Table 3.
Model | Predictorsa | Pollutant |
||
---|---|---|---|---|
NO2 | NO | NOx | ||
1 | Distances | 0.24 | 0.19 | 0.24 |
2 | Volume | 0.20 | 0.22 | 0.23 |
3 | Elevation | 0.32 | 0.31 | 0.34 |
4 | Population density | 0.04 | 0.05 | 0.05 |
5 | Land-use categories | 0.08 | 0.03 | 0.05 |
6 | Distance, elevation, population | 0.51 | 0.45 | 0.53 |
7 | Distance, elevation, population, land use | 0.50 | 0.46 | 0.53 |
8 | Distance, volume, elevation, population | 0.63 | 0.55 | 0.63 |
9 | CALINE-modeled TRP | 0.65 | 0.59 | 0.67 |
10 | CALINE-modeled TRP, distance, elevation, population | 0.66 | 0.61 | 0.70 |
11 | CALINE-modeled TRP, distance, volume, elevation, population | 0.68 | 0.61 | 0.71 |
12 | CALINE-modeled TRP, distance, volume, elevation, population, land use | 0.67 | 0.61 | 0.71 |
Each set of predictors includes all of the variables listed in Table 2 under the respective heading. Squares of the distance and volume variables were also considered. Stepwise selection was used to obtain the best subset of predictors for each model.