Carbon Monoxide is poisonous and can kill cells of the body. Carbon Monoxide also replaces oxygen in the bloodstream, leading to suffocation. Mild effects feel like the flu, while severe effects include difficulty breathing and even death. Just how sick people get from Carbon Monoxide exposure varies greatly from person to person, depending on age, overall health, concentration of exposure (measured in parts per million), and length of exposure.
Higher concentrations are dangerous even for a short time. When blood carries Carbon Monoxide rather than oxygen, the Carbon Monoxide-carrying cells are called carboxyhemoglobin (COHb), in Carbon Monoxidentrast to normal oxygen-carrying hemoglobin.
The percentage of the blood that is carboxyhemoglobin -- also called carboxyhemoglobin saturation -- measure show badly a person is affected by Carbon Monoxide. A doctor can measure COHb in the blood but cannot measure Carbon Monoxide in the body directly. The more Carbon Monoxide in the body, the higher the COHb, and the sicker the person will be.