the Impacts of Global Change on Regional U.S. Air Quality : A Synthesis of Climate Change Impacts on Ground-Level Ozone , '' is the culmination of a study started in 2000 , the EPA said . The White House moved quickly to try to squelch any concerns that the EPA would immediately issue any regulations concerning the gases . `` The president has made clear his strong preference that Congress act to pass comprehensive legislation rather than address the climate challenge through administrative action , '' White House spokesman Ben LaBolt said . `` That 's why the president has repeatedly called for a bill to provide for market-based solutions to reduce carbon pollution and transition to a clean-energy economy that creates millions of green jobs . '' The EPA announcement comes amid efforts by Congress to enact a limit on global warming pollution . The House Energy and Commerce Committee is scheduled to begin hearings next week on a comprehensive energy and climate bill , called the American Clean Energy and Security Act . Committee Chairman Henry Waxman is said to want the bill out of committee by Memorial Day , which falls on May 25 , and House
WASHINGTON -LRB- CNN -RRB- -- Six heat-trapping gases that contribute to air pollution pose potential health hazards , the Environmental Protection Agency said Friday in a landmark announcement that could lead to regulation of the gases . `` This finding confirms that greenhouse gas pollution is a serious problem , '' EPA Administrator Lisa Jackson said . The gases -- carbon dioxide , methane , nitrous oxide , hydrofluorocarbons , perfluorocarbons and sulfur hexafluoride -- have been the subject of intensive analysis by scientists around the world , the EPA said . The U.S. Supreme Court ordered the EPA 's scientific review in 2007 . `` This finding confirms that greenhouse gas pollution is a serious problem now and for future generations , '' EPA Administrator Lisa P. Jackson said in a release , later adding , `` The science clearly shows that concentrations of these gases are at unprecedented levels as a result of human emissions , and these high levels are very likely the cause of the increase in average temperatures and other changes in our climate . '' The EPA 's finding now goes into a public comment period . The report , titled `` Assessment of