Thanks for that interesting link, rebbonk.
Hearing about passive smoking always reminds me of the very versatile and talented musician, Roy Castle who , as you may remember passed away in 1994, from Lung cancer. Unfortunately, all the while he played in Jazz clubs and similar venues where smoking was allowed and he maintained that inhaling gulps of smoke while entertaining caused his lung cancer.
Very sad really.
I'm not sure that all lung cancer is caused by smoking, I'm not a medic nor have ever studied the cause.
A long time ago, when I was a little bitty girl,

I remember when smoking on buses was allowed. I hated it!
Also, my dad had a hard job at the local Colliery, on the surface , he smoked when he got home and at the weekends the living room was always full of smoke. So I guess me and my other siblings breathed this in all the time, yet I remain in good health to this day. All of us do, except my brother in Canada in his 60's has been having treatment for prostate cancer, with success. He has never smoked either.