Apparently, most of a cigarette smolders away without the smoker
actually puffing on it. The lower temperature of combustion when a cigarette
is smolder results in higher amounts of incomplete combustion products, such
as CO, and large organic compounds. Ultimately, the sidestream smoke, as it
leaves the tip of the smoldering cigarette, contains higher quantities of the
hazardous gases and particles than the stuff the smoker inhales. Fortunately,
sidestream smoke gets diluted considerably as one's distance from the cigarette
increases.