Using the Quarterly Compound Fractional Grey Model to Predict the Air Quality in 22 Cities of China

Table 1

Research cities.

Anyang	Baoding	Yuncheng	Linyi
Jiaozuo	Handan	Jinzhong	Liaocheng
Hebi	Xingtai	Zibo	Xianyang
Xinxiang	Tangshan	Zaozhuang	Xian
Zhengzhou	Jincheng	Jinan	Weinan
Luoyang	Yangquan