Pollution is bad for your health—that’s pretty much a given. You suck up 3,000 gallons worth of air each day so when it comes with a side of toxic chemicals, there’s bound to be some blowback. Your lungs, mouth, nose, and throat are obvious victims.

But a slew of recent studies have also showed that in addition to the physical health problems that have been associated with pollution, inhaling toxic emissions can have a big impact on your brain. High-pollution areas have been linked to an increase in dementia, struggling students, and now: a growth in violent crime.

Researchers Evan Herrnstadt, from Harvard’s Center for the Environment, and Erich Muehlegger, from University of California, Davis, teamed up to analyze the effect air quality has on crime.

Using data from the Chicago Police Department, which detailed locations and dates on more than 2 million crimes committed between 2001 and 2012, the researchers compared incidents to National Oceanic and Atmospheric Administration (NOAA) wind direction measurements taken along highways.

The researchers found an increase in aggressive behavior in whichever area was downwind from emissions: When a neighborhood was baring the brunt of wind-blown pollution, there was a 2.2 percent increase in violent crime—but no effect on petty crimes like robberies.

While that number may seem small, in their recently released paper published in the National Bureau for Economic Research, the researchers explained the economic cost of this increase could be up to $200 million each year.

“We think the mechanism here is that you’re exposed to more pollution, either it’s an irritant, or it affects your impulse control in some other way, and basically results in you crossing lines that you wouldn’t otherwise cross,” Herrnstadt tells The Washington Post. He explains that their research showed pollution prompted escalation of violent crimes that might otherwise have been less serious.

The researchers only included vehicular emissions in their study but that’s just one part of the pollution mix. A separate study published earlier this year that looked at how pollution affects school performance for fourth and fifth graders showed that “non-road mobile sources”—including airports, trains, and construction vehicles—had higher negative impact on GPA than roads and highways.

The good news is air pollution overall is declining. The Environmental Protection Agency reports that there’s been a 68 percent drop in emissions since 1970 thanks to policies like The Clean Air Act. But in the United States, there’s still a long way to go: Nearly 44 percent of the population—close to 139 million people—live in communities where the air is considered dangerous to breathe.

While the researchers emphasize that their findings don’t prove inhaling emissions will automatically make you violent, the study adds to a growing body of research that shows how reducing pollution will have important health—and economic—benefits.

“Our results suggest that pollution may affect cognition in ways that extend beyond impairing performance on standardized tests and may influence individual behavior in more subtle ways that previously considered,” the researchers conclude. “Furthermore, our results suggest that the external costs of pollution may be greater than previously estimated—implying optimal policy should more stringently regulate air pollution.”