Carbon monoxide is a poisonous gas. A smoker inhales this gas which is also found in the exhaust of a car. This gas interferes with our respiratory (breathing) and circulatory (heart, arteries, and veins) systems. When we breathe in air through our nose and mouth, the air passes down the windpipe (trachea) and bronchial tubes into the lungs. The cilia which are made up of small hairs and mucous (a sticky fluid also found in the nose) help to clean this air as it moves down and into the lungs. The cilia remove small pieces of dirt, dust, and germs.
windpipe