Come 2008, the air down on the farm should be cleaner if a proposed federal rule on reducing the emissions from diesel-powered equipment goes through.
The Environmental Protection Agency wants to include all those chortling tractors, bulldozers, and other off-road diesel vehicles and engines under the same standards recently adopted for on-road diesel trucks and buses. This would reduce harmful emissions by 90 percent or more.
Though few in number, off-road diesel vehicles account for 44 percent of soot and 12 percent of smog- producing nitrogen oxides from all vehicles. One bulldozer produces as much pollution as 26 new cars.
Since the public-health benefits of the measure far outweigh the costs to manufacturers of investing in better technology, it's worth asking why the government took so long. The answer: Until recently, most debate about air quality has focused on pollutants, such as carbon monoxide, from cars and trucks. The measure is also more timely because oil refiners are poised to reduce sulfur levels in diesel fuel.
The move strikes a good compromise between environmentalists and industry - diesel manufacturers will have time to comply because the regulations are phased in. And it marks a success for EPA Administrator Christine Todd Whitman, while greening up President Bush's tarnished environmental credentials.