Airborne particulate matter is a serious threat to both our health and the environment, say the researchers behind the Air Visibility Monitoring project. It is also the primary cause for visibility degradation in urban metropolitan areas. University of Southern California researchers are working towards an optical technique to measure air visibility (and hence an estimate of some kinds of air pollution) using cameras and other sensors available on smartphones.
 
The idea is that using a simple application for the Android phone, citizen scientists take pictures of the sky. Each picture is tagged with location, orientation and time data and transferred to a backend server. Visibility is estimated by first calibrating these image radiometrically and then comparing the intensity with an established model of sky luminance.
 
Citizen scientists with an Android smartphone can help USC researchers improve their app by contributing data.