Green groups urge tighter ozone standard for ecosystems

摘要

Conservationists are urging U.S. EPA to set a separate, more protective national standard tornshield trees, crops and other plants from the effects of ozone pollution.rnIn a letter to the agency, 17 conservation groups this week said EPA's proposed range for thernsecondary ozone standard -- a standard aimed at protecting ecosystems and public welfare,rnrather than public health -- was not stringent enough to avoid adverse effects to plants.