You need to look no further than the (single) reference this blogger gives at the bottom of his post. His link is behind a pay-wall, but a google search leads you to a pre-print draft posted by one of the reference's original authors.
The article is a review of scores of other studies, and perhaps the original authors said it best (in the Conclusion):
...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
Nevertheless, given the importance of woodsmoke as a
contributor to particle concentrations in many locations, strategies
to reduce woodsmoke emissions may be an effective means of lowering
particle exposures. In addition, given the weight of toxicologic
evidence, additional epidemiologic studies are needed to confirm our
With the above in mind, it would seem that the original blogger overstated his case a bit, in a provocative manner, when he said things like:
[Wood smoke] is at least as bad for you as cigarette smoke, and probably much worse.
The case against burning wood is every bit as clear as the case
against smoking cigarettes. Indeed, it is even clearer, because when
you light a fire, you needlessly poison the air that everyone around
you for miles must breathe.
It should be no surprise that breathing wood smoke is bad for you. The question would seem to be "how bad is it?", and while the blogger paints a picture of global disaster/catastrophe, the scientific research is far more tentative (right now, at least).