EPA's Acid Rain Program Progress Report

摘要

EPA's acid rain program, which regulates emissions of sulfur dioxide (SO_2) and nitrogen oxides (NO_x), was established under Title Ⅳ of the CAA. The program calls for major reductions of SO_2 and NO_x, the primary acid rain precursors. SO_2 emission reductions are achieved through a market-based approach, under which participants can trade or bank emission credits (or allowances). NO_x emission reductions are achieved through defined emission rate limits imposed on regulated facilities. The acid rain program establishes a permanent cap on the total amount of SO_2 that may be emitted by electric utilities nationwide at about 50% of the amount emitted in 1980. The cap is expressed as allowances, and each allowance represents one ton of SO_2 emissions. To meet the requirements, individual utility units are allowed the flexibility to select the compliance method that is best suited to their facility. The acid rain program also sets NO_2 emission limitations (in lb/MMBtu) for electric utilities, which represent about a 27% reduction from 1990 levels.