I, of course, am not a scientist, but I don't accept every conspiracy theory that is dropped. This is all I feel about the second hand smoke situation. I am almost 76 years old. Every person in my family smoked, except my mother. It was constant exposure. Sitting around talking, riding in cars, watching TV and every other aspect in life. Now no one, including myself, in my family smokes. All the rest died of old age or some other problem unrelated to smoking. I smoked for 40 years before I quite, with great effort, and I have a few minor problems related to it, but I guarantee you it wasn't from second hand smoke, it was direct.
My observation is that I have never seen the degree of kids with asthma since the ban and social approval made it a crime to smoke. Compared to when when I grew up where I don't remember any child having those problems. So what is causing our younger generation to have breathing problems when smoking is no longer a significant part of life? The only thing I can think of is the amount of air pollution generated by our industry that expanded over time. Apparently that second hand smoke was not the culprit that we think it was. Good? No! But as harmful as it is made out to be? Also, no! More children have died from current respiratory problems, crazy people with AR15's, drunk drivers and drug addled parents then any conceivable second hand smoke ever did, yet we turn a blind eye to all of it. We are a society of idiots that believe anything we are told. And then ignore the real problems so we cannot blame ourselves for it. I don't care how many times they say it... No one has ever gotten lung cancer from walking past a smoker and smelling the smoke. It just isn't possible. People get lung cancer even if they were never near a cigarette.