U.S. EPA may regulate CO2 emissions

The U.S. Environmental Protection Agency (EPA) in April classified carbon dioxide (CO2) as a hazard to human health, due to increasing concentrations of it in the air. The EPA grouped CO2, along with five other “greenhouse gases”—methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride— into a single class for regulatory purposes, as they share similar properties, such as being long-lived and well mixed in the atmosphere which traps heat that would otherwise escape into outer space. Media reports said that the agency’s move could pave the way for the U.S. Congress to formulate comprehensive environmental legislation, and may also lead to rules that are likely to heavily affect cars and trucks, which account for nearly a quarter of U.S. greenhouse gas emissions. (February 20/ April 17, 2009)