Be deadly if

How do various substances contained in polluted air affect human health? For example, carbon dioxide does not cause much harm if its content is not excessive, but causes a feeling of discomfort. Curular gas can be deadly if its content in the air exceeds 0.05%. An increase in the concentration of this substance can occur if the windows and doors are closed in the room where the inclined heating device is used. In such cases, oxygen is not fully burned, which leads to the formation of carbon monoxide instead of carbon dioxide.