A study published last week by a team of researchers in economics, atmospheric science, and statistics from Colorado State University and the University of Minnesota School of Public Health found strong links between short-term exposure to air pollution and aggravated assaults and other violent crimes across the United States.  These results mirror another study published in 2018 from researchers from the Columbia and Harvard business schools and the University of Michigan found that the stress and anxiety caused by living in areas with high levels of damaging particulate matter were linked to a rise in violent crimes, robbery, and burglary.

Why This Matters:  Air pollution can result in more than just the health risks caused by breathing dirty air.  The study’s economists calculated that a 10 percent reduction in daily fine particulate pollution could save $1.1 million in crime costs per year, which they called a “previously overlooked cost associated with pollution.” The researchers also noted that 56 percent of violent crimes and 60 percent of assaults occurred within the home, which is an indication that many such crimes are tied to domestic violence.  So the costs of pollution are even greater than we might have understood previously, making environmental justice arguments that much more compelling.

Strong Correlation

The Colorado State researchers analyzed data from the daily Federal Bureau of Investigation crime statistics overlayed with detailed maps of daily U.S. air pollution and found that air pollution makes people marginally more aggressive. The researchers studied the association between daily violent and non-violent crimes and short-term increases in air pollution across 301 counties in 34 states during a 14-year period. They did not attempt to determine exactly how exposure to pollution leads someone to become more aggressive.  And they were careful to correct for other possible explanations for such aggression, including weather, heat waves, precipitation, or more general, county-specific confounding factors.  The research was borne out of personal experience — one of the authors noticed his own frustration level grew when Fort Collins, Colorado experienced a fairly severe wildfire season, which led him to wonder if frustration and aggression would show up in aggregate crime data.

The 2018 Study

The earlier research had similar findings. Its authors determined that the “psychological experience of air pollution increased anxiety, which in turn increased people’s tendency to behave unethically,” the report, titled Polluted Morality: Air Pollution Predicts Criminal Activity and Unethical Behaviour, said.   Those researchers concluded that “[w]hen individuals experience a polluted environment, their overall concern for moral appropriateness may diminish, which may make them more prone to unethical and unlawful acts.”