I used the 3m filter mask biking in the wildfire smoke a while ago. There is a blowout hole, which makes it much easier to get stale air out. The sport-specif

I used the 3m filter mask biking in the wildfire smoke a while ago. There is a blowout hole, which makes it much easier to get stale air out. The sport-specifc one from MEC made it hard to get fresh air when biking up hill. I used the air warmer mask during this last cold snap. It made it so much more comfortable! Last year I was fine biking in the cold snap, except for one time biking up a hill. Actually breathing hard, I got a lot more cold air in my lungs, and ended up with a cough for a week. Wanted to avoid that this year.