Computer scientists at the University of California's School of Engineering have launched an Android app called Visibility, which crowd-sources the task of analyzing and measuring air pollution. Using the phone's camera, Android users simply point their phone at the sky and snap a photo. Many estimates of air pollution in developing countries are inaccurate, as there’s no network of surface-based sensors that can find the worst-polluted areas. Scientists regularly have to rely on a few dated observations of questionable veracity.