The European Union project iSPEX recently asked residents in 11 European cities to participate in crowdsourcing air quality measurements using their smart phones. Participants used their smartphones, an app and a lens called a spectropolarimeter, to collect data about air quality across the continent, which will be used by iSPEX to make comprehensive maps. The residents placed the lens over their smartphone camera and photographed the sky in multiple directions. The app registered the location and direction of each picture and measured the light spectrum and the polarization of the light. From the data, iSPEX are able to calculate how much fine dust — known as aerosols — there is in the atmosphere in that place and create a map showing levels of air pollution across Europe. The crowdsourced data can be used to aid government research by filling in any blank spaces and ensuring that the official data is honest. (Read more: Springwise article: Crowdsourced pollution data via smartphones).