Well that's all very well for those who have the ability to make extra mucus. I've no quarrel with smokers who keep their smoke to themselves, I hasten to say, but I've been given the line about smoking's benefits often enough. It is usually fed to me while the smoker is breathing their smoke in my face. Often in a non-smoking area!
The autoimmune disease from which I suffer is not at all rare. It damages the moisture-producing cells throughout the body. It's particularly damaging to the lungs where it destroys the supporting connective tissue and the mucus lining. Being in a room with even one smoker becomes a very risky encounter. A fatal attack of asthma is not the way I want to go. Joy