I'd just like to say that I smoke but I am not like anyone in your list, I'm working class, middle-aged, quite intelligent and I have never mugged anyone. Many different types of people smoke cigarettes and dope that don't fall into those catagories you listed.
Smoking dope doesn't automatically lead to hard drugs. people use cannabis as pain relief so how is that any different to being addicted to prescribed drugs?
I think pollution levels are high because of many other reasons as well as smoking such as factories, the number of cars on the road (do you drive?)etc
Your ideas wouldn't work because where would you end the discrimination, because that is what you are doing - discriminating against smokers.
I realise that you wanted a reaction to your question but I think it's all rather pathetic not to mention a tad fascist!