What is secondhand tobacco smoke?

Secondhand tobacco smoke, sometimes referred to by its acronym SHS, is the material that is emitted from a burning cigarette, cigar, or pipe -- and then mixed in the air. Secondhand tobacco smoke consists of both the smoke that comes from the butt end of the cigarette or cigar, or the pipe bowl, and smoke that is inhaled by the smoker and subsequently exhaled. Secondhand tobacco smoke contains many dangerous chemicals and has been associated with a variety of health problems, including lung cancer, asthma, and heart disease mortality. You can find out more about secondhand tobacco smoke in the scientific literature, in general news articles, or on various web pages.