TABLE IV.
The multiple linear regression models for continuous diesel exhaust measurements with corresponding environmental variables and categorical DPM levels conducted in the study.
| Parameter | Parameter Estimate |
Standard Error |
Pr > |t| |
Standardized Estimate |
Variance Inflation Factor |
Model/ Partial R2 |
|---|---|---|---|---|---|---|
| ECrealtime (µg/m3) | - | - | <.01 | - | - | 0.54 |
| Intercept | 11.57 | 34.87 | 0.74 | - | - | - |
| DPM Level (Low=0, High=1) | 281.37 | 6.25 | <.01 | 0.60 | 1.32 | 0.50 |
| Relative Humidity (%) | 2.72 | 0.15 | <.01 | 0.23 | 1.29 | 0.04 |
| Temperature (°F) | −0.35 | 0.50 | 0.48 | −0.01 | 1.06 | <0.01 |
| PM2.5 (µg/m3) | - | - | <.01 | - | - | 0.71 |
| Intercept | 55.42 | 9.98 | <.01 | - | - | - |
| DPM Level (Low=0, High=1) | 123.33 | 1.79 | <.01 | 0.74 | 1.32 | 0.68 |
| Relative Humidity (%) | 0.84 | 0.04 | <.01 | 0.20 | 1.29 | 0.03 |
| Temperature (°F) | −0.39 | 0.14 | 0.01 | −0.03 | 1.06 | <0.01 |
| PNC (particles/cm3) | - | - | <.01 | - | - | 0.65 |
| Intercept | 103,581 | 14,107 | <.01 | - | - | - |
| DPM Level (Low=0, High=1) | 181,803 | 2,527 | <.01 | 0.85 | 1.32 | 0.64 |
| Relative Humidity (%) | −464 | 62 | <.01 | −0.09 | 1.29 | 0.01 |
| Temperature (°F) | −346 | 201 | 0.09 | −0.02 | 1.06 | <0.01 |
| CO (mg/m3) | - | - | <.01 | - | - | 0.67 |
| Intercept | −3.06 | 0.77 | <.01 | - | - | - |
| DPM Level (Low=0, High=1) | 8.87 | 0.14 | <.01 | 0.74 | 1.32 | 0.65 |
| Relative Humidity (%) | 0.03 | 0.00 | <.01 | 0.11 | 1.29 | 0.01 |
| Temperature (°F) | 0.09 | 0.01 | <.01 | 0.09 | 1.06 | 0.01 |