Honestly, my concern was really never about the second hand smoke getting into my hair (or anybody else's hair), but the fact that second hand smoke gets into the non-smoker's lungs and can cause emphysema, COPD , asthma, and all types of respiratory diseases...and cancer. I had a good friend whose husband smoked for 30 years and she got COPD. Her husband quit smoking, but she still had COPD, which weakened one of her lungs to the extent that caused her to get pneumonia so many times that the last round of pneumonia she had in 2009 killed her. BTW, my friend never smoked.
Right now, I am married to a man who was a smoker (but had quit in 1991 before I knew him). He has multiple respiratory problems...shortness of breath, COPD and asthma....probably from the first-hand smoke.