Carbon monoxide binds with Hemoglobin about 230 times more readily than oxygen. When a person inhales carbon monoxide, it diffuses from the alveolar air to the blood and binds to Hemoglobin forming carboxyhaemoglobin. The latter is a relatively stable compound and cannot bind with oxygen molecules. So, the amount of Hemoglobin available for oxygen transport is reduced. The resulting deficiency of oxygen causes headache, dizziness, nausea and even death.