Known as Project Air View, Google first began equipping its Street View cars with air pollution sensors in Oakland back in 2012 after a proposal by the Environmental Defense Fund. The company teamed up with Aclima, a San Francisco-based company that makes internet-connected air quality sensors, and has since expanded to other regions of the state. The sensors can detect greenhouse gas methane, as well as particulate matter, ozone, nitrogen dioxide and more. The company already has similar projects underway in Houston, Salt Lake City, Copenhagen, Amsterdam, and London. Last year, EDF Europe (through an initiative called Breathe London) launched Google Street View cars throughout the city, as well as 100 sensor pods on lampposts and buildings.

Google is planning to expand Project Air View to Asia, Africa, and South America by the end of 2019. The company is planning to equip 50 more Street View cars with air quality sensors by the end of the year. "In the future, we hope existing fleets of vehicles can be used in cities around the world for air quality measurement," wrote Google in a blog post.