As a female non-smoker, I am now officially concerned!  My mother smoked my entire childhood life.  I always thought that I would be unlikely to get lung cancer since I made the decision to not follow in her footsteps.  I always knew that second hand smoke was harmful, but it now makes me question "how much is too much"?  Are my college days hanging out in smokey bars going to kill me?  I hope not.  I definitely will be watching for more info on this subject.