The federal government has strengthened the national air quality standard for soot and fine particle pollution. The new standard is 20 percent more stringent than the current standard, which was set in 1997. It will require communities to make sure fine particle pollution is limited to 12 micrograms per cubic meter annually (the current limit is 15).
EPA Tightens Air Quality Standard for Soot Pollution
By Erica Peterson & WFPL News • Dec 14, 2012