(WASHINGTON POST)  Juliet Eilperin and Joby Warrick — 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 summer. But the lowering of the ozone limit—from 75 to 70 parts per billion—angered environmentalists and public-health groups that had sought an even tougher standard.

Industry trade groups, who had warned of severe economic damage and job losses, criticized the rule but said it could have been worse.

EPA officials said the first change in the federal ozone limit in seven years was prompted in part by new scientific research linking exposure to development of asthma, particularly in young children. EPA Administrator Gina McCarthy said the stricter standard will improve the lives of tens of millions of Americans suffering from respiratory disorders.

Source: Obama administration tightens smog limits but satisfies few – The Washington Post