Does anybody know?

Several months ago I walked into the bathroom in a cafe/bar. It was a small onesie kind of deal with very little ventilation. When I turned on the light the air was as clear as... well I don't want to say "crystal clear" to describe a public bathroom, but it was not that murky, fuzzy, air that you find in most bars here where the smoke makes them blurry and yellow like an old photo from the early '80s. But then when I stepped in I was slapped with a facefull of old cigarette smoke smell. It was clear that some time between 10 and 30 minutes ago someone had stood in that bathroom with the door closed smoking a frantic cigarette and ashing into the toilet (anyone who's gone to high school knows how this works), and then flushed and closed the door behind them. Thirty seconds before entering this lavatory I'd been thinking about exactly what little, tiny details in my life I could change to get the edge and become a better athlete. So when I stepped into that clear, stinky bathroom I started thinking about something I'd never thought about before:

We all know that secondhand-smoke (or "passive smoking" which it's sometimes more aptly called) is as bad as (if not in some cases worse than) regular puffing. But is it something in the smoke that makes you cough up brown blobs of lung sludge, or is it something that stays in the air after the smoke is cleared? To clarify: as in the case of my bathroom, the smell of smoke remains even after the smoke is no longer visible (as anyone who has hugged a smoker knows). And the way we perceive smell is that teeny-tiny particles of a substance stick in teeny-tiny little receptors in our nasal passages which allow us to sense, and therefor "smell" an odor/scent. So clearly, even at 9 in the morning in a smoking bar (yes, those still exist), long after all the smokers from the night before have left, since you can still smell that stale, smokey smell, there is still some remenant of the tobacco in the air. Which leads to my question:

Is it something directly in the smoke itself that damages lungs (ergo something that clears when the smoke clears out), or is it something in the presence of burt tobacco which is as lasting as yellowing wallpaper and that musty smell that causes damage from second-hand smoke?



Really, really I'd like to know. I've asked all my friends who are good at useless trivia or know a lot about fitness and no one seems to know the answer to this.