TOMS can detect smoke, volcanic ash, pollutants, dust storms, and ozone. The Environmental Protection Agency sometimes uses TOMS to decide where and when people should be alerted to high pollution in the air. TOMS also spots smoke plumes, to help firefighters, especially in places where there are no people to report fires. They update their world map of smoke and other aerosols and put it on the TOMS web site for everyone to see. A series of TOMS aerosol maps which shows the changing distribution of smoke from Western wildfires between July 31 and August 2, 2000.
Aerosols absorb light.
So by looking at sunlight reflected from the Earth, scientists can see where pollutants are. But it's not quite that simple. Clouds absorb light, too. But TOMS solves the problem by looking at two different wavelengths of light. Wavelength is what gives light color.