亚硝酸盐作为一种化学性污染物，与人们的饮食、健康有密切的关系。
Nitrite as a chemical pollutant has a bad effect on people's health.
前言： 图书馆内污染物按性质分为化学性污染物、物理性污染物、 生物性污染物和放射性污染物。
In library, the contaminations can be divided into four parts: i. e. chemical contamination, physical contamination, biological contamination and radioactive contamination.
应用推荐