The aim of the Public Air Quality Indicator project is to make existing information on air quality and pollution levels accessible. The indicator gives information specific to the location in which it is placed in the city and is updated 4 times a day.
The prototype takes data from the Internet about the current degree of pollution and prognosis for the next two days. The information is then sent to the serial port. This is connected to a processor that controls a series of LEDs.
The Indicator is Open Source and copyright free.
I like their Window indicator proposal. A similar system controls a window opener on the city hall. Depending on the current pollution level, the window will close (warning) or open (pollution below average) enabling the public to read the indicator from the street.
Via Free Soil.