Table 4.
Land-use regression model results for benzene, BTEX, and formaldehyde. Final model terms listed in order of importance based on partial R2
| R2 | |||||
|---|---|---|---|---|---|
|
Covariate |
Coefficient |
Standard Error (SE) |
p-value |
Model |
Partial |
|
Benzene (n = 69) |
|
|
|
0.65 |
|
| Intercept |
0.052 |
0.188 |
0.783 |
|
-- |
| Number of signals within 400 meters |
0.017 |
0.002 |
<.0001 |
|
0.36 |
| Length of interstate, state, and county highways within 100 meters (km) |
0.591 |
0.101 |
<.0001 |
|
0.18 |
| Reference site mean |
0.799 |
0.340 |
0.022 |
|
0.03 |
|
BTEX (n = 67) |
|
|
|
0.70 |
|
| Intercept |
0.568 |
0.801 |
0.481 |
|
-- |
| Number of signals within 450 meters |
0.074 |
0.009 |
<.0001 |
|
0.34 |
| Kernel-weighted smooth of solvent-based industry locations (500 meter radius) |
0.072 |
0.013 |
<.0001 |
|
0.14 |
| Reference site mean |
0.873 |
0.328 |
0.010 |
|
0.03 |
|
Formaldehyde (n = 69) |
|
|
|
0.83 |
|
| Intercept |
−0.725 |
0.224 |
0.002 |
|
-- |
| Reference site mean |
1.209 |
0.119 |
<.0001 |
|
0.28 |
| Number of signals within 400 meters |
0.020 |
0.004 |
<.0001 |
|
0.07 |
| Road length within 100 meters (km) |
0.561 |
0.112 |
<.0001 |
|
0.07 |
| Built space within 100 meters (km2) | 2.477 | 0.716 | 0.001 | 0.03 | |