While we’ve grown used to the idea of Google’s StreetView cars zooming around town snapping photos for mapping purposes, some of those vehicles have been equipped with a pollution monitoring system to help researchers get a better picture of what is in the air we breathe every day.

There are two of these Google Earth Outreach vehicles with a mobile-air-quality platform developed by a company called Aclima, reports Fast Company.

The cars have been driving for up to eight hours a day around Oakland and sampling every street in a certain area of the city to collect urban air pollution data, according to a new study published by researchers at the University of Texas at Austin.

They’ve made three million unique measurements while driving more than 14,000 miles, creating “one of the largest, most spatially precise datasets of mobile air pollution measurements ever assembled.” It’s all part of a partnership between Google and the Environmental Defense Fund.

“Maybe the most striking thing is how much air pollution can vary even within a city block,” Joshua Apte, an assistant engineering professor at the University of Texas at Austin and lead author of the study, told Fast Company. “One end of the block could be five, eight times more polluted than the other end of the block.”

For example: Researchers found that streets with city bus routes were more polluted than those without, and neighborhoods closer to highways that ban trucks are less polluted than those near interstates that have truck traffic.

You could use such detailed data to make decisions on whether or not to buy a house, or push for change in your neighborhood. Cities could also use it to improve certain areas, or show the positive effects of efforts to cut down on pollution.

“Our findings validated community concerns about poor air quality near the port and major freeways,” Steven Hamburg, EDF Chief Scientist, said “But it’s also shocking to see how close homes and playgrounds have been built—and are continuing to be placed—near major pollution sources. This data can inform decisions about zoning and planning and result in concrete health benefits for communities.”

The hope is that this system could eventually roll out in other cities and other kinds of vehicles: Aclima is currently working on a smaller prototype of its system that could be deployed even in compact vehicles.

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