Scientists collect samples of air, water, soil, plants, and tissue to detect and monitor pollution. Pollutants are most often extracted from samples, then isolated by a technique called chromatography and analyzed by appropriate detection methods. Many pollutants are identified by their spectral fingerprints, unique patterns of absorbed or emitted radiation in the ultraviolet (UV), visible, or infrared (IR) region of the electromagnetic spectrum. Biomonitoring and technologies including satellite observation, sidescan sonar, and bioluminescent reporter chips are also used for pollution monitoring. In the United States, the U.S. Environmental Protection Agency (EPA) approves the methods for monitoring regulated pollutants such as pesticide residues and those in air and drinking water.

Sampling and Extraction

Air can be actively or passively sampled. Actively sampled air is pumped through a filter or chemical solution. For example, airborne lead, mostly originating from metals processing plants, is collected on filters by active sampling...