"The Environmental Protection Agency on Thursday proposed a stricter standard for smog-causing pollutants that would bring substantial health benefits to millions of Americans while imposing large costs on industry and local governments.
The standard would replace one set by the Bush administration in March 2008, which has been challenged in court by state officials and environmental advocates as too weak to adequately protect human health and the environment.
The Obama administration’s proposal sets a primary standard for ground-level ozone of no more than 0.060 to 0.070 parts per million, to be phased in over two decades. Regions with the worst smog pollution, including much of the Northeast, Southern and Central California and the Chicago and Houston areas, would have more time than other areas to come into compliance.
The new rule would replace the standard of 0.075 parts per million imposed by the Bush administration over the objection of an E.P.A. scientific panel, which wanted a tighter limit. The previous standard of 0.084 parts per million was set in 1997 by the Clinton administration."