Explain carbon monoxide poisoning.

Carbon monoxide (CO) is a toxic air pollutant. It is exhaled from motor vehicles as one of the exhaust gases, and also from cigarette smoke. Our blood has respiratory pigment, hemoglobin (Hb) in the erythrocytes (RBCs) and it has high affinity for oxygen. As a result, oxygen combines with hemoglobin in the lungs and is carried by blood to various body tissues as oxyhemoglobin (OHb). Carbon monoxide (CO), a poisonous gas, has 200 times more affinity for hemoglobin than
oxygen. When the polluted air containing large amount of CO is inhaled, the CO then combines with hemoglobin to form a stable poisonous compound called carboxyhemoglobin (COHb). This drastically reduces the availability of oxygen to the body tissues and leads to suffocation and finally death.