Smokers injure their health by inhaling tar, nicotine and by elevating the carbon monoxide (CO) levels in their blood. CO is a colorless, odorless gas created by incomplete combustion. Relatively common, CO is found in many sources (e.g. automobile exhaust, smoke from coal and wood fires) and smoke from burning tobacco products. When inhaled, CO can be hazardous to one’s health. However, it may not be noticed since it does not irritate the membranes of the nose, eyes, or cause coughing. Small doses are relatively harmless, but large doses cause headaches, nausea, and vomiting, and could also lead to coma and death.

CO in the air breathed alters natural processes of respirations. CO combines with the hemoglobin in red blood cells 230 times faster than oxygen. Therefore, when CO is in the lungs, the red blood cells pick it up before oxygen. CO combines with hemoglobin to create a stale compound called carboxyhemoglobin (COHb), which is released from the red blood cells much more slowly than oxygen. As more CO is inhaled, the blood becomes saturated with COHb and the amount of oxygen available to the cells is reduced. Normally, people have a COHb level of <1% in the blood. As the CO dose and the time of exposure increases, the blood saturation level of COHb increases.

This chart shows the COHb levels compared to the effects on health.

Sponsored by AHEC with funding by the Florida Department of Health

Reprint permission from Tobacco Dependence Program at
UMDNJ-School of Public Health