Yet a simple look at the chemistry shows us that its: 

The Chemistry of Secondary Smoke About 94% of secondary smoke is composed of water vapor and ordinary air with a slight excess of carbon dioxide. Another 3 % is carbon monoxide. The last 3 % contains the rest of the 4,000 or so chemicals supposedly to be found in smoke… but found, obviously, in very small quantities if at all.This is because most of the assumed chemicals have never actually been found in secondhand smoke. (1989 Report of the Surgeon General p. 80). Most of these chemicals can only be found in quantities measured in nanograms, picograms and femtograms. Many cannot even be detected in these amounts: their presence is simply theorized rather than measured.