The NSPSs normally specified how many pounds of a pollutant could be emitted per unit of plant input or output, leaving it to each source to decide what combination of technological measures and fuel changes to use.

• 规定了工厂输人和输出的每套装置可以排放多少磅污染物，让每个污染源决定使用哪种技术措施结合燃料改良。