Researchers at Colorado State University have found strong links between short-term exposure to air pollution and aggressive behaviour in the form of violent crimes.
The team of Colorado State University researchers in economics, atmospheric sciences and statistics cross-analyzed daily criminal activity statistics from the FBI, daily county-level air pollution from the EPA, and daily data on wildfire smoke plumes provided by the NOAA.
Their research results show a 10 microgram-per-cubic-meter increase in same-day exposure to PM2.5 is associated with a 1.4% increase in violent crimes, nearly all of which is driven by crimes categorized as assaults. PM2.5 is a particulate matter 2.5 microns in diameter or small, which has known detrimental health effects.
The 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.
“We’re talking about crimes that might not even be physical – you can assault someone verbally,” co-author Jude 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.
Eighty-three per cent of crimes considered “violent” by the FBI are categorized as assaults in crime databases. In the researchers’ study, they observed whether crimes occurred inside or outside the home; they found that 56% of violent crimes and 60% of assaults occurred within the home, which is an indication that many such crimes are tied to domestic violence.
“The results are fascinating, and also scary,” Pierce said. “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% reduction in daily PM2.5 could save $1.4 billion in crime costs per year, which they called a “previously overlooked cost associated with pollution”.
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