When smoke from regional bushfires has clouded the suburbs of Melbourne (and when I used to live there), I have worn a surgical mask when walking outside. I've also worn one while cycling during dusty conditions from the unsealed roads where I currently live. I don't know how comfortable/effective such a mask would be for the more intense aerobic running you do. Should be good for some outdoor weight training though. Wearing of masks to counter the traffic pollution is quite a common sight in Asian cities such as Bangkok.
I don't watch tv much so get most of my news through internet radio into my headphones, so of course I've been hearing about the LA fires. For the first time I saw some aerial video of the aftermath yesterday - I was shocked, I didn't realise it was so bad - huge areas of housing estate looked like a nuclear bomb had gone off