Optical Remote Sensing (ORS) uses light (UV, visible, or infrared electromagnetic wavelengths) to detect chemicals or particles in the air. Essentially, the instruments measure chemicals by shining a light beam through the air and detecting changes in the intensity and color of the light absorbed by contaminants. Just as visible light can be sorted into a spectrum of different wavelengths corresponding to various colors of light, UV or infrared light can be sorted into a spectrum corresponding to different temperatures or energy levels. A particular chemical will absorb energy only at particular wavelengths in the spectrum, producing a unique pattern or "fingerprint" spectrum for each compound. There are many ORS instruments that go by funny names like DOAS, DIAL, LIDAR and OP-FTIR.
There are many applications for ORS instruments, but two immediate uses stand out. One is for monitoring community air pollution emissions, such as from smoke stacks, around freeways, and airports. Another is to use the instrument in investigating contaminants at worksites, particularly in cooperation with the activities of our field consultation research group. These research activities provide immediate benefit and value to the workers and community presently served by the Department of Environmental Health.