EPA tightens standards for soot pollution - Article Photos 2/2

FILE - This April 28, 2009 file photo shows smog covering downtown Los Angeles. In its first major regulation since the election, the Obama administration will impose a new air quality standard that reduces by 20 percent the maximum amount of soot released into the air from smokestacks, diesel trucks and other sources of pollution. The Environmental Protection Agency (EPA) is set to announce the new standard on Friday, meeting a court deadline in a lawsuit by 11 states and public health groups. (AP Photo/Nick Ut, File)