I think whether or not I mind training with smokers depends on how much they smell...Luckily, not many people in our dojo smoke. One of my instructors has smoked like a chimney for at least the past 20-30 years or so and it doesn't seem to prevent him from doing aikido... however, I'm sure that if he quit he'd do better. But I suppose he enjoys it too much
Anyway, good luck with quitting! No more black lungs..