UMass Amherst Researcher Reveals Link Between Wildfire Smoke and Increased Suicide Risk in Rural Counties

New research co-written by a University of Massachusetts Amherst resource economist finds large-scale evidence that air pollution from drifting wildfire smoke disproportionately elevates the risk of suicide among rural populations in the U.S.

Each 10% increase in airborne particulate matter in rural counties causes monthly suicide rates to rise by 1.5% on average, according to Jamie T. Mullins, associate professor of resource economics at UMass Amherst and co-author of the study.

“Unfortunately, these findings suggest an additional mechanism through which our changing environment negatively impacts human health and well-being. Even as we are changing the world around us, we see again how our environment influences us in turn,” Mullins says. “While there is a growing body of evidence linking air pollution to negative mental health outcomes, this is the first work showing that wildfires – the magnitude and intensity of which have been increasing in recent years – negatively affect mental health through the smoke that can spread hundreds of miles beyond the flames.”

The paper, published in the Proceedings of the National Academy of Sciences, was co-written by David Molitor at the Gies College of Business at the University of Illinois Urbana-Champaign and Corey White of Monash University in Australia and the IZA Institute of Labor Economics in Germany.

Using data on all deaths by suicide, satellite-based measures of wildfire smoke and ambient fine particulate matter concentrations in the U.S. from 2007-2019, the researchers compared year-over-year fluctuations in county-level monthly smoke exposure to changes in suicide rates, and then analyzed the effects across local areas and demographic groups.

They found that worse air quality leads to higher rates of suicide – although the data shows that effect emerged only among certain demographic groups in rural areas.

According to the paper, the effects were concentrated among demographic groups with both a high baseline suicide risk and high exposure to outdoor air: rural white males of working age, and rural adults with no college education. By contrast, the researchers found no evidence that smoke pollution increases suicide risk among any urban demographic group.

The results provide important insight for identifying and protecting vulnerable groups – and for accurately quantifying the full costs of air pollution and wildfires, Molitor notes.

“As we all experienced over the summer, air pollution poses a major threat to human health and well-being,” he says. “Long recognized for its impacts on physical health, our findings also suggest that air pollution exposure harms mental health – which, in turn, leads to greater loss of life by suicide. Taken together, it’s something that policymakers can’t ignore.”

The research was supported by the National Institute on Aging of the National Institutes of Health.