EPA Proposes Smog Standards to Safeguard Public Against Pollution

摘要

EPA is proposing to strengthen air quality standards based on recent scientific evidence about the harmful effects of ground-level ozone, commonly known as smog. Smog forms in the atmosphere when emissions of nitrogen oxides and volatile organic compounds cook in the sun from sources such as automobiles, power plants and chemical fumes. Those most at risk include people with asthma, children and older adults, as well as those who are active or work outside. The agency seeks to lower emission levels to within a range of 65 to 70 ppb to better protect Americans' health and the environment, while taking comments on a level as low as 60 ppb. The last update came in 2008, setting the maximum at 75 ppb. The existing Clean Air Act requires EPA to review the standards every 5 years by following a set of steps and considering the advice of an expert panel.