| 09 August 2010

Image via Instructables The idea of showing air quality by emitting glowing colors is fairly old. In fact, in 2007, Pairs launched hot air balloons above the city that would show citizens the level of cleanliness of the air they were breathing in. Even air filters have started to sport glowing colors to indicate the level of pollutants in the air. But having such a cool air qualit... Read the full story on TreeHugger