Table 4 Description of Distributions of Monthly Levels of PM2.5

Years	Months												Mean	SD	Min	Max
	1	2	3	4	5	6	7	8	9	10	11	12
2015	28	32	30	24	26	26	21	23	17	26	24	30	25.58	4.19	17	32
2016	30	26	32	29	29	26	18	20	22	21	30	30	26.08	4.70	18	32
2017	32	28	36	26	26	23	21	13	21	-	-	-	25.11	6.72	13	36

*AC = Average rate of change of PM2.5 concentration change from 2015 to 2017 of study period is –0.66%