Table 4 Association between PM2.5 levels and daily traffic load of different type of vehicles at traffic station in Chiayi County through the generalized estimating equation approach
Car type | Mean (SD) | Min–Max |
|---|---|---|
Motorcycle (10,000/day) | 0.25 (0.32) | 0–1.53 |
Sedan (10,000/day) | 0.92 (0.71) | 0.05–2.84 |
Bus (1000/day) | 0.16 (0.13) | 0–0.7 |
Truck (1000/day) | 0.54 (0.52) | 0.01–1.93 |
| Â | Unstructured structure | Exchangeable structure | Autoregressive structure | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Car type | β | SE | p-value | QIC | β | SE | p-value | QIC | β | SE | p-value | QIC |
Motorcycle | − 0.66 | 0.55 | 0.23 | 1880.28 | 0.65 | 0.61 | 0.29 | 1930.55 | 1.40 | 0.58 | 0.02 | 1920.68 |
Sedan | 1.00 | 0.19 |  < 0.01 | 190.85 | − 0.10 | 0.33 | 0.76 | 194.36 | 0.26 | 0.34 | 0.44 | 194.13 |
Bus | 5.48 | 1.75 |  < 0.01 | 190.92 | − 0.64 | 1.44 | 0.66 | 193.61 | 1.97 | 1.25 | 0.16 | 192.38 |
Truck | 0.98 | 0.18 |  < 0.01 | 190.50 | − 0.46 | 0.54 | 0.39 | 195.78 | − 0.57 | 0.43 | 0.18 | 193.60 |