Let us be clear about it. Second-hand smoke also kills. Far from being a mere annoyance or a minor discomfort, exposure to second-hand smoke causes cancer and contributes to various lung and heart diseases. It can cause asthma and other respiratory illnesses in children, and has been implicated in various other childhood diseases such as sudden infant death syndrome or middle-ear infections. Breathing in second-hand smoke is harmful for everybody, child or adult.
Scientists agree that there is no safe level of exposure to second hand smoke.
It should simply be avoided. Neither air conditioning nor separation of smoking areas completely clears the air of this significant pollutant. The best protection is not to be exposed to second-hand smoke at all, whether it is within the home or outside it. However, we are all exposed to second-hand smoke everywhere we go. Many of us are exposed to it all day, every day.