Did you read the linked paper? It’s a literature review which includes an assessment of a huge assortment of papers, mostly about stuff like forest fires and fires used for clearing agricultural land. The studies which were related to the health effects of indoor recreational wood fires were mostly small sample sizes, pretty minor effects.

Here are some bits from the paper:

“To date, only a single controlled exposure study of human
exposure to woodsmoke itself seems to have been published (Barregard et al., 2006; Sallsten et al., 2006). Thirteen subjects were exposed to realistic concentrations of woodsmoke (200–300 μg/m3 PM2.5) generated under controlled conditions for two 4-h sessions, spaced 1 wk apart. In this study, exposure to woodsmoke resulted in small exposure-related changes in levels of inflammatory mediators and coagulation factors.”

“A questionnaire study of respiratory symptoms compared residents of 600 homes in a high woodsmoke area of Seattle, WA, with 600 homes of a low woodsmoke area. [...] When all age groups were combined, no significant differences were observed between the high- and low-exposure areas.”

“In Seattle, WA, 326 elementary school children were stud- ied during the heating seasons of 1988–1989 and 1989–1990. [...] The 26 children with asthma showed a significant decrement (18 ml/μg/m3 PM2.5) for both measures of lung function. Children without asthma showed no significant changes in lung function associ- ated with PM values.”

“In contrast, in a larger, prospective study of 904 infants in Connecticut and Virginia, Pettigrew et al. found no relation- ship between either woodstove or fireplace use and either single episodes of otitis media or recurrent otitis media, which was defined as 4 or more episodes during 1 yr (Pettigrew et al., 2004). Data on infant respiratory symptoms (in this case, a physician’s diagnosis of an ear infection) and hours of use of secondary heating sources were collected in telephone interviews with the mothers every 2 wk for 1 yr. Although both woodstove and fireplace use were significantly associated with the outcomes in bivariate models, these associations were absent in multivariate models that adjusted for gender, race, day care, number of chil- dren in the household, duration of breast-feeding, winter heating season, use of gas appliances, season of birth, maternal education, maternal history of asthma and allergy, and pets.”

And here, the most “damning” bits of summary. They’re awfully circumspect.

“Surprisingly relatively few studies examining the health impacts of woodsmoke have been conducted in developed countries, partly due to the difficulty of disentangling risks due to woodsmoke from those associated with other pollutants also present. In addition, most available studies are ecologic in design, limiting the ability to infer causality. Those that have been done, however, indicate that exposure to the smoke from residential woodburning is associated with a variety of adverse respiratory health effects, which are no different in kind and, with present knowledge, show no consistent difference in magnitude of effect from other combustion-derived ambient particles.”

“Since source apportionment studies show that woodsmoke is a major contributor to PM in many communities, it is likely that woodsmoke exposure plays a role in the spectrum of adverse effects linked to PM exposure. The large effects seen at higher exposures in the developing world provide additional evidence of the toxicity of woodsmoke.”

The paper’s conclusion includes:

“Finally, returning to the questions posed at the start, we conclude that although there is a large and growing body of evidence linking exposure to wood/biomass smoke itself with both acute and chronic illness, there is insufficient evidence at present to support regulating it separately from its individual components, especially fine particulate matter. In addition, there is insufficient evidence at present to conclude that woodsmoke particles are significantly less or more damaging to health than general ambient fine particles.”

* * * * * * *

But if you read the main story under discussion, we instead get:

"The unhappy truth about burning wood has been scientifically established to a moral certainty: That nice, cozy fire in your fireplace is bad for you. It is bad for your children. It is bad for your neighbors and their children. [...] In fact, wood smoke often contributes more harmful particulates to urban air than any other source.

"In the developing world, the burning of solid fuel in the home is a genuine scourge, second only to poor sanitation as an environmental health risk. In 2000, the World Health Organization estimated that it caused nearly 2 million premature deaths each year—considerably more than were caused by traffic accidents."

The first paragraph is hyperbolic (there are a few places in industrial countries where woodsmoke is the biggest source of pollution, but this is still pretty low by world and historical standards, and typically those areas don’t have much other air pollution to speak of, so this is unsurprising). The stuff about “moral certainty” is just crap. Maybe if you live in a place with relatively high population density and every house is mainly heated by wood, you’ll get noticeable amounts of air pollution, but this is also a different case than the author is trying to make us feel guilty about, which is having a fireplace in your living room every-once-in-a-while.

The second paragraph is much worse though, because, while accurate, is grossly misleading when included in an argument about industrialized countries without providing additional context and explanation.

* * * * *

In summary, if the conclusion was “don’t heat your house all the time using only a woodstove, especially if you have infants or asthmatics in the house” then I would agree 100%. Or if the summary was “we really should work on improving access to gas and electricity to the developing world, so they can stop using dangerous wood fires for heating and cooking”, I would also agree 100%. I would even agree if he said “we should convince people in those US/European ski towns that they should use gas for heating, and limit their wood burning to the occasional fire in the fireplace”. But unfortunately, the author didn’t limit himself to supportable conclusions.