ABSTRACT
Emission reductions that are certified are termed emission reduction credits (ERC). For emission reductions to be certified as ERC, they must have five characteristics. The requirements for certification are: real, quantifiable, surplus, permanent, and enforceable. An emerging regulatory requirement is to require offsets for toxic air pollutants. Regulations have been proposed that would require toxic air pollutant emission reductions adequate to offset toxic air pollutant increases from a new or modified source. The offset ratio between emission reductions and new emissions is established to provide no net increase in health risk or burden from the combination of reductions and the new emissions. The federal Clean Air Act requires that areas of the country that are nonattainment for any of the criteria pollutants must develop a plan by which emissions can be reduced and attainment achieved. Emission reduction offsets for new/modified sources with emission increases are required to be part of that plan under the provisions of the 1990 Amendments.
