If I am around smokers or I am in a polluted city - I usually catch a cold and have great difficulty breathing. I'd say I don't have asthma or allergies, but I seriously cannot breath if I'm around a smoker - so that may not be an accurate statement.

So I avoid smokers, smoke, and polluted cities. Europe is terrible for smoking. Basically, I just make myself a pain in the *** when in europe and refuse to go to any restaurant with smokers and move if someone near me starts lighting up. It helps a little bit. But people aren't always so tolerant of it.

I know smokers get a lot more colds because the cigarette smoke kills the cilia on the mucous membranes - these cilia are usually what forces foreign particles, bacteria out of your nose, breathing passageways, etc - so without them, you get more bacteria or viruses that can stay down on your mucous membranes. I don't know if second hand smoke has that same effect.