PM_2.5/PM₁₀ Ratios in Eight Economic Regions and Their Relationship with Meteorology in China

Table 6

Gray relational grades of meteorological parameters on PM_2.5/PM₁₀ ratio.

Rank	NR	NCA	ECA	SCA	MYR	MRYR	SC	BNC
1	RH (0.909)	RH (0.949)	RH (0.900)	P (0.903)	RH (0.921)	PP (0.915)	RH (0.917)	RH (0.911)
2	P (0.904)	PP (0.942)	PP (0.898)	PP (0.894)	P (0.908)	P (0.911)	P (0.914)	PP (0.906)
3	PP (0.902)	P (0.935)	P (0.879)	RH (0.886)	PP (0.907)	RH (0.910)	PP (0.912)	P (0.883)
4	WD (0.886)	WD (0.923)	WD (0.873)	WS (0.873)	WD (0.874)	WS (0.906)	WS (0.896)	WD (0.876)
5	WS (0.882)	WS (0.919)	WS (0.871)	WD (0.870)	WS (0.872)	WD (0.903)	WD (0.892)	WS (0.870)
6	SD (0.864)	T (0.916)	T (0.864)	SD (0.861)	T (0.871)	SD (0.883)	SD (0.879)	SD (0.868)
7	T (0.857)	SD (0.909)	SD (0.852)	T (0.856)	SD (0.862)	T (0.879)	T (0.873)	T (0.867)