Now, I can't stand people who smoke. I can even tell if you smoked awhile ago. And eating is a lot better. I can taste the food better. I sleep early and wake up refreshed. Before I have to smoke just to get out of the bed.
You don't have to shun friends or colleagues who smoke. Give them sound advice: tell them don't smoke. If they quit. good. If not, it's their life to live - don't press yourself on them.
I've friends who smoke. When they light up, I just either go away for a couple of minutes or they ask me if I mind. If I do, they usually move away for a couple of minutes.