air pollutants
/ˈeə kəndˈɪʃənɪŋ ˈsɪstəm/
n
English · air pollutants中文 · 空气污染物Español · contaminantes del aireFrançais · polluants atmosphériques
意味：The principal air pollutants are sulfur dioxide, nitrogen oxides, hydrocarbons, methane and carbon dioxide.