Balance of Power

Critics at the time charged that the Bush administration ignored the advice of EPA's Clean Air Scientific Advisory Committee, which recommended the agency lower the primary ozone standard further, to 70 ppb or lower.

"This is one of the most important protection measures we can take to safeguard our health and our environment," said EPA Administrator Lisa P. Jackson. "Smog in the air we breathe can cause difficulty breathing and aggravate asthma, especially in children. Reconsidering these standards and ensuring acceptable levels of ground-level ozone could cut health care costs and make our cities healthier, safer places to live, work and play."

The notice came in the form of a filing in the U.S. Court of Appeals for the District of Columbia Circuit, in which the EPA cited concerns that Bush administration policy did not adhere to federal air pollution laws. Eleven states, joined by health and environmental groups, had sued to overturn the Bush standards, citing the advisory panel's tougher recommendation.

Jackson said EPA will conduct a thorough review of the science that guided the 2008 decision, including more than 1,700 scientific studies and any public comments from that rulemaking process. The agency will also review the findings of the advisory panel.

The news was cheered by green groups, who are sensing more energetic advocacy on environmental issues from the White House. Frank O'Donnell, president of the advocacy group Clean Air Watch, said if the EPA takes an unbiased look at the scientific evidence, it will surely propose tougher smog standards.