Well i tried googling this. i know its not a good thing to do, but why? I mean if i smoke near my grow box 4 or 5 times in a matter of 7 days, will i be risking hermies, etc? +rep for a informative and detailed reply!
I do it constantly, and never had a problem. I figure the damn things grow in cities with heavy smog, all day long, so a couple minutes of smoke won't hurt them.LOL I'm not sure about the scientific specifics, so i can't help you there.
It can cause them to close some of their stomata, and those are what let the plants breathe CO2. It must be minimal and temporary though, or my plants would be dead by now.LOL