. Author manuscript; available in PMC: 2011 Apr 6.

Published in final edited form as: Environ Res. 2009 Feb 3;109(3):334–342. doi: 10.1016/j.envres.2008.12.006

Table 4.

Pearson’s correlation coefficients between pollutants and logarithm of roadway proximity after adjusting for regional gradients.

Metric	Session	L_eq	NO	NO₂	UFP^a
Logarithm of distance to nearest major road^b	Chicago 2006 (N = 69)	−0.41^***	−0.40^***	−0.22^*	-
	Chicago 2007 (N = 36)	−0.51^**	−0.46^***	−0.40^**	0.16 (0.04)
	Riverside 2007 (N = 46)	−0.52^***	−0.30^**	−0.31^**	−0.51^***
Logarithm of distance to nearest highway^c	Chicago 2006 (N = 69)	−0.18	−0.51^***	−0.50^***	-
	Chicago 2007 (N = 36)	−0.57^***	−0.43^***	−0.39^**	−0.16 (−0.16)
	Riverside, 2007 (N = 46)	−0.42^***	−0.53^***	−0.59^***	0.01

The highest correlated pollutant is shown in bold.

Correlations after adjusting measurements using regional gradient modeling equations in Table 3 (see text).

Value in parentheses is the correlation after removing one extreme UFP value from the 2007 monitoring session in Chicago.

Major road defined as census feature classification code A1, A2, or A3.

Highway defined as census feature classification code A1 or A2.

p < 0.10.

^**

p < 0.05.

^***

p < 0.01.