The Environmental Protection Agency on Jan. 7 proposed tougher standards for how much smog can be in the air, a move the agency said would save money and protect health, especially in children.

"EPA is stepping up to protect Americans from one of the most persistent and widespread pollutants we face. Smog in the air we breathe poses a very serious health threat, especially to children and individuals suffering from asthma and lung disease," EPA Administrator Lisa Jackson said in a statement.

"It dirties our air, clouds our cities, and drives up our health care costs across the country," she said.

The new standards would replace those set by the previous administration, "which many believe were not protective enough of human health," the EPA said.

Under the proposals, the "primary" standard for smog -- the standard to protect public health -- would be tightened up to the strictest level ever in the United States -- between 0.060 and 0.070 parts per million (ppm) measured over eight hours.

The Bush administration in 2008 set the primary standard for smog at 0.075 ppm for eight hours.

The EPA also proposed setting a separate "secondary" standard designed to protect plants and trees from damage from repeated ozone exposure, which can reduce tree growth, damage leaves and increase susceptibility to disease.

Smog, which is also known as ground-level ozone, forms when emissions from industrial facilities, power plants, landfills and motor vehicles react in the sun.

Three public hearings will take place on the proposals, starting early next month.

Copyright Agence France-Presse, 2010