The Environmental Protection Agency is clamping down on smog and low-lying pollutants that cause asthma and premature deaths. The change will cost industry billions to implement.

The tougher limits override those set under the Bush administration, which many environmentalists criticized as too lax.

The rules will undergo 60 days of public comment before being finalized. The agency is holding public hearings in Arlington, Va.; Houston; and Sacramento next month.

Under the new guidelines, state and local governments will have to ensure that their air ozone levels are between 60 to 70 parts per billion. It's not much less than the 75 ppb previously required, but health experts say the change will have a long-lasting impact on public health.

The EPA claims that the benefits will outweigh costs, since cleaner air will reduce hospital visits by people suffering from respiratory problems.

Children are especially vulnerable to smog, as are people with heart and lung disease.

"Using the best science to strengthen these standards is a long overdue action that will help millions of Americans breathe easier and live healthier," EPA Administrator Lisa P. Jackson said in a statement.

-- Ambreen Ali, Congress.org