Western Montana is a wonderful place. Mountains, streams, rivers, wildlife - all in goodly numbers. But particulate-related haze often is present and arises from various sources.
Indeed, my impression of Montana is tempered by the fact that visual images are often hazy due to particulates from dusty roads, agriculture, and wood burning - whether during wildfires or prescribed burns.
Dealing with a Wood Smoke Problem
Dec 9, 2008 ...according to US EPA data, “wood smoke emits over 9600% more lead than natural gas!” It also emits arsenic, formaldehyde, mercury... http://www.shirleybrandie.com/car_newsletter_jan2009.pdf