. 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 5.

Pearson’s correlation coefficients between L_eq and air pollutants.

		Raw correlation			Adjusted for regional gradient^a

		NO	NO₂	UFP^b	NO	NO₂	UFP^b
Chicago, December 2006 (N = 69)	NO₂	0.71^***			0.25^**
	UFP	-	-		-	-
	L_eq	0.20^*	−0.08	-	0.49^***	0.16	-
Chicago April 2007 (N = 36)	NO₂	0.82^***			0.65^***
	UFP^b	0.45^* (0.57^*)	0.45^* (0.51^*)		0.17 (0.35^**)	0.16 (0.16)
	L_eq	0.60^***	0.38^**	0.26 (0.33^*)	0.62^***	0.41^**	0.22 (0.31^*)
Riverside April 2007 (N = 46)	NO₂	0.74^***			0.68^***
	UFP	−0.05	0.11		−0.02	0.18
	L_eq	0.40^***	0.46^***	0.41^***	0.50^***	0.62^***	0.41^***

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.

p<0.10.

^**

p<0.05.

^***

p<0.01.