Carbon Monoxide

Yes, we're talking about the same dastardly poisonous gas that causes suffocation-related deaths. The kind that are caused by big, black clouds of smoke and pollution. It's highly toxic to human beings and animals, especially when encountered in higher concentrations. Every time you light up a cigarette, you're allowing more of it out into the atmosphere, and your immediate surroundings.

Now that you know, think about it. Would you consider putting yourself in a room filled with carbon monoxide under any other circumstances?