Greenhouse Gases 

An official familiar with Obama’s decision said the president will reveal the policy today. The official spoke on condition of anonymity because the decision has not been publicly announced.

Maine and at least 13 other states want waivers from the federal Clean Air Act so that they can impose stiffer air pollution standards than the federal government requires.

Maine and other states have adopted California’s standards, but the Bush administration denied the states that permission. Obama’s move would empower the Environmental Protection Agency to reverse that conclusion.