Google and SF startup Aclima have been working together for more than a year upon air quality data collection with sensors attached to Street View cars. A reasonable question arises here: How can the data be useful? Trees consume a lot of “bad” gases, but recently there was no way to figure out which city areas drastically need these absorbers to be planted. With the sensors created by Aclima, the city governors will have a real image of what is going on with air pollution zone by zone. This info will allow them to green the areas which require air cleaning.
Similar indoor sensors were used for the first time by Google to estimate the air condition in conference rooms throughout the day. The sensors took measurements of the CO2 level, and the company could follow the level changes and determine whether it was high enough to degrade brain function.
Going back to outdoor sensors, they are expected to make the air pollution data as available to anyone as weather forecasts are nowadays. The creators, Google and Aclima, are planning to continue their tests in new areas. Also, Google has agreed to buy more sensors to provide a better and bigger rollout to air condition map quality.
You can also have a look at how the program works: