| Parameter
City/ Semi-urban | Traffic density | PM2.5 (µg/m3) | NO2 (µg/m3) | SO2 (µg/m3) | O3 µg/m3 | CO (ppm) |
| Enugu | 2873 | 12.16 ± 0.31 | 23.83 ± 2.40 | 30.09 ± 1.22 | 66.54 ± 2.67 | 15.17 ± 0.86 |
| Nsukka | 2015 | 7.88 ± 1.06 | 15.40 ± 0.77 | 21.92 ± 0.84 | 80.31 ± 3.03 | 10.31 ± 0.65 |
| Awgu (control) | 587 | 1.67 ± 0.11 | 3.72 ± 0.43 | 2.96 ± 0.22 | 5.45 ± 1.24 | 1.18 ± 0.09 |
| F test P value |
| 0.01 | 0.01 | 0.01 | 0.00 | 0.01 |
| [16] permissible limits | 0 | 10 | 40 | 50 | 100 | 10 |