Georgina, about all the sensitive people, while your mother may be more dramatic about it, I think there are plenty of us who have always been sensitive to smoke, but years ago, nobody really cared that we were, or we just didn't put 2 and 2 together and realize it was the smoke that was the problem. I have a cousin who is asthmatic. My uncle is a smoker (my aunt used to be, and quit sometime around when she got pregnant or soon after). My cousin used to have horrible asthma attacks as a kid, was in the hospital for a lot of them, and they were always getting rid of something else in the house, blaming that for the latest attack...no pets, no plants, pull up the carpet, get a humidifier, no get a dehumidifier, close up the windows and keep the kid indoors protected from all the allergens outside...and then, one day, someone finally realized it was his father's smoking. For a while, my uncle moved his smoking to the basement, and that wasn't enough...the smoke still wafted up to the main floor, so then he was banished to the garage to smoke. Only then did my cousin's asthma ease up and stop causing him such problems.
For me, whenever I'd go to family parties, everyone was smoking, and I always had the sore throat and headache by the end. I just never realized it was from the cigarette smoke when I was that age, I just thought it was from being tired or talking too much, or that I caught something from one of the other kids there. My father was always sensitive to the smoke then too; he came home with the same headaches, but since smoking was the "fashionable" thing at the time, you just didn't ask people to stop smoking to accommodate you, so you didn't say anything. My father would make excuses to not attend the parties or to leave early. Now, I can only speak from personal experience there, but if others were all the same way, there were always people sensitive to smoke, we just didn't feel it was okay to say so years ago, or hadn't really nailed down that that's what was causing the headaches or sore throats. The watering eyes and sore throat are pretty much the same response as when you're grilling on a charcoal barbecue, and the wind shifts the smoke into your face. For me, anyway, it's not specific to cigarette smoke, it's just smoke of any kind. The headaches come more with the prolonged exposure. I don't suddenly get a headache if I walk through the smoke cloud of someone smoking out on the street, though it does temporarily irritate my nose and throat.
As for comparing it to bus fumes, well, I'd like to reduce those too. I just look at it as trying to reduce any form of pollutants. Some we can reduce more easily than others.
Zooby, as for the comparison between alcohol and smoking, while both are unhealthy to the person choosing to indulge in either, only smoking is forced upon those around you as well. If I'm sitting next to someone having a beer, my liver isn't affected by their choice. We already do have laws against and/or frown very heavily on those whose alcohol consumption is affecting others, such as prohibiting drinking and driving or making it very socially unacceptable for a woman who is pregnant to drink (have you ever noticed the glares a pregnant woman gets if someone even
thinks she's having a drink, even if she isn't? If you haven't noticed, try going out somewhere with a pregnant woman and have her get some apple juice in a wine glass...just watch the reactions of others around her). So, I think for the most part, we are tolerant of people choosing to make bad health decisions for themselves, but are not tolerant when their bad decisions are forced on others around them who may have chosen to avoid those health risks. I can choose to be a couch potato too, but as long as I'm not tying all the fitness nuts to a chair and making them watch Oprah, that's fine.
Now, there are issues in terms of things like increasing healthcare costs and such, where it doesn't make sense to single out smoking any more than drinking or couch-potatoing

, but I think that's a separate issue from the reasons for making some things unacceptable in public places when others are not.
As I said before though, I don't think an entire outdoor ban is required, but a ban of smoking from say 10 feet or so from building entrances, so people who need to enter those buildings aren't forced to walk into a cloud of smoke. The thing is, in a city, that would almost effectively be a ban of smoking from all public sidewalks anyway, because building entrances are so close together. But, if you want to go sit in a park, that's fine. I think in an open space like a park, I'm capable of finding enough room to stay away from any smokers if it bothers me.