| Variables | Variables in level | Variables in first difference | ||
| Statistic13 | P-value | Statistic | P-value | |
| CO2/pop | 1.40 | 0.91 | −45.31 | 0.00 |
| SO2/pop | 3.57 | 0.99 | −31.97 | 0.00 |
| GDP/pop | 12.74 | 1.00 | −38.74 | 0.00 |
| Squared GDP/pop | 14.49 | 1.00 | −32.90 | 0.00 |
| Investment/pop | 5.01 | 1.00 | −42.18 | 0.00 |
| FDI/pop | 9.58 | 1.00 | −31.61 | 0.00 |
| Trade openness | −1.10 | 0.13 | −51.79 | 0.00 |