This is easier to answer about smoke since there are actual microscopic particles so yes there is actual proof that it can hurt an asthmatic. But even fumes like perfume is enough to trigger asthma. So the actual larger microscopic particles of smoke can cause asthma but also the smell which is the even smaller particles can too.
The smoke is what you can see, larger microscopic particles, and the smell is the smaller microscopic particles I think. Either way both can cause breathing problems for sure. And I know personally my self for a fact as I feel it my self. I can't sit next to a smoker indoors, no way. Even if they smoked hours before coming next to me it hurts. Not that I just don't like it, it really is a physical feeling to some people and they are not complaining about just not liking the smell. It's more than that, way more.
Well you need to understand what smoke is and how we smell it. Smoke is a suspension of particles in a gas. These particles are irritants to people with asthma. Not the same but kinda like people with allergies when they come in contact pollens. The body reacts to the pollen making their nose run or something. With asthma these particles on contact can cause swelling for an asthmatic similar to the way a person with allergies react to pollen. It might not be histamine production but they are having a reaction to the particle. These particles will get stuck in the smokers clothing and as they move will be released out where the asthmatic can breathe in even if they are no longer smoking.
Sure I don't see why not. The smell of smoke is still smoke just less of it. That all depends on how sensitive the asthmatic is.
I know that smoke and odors can cause asthma attacks. I am very sensitive to irritants like smoke, and had to share an office with someone who smoked. Sometimes just the smell of it on his clothes would start me coughing when he returned from break. After using my long term controller medicine, I became far less sensitive but it still remained an occasional problem.