Publisher Summary Environmental matters have become an area of widespread public concern particularly those concerning the issues of pollution and contaminants. Pollutants and contaminants come in many forms and can have an effect on the air, land, or water courses. As pollutants move from one medium to another they may be deposited on equipment and equipment housing that can cause extensive damage. Pollution of the air can occur in both the troposphere and stratosphere. In the troposphere, pollutants from, for example,the chimneys are carried by the air, which can be deposited over time and distance, thus having a limited life span before they are washed out or deposited on the ground. If pollutants are injected straight into the stratosphere (as with a volcanic eruption), they remain there for some time, and result in noticeable effects over the entire region. The roughness of the ground produces turbulence in the air promoting the mixing of pollutants. In general, low-wind speeds result in high pollutant concentrations. Chemical pollution is the introduction of substances into the environment (by man) that are liable to harm human health, living resources, the ecological systems, damage structures, or generally interfere with the legitimate use of the environment. Although pollutant gases are normally only present in low concentrations, they can cause significant corrosion and a marked deterioration in the performance of contacts and connectors. The gases in operating environments that cause corrosion are: oxygen, water vapor, and the so-called pollutant gases that include sulphur dioxide, hydrogen sulphide, nitrogen oxides, and chlorine compounds.