| Total | First-Tier and Second-Tier Cities | Other Cities |
Subjective well-being | 3.743 | 3.738 | 3.748 |
(6017) | (2920) | (3097) | |
City size | 0.596 | 2.222 | 0.216 |
(111) | (21) | (90) | |
Environmental pollution | 0.009 | 0.0151 | 0.00759 |
(111) | (21) | (90) |