EPA proposes tighter US air-quality rules

摘要

The US Environmental Protection Agency (EPA) has called for stricter air-quality standards relating to the small particles that cause smog and lodge in lungs. Last week's announcement opens a 60-day period for public comment and a final set of rules is due in June 1997, The EPA said that it will 1 equire plans to meet the new smog sstandards to be drawn up by 2000 and those to meet the particle standards by 2002, The EPA's proposals include a reduction in the limit for smog-forming ozone pollution in metropolitan areas from 120 ppb measured over one hour, to 80 ppb measured over eight hours. The recommendations also feature stricter standards for airborne particles such as soot and sulphates, particularly particles of less than 2.5 microns in diameter. These tiny particles come from a variety of sources, including motor-car exhausts. The EPA proposes a limit on the allowable daily average concentration of these particles of 0.050 mg/m~3 and on the annual average of 0,015 mg/m~3. The EPA administrator, Carol Browner, said that the proposed measures would cut premature deaths from these sources by 20,000 annually, equivalent to 50 percent, and reduce the number of cases of aggravated asthma. She claimed that, although the annual cost would be 6.5-8.5 billion US dollars, the savings, including those from health costs and lost working days, would amount to 120 billion US dollars.