A new series of studies from Colorado State University (CSU) reveal a strong association between short-term exposure to air pollution and aggressive behavior, in the form of aggravated assaults and other violent crimes across the continental United States.
The findings, published in the Journal of Environmental Economics and Management, were derived from daily Federal Bureau of Investigation crime statistics and an eight-year, detailed map of daily U.S. air pollution.
The paper’s lead author is Dr. Jesse Burkhardt, assistant professor in the Department of Agricultural and Resource Economics, who teamed up with fellow economist Dr. Jude Bayham in the same department; Dr. Ander Wilson in the Department of Statistics; and several air pollution experts in civil engineering and atmospheric science.
Air pollution scientists typically measure rates of pollution through concentrations of ozone, as well as of “PM2.5,” or breathable particulate matter 2.5 microns in diameter or smaller, which research has linked to health effects.
Eighty-three percent of crimes considered “violent” by the FBI are categorized as assaults in crime databases. The findings show that a 10 microgram-per-cubic-meter increase in same-day exposure to PM2.5 is linked to a 1.4% increase in violent crimes, nearly all of which is driven by crimes categorized as assaults.
Researchers also found that a 0.01 parts-per-million increase in same-day exposure to ozone is associated with a 0.97% increase in violent crime, or a 1.15% increase in assaults. Changes in these air pollution measures had no statistically significant effect on any other category of crime.
The team also discovered 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.
“We’re talking about crimes that might not even be physical — you can assault someone verbally,” co-author Bayham said. “The story is, when you’re exposed to more pollution, you become marginally more aggressive, so those altercations – some things that may not have escalated – do escalate.”
The researchers were careful to correct for other possible explanations, including weather, heat waves, precipitation, or more general, county-specific confounding factors.
They also made no claims on how exposure to pollution can lead someone to become more aggressive; their results only show a strong link between such crimes and levels of air pollution.
The team published a companion paper in the Journal of Environmental Economics and Policy with similar results that used monthly crime statistics. A third paper in Epidemiology, with lead author Jesse Berman from the University of Minnesota and co-authors from CSU, used EPA pollution monitor databases and different statistical techniques and came to similar conclusions.
“The results are fascinating, and also scary,” said co-author Jeff Pierce, associate professor in the Department of Atmospheric Science and a Monfort Professor. “When you have more air pollution, this specific type of crime, domestic violent crime in particular, increases quite significantly.”
The economists calculated that a 10 percent reduction in daily PM2.5 could save $1.1 million in crime costs per year, which they called a “previously overlooked cost associated with pollution.”
Source: Colorado State University