sulphur dioxide
noun [ U ] mainly UK (US usually sulfur dioxide) uk/ˌsʌl.fə daɪˈɒk.saɪd/ us/ˌsʌl.fɚ daɪˈɑːk.saɪd/
二氧化硫
a gas that has a strong, unpleasant smell and dissolves in water. It is used in various industrial processes, and can cause air pollution.