EPA recommends trighter standards for fine particulate matter

摘要

In a final report issued July 1, Environmental Protection Agency (EPA) staff recommended significantly tighter air-quality standards for fine particulate matter (PM2,5). The National Stone, Sand and Gravel Association says EPA staff favored setting a standard for PM2.5 between 25 and 35 micrograms per cubic meter of air averaged over a 24-hour period. The current standard is 65 micrograms. EPA also favored a standard of 15 to 20 micrograms, averaged over one year. The current annual standard is 15 micrograms.