Burn wood, not lungs

THROUGHOUT New England, wood can be an affordable alternative to heating oil, natural gas, and electricity. The trick is to make sure that wood-burning units emit as little harmful fine-particle pollution as possible. While indoor stoves have had to meet federal Environmental Protection Agency standards since 1992, many outdoor wood boilers flunk that test. The result can be noxious emissions that are hard on the nose, the lungs, and the heart.

The Massachusetts Department of Environmental Protection is at work on regulations that would set criteria for thermal efficiency in outdoor wood boilers and thus emissions, best operating practices, setbacks, and minimum smokestack heights. Such rules are needed, as more people use outdoor boilers to heat homes, garages, barns, pools, and hot tubs.

To make the biggest impact on the boilers' pollution, new rules should provide for modifying existing units. Many older units cut down on wood consumption by limiting air intake. When wood smolders instead of burning at a high heat, it emits a large amount of uncombusted pollutants. In 2007, the EPA recognized the growing popularity - and problems - of the outdoor boilers and got 20 manufacturers representing more than 85 percent of the market to commit to voluntary improvements in new units. In the first phase, the units burn 70 percent cleaner than before and in the second phase 90 percent.

But outdoor boilers already in use can produce significant pollution. New rules on boilers won't solve every problem; some people use them improperly, burning trash and painted boards. Still, the state should do what it can to make sure that, at least when families burn well-seasoned firewood, their neighbors and the environment don't suffer.