Sulfur dioxide poisoning

Sulfur dioxide (SO2) is a colorless, highly water-soluble, pungent irritating gas that is heavier than air. Widely used in industry, it is a by-product of sulfur ore, paper industry, fossil fuel combustion, and a common pollutant in the atmosphere. Sulfur dioxide can be detected at a concentration of 1.5 mg / m3, and when the concentration is 1.8 to 3.0 mg / m3, it stimulates the nasal cavity and throat, and a slightly higher concentration causes obvious upper respiratory tract discomfort and persistent cough. Acute poisoning is rare and can cause clinical symptoms similar to chlorine poisoning. Relatively low concentrations of sulfur dioxide (3.0 to 150 mg / m3) are mostly deposited in the nasopharynx and throat. Because of its high water solubility, exposure to 18-30 mg / m3 of sulfur dioxide can cause severe irritation of the conjunctiva and upper respiratory mucosa. Exposure to higher concentrations of sulfur dioxide can cause damage to the throat, trachea, distal airways, and alveoli, stimulate mucosal secretion, cause bronchospasm, and even pulmonary edema.