With a little help...

[gPink]

Man, my Dad would not crack a window. It's no wonder I took up smoking at a young age.

[Strawboss]

Guess I should have been a little more specific, while air born particle or contaminants may contribute to lung cancer, you don't have to smoke, be exposed to, work in, be around, inhale, digest, coal, cigarettes, cigars, asbestos, particle board, sawdust, sheetrock, wood smoke, dust, and any number of things in the air to contract lung cancer.

[Deziner]

^^^Nicely put. Also, not everyone that smokes or has been exposed to "substances that have been known to cause cancer." actually gets cancer.

[VirginiaJim]

True again.  My wife's grandfather lived into his 90s and smoked heavily.  He didn't die of lung cancer.  My mother smoked until she was about 70 and then stopped because she was having breathing difficulties.  She died at 79 but fought COPD and emphysema until she died at 79.  My father died at 45 from lung cancer.  He was a smoker.  I think that cigarettes had a factor in it but he could have been exposed to any number of things to cause it.  Could have been genetic as well, although his siblings all died in their 80s, all were smokers.  So I totally agree that it could be that it just happened but my bet is on smoking as a contributing factor.