Washington Post: The Obama administration tightened limits Thursday on a key air pollutant that causes urban smog, a move that officials say will alleviate suffering for millions of Americans who suffer from asthma and other respiratory illnesses.
The new restrictions announced by the Environmental Protection Agency will require scores of cities and counties to take steps to reduce levels of ground-level ozone, a byproduct of fossil-fuel burning responsible for hazy skies over many U.S. cities, especially in the...