如果有是什么引起污染的？

If so, what causes the pollution?

youdao

如果你能消除引起污染的控制缺陷和破损设备，接着你要看看系统配置、材料特征和工艺条件。

If you can eliminate control failures and worn equipment as causing the contamination, look next at system configuration, material characteristics, and process conditions.

youdao

注意一定不要用任何东西接触滴管或瓶子上端，这些可能会引起污染的物质包括：物体表面，任何物体(特别是你舌头)，或者你的手指。

Be careful to not touch the dropper or the top of the bottle with anything that could cause contamination: surfaces, objects (especially not your tongue!), or fingers.

youdao

that your form of transportation is causing each day on your way to school or work.

不用担心你每天上学或上班的路上，你使用的交通工具会引起污染。

地铁的好处 - SpeakingMax英语口语达人