildfires in the western United States are increasingly dense and frequent, leading to significant increases in smoke-related emissions in densely populated areas. This is likely to result in reduced air quality and increased attributable mortality," Wang and his team wrote.

The fires are also affecting the Midwest. The spread of smoke through the atmosphere can affect air quality, although direct health effects currently appear to be minimal. But, Wang said, "We are on the edge. If fires increase or become more frequent, our air quality will get worse."

There were no major declines in air quality in the eastern United States between 2000-2020.

Research methods and significance

The researchers derived estimates of black carbon concentrations and premature deaths from satellite data and 500 ground stations that monitor air quality. Data from ground stations may be extensive but do not provide complete spatial coverage and may be lacking in rural areas. Therefore, the researchers used "deep learning" to calculate black carbon concentrations. "Deep learning" enables computer systems to cluster data and make accurate predictions. They calculated the number of premature deaths using a formula that included average life span, exposure to black carbon and population density.

This is the first time black carbon concentrations have been observed across locations with a resolution of one kilometer. The study's first author, Jing Wei, led the collection of satellite data on fine particulate matter and the analysis of the public health impacts of these pollutants while working as a postdoctoral research scholar in Xiaodong Wang's group at Iowa State.

"The increase in the number and intensity of wildfires in the United States has offset or even masked reductions in anthropogenic emissions, exacerbating air pollution and increasing the risk of morbidity and mortality," said Jing Wei, now an assistant research scientist at the University of Maryland Interdisciplinary Center for Earth System Science.

Compiled source: ScitechDaily