"The latest science supports substantially tightening U.S. EPA's air quality standards for soot in order to safeguard public health and the environment, according to a draft report from agency scientists.
Current evidence 'calls into question whether the current suite' of health-based standards for fine particulate matter, or soot, 'protects public health with an adequate margin of safety from effects associated with long- and short-term exposures,' says the draft report issued this month.
EPA last revised its soot standard in 2006 under the George W. Bush administration, when the agency tightened the allowable concentrations of fine particulate matter from 65 micrograms per cubic meter to 35 micrograms when measured over a 24-hour period. EPA also opted to retain the annual soot standard at 15 micrograms per cubic meter, even though EPA's staff and scientific advisers had recommended a standard between 13 and 14 micrograms. EPA set an identical welfare-based standard at 15 micrograms.
A federal appeals court last year sent the annual standard back to EPA for review, finding that the Bush administration's standards were, 'in several respects, contrary to law and unsupported by adequately reasoned decisionmaking'."