题目内容 (请给出正确答案) [单选题] 当环境空气中硫化氢浓度超过()时,应佩带正压式空气呼吸器。(按教材) A.30ppmB.15mg/m³(10ppm)C.30mg/m³(20ppm)D.150mg/m³(100ppm) 答案 查看答案