A handful of Google Street View cars are mapping more than roads.

Google has teamed up with Aclima, a San Francisco-based company that designs and deploys environmental sensor networks, to equip a small portion of its fleet of Street View cars with mobile sensors. These sensors can track levels of nitrogen dioxide, nitric oxide, ozone, carbon monoxide, carbon dioxide, methane, black carbon, particulate matter, and Volatile Organic Compounds (VOCs).

The project has already kicked off in Denver, with three Street View Cars. According to Aclima, those cars drove over 750 hours and took in 150 million points of data. Both NASA and the EPA were part of the pilot study.

“Environmental air quality is an issue that affects everyone, especially those living in big cities,” said Karin Tuxen-Bettman, Program Manager for Google Earth Outreach. “This partnership with Aclima builds on our ongoing partnership with the Environmental Defense Fund, enabling us to take the next steps in our pilot project to use Street View and Google Maps as an environmental mapping platform. We hope this information will enable more people to be aware of how our cities live and breathe, and join the dialog on how to make improvements to air quality.”

Aclima and Google aren’t new partners. In fact, the two have been working together to track air quality for years – inside 21 Google offices across the world.

The next step is to equip Street View cars in San Francisco.

You can check out some of Denver data here.