People's life activities can't be separated from oxygen. There are about 750 million alveoli in the lung. If the surface area of these alveoli is fully developed, it is about 130 square meters. In such a vast area, countless capillaries are closely intertwined. People breathe oxygen into the lungs, then give it to the blood through the alveoli, combine with hemoglobin in the blood, and transport it to all parts of the body through blood circulation. If carbon monoxide is mixed in the air, And being sucked into the lungs, people can't normally absorb and utilize oxygen. Because the binding force between carbon monoxide and hemoglobin is 270 times stronger than that between oxygen and hemoglobin. If there is 1‰ carbon monoxide in the air, about half of the hemoglobin in the blood will combine with carbon monoxide and lose the ability to carry oxygen to all parts. At this time, people will feel groggy, weak limbs and mild nausea and vomiting. In severe cases, the heart beats faster, he is unconscious, his face is pink, and his hands and feet are cold. If he is not rescued immediately, he will be in danger of death. This is carbon monoxide poisoning.