Welcome to Brainstuff from house stuff Works dot com where smart happens. Hi, I'm Marshall Brain with today's question, why is carbon monoxide so poisonous? Every poison has a particular trait that causes it to be poisonous. In the case of carbon monoxide, the trait has to do with hemoglobin in your blood. Hemoglobin is made up of proteins that bind iron atoms. The structure of hemoglobin causes oxygen to
bind the iron atom very loosely. When blood passes through the lungs, the iron atoms and hebi globe pick up oxygen atoms. When the blood flows into areas of the body that are lacking in oxygen, the iron atoms release their oxygen. Carbon monoxide, on the other hand, binds very strongly to the iron and hemoglobin. Once carbon monoxide attaches it's very difficult to release it. So if you breathe in carbon monoxide, it sticks to your hemoglobe and it
takes up all the oxygen binding sites. Eventually, your blood loses all of its ability to transport oxygen and you suffocate. Because carbon monoxide binds the hemoglobe and so strongly, you can be poisoned by carbon monoxide, even at very low concentrations if you're exposed for a long period of time. Concentrations as low as twenty to thirty parts per million can be harmful if you're exposed for several hours. Exposure at two thousand parts per million for one hour will
cause unconsciousness. Many common devices produce carbon monoxide, including cars, gas appliances, woodstoves, and cigarettes. For moralns, and thousands of other topics. Is it how stuff works dot com