To be fair, the critics do have a point, although their extremism can be off-putting. There are places, mainly communities in sheltered mountain valleys, where, when the locals fire up their stoves and fireplaces during a cold snap, the smoke gets so thick you can't see across the street. A frigid, stagnant air mass traps the smoke close to the ground. It smells terrible, affects everybody and makes some people sick. For most of us, though, wood smoke is rarely seen as an issue because the particular topographical and climatological features that trap smoke don't exist everywhere.
Wood smoke tends to blow away before it annoys anybody.
Smoke pollution only becomes a problem when the odd person can't or won't burn clean, thus attracting the ire of the neighbors. In truth, the majority of woodburning devices currently installed are filthy in the smoke emissions department. That is, they emit particulates at the rate of 20 to 60 grams per hour of operation. A person who sets out to burn without smoke could easily get below this range by using decent fuel and burning smaller, hotter fires. Unfortunately, many people don't know how.