Null hypothesis | Fog-haze risk comprehensive index equation | Industrial structure equation | Energy use efficiency equation |

${H}_{01}:{\theta}_{3}=0$ | 10.71** (0.57) | 2.18** (0.05) | 5.88** (0.07) |

${H}_{02}:{\theta}_{2}=0|{\theta}_{3}=0$ | 11.68* (0.52) | 1.16** (0.02) | 3.61** (0.01) |

${H}_{03}:{\theta}_{1}=0|{\theta}_{2}={\theta}_{3}=0$ | 1.65** (0.04) | 0.36** (0.29) | 0.97** (0.00) |