San Antonio narrowly in compliance with new EPA soot rules

The San Antonio area barely slipped in under a new U.S. Environmental Protection Agency rule aimed at reducing particulate matter, or soot, in the air — a change the agency said could prevent up to 4,500 premature deaths annually nationwide. The long-anticipated regulatory change cuts the amount of soot allowed in the air to 9 micrograms per cubic meter annually, down from the prior allowable level of 12 micrograms. It's the first time the EPA has changed those limits in a dozen years.