Table 2. Participants Personal and Environmental Characteristics Stratified by Traffic Exposure Category.

		Total (%)	Living near a highway (%)	Not living near a highway (%)
Gender	Female	3262 (77)	1281 (76)	1981 (77)
Generation	Parents	4019 (94)	1593 (94)	2426 (95)
Home ownership	Own	2796 (64)	1124 (65)	600 (63)
ETS	Yes	2227 (51)	896 (52)	1331 (50)
Frequency of opening window in winter	Always	278 (6)	105 (6)	175 (7)
	Sometimes	1176 (28)	453 (27)	723 (28)
	Never	1671 (66)	723 (67)	173 (65)
Building Age	After 2006	808 (18)	332 (19)	476 (18)
	2001–2005	1567 (36)	613 (35)	954 (36)
	1991–2000	1066 (24)	427 (25)	639 (24)
	1980–1990	620 (14)	245 (14)	375 (14)
	Before 1980	313 (7)	11 3(7)	200 (8)
Air cleaning device	Yes	477 (11)	172 (11)	305 (12)