Abbreviation for Combined Available Chlorine. Undesirable, foul-smelling, body-irritating compounds formed when insufficient levels of free available chlorine react with ammonia and other nitrogen-containing compounds (swimmer and bather waste, fertilizer, perspiration, urine, etc.). Combined chlorine is still a disinfectant but it is a much weaker, ineffective form of chlorine. Destroyed by Superchlorination or shocking.
Criteria Air Contaminant. There are seven air pollutants that are considered Criteria Air Contaminants (CAC) that are emitted predominantly to the air. The seven contaminants are Total Particulate Matter, Particulate Matter with a diameter less than 10 microns, Particulate Matter with a diameter less than 2.5 microns, Carbon Monoxide, Nitrogen Oxide, Sulphur Dioxide, and Volatile Organic Compounds. A brief description of each CAC is provided in this glossary.