David
I have never lived there, but isn't the local air quality in Quesnel more a product of a pulp mill and other heavy industry located in a valley that often is caught in a thermal inversion (the pollution is trapped in the valley by a blanket of cold air above) than any exhaust produced by diesel pick-ups and logging trucks?  The beauty of a town like Quesnel is that a short drive in almost any direction will get you to an area with great air quality.
Just wondering? 
George
"85 Westfalia
Regina SK (where the wind always blows and the smoke never stays for long)   
Local air pollution in Quesnel is quite high and since I have
moved here in 1992 my breathing health is not as good as it used to be.