There's no border fence in the sky between North Carolina and states upwind of us, keeping air pollution out. Toxic emissions from coal-fired power plants breeze right across state lines uninvited.

Republican Sen. Lamar Alexander of Tennessee understands this. That's why he voted last week to protect states from emissions in other states. Alexander was one of 56 senators who rejected a bill Thursday that would have blocked the EPA from enforcing cross-state rules.

"People come to see the Great Smoky Mountains, not the Great Smoggy Mountains," Alexander said. "The only reason for (this bill) is a political message. And what kind of message is it? That we favor dirty air blowing from Kentucky into Tennessee."

Or into North Carolina.

Our state has come a long way in the past 10 years. We used to be home to 14 of the dirtiest coal-fired power plants in the nation. But with the backing of Duke Energy, legislators passed the Clean Smokestacks Act in 2002, designed to reduce ozone, mercury and other pollutants by as much as 75 percent.

That was landmark legislation, but it didn't solve the problem, in part because pollutants continue to float in from other states. That's why North Carolina would benefit from the EPA cross-state rule that Sen. Rand Paul, R-Ky., tried to block. The rule will require plants in 27 states to cut power plant emissions crossing state lines.

North Carolina is downwind from polluting plants in Tennessee, Kentucky, Alabama and elsewhere. We are not upwind of anyone, so we had everything to gain and nothing to lose.

That's why Sen. Kay Hagan, D-N.C., voted against scrapping the EPA rule and why it's disappointing that Sen. Richard Burr, R-N.C., voted for killing it, declining to join Alexander and five other Republicans in its defense. It's understandable that a senator from Kentucky, which has dirty power plants and is an upwind state, would oppose the rule. But we had hoped Burr would be interested in protecting North Carolina's interests.

The EPA estimates that the rule will save up to 34,000 lives, including up to 1,900 in North Carolina, not to mention protecting residents against respiratory illnesses, asthma attacks and other woes.

It's not just an environmental and health issue. Dirty air hurts crops, drives away tourists and jobs in the tourism industry, and makes it harder to recruit manufacturers. Many business groups support the EPA rule, saying its economic benefits outweigh the cost of compliance.

North Carolina has gotten tough and utilities here have spent many millions of dollars doing their part to cut emissions. Why should plants in other states avoid cleaning up, at our expense?

Charlotte-based Duke Energy had no comment on the fight Friday. But Duke Chairman Jim Rogers said last week that "I think three years is doable" for complying with proposed EPA emission limits.

Next up in Congress will be attempts to delay implementing the EPA rules. In that fight, Hagan and Burr should stand up for North Carolinians and clean air, and against special interests.