Exposure measurement error in PM2.5 health effects studies: A pooled analysis of eight personal exposure validation studies

Table 2 Basic characteristics of exposure variables

	# person-months	Mean ± SD
	(# subjects)	( μ g/m³)
All Year
Total Personal PM_2.5	919 (490)	24.54 ± 18.97
Personal PM_2.5 of ambient origin	261 (141)	9.71 ± 4.32
Personal/Ambient ${SO}_{4}^{2 -}$ ratio ^a	241 (131)	0.64 ± 0.25
Model Predicted PM_2.5	1029 (502)	15.47 ± 4.77
Monitor PM_2.5	1029 (502)	15.86 ± 5.58
Summer
Total Personal PM_2.5	429 (312)	23.92 ± 16.92
Personal PM_2.5 of ambient origin	130 (90)	10.95 ± 4.12
Personal/Ambient ${SO}_{4}^{2 -}$ ratio ^a	125 (86)	0.70 ± 0.23
Model Predicted PM_2.5	493 (327)	15.67 ± 4.84
Monitor PM_2.5	493 (327)	15.69 ± 4.79
Winter
Total Personal PM_2.5	490 (353)	23.94 ± 19.67
Personal PM_2.5 of ambient origin	131 (97)	8.73 ± 4.27
Personal/Ambient ${SO}_{4}^{2 -}$ ratio ^a	116 (87)	0.59 ± 0.24
Model Predicted PM_2.5	536 (367)	15.36 ± 4.71
Monitor PM_2.5	536 (367)	16.10 ± 6.21

ISSN: 1476-069X