CHICAGO — Examining millions of crimes in Chicago, a pair of researchers conclude in a new study that tailpipe pollution from city expressways may be linked to spikes in neighborhood violence.
The researchers looked at expressways in Chicago and compared area crime data and weather. They found upticks in violent crime in neighborhoods on one side or the other of the highways depending on which way the wind was blowing.
The researchers from the National Bureau of Economic Research write "that violent crime increases by 2.2 percent on the downwind side."
Pollution can impact behavior either by affecting the central nervous system or because it "causes discomfort which itself leads to anti-social behavior," write Evan Herrnstadt of Harvard University and Erich Muehlegger of the University of California-Davis.
The pair cite earlier studies showing that pollution has been found to increase aggression, impulsive behavior and depression.
Herrnstadt tells the Washington Post that exposure to auto-related pollution "basically results in you crossing lines you wouldn't otherwise cross."
The researchers used data from 2 million common crimes between 2001 and 2012, including murder, rape, robbery, robbery, burglary, arson and auto theft. While they detected an increase in violent crimes, there was no significant effect on property crimes.
They describe their findings as "the first quasi-expermental evidence that air pollution affects violent criminal activity."
The researchers note that both crime and pollution overall have been decreasing over time in Chicago.
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