Human Settlement Quality Evaluation Based on Air Quality in Major Cities of China

Table 2

Ratings and index.

Ratings	Level I	Level II	Level III	Level IV	Level V
Index (I)	0.69 ≤ I ≤ 0.89	0.6 ≤ I ≤ 0.69	0.45 ≤ I ≤ 0.6	0.3 ≤ I ≤ 0.45	0.1 ≤ I ≤ 0.3
Condition	A	B/C	D	E	F