The stoves just put off a lot of particulate pollution. Stoves don't completely combust the wood or do so at the wrong temperature which results in much more pollution than burning an equivalent energy amount gas.
That certainly makes sense; I've only ever used fireplaces and you can visibly see the particulate those emit.
I'm guessing it's outside of the economic envelope in which people are burning wood anyways, but the article makes it sound like combusting at the "right" temperature essentially solves that problem. But I suppose at that point you might as well just burn something cleaner and retain the other advantageous parts of the design.
Look up rocket stoves, and rocket mass heaters. Properly built, they effectively produce only co2 and steam, even all carbon monoxide is consumed.
Of course, since each rmh is custom built, you need to actually test the exhaust of every one to ensure it works as intended.
Mine is pretty swell, albeit a tad annoying to keep going if we leave for a few days and the whole mass cools. With that said, it uses about 1/10th the wood of a new high efficiency wood stove we use in a different building.
Reading that article, I am curious as to why they say that rmh are less efficient than tile stoves. The exhaust temp on mine is around 130-150 degrees F- cooler than a fresh cup of coffee. And yet, I get pretty complete combustion- so all of the heat from the wood is captured inside my house.
I recently saw a claim that rmh can produce less CO2 for the same heat than gas furnaces, though that was just someone on the internet, I would definitely want more research to claim that.
I'm guessing it's outside of the economic envelope in which people are burning wood anyways, but the article makes it sound like combusting at the "right" temperature essentially solves that problem. But I suppose at that point you might as well just burn something cleaner and retain the other advantageous parts of the design.