This Fall, there are a lot of large fires burning in the pacific northwest of the US and the air quality on many trails and mountains is poor as a result. This makes hiking and climbing unpleasant, unhealthy and possibly unsafe.
To be clear, I am not asking about areas that are directly threatened by the flames, but there are many places that are relatively far away from the fires but are still unhealthy to hike in due to receiving many wind-borne pm2.5 particulates from the fire (which are apparently the main health hazard).
Are there are any good ways to mitigate the smoke? I looked into face masks and there are some that claim to be suitable for exercise (not sure if there's any truth to that). However, it seems that it can be difficult to tell if the mask fits properly and if it does not then it will not provide a proper seal and will be ineffective.
I'd be very interested to hear about any effective methods for dealing with the smoke.