What are the hazards of sulfur dioxide?

SO2 is a colorless gas with a strong, irritating odor, and it is readily soluble in human blood and other mucous fluids. SO2 in the atmosphere can cause conditions ranging from inflammation to bronchitis, emphysema, and conjunctivitis. It also reduces teenagers’ immunity and weakens their resistance to diseases. Under the action of oxidants and light, SO2 can produce sulfate aerosols; these sulfate aerosols can cause diseases in humans and increase mortality rates. According to research by the Organization for Economic Co-operation and Development (OECD), when the annual sulfate concentration is around 10 μg/m3, a 10% reduction in this concentration can lead to a 0.5% decrease in mortality rates ； SO2 can also adhere to dust particles in the atmosphere; when humans breathe in such dust particles containing SO2, it increases the toxicity of SO2. Studies have shown that under the influence of high concentrations of SO2, plants suffer acute damage; necrotic spots appear on the leaf surface, or the plant leaves wither and fall off directly ； Under the influence of low concentrations of SO2, the growth mechanisms of plants are affected, resulting in reduced yields and poorer quality. The corrosion of metals by SO2, especially steel structures. It causes significant losses to the national economy every year.

1. SO2 is a colorless gas with a strong, irritating odor; it dissolves easily in human blood and other viscous fluids. SO2 in the atmosphere can cause conditions ranging from inflammation to bronchitis, emphysema, and conjunctivitis. It also reduces teenagers’ immunity and weakens their resistance to diseases. 2. Under the action of oxidants and light, SO2 can produce sulfate aerosols; these sulfate aerosols can cause diseases in humans and increase mortality rates. According to research by the Organization for Economic Co-operation and Development (OECD), when the annual sulfate concentration is around 10 μg/m3, a 10% reduction in this concentration can lead to a 0.5% decrease in mortality rates ； SO2 can also adhere to dust particles in the atmosphere; when humans breathe in such dust particles containing SO2, it increases the toxicity of SO2. 3. Under the influence of high concentrations of SO2, plants suffer acute damage; necrotic spots appear on the leaf surface, or the plant leaves wither and fall off directly ； Under the influence of low concentrations of SO2, the growth mechanisms of plants are affected, resulting in reduced yields and poorer quality. 4. Corrosion of metals by SO2, especially steel structures. It causes significant losses to the national economy every year. It is estimated that in industrially developed countries, the direct economic losses resulting from metal corrosion each year account for 2% to 4% of the total gross national product.

This post was last edited by wamj6566 on 2015-11-5 at 13:00. Sulfur dioxide is one of the main pollutants in the atmosphere, and it serves as an important indicator of whether the atmosphere is polluted. Many cities around the world have experienced severe incidents caused by sulfur dioxide, which have led to many people being poisoned or dying. In some towns and cities in our country, the hazards of sulfur dioxide in the atmosphere are quite widespread and severe. Once sulfur dioxide enters the respiratory tract, it is readily soluble in water, so most of it gets trapped in the upper respiratory tract. There, it forms corrosive substances such as sulfurous acid, sulfuric acid, and sulfates on the moist mucosa, thereby increasing the irritating effect. The smooth muscles of the upper respiratory tract contain peripheral nerve receptors, and upon stimulation they undergo a constrictive response that narrows the lumen of the trachea and bronchi, thereby increasing airway resistance. This retention of sulfur dioxide by the upper respiratory tract can, to some extent, reduce the irritation of sulfur dioxide to the lungs. However, sulfur dioxide that enters the bloodstream can still reach the lungs via the blood circulation and cause irritation. Sulfur dioxide can be absorbed into the blood, causing toxic side effects throughout the body. It can destroy the activity of enzymes, thereby significantly affecting the metabolism of carbohydrates and proteins, and it can also cause damage to the liver. Animal experiments have shown that chronic exposure to sulfur dioxide leads to a significant suppression of the body’s immune system. When the sulfur dioxide concentration is between 10 and 15 ppm, both the ciliary movement in the respiratory tract and the secretory function of the mucosa are suppressed. At a concentration of 20 ppm, it causes coughing and eye irritation. If the inhalation concentration is 100 ppm for 8 hours per day, significant irritation symptoms occur in the bronchi and lungs, causing damage to the lung tissue. Concentrations of 400 ppm can cause breathing difficulties. Sulfur dioxide is inhaled along with airborne dust, and the particles of this dust aerosol can carry sulfur dioxide into the lungs, increasing its toxicity by 3 to 4 times. If metal particles are adsorbed on the surface of floating dust, their catalytic action causes sulfur dioxide to be oxidized into sulfuric acid mist, whose irritant effect is about twice that of sulfur dioxide. Living in an environment with air pollution for a long time, due to the combined effect of sulfur dioxide and dust particles, can lead to alveolar fibrosis. If the area of hyperplasia is extensive and fibrotic changes occur, further progression can lead to fiber rupture and the development of emphysema. Sulfur dioxide can enhance the carcinogenic effect of the carcinogen benzo(a)pyrene. According to animal experiments, under the combined effect of sulfur dioxide and benzo(a)pyrene, the incidence of lung cancer in animals is higher than that caused by either factor alone, and it can induce pulmonary squamous cell carcinoma in a short period of time.