Table 2.
National LUR model results for PM2.5, NO2, benzene, ethylbenzene, and 1,3-butadiene.
| Variable | Distancea | Value | SE | p-Value | ||||
|---|---|---|---|---|---|---|---|---|
| PM2.5 model (R2 = 0.46, RMSE = 1.529) | ||||||||
| Intercept | — | 2.802 | 0.497 | < 0.0001 | ||||
| Satellite PM2.5 (µg/m3) | — | 2.392 | 0.263 | < 0.0001 | ||||
| NPRI emissions (tonnes) | 5 km | 1.63e–3 | 5.95e–4 | 0.007 | ||||
| Industrial land use (m2) | 1 km | 1.03e–6 | 4.18e–7 | 0.014 | ||||
| NO2 model (R2 = 0.73, RMSE = 5.470) | ||||||||
| Intercept | — | 13.179 | 1.374 | < 0.0001 | ||||
| Satellite NO2 (ppb) | — | 1.4903 | 0.355 | < 0.0001 | ||||
| Industrial land use (m2) | 2 km | 3.21e–6 | 5.73e–7 | < 0.0001 | ||||
| Road length (m) | 10 km | 7.42e–6 | 9.04e–7 | < 0.0001 | ||||
| Summer rainfall (mm) | — | –0.010 | 0.002 | < 0.0001 | ||||
| Benzene modelb (R2 = 0.62, RMSE = 0.298) | ||||||||
| Intercept | — | 0.346 | 0.069 | < 0.001 | ||||
| Major road length (m) | 10 km | 1.18e–6 | 2.56e–7 | < 0.001 | ||||
| NPRI emissions (present) | 10 km | 0.526 | 0.089 | < 0.001 | ||||
| Ethylbenzene modelc (R2 = 0.67, RMSE = 0.193) | ||||||||
| Intercept | — | 0.152 | 0.039 | < 0.001 | ||||
| Population (count) | 10 km | 6.74e–7 | 7.25e–8 | < 0.001 | ||||
| NPRI emissions (present) | 2 km | 0.272 | 0.071 | < 0.001 | ||||
| 1,3-Butadiene modeld (R2 = 0.68, RMSE = 0.034) | ||||||||
| Intercept | — | 0.011 | 0.009 | 0.208 | ||||
| Road length (m) | 750 m | 3.89e–6 | 7.93e–7 | < 0.001 | ||||
| Highway (present) | 500 m | 0.041 | 0.012 | 0.002 | ||||
| Commercial land use (m2) | 10 km | 1.60e–9 | 5.97e–10 | 0.010 | ||||
| Satellite PM2.5 and NO2 are satellite-derived estimates of PM2.5 and NO2. Land use is the area of specific land-use types (industrial, commercial) within the associated buffer distance. Road length refers to the length of different road classifications (all, major, highways) within the associated buffer distance. Summer rainfall refers to the amount of rainfall recorded from May to September from the nearest meteorological station. NPRI emissions refer to the amount of annual emissions of the model substance released from industries that reported to the NPRI. NPRI emissions (present) refers to the presence of NPRI facilities that have released a model substance into the air. Population (count) refers to the number of individuals who resided within the associated buffer distance. aRadius of cicular buffers used to derive variables. bOne outlier removed with benzene concentration of 3.55 µg/m3. cOne outlier removed with ethylbenzene concentration of 2.57 µg/m3. bOne outlier removed with 1,3-butadiene concentration of 0.82 µg/m3. | ||||||||