| The marginal utility of air pollution | ||||||
| Happiness | regression coefficient | happiness index: one | happiness index: two | happiness index: three | happiness index: four | happiness index: five |
| AQI | −0.0037** (0.0005) | 0.0005* (0.0003) | 0.0003*** (0.0005) | 0.0006*** (0.0004) | −0.0005*** (0.0003) | −0.0006*** (0.0002) |
| income | 0.144** (0.0221) | −0.1001* (0.0034) | −0.0203*** (0.0040) | −0.0002** (0.0038) | 0.0113* (0.0029) | 0.0114** (0.0030) |