Sampling Method Selection

A substance, such as carbon monoxide, exists only as a gas; an inorganic compound like iron oxide exists only as a particle. Many substances exist as either particles or vapors, however; substances that are gases can be attached by some means to particulate matter in the air.

To conduct sampling, environmental engineers must have prior knowledge of the physical state in which a substance exists or make a judgment. Devices suitable for collecting particulate matter do not usually collect gases or vapors; hence, selection of an incorrect sampling method can lead to erroneous results. Fortunately, considerable knowledge concerning the more common pollutants is available, and in most cases, selecting a suitable sampling method is not difficult.

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