SO2 is a colorless gas with a strong pungent smell, which is easily soluble in viscous liquids such as human blood. SO2 in the atmosphere can cause inflammation, bronchitis, emphysema and conjunctival inflammation. At the same time, it will also reduce the immunity of teenagers and weaken their disease resistance. Under the action of oxidant and light, SO2 will generate sulfate aerosol, which will make people sick and increase the mortality of patients. According to the research of the Organization for Economic Cooperation and Development (OECD), when the annual sulfate concentration is about 10μg/m3, every reduction of 10% can reduce the mortality rate by 0.5%; SO2 will also attach to the floating dust in the atmosphere. When people inhale floating dust containing SO2, the toxicity of SO2 will be enhanced. The research shows that under the influence of high concentration of SO2, plants suffer acute injury, which leads to necrotic spots on the surface of leaves, or directly leads to the withering and shedding of plant leaves. Under the influence of low concentration of SO2, the growth function of plants is affected, which leads to the decrease of yield and the deterioration of quality. Corrosion of SO2 on metals, especially steel structures. It brings huge losses to the national economy every year. It is estimated that the direct economic loss caused by metal corrosion in industrialized countries accounts for 2% ~ 4% of the total national economic output value every year.