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

Table 4

Fitting results of the PM_2.5 concentrations in North and Northeast China.

Year	Beijing			Hebei			Shanxi
	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result
2006	0.279	77.1	77.1	0.358	83.6	83.6	0.414	56.7	56.7
2007	0.281	69.8	72.3	0.350	71.0	76.5	0.416	50.1	54.8
2008	0.296	70.3	72.6	0.376	75.0	76.1	0.415	45.6	54.7
2009	0.292	71.3	69.5	0.380	71.6	75.4	0.426	50.9	53.7
2010	0.252	66	67.9	0.373	72.7	75.5	0.411	59.1	54.1
2011	0.263	73.7	76.6	0.369	85.9	75.8	0.403	82.5	56.3
2012	0.256	63.8	73.6	0.356	71.5	76.1	0.390	64.6	58.5
2013	0.251	84.6	74.6	0.349	91.2	76.6	0.388	64.5	60.1
2014	0.274	79.5	77.7	0.330	82.4	77.2	0.374	56.4	61.9
2015	0.295	78.5	73.9	0.349	74.8	77.2	0.437	50.7	56.8
2016	0.286	69.5	69.4	0.343	67.3	76.9	0.397	50.4	54.4
MAPE	4.67%			6.20%			3.75%
2017	0.287		71.2	0.342		77.0	0.396		58.5
2018	0.288		71.0	0.341		77.1	0.395		58.7
2019	0.290		70.9	0.339		77.1	0.394		58.9
Year	Inner Mongolia			Liaoning			Heilongjiang
	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result	Gini coefficient	PM2.5	Result
2006	0.399	26.9	26.9	0.357	46.8	46.8	0.386	21.5	21.5
2007	0.388	21.8	24.2	0.358	37.1	44.5	0.380	19.2	23.9
2008	0.397	22.1	24.7	0.367	46.9	46.0	0.374	23.5	24.4
2009	0.413	25.3	25.0	0.363	44.0	45.6	0.372	20.8	24.9
2010	0.398	26.7	24.3	0.343	39.9	42.4	0.336	25.8	25.3
2011	0.378	26.5	23.9	0.342	46.1	41.6	0.300	32.1	28.1
2012	0.361	24	23.7	0.325	38.3	39.1	0.275	26.0	31.1
2013	0.372	24.3	24.3	0.346	41.5	41.8	0.267	29.8	33.4
2014	0.376	26.1	24.3	0.360	49.2	44.5	0.295	40.1	34.7
2015	0.389	24.8	24.6	0.352	49.0	43.7	0.366	35.9	32.0
2016	0.373	21.8	23.9	0.330	37.8	40.0	0.327	25.3	25.8
MAPE	4.67%			6.40%			10.91%
2017	0.371		24.1	0.327		39.1	0.323		29.0
2018	0.368		24.0	0.325		38.7	0.320		29.3
2019	0.366		24.2	0.323		38.3	0.316		29.6