Assessing the distribution of volatile organic compounds using land use regression in Sarnia,

Table 5 Land use regression model results for BTEX compounds

Variables	Benzene	Toluene	Ethylbenzene	(M+P) xylene	O – xylene	BTEX
Intercept	-1.086 ± 0.141	0.486 ± 0.092, 5.258**	-1.879 ± 0.127, -14.758**	-1.079 ± 0.127, -8529**	-2.009 ± 0.144, -13.996**	0.587 ± 0.119, 4.927**
Industry 1600 m	0.005 ± 0.001 (0.640), 9.409**	---	---	0.003 ± 0.000 (0.339), 6.887**	0.003 ± 0.001 (0.526), 5.929 **	---
Industry 2500 m	---	---	---	---	---	0.002 ± 0.001 (0.464), 9.095**
Industry 2600 m	---	---	0.002 ± 0.000 (0.570), 10.084 **	---	---	---
Industry 2800 m	---	0.002 ± 0.000 (0.558), 8.181 **	---	---	---	---
Open 600 m	---	-0.007 ± 0.002 (0.119), -3.444 **	---	---	---	---
Dwelling 1200 m	0.002 ± 0.001(0.066), 3.153 **	---	---	0.004 ± 0.001 (0.398),7.379 **	0.003 ± 0.001 (0.219), 5.724 **	---
Dwelling 1400 m	---	---	0.002 ± 0.001 (0.157), 4.081 **	---	---	0.003 ± 0.000 (0.224), 4.997**
Highway 800 m	0.076 ± 0.024(0.073), 3.162 **	0.094 ± 0.021 (0.134), 4.543 **	0.079 ± 0.022 (0.081), 3.611**	0.062 ± 0.021 (0.060), 2.926**	0.062 ± 0.022 (0.056), 2.889 **	---
Highway 900 m	---	---	---	---	---	0.079 ± 0.018 (0.126), 4.418**
Model R ²	0.779(0.757)	0.811 (0.792)	0.808 (0.790)	0.797 (0.776)	0.800 (0.780)	0.813 (0.794)^b
Average VIF ^c	1.01	1.13	1.07	1.01	1.13	1.05
Model validation
R ²	0.75 – 0.81	0.77 – 0.86	0.79 – 0.86	0.78 – 0.81	0.77 – 0.79	0.80 – 0.84
RMSE^d	0.25 – 0.87 μg/m³	0.16 – 0.55 μg/m³	0.14 – 0.17 μg/m³	0.27 – 0.42 μg/m³	0.07 – 0.21 μg/m³	0.58 – 1.48 μg/m³

Note: ^a C = coefficient, SE = Standard Error, Cont = R ² contribution; ^b Numbers in brackets are adjusted R ²; ^c VIF = Variance Inflation Factor;
** Significant at 95%; ^c RMSE = Root mean square error

ISSN: 1476-069X