I didn't say useless, I said overkill.

That being said, I have no idea what wildland FF's are using. However, I think that the risks of breathing gunk in during the fires isn't too extreme. Why? Well, because of some simple "thought excercises." Smokers don't develop cancer overnight. Asbestos workers didn't get mesothelioma after their first shift. Coal miners don't get black lung in their first hours of work. What does this mean? That there is a dose/event curve. Sure, a few days of LA fires will make your snot black, and you might cough up some dark crud. Which is GOOD. That's what your body is supposed to do.

Another point here, just on the effectivness of N95's. As mentioned, they're good for filtering 95% of particulate matter, 3 microns or larger. According to my pathology book from medical school (Robbin's Pathologic Basis of Disease, 7th Ed., p 732) "The most dangerous particles range from 1 to 5 microns in diameter..." So, you only get partial protection (better than none) from a N95.

So, while it may be overkill to me, it still might be a good idea if A) you constantly live near some source of smoke, B) you have underlying lung disease, or 3) work in a profession with a prevalance towards developing lung disease. Or you smoke, in which case, you should consider the nearby fire a chance for you to save a few bucks by delaying your next pack. Stop smoking.