Pollution monitoring. Researchers operating Light Detection and Ranging (LIDAR) equipment from the back of two trucks. LIDAR equipment measures the composition of clouds of pollutants in the atmosphere over a 100 kilometre range. It works because each type of molecule absorbs different and specific wavelengths of light. LIDAR fires a laser (green beam of light) of a specific wavelength into the sky. The equipment measures the intensity of the light reflected back. From this the absorption of light can be calculated and hence the level of the specific pollutant. LIDAR was developed at Lausanne Polytechnic (EPFL), Switzerland. Photographed in Lausanne.
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