The 1990 Clean Air Act Amendments require certain large polluters to perform enhanced monitoring to provide an accurate picture of their pollutant releases. Enhanced monitoring may include keeping records on materials used by the source, periodic inspections, and installation of continuous emission monitoring systems that measure how much pollutant is being released into the air. The act also requires states to monitor community air in polluted areas to determine whether the areas are being cleaned up according to schedules set out in the law. A criteria air pollutant. Nitrogen oxides are produced from burning fuels, including gasoline and coal.
Nitrogen oxides are also a precursor pollutant that contributes to the formation of acid rain.
A geographic area in which the level of a criteria air pollutant is higher than the level allowed by federal health-based primary standards. A method used in the 1990 Clean Air Act Amendments to give companies that own or operate major sources of pollutants in nonattainment areas flexibility in meeting overall pollution reduction requirements when changing production processes. A gas that is a type of oxygen. Ground-level ozone, however, is the main contributor to urban smog. Ground-level ozone is the product of reactions among chemicals produced by burning coal, gasoline and other fuels, and chemicals in products such as solvents and paints.