impurity gas

例句：

1. 1. The air in the room was filled with impurity gas, making it hard to breathe.
   房间里充满了杂质气体，让人难以呼吸。
2. 2. The scientist detected a trace of impurity gas in the sample.
   科学家在样本中检测到了微量的杂质气体。
3. 3. The factory produces impurity gas for use in industrial processes.
   该工厂生产用于工业过程的杂质气体。