Wood Stove Safety

Though there's a long way to go in categorizing and measuring all the effluents involved, research done in the past year has produced a wealth of new information on wood smoke and wood stove safety.

| November/December 1981

Ever since the first alarms about wood stove emissions were sounded, almost two years ago, there's been a flurry of research done on the subject of wood stove safety. Many of the findings of the spring-of-1980 Monsanto study that formed the groundwork for concern have been supported. But some of the new data have led to questions about the relevance of the testing methods that the Monsanto/Auburn University researchers used to reach their startling conclusions.

Pollution Today

Work done by more than a dozen different laboratories has confirmed that "airtight" wood stoves do emit large amounts of carbon monoxide, particulates, and unburned hydrocarbons. But the importance of the Monsanto team's discovery of significant amounts of "polycyclic organic matter," or POM (sometimes called "polycyclic aromatic hydrocarbons", or PAH ... many of which are known carcinogens), in smoke is now in doubt.

Throughout the course of its research, the Monsanto/Auburn group maintained burn rates of 15 (or more) pounds of wood per hour; most homeowners fire between two and six pounds of wood per hour. It was assumed at the time that the lower, more common burn rates would yield even greater quantities of POM than those noted in the tests since hydrocarbon emissions—in general—increase as wood consumption drops. But work done in the last year has failed to confirm that theory. Though scientists emphasize that the new data are far from complete or conclusive, the emissions of some POM compounds seem to drop at the lower burn rates typical of home wood stoves. Argonne National Laboratories tests, for example, have found little evidence of benzo (a) pyrene (a particularly toxic PAH) at typical household firing levels.

However, before we breathe a possibly premature sigh of relief (and, perhaps, inhale something that we might later regret), we must accept the fact that there's a great deal left to be learned about wood stove smoke. For example, a recently released report of the preliminary findings in a Dow Chemical study suggests that dioxins (see "Bonnie Hill: Oregon Environmental Activist" for more information on these extremely hazardous compounds) may be produced in woodburning appliances. (The cynical among us might question Dow's motives in conducting this bit of research, however, since the report concluded that the offending toxins did not come from herbicide-contaminated wood.).

Perhaps the newest and least understood of the woodburning-related pollution problems came to light with the discovery (by a Geomet Technologies team) that many wood stove-equipped homes have indoor levels of carbon monoxide, breathable particulates, and even members of the POM family that are more than ten times greater than outdoor measurements taken at the same time. Unfortunately, it'll be a while before we learn just how such a predicament occurs, since the financially gutted Environmental Protection Agency has no funding to build on the work done by Geomet.

In fact, our understanding of the elements and compounds that occur in wood stove smoke is far from complete. Scientists have been studying automobile and coal-fired powerplant emissions for decades, but we're just beginning to get an idea of the possible environmental impact of woodburning heaters.

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