Researchers have found that breathing polluted air does not only make you sick, but it could also make you more aggressive.
The research team from the Colorado State University found that strong links between short-term exposure to air pollution and aggressive behaviour, in the form of aggravated assaults and other violent crimes across the continental US.
The results were derived from daily Federal Bureau of Investigation (FBI) crime statistics and an eight-year detailed map of daily US air pollution.
"We're talking about crimes that might not even be physical, you can assault someone verbally, when you're exposed to more pollution, you become marginally more aggressive, so those altercations, some things that may not have escalated, do escalate," said the study's researcher Ander Wilson.
For the study, researchers cross-analysed three highly detailed datasets: daily criminal activity; daily county-level air pollution from 2006-2013 and daily data on wildfire smoke plumes from satellite imagery.
Air pollution scientists typically measure rates of pollution through concentrations of ozone or breathable particulate matter (PM) 2.5 microns in diameter or smaller, which has documented associations with health effects.
According to the researchers, 83 percent of crimes considered "violent" by the FBI were categorised as assaults in crime databases. In the study, they observed whether crimes occurred inside or outside the home.
They found that 56 percent of violent crimes and 60 percent of assaults occurred within the home.
The research results showed that a 10 microgram-per-cubic-meter increased in same-day exposure to PM2.5 was associated with a 1.4 per cent increased in violent crimes, nearly all of which was driven by crimes categorised as assaults.
Researchers also found that a 0.01 parts-per-million increased in same-day exposure to ozone was associated with a 0.97 per cent increased in violent crime, or a 1.15 per cent increased in assaults.
Changes in these air pollution measures had no statistically significant effect on any other category of crime.
The researchers made no claims on the physiological, mechanistic relationship of how exposure to pollution leads someone to become more aggressive; their results only show a strong correlative relationship between such crimes and levels of air pollution.
The study is set to be published in a forthcoming edition of the Journal of Environmental Economics and Management.
