62.A useful definition of an air pollutantis a compound added directly or indirectly by humans to the atmosphere in suchquantities as to affect humans, animals，vegetation，or materials adversely．

(特殊结构such…as to——如此…以致)

空气污染物的一个有用定义是：一种直接或间接加入到空气里的化合物，其数量足以对人类、动物、植物或物质产生不利影响。

分句1.A usefuldefinition of an air pollutant is a compound added directly or indirectly byhumans to the atmosphere

分句2.in suchquantities as to affect humans, animals，vegetation，or materials adversely

1和2嵌套