According to the National Cancer Institute and American Cancer Society, secondhand smoke is the combination of two types of smoke that is produced when burning tobacco: the smoke that comes from the burning end of a cigarette, cigar or pipe and the smoke that is exhaled by the smoker.
That's when all eyes will turn to the 6-foot-high copper chimney erected atop the Sistine Chapel to pipe out puffs of smoke to tell the world if there's a new pope.