iPhone owners aren’t the only ones with green apps. Android toters can help fight air pollution — albeit somewhat indirectly — by downloading an app called Visibility.

Created by computer scientists at the USC Viterbi School of Engineering, Visibility is a tool for the clean air advocate surrounded by dirty air. Get the app, take a photo of the sky, crop out the highrises and tall palm trees and then hit send. The image then goes to a USC database, where it gets analyzed. As the L.A. Times’ Technology blog describes it:

The USC team has devised an algorithm that uses the phone’s location and the direction it was pointing to determine how bright the sun should be in your image. It then looks at your photo to see how much that theoretical sunlight has been obscured, and from that calculates how much gunk is in the air (it doesn’t work yet on highly cloudy days).
Want details on that algorithm? Then I hope you can decipher equations like this one:
5024698206 798c1c6739 Track air pollution with your Droid

so you can make it through the detailed document about the algorithm (PDF) put together by the USC computer scientists.

Obviously, sending in these sky images in itself won’t clean our air — but Droid owners’ efforts can help get us a better picture of the problem that is air pollution. As Sierra Club’s The Green Blog points out, “With enough photos snapped in enough places, problem areas will be much more easily identified.”

L.A. Times’ tech blog suggests that an iPhone app is on its way, but for now, Droid owners are the only people with the power of Visibility. Use it often — more photos will create better data. And for more green Droid power, read Earth 911′s roundup of the top 5 green Droid apps.

Track air pollution with your Droid
Help crowdsource air pollution data by taking photos of the skyline with your Droid.