Google Street View cars are now doing more than taking 360-degree photos of roads for Google Maps. The vehicles can also be used to monitor air pollution.

For the past year, Google has used two Street View cars to track and store data about air pollution levels block-by-block in Oakland, California.

Working with the Environmental Defense Fund and scientists in the Bay Area, Google hooked up the cars with an environmental sensor network made by the tech startup Aclima.

The vehicles then drove down every road of east, west, and downtown Oakland dozens of times. In a press call, Joshua Apte, an environmental scientist at UT Austin, said the cars passed each road an average of 30 times. In total, the cars collected 2.7 million data points about air pollution, which Google turned into an interactive map. On June 5, the team published its findings in Environmental Science & Technology.

Perhaps unsurprisingly, the researchers saw a correlation between traffic-ridden roads, like the I-880 freeway, industrial areas, like the city's shipping port, and high levels of air pollution. On certain intersections, air pollution reached five to eight times higher than in surrounding neighborhoods.

The larger goal is to pilot the project in other US cities and make the data available to local lawmakers and nonprofits, according to the team.

"We need better, more hyperlocal measurements," Melissa Lunden, chief scientist at Aclima, says. "This type of data has the potential to be transformative. It can help us understand how the local urban landscape contributes to climate change, and how trees and vegetation and protect us from pollution."

Until recent years, pollution scientists needed to use weather models, which are often unspecific and expensive, to find where emissions came from.

But by using Google Street View cars, researchers can monitor pollution on a more granular level. If a car finds a pollution hotspot on a particular street, for example, it could also detect if it's coming from a nearby highway or set of warehouses that are not up to code. As Wired notes, chemists at UC Berkeley are also installing sensors on school and museum rooftops that track seven different pollutants in Oakland and San Francisco.

As areas rapidly urbanize, air pollution is becoming a more critical public health issue. An estimated 8.2 million deaths a year are linked to air pollution, according to the World Health Organization. In 2015, the number of asthma emergency department visits for parts of East and West Oakland was double the overall Alameda County rate.

"We have a shared responsibility for our planet. Now more than ever, cities are on the front lines of fighting climate change and air pollution," Lunden says.