In a decision that could help reduce air pollution from being blown into New Jersey from neighboring states to the west and south, the U.S. Supreme Court yesterday upheld a [link:http://www.epa.gov/crossstaterule/|rule to curb harmful emissions from power plants.

The regulation was adopted by the federal Environmental Protection Agency in 2011 but later overturned by the U.S. Court of Appeals. The nation’s highest court reversed the decision in a 6-2 vote.

The long-litigated rule will now go into effect, a step proponents say will help New Jersey better protect residents from dangerous soot emissions from coal-burning power plants, as well as reducing pollution from smokestacks that contributes to smog, or ground-level ozone.

For years, state officials have complained that no matter how hard they ratchet down on facilities in New Jersey with some of the stiffest air pollution rules in the country, it would still be exceedingly difficult to achieve national health standards for some pollutants.

For example, the state has never achieved the health standard for ozone, which causes respiratory problems for the young and elderly when pollutants from factories, power plants and vehicle cook together on hot summer days to form smog.

The rule aims to reduce that pollution by requiring 27 states upwind of New Jersey and other Northeastern states to curb emissions that contribute to downwind air-quality problems.

“Today is an important victory not only for clean air, but for our lungs,’’ said Jeff Tittel, director of the New Jersey Sierra Club, who added that New Jersey gets about a third of its air pollution from out of state.

Many Northeastern states and the Sierra Club were part of the lawsuit supporting EPA’s rule, but not New Jersey. The issue created some unusual alliances with big energy companies, like Public Service Electric & Gas, and the State Chamber of Commerce, siding with environmentalists, such as the Sierra Club, and the federal agency in support of the rule.

The Christie administration filed a successful lawsuit against a power plant on the Delaware River in Pennsylvania, long accused of polluting New Jersey’s air, an action that led to an agreement to shutter the plant.

Beyond the potential health impacts, the differing emission standards in southern and western states put a New Jersey plant at a competitive disadvantage compared with its counterparts upwind. With less expensive pollution controls, those facilities can operate cheaper than plants in state, leading them to be more heavily relied upon by the regional operator of the power grid.

Critics of the rule, the upwind states and power plants located there, argued that the measure would cost hundreds of millions of dollars and lead to the shutdown of many coal plants, which provide the bulk of electricity in the region.

“While New Jersey has taken some proactive measures to reduce its own hazardous plant emissions, our residents continue to suffer at the hands of upwind polluters,’’ said Sen. Robert Menendez (D-NJ), applauding the court’s ruling.

“By recognizing that dirty emissions don’t stop at the state line, the Supreme Court’s ruling will save tens of thousands of lives every year and reduce healthcare costs in New Jersey and across the nation,’’ he said.

The new rule, he argued, could save over 1,200 lives per year in New Jersey and eliminate as many as 34,000 premature deaths nationwide, and prevent 400,000 asthma attacks.