first pollution

• 一次污染

first pollution的用法和样例：

例句

1. We should control the secondary pollution.
   我们应该控制二次污染。
2. No wastewater release in manufacture procedure, remaining and soil assimilate after degradation, no second pollution formed.
   产品在生产过程中，无污水排出，降解后，残余物质与土壤同化，不会形成二次污染。