Table 2.

Participants’ mean exposure levels to air pollutants during the follow-up period.

Air pollutant	Mean (SD)	Median	Range	IQR
PM2.5	31.76(6.73)	31.49	10.42–72.66	10.29
PM10	56.31(11.37)	54.34	24.26–115.66	19.22
CO	0.57(0.16)	0.53	0.1–1.69	0.21
NO	8.84(5.84)	6.59	0.1–52.61	7.11
NO2	18.97(4.57)	18.38	2.83–44.25	7.23
NOx	27.63(9.98)	25.18	4.71–93.61	13.46
O3	27.53(2.3)	27.7	12.15–44.31	3.35
SO2	4.35(1.35)	3.92	1.39–20.82	1.33

IQR = the 75th percentile–the 25th percentile.