If you have to smoke when you're riding, you're better off having a big enough windscreen that it deflects the wind above your head. 25 years ago, when I still smoked, I tried smoking while riding, and invariably, some hot ash would still end up getting blown back in my face or down my shirt. Nothing like having your chest hair catch fire to break your concentration.
If you smoke through a hole in a full face helmet, where are you going to blow the smoke?
At my peak I was a two pack a day smoker, and even at that rate, after a few aborted attempts, I stopped trying to smoke on the bike. If for no other reason than you look like a dork when you do it.
"No matter where you go, there you are."