Analyzing the Relationship between the PM_2.5 Concentration and the Gini Coefficient Using the Grey Model

Table 6

Fitting results of the PM_2.5 concentrations in southwest and central China.

Year	Chongqing			Sichuan			Guizhou
	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result
2006	0.447	72.3	72.3	0.403	70.1	70.1	0.488	37.3	37.3
2007	0.427	61.8	70.0	0.403	59.4	64.0	0.489	39.7	38.6
2008	0.419	67.4	66.6	0.395	59.0	63.4	0.478	36.1	38.5
2009	0.416	63.5	65.4	0.405	60.8	63.5	0.482	38.0	38.5
2010	0.429	72.2	66.6	0.394	76.1	63.3	0.464	39.4	38.4
2011	0.390	71.6	63.7	0.387	69.8	61.9	0.433	45.7	38.2
2012	0.377	68.6	58.2	0.351	66.4	58.7	0.419	48.6	38.1
2013	0.372	59.6	56.4	0.351	64.8	56.1	0.409	35.3	38.0
2014	0.331	53.1	52.1	0.359	54.3	56.6	0.427	36.0	38.0
2015	0.411	46.2	55.9	0.388	45.0	59.4	0.454	32.6	38.2
2016	0.349	45.2	57.6	0.373	44.3	60.4	0.453	30.9	38.3
MAPE	9.74%			13.20%			9.58%
2017	0.342		51.0	0.370		59.1	0.449		38.3
2018	0.336		49.9	0.368		58.7	0.446		38.2
2019	0.329		48.7	0.366		58.3	0.443		38.2
Year	Tibet			Henan			Hubei
	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result
2006	0.394	6.7	6.7	0.394	82.8	82.8	0.389	60.5	60.5
2007	0.358	7.3	7.1	0.392	81.4	78.9	0.386	65.6	68.7
2008	0.349	8.2	7.1	0.397	72.0	78.9	0.386	63.3	68.5
2009	0.360	6.8	7.1	0.407	75.1	79.0	0.388	68.7	68.6
2010	0.413	6.5	7.1	0.392	84.0	79.0	0.370	74.2	67.8
2011	0.363	6.3	7.1	0.362	90.6	78.7	0.347	76.4	65.6
2012	0.307	8.0	7.1	0.338	77.1	78.5	0.333	61.4	63.8
2013	0.303	6.1	7.2	0.336	89.5	78.4	0.327	69.3	62.8
2014	0.323	7.7	7.2	0.328	77.2	78.3	0.323	64.5	62.3
2015	0.410	6.7	7.1	0.357	73.7	78.4	0.342	57.8	63.0
2016	0.406	7.6	7.1	0.363	65.7	78.6	0.345	50.5	64.1
MAPE	8.23%			7.15%			8.03%
2017	0.410		7.1	0.360		78.6	0.341		64.1
2018	0.414		7.1	0.357		78.6	0.337		63.7
2019	0.419		7.1	0.355		78.6	0.333		63.3