Skip to main content

Table 2 Characteristics of the air pollutants in different cities

From: Air Pollutants are associated with Dry Eye Disease in Urban Ophthalmic Outpatients: a Prevalence Study in China

Type City Median (P25–P75) Days*
CO Tianjin 1.72 (1.37–2.29) 250
Xi’an 1.70 (1.26–2.47) 211
Xingtai 1.54 (1.11–2.46) 198
Guangzhou 1.00 (0.89–1.19) 27
Fuzhou 0.73 (0.63–0.94) 10
Guiyang 0.77 (0.63–0.95) 10
NO2 Xingtai 61.79 (47.67–82.99) 232
Chengdu 51.76 (42.45–65.44) 178
Ji’nan 49.70 (35.48–68.42) 162
Kunming 36.50 (28.90–44.51) 26
Dalian 28.94 (23.58–37.33) 17
Guiyang 31.05 (24.03–39.59) 16
O3 Wuhan 79.06 (51.67–110.33) 181
Shanghai 77.55 (58.89–96.12) 165
Ji’nan 72.48 (40.46–102.40) 160
Zunyi 64.79 (57.48–73.13) 31
Hefei 55.23 (38.77–67.33) 29
Fuzhou 49.42 (39.63–62.93) 27
PM10 Xingtai 251.43 (172.92–359.36) 308
Ji’nan 166.03 (120.06–237.78) 215
Xi’an 143.05 (98.79–218.76) 173
Shenzhen 59.83 (38.44–94.45) 19
Kunming 72.19 (46.77–99.89) 15
Fuzhou 62.29 (45.56–87.95) 14
PM2.5 Xingtai 119.29 (78.09–196.94) 258
Ji’nan 84.93 (59.76–129.42) 192
Tianjin 80.58 (54.03–113.46) 178
Shenzhen 36.92 (21.18–58.11) 27
Fuzhou 31.65 (20.53–49.52) 12
Kunming 37.88 (24.00–53.04) 9
SO2 Xingtai 84.58 (51.71–137.72) 291
Ji’nan 61.47 (40.98–104.46) 256
Shenyang 40.98 (24.26–98.12) 169
Wenzhou 20.14 (13.46–29.00) 13
Guangzhou 20.19 (15.07–26.22) 6
Shenzhen 9.83 (7.43–14.57) 1
  1. * The days of a specific city that the pollutant concentration exceeds the “extreme value”