Particulate in the United States

Particulate in Environmental Law

A substance, either liquid or solid, that is small enough to be suspended in air. Particulates may be tiny enough to be invisible, or they may compare to soot in size. Those larger than 10 microns in diameter tend to be filtered out by the respiratory system when we breathe. Some are caught by the hairs within the nostrils; others get stopped before they get to the lungs. But the Environmental Protection Agency (EPA) has concluded that particulates 10 microns or less in diameter can be inhaled into the lungs. These particulates, called PM10, are one of the air contaminants regulated by the National Ambient Air Quality Standards.

Most particulate matter in the air is the result of incomplete combustion of fossil fuels, primarily from automobiles and power plants. Power plants and automobiles reduce the amount of particulates in their emissions by using several different technologies. See mobile sources; nonattainment areas.
Based on “Environment and the Law. A Dictionary”.