Results of regression models for particulate matter with a 50% cut-off aerodynamic diameter of 2.5 µm (PM2.5), PM2.5 absorbance and nitrogen dioxide
| Variable | Slope | Standard error | Sequential R2 |
|---|---|---|---|
| NO2, nitrogen dioxide; PM2.5, particulate matter with a 50% cut-off aerodynamic diameter of 2.5 µm. | |||
| Model for PM2.5 | 0.358 | ||
| Land coverage factor (100–250 m) | 2.56570 | 0.896 | 0.167 |
| Length of rural roads (100–250 m) | 0.847×10−3 | 0.364×10−3 | 0.144 |
| Distance to nearest motorway | −0.22740×10−3 | 0.273×10−3 | 0.013 |
| Population density (500–1000 m) | 0.10374×10−3 | 0.752×10−4 | 0.035 |
| Model for PM2.5 absorbance | 0.420 | ||
| Household density (2500–5000 m) | 4.58×10−5 | 2.68×10−6 | 0.249 |
| Distance to nearest federal roads | −1.322×10−4 | 5.855×10−5 | 0.069 |
| Land coverage factor (100–250 m) | 0.464 | 0.223 | 0.060 |
| Length of county roads (0–1000 m) | 5.500×10−4 | 4.984×10−4 | 0.041 |
| Model for NO2 | 0.510 | ||
| Length of state roads (1000–2500 m) | 6.171×10−4 | 5.661×10−4 | 0.327 |
| Land coverage factor (100–250 m) | 8.821 | 3.772 | 0.084 |
| Land coverage class | −3.447 | 2.444 | 0.059 |
| Household density (2500–5000 m) | 5.997×10−5 | 4.152×10−5 | 0.032 |
| Length of rural roads (250–500 m) | 5.457×10−4 | 7.671×10−4 | 0.008 |