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. Author manuscript; available in PMC: 2016 Nov 21.
Published in final edited form as: Res Rep Health Eff Inst. 2012 Dec;(172):5–82.

Table 25.

Summary Statistics for Nonsmoking Driver Exposures for Two Visits at Six Terminalsa

First Visit Second Visit Significant
Differencea
and
Direction
Location /
Compound		 Observations
(n)		 GM
(µg/m3)		 GSD
(µg/m3)		 Observations
(n)		 GM
(µg/m3)		 GSD
(µg/m3)
Philadelphia
EC 12 0.8 1.8 18 1.0 1.5
PM2.5 12 18.1 1.8 18 17.8 1.6
Benzene 12 1.7 1.3 15 1.2 1.4 −b
Toluene 12 4.2 1.9 15 4.1 1.7
Ethylbenzene 12 0.7 1.5 15 0.5 1.4 −b
m&p-Xylenes 12 2.8 1.6 15 1.8 1.4 −b
o-Xylene 12 0.9 1.6 15 0.6 1.4
Formaldehyde 13 7.1 1.3 15 4.4 3.9
Columbus
EC 9 1.1 1.6 11 0.8 1.6
PM2.5 9 12.2 1.5 11 13.8 1.5
Benzene 2 2.1 1.3 10 1.2 1.3 −b
Toluene 2 4.5 1.4 9 5.0 1.6
Ethylbenzene 2 1.2 1.2 10 0.9 1.7
m&p-Xylenes 2 3.9 1.1 10 3.1 1.8
o-Xylene 2 1.5 1.1 10 0.9 1.6 −b
Formaldehyde 2 12.1 1.4 10 6.2 1.3 −b
Milwaukee
EC 13 0.7 1.6 17 0.8 1.7
PM2.5 13 6.7 1.5 17 12.8 1.5 +b
Benzene 17 0.8 1.7 16 0.9 1.4
Toluene 17 2.0 1.9 16 3.3 1.6 +b
Ethylbenzene 17 0.4 2.2 16 0.5 1.7
m&p-Xylenes 17 1.7 2.3 16 1.6 1.7
o-Xylene 17 0.5 2.1 16 0.5 1.7
Formaldehyde 17 12.3 1.7 16 7.4 1.3 −b
Phoenix
EC 10 1.3 1.5 16 1.3 1.2
PM2.5 10 23.3 3.1 16 13.5 1.6
Benzene 9 1.4 1.3 17 1.2 3.1
Toluene 9 5.7 1.3 17 4.4 5.4
Ethylbenzene 9 1.2 1.5 17 1.4 8.7
m&p-Xylenes 9 4.5 1.5 17 6.0 6.0
o-Xylene 9 1.4 1.4 17 2.4 5.9
Formaldehyde 9 13.2 1.4 17 9.4 1.4 −b
Portland
EC 13 1.7 1.9 12 1.1 1.6
PM2.5 13 15.6 1.4 12 11.4 1.5 −b
Benzene 12 1.7 1.5 12 0.9 1.2 −b
Toluene 12 4.6 1.6 12 3.3 1.5
Ethylbenzene 12 0.9 1.4 12 0.7 1.8
m&p-Xylenes 12 3.1 1.3 12 2.7 1.9
o-Xylene 12 1.1 1.3 12 1.0 1.9
Formaldehyde 12 8.6 1.8 12 5.5 1.3 −b
Denver
EC 16 0.9 2.1 12 0.6 7.0
PM2.5 16 9.3 1.5 12 11.7 1.6
Benzene 11 1.8 1.5 13 1.9 1.3
Toluene 11 6.8 1.8 13 7.6 1.6
Ethylbenzene 11 0.9 1.6 13 1.4 3.6
m&p-Xylenes 11 2.7 1.6 13 4.7 3.5
o-Xylene 11 0.9 1.7 13 1.6 3.3
Formaldehyde 14 10.6 1.5 13 4.6 7.1 −b
a

Summary statistics were limited to nonsmoking drivers to eliminate the effect of smoking on the comparisons.

b

Significant differences (P <0.05) in median values using Wilcoxon rank sum non-parametric comparison test. − indicates decrease in GM; + indicates increase in GM.