One or two of our neighbours burn old fence panels (complete with vestiges of creosote on them) old pallets, damp/mouldy wood from rotten branches, cardboard, their own rubbish and suchlike. Sometimes it smells as if they're cremating a body. (Could be so I suppose hee hee)
They tow trailers behind their tractors loaded with this combustible material.
Normally the wind here is quite strong and whisks away any smoke, but if it's a cold, still evening the pollution is pretty bad. The smoke coming out of their chimneys is often a queer orangey-brown colour, or thick black billows.
Also, they all installed their wood burners themselves, and since we're all in bungalows, the chimneys aren't high enough to get the smoke away, and it descends around us all like a fog.

Gosh it felt good getting all that moaning of my chest!