| Direct | t值 | Indirect | t值 |
SO2 | 0.0687 | 0.0584 | −0.0155 | 0.0588 |
NO2 | 0.2015 | 0.0417 | −0.0427 | 0.0454 |
日照 | 0.3929 | 0.0307 | −0.0838 | 0.0350 |
人口 | 0.0321 | 0.0729 | −0.0062 | 0.0761 |
降水量 | −0.3358 | 0.032 | 0.0725 | 0.085 |