Table 1.

Basic statistical information of ρ(PM_2.5) monitoring data in Xi’an city.

Number	Monitoring Sites	Samples		Maximum		Minimum		ρ(PM2.5)/(μg/m3)
								Mean		Standard Deviation
		2013	2014	2013	2014	2013	2014	2013	2014	2013	2014
1	High-voltage Switch Factory	365	365	500	500	18	15	144.752	108.156	107.074	71.822
2	Xingqing district	365	365	500	500	13	10	112.621	103.942	105.785	85.320
3	Textile city	365	365	496	470	15	13	129.704	106.948	94.877	68.811
4	Xiaozhai	365	365	500	496	10	10	125.724	97.426	98.628	70.467
5	People’s Stadium	365	365	500	500	18	20	152.915	114.319	109.554	80.374
6	High-tech Western	365	365	500	500	15	5	142.112	99.873	106.453	79.108
7	Economic development district	365	365	474	500	16	15	131.985	102.775	96.902	72.520
8	Chang’an district	365	365	500	430	10	16	122.815	89.431	98.070	66.200
9	Yanliang district	365	365	452	484	15	16	127.734	94.181	92.069	65.968
10	Lintong district	365	365	500	500	13	15	136.406	98.365	102.559	72.012
11	Qujiang cultural group	365	365	500	376	3	12	114.521	95.695	94.720	64.349
12	Guangyun Tan	365	365	500	460	18	18	123.643	95.503	102.280	63.695
13	Cao Tan	365	365	500	500	12	12	163.705	111.151	107.575	80.394