. Author manuscript; available in PMC: 2015 Apr 9.

Published in final edited form as: J Expo Sci Environ Epidemiol. 2012 Jan 18;22(2):135–147. doi: 10.1038/jes.2011.45

Table 4.

Percent change in pollutant level per increase of one interquartile range (IQR) in the indicated predictor based on analysis of all 12 communities.

Predictor variable	NO₂	NO	NO_X

	% Change	% Change	% Change
CALINE-modeled TRP (freeway)	8.8^***	19.6^***	13.4^***
CALINE-modeled TRP (non-freeway)	4.7^***	16.8^***	10.4^***
Distance to nearest freeway	−2.0^*	−2.9^*	−4.0^***
Squared distance to nearest freeway	0.4	1.1^*	1.0^*
Distance to nearest non-freeway major road	−1.9^***	−2.4^***	−2.4^***
Non-freeway traffic volume within a 300m buffer	1.1^**	−0.5	0.0
Population within a 300m buffer	1.5^***	2.7^**	2.3^***
Neighborhood elevation relative to the community	−3.5^***	−6.8^***	−4.9^***
LRT fixed versus spatial model	437.8^***	485.3^***	596.8^***
10-fold cross-validation R²	71%	63%	71%

The IQRs are 1.9U (scaled to p.p.b. of NO_x) of freeway TRP, 1.6U non-freeway TRP, 1.2 km distance to the nearest freeway, 0.88 km of freeway distance squared, 0.36 km distance to the nearest non-freeway major road, 0.31U of volume in a 300m buffer, 371 people per km², and 41m in a neighborhood elevation relative to the mean community elevation.

P<0.05;

^**

P<0.005;

^***

P<0.0005.