Harvey, I, too, like your idea of posting a "please don't smoke" sign.
One thing that continually amazes me (and irritates me, both figuratively and literally) is the overuse of irritant substances (powdery air fresheners or carpet shampoos, perfumes, and noxious-chemical-based disinfectants) in nursing and convalescent homes. I do music therapy and entertainment in these places regularly and, as likely as not, if I say or do anything to try to cope with this indoor air pollution, I risk not being invited back because "our air freshener seemed to bother you," etc.!
I am surprised that the state service agencies that regulate such facilities so tightly do not recognize this as an important issue in patient/resident health. Many, if not most, of these seniors have some respiratory problem, and many either cannot identify what is making it hard to breathe or cannot effectively voice their complaints. When taking a deep breath irritates your throat, it's natural to start breathing very shallowly, of course. So I would think that indoor air quality would be a focus of concern in facilities for the infirm or elderly. So far, it does not seem to be. In its own way, the air in these places can be as hard on an asthmatic as is a smoke-filled bar.

Good to have a doc weigh in on this, Mark.

Fibula, One "alternative" treatment that help in the case of an asthma attack when no medicine is on hand is VISUALIZATION. The idea is to conjure up and focus on the way your lungs/breathing feels after you've used the rescue inhaler. For most of us, this may not diminish the attack enough to sing like Pavarotti or Joan Baez (assuming, of course, that you could when you WEREN'T having an attack), but it could very well save your life in an emergency. This seems to go with the Yoga idea.

BTW, this morning I got up and left for a music therapy gig without using my inhaler and forgot my purse (and my inhaler). By making a point of breathing through my nose, not singing too loud, and taking smaller, more frequent breaths during songs, I managed to get through it OK without wheezing. It was good to find out I do have SOME control over the asthma without the inhaler!

Genie