Editorial — The New York Times.

Between them, the Obama administration and the federal courts have reversed most of the Bush administration’s wrongheaded environmental regulations. But a few bad rules linger on the books, among them an inadequate health standard governing harmful ozone, which most people call smog.

Mr. Obama’s Environmental Protection Agency is now proposing to get rid of this rule and replace it with a stronger standard. This would result in cleaner air and better health for millions of Americans.

Ozone is a photochemical reaction that occurs when sunlight mixes with nitrogen oxides and other pollutants from power plants, vehicles, refineries and industrial facilities. It poses a serious health threat, especially in children and people suffering from asthma and lung disease, and is responsible for respiratory-related emergency room visits, hospitalizations and premature deaths.

Apart from their health advantages, the new rules proposed reflect the administration’s effort to restore science, as opposed to politics, to its rightful place in environmental rule-making. In 2008, the E.P.A.’s independent board of scientific advisers unanimously recommended that the ozone standards be set at somewhere between 0.060 and 0.070 parts per million.

Responding, in part, to industry pressure, the Bush administration imposed a less exacting and less protective standard of 0.075 parts per million. The new proposal, to be issued after a 60-day comment period, is expected to be somewhere in the range originally proposed by the scientific panel.

Some big polluters, including the oil companies, are likely to resist since the new standards would require investments in stronger pollution controls on power plants, refineries and chemical plants. The standards could also provide the impetus for cleaner vehicles.

Lisa Jackson, the E.P.A.’s administrator, should stick to her guns. When Carol Browner, then the administrator, first tightened health standards for smog and other pollutants like soot in 1997, industry groups rose up as one, predicting bankruptcy. But technology almost always catches up. In the end, costs are a fraction of the original claims, and the air is a lot cleaner.