| Trace Elements | Ambient Exposure (µg/m3) | Inhalation Unit Risk (µg/m3) | ECR (µg/m3) |
| Cd | 0.098 | 1.8 × 10−3 | 1.08 × 10−4 |
| Cr | 0.008 | 1.2 × 10−2 | 7.21 × 10−4 |
| As | 0.016 | 1.6 × 10−3 | 4.4 × 10−6 |
| Be | 0.03 | 4.0 × 10−4 | 4.6 × 10−6 |
| Ni | 0.012 | 2.0 × 10−2 | 2.4 × 10−6 |