Table 3.
Effect of hourly traffic and weather on PM2.5 concentrations at U2
| Variable | Beta Estimatea (p-value) | |
|---|---|---|
| Trucks/Buses (443/hr increase) | 3.0 (0.04) | |
| Cars (1895/hr increase) | 1.3 (0.24) | |
| Wind Direction | NW to NE | Reference |
| NE to SE | −15.5 (<0.0001) | |
| SE to SW | 1.3 (0.73) | |
| (U2 downwind of roadway) | SW to NW | 6.4 (0.03) |
| Wind Speed (3.4 m/s increase) | −9.8 (<0.0001) | |
| Humidity (50.8% increase) | 8.0 (0.003) | |
| Temperature (5.1°C increase) | −0.63 (0.56) | |
| Mixing Height (354 m increase) | −1.5 (0.10) | |
a
Describes change in concentration of PM2.5 (μg/m3) per interquartile range increase in dependent variable, adjusted for other variables in the model.
b
Variables significantly associated with changes in PM2.5 (p<0.05) are in bold.