Table 2.
Descriptive statistics of main variables
| Variable | Definition | 2015 (12520) | 2018 (13358) | ||
|---|---|---|---|---|---|
| Mean | SD | Mean | SD | ||
| ADL disability | 1 ~ 5; higher score indicated lower ADL disability | 4.651 | 0.513 | 4.636 | 0.595 |
| SO2 | SO2 content in air (μg /m3) | 27.53 | 17.96 | 16.26 | 10.58 |
| NO2 | NO2 content in air (μg /m3) | 32.74 | 11.62 | 39.23 | 15.93 |
| PM10 | PM10 content in air (μg /m3) | 94.38 | 40.94 | 89.74 | 40.32 |
| AQI | Dimensionless air quality; greater value indicated poorer quality | 85.76 | 25.79 | 72.14 | 16.55 |
| Fiscal expenditure | Total annual financial expenditure of the region (million yuan) | 544.9 | 729.6 | 688.0 | 1030 |
| Sunshine duration | Total sunshine duration in the whole year, (hour) | 1814 | 469.0 | 1903 | 354.4 |
| Rainfall | Annual total rainfall (mm) | 1067 | 624.8 | 997.3 | 441.2 |
| Per capita GDP | Annual regional GDP to population ratio, (yuan / person) | 49,467 | 34,418 | 56,468 | 35,992 |
| Population density | Annual area to population ratio (Person / m2) | 490.1 | 479.4 | 492.6 | 473.1 |
| Average temperature | Annual average temperature (centigrade) | 15.24 | 3.867 | 15.08 | 3.926 |
| GDP growth | Regional GDP growth compared with the previous year | 8.078 | 2.081 | 7.054 | 1.823 |
| Green space coverage | Ratio of green area to total area (in built up area) | 39.54 | 9.130 | 39.96 | 5.022 |
| Relative humidity | Percentage of water vapor pressure in air to saturated vapor pressure at the same temperature | 64.65 | 12.39 | 65.03 | 10.64 |
| Household register | Urban = 1, rural = 0 | 0.401 | 0.490 | 0.405 | 0.491 |
| Income | 1 ~ 5 respectively represent high income, middle-high-income, middle income, lower-middle-income and low income | 2.605 | 0.783 | 2.754 | 0.803 |
| Basic medical insurance | Enjoying basic medical insurance = 1, no = 0 | 0.945 | 0.137 | 0.971 | 0.168 |
| Marital status | Widowed = 1, no = 0 | 0.103 | 0.304 | 0.125 | 0.330 |
| Serious illness | Number of serious illnesses diagnosed; higher value indicates a greater number of illnesses | 0.0294 | 0.286 | 0.724 | 1.052 |
| Depression | 1–4; higher score indicates more severe depression | 2.468 | 0.740 | 2.275 | 0.783 |
| Self-reported health | 1 ~ 5; higher value indicates better health | 2.955 | 0.721 | 2.946 | 0.986 |
| Body disability | 0–5; higher score indicates more severe body disability | 0.154 | 0.444 | 0.145 | 0.445 |
| Physical pain | 1–5; higher score indicates more severe pain | 1.705 | 0.456 | 2.159 | 1.267 |
| Age | Actual age of the individual in the survey year | 59.14 | 10.32 | 58.74 | 10.32 |
| Gender | Male = 1, female = 0 | 0.478 | 0.500 | 0.474 | 0.499 |
| Education level | 1–11 respectively represent No formal education (illiterate),Did not finish primary school, Sishu/home school, Elementary school, Middle school, High school, Vocational school, Two−/Three-Year College/Associate degree, Four-Year College/Bachelor’s degree, Master’s degree, Doctoral degree/Ph.D. | 3.390 | 1.001 | 3.477 | 1.935 |
Abbreviations: ADL Activities of Daily Living, AQI Air Quality Index, SO2 Sulfur Dioxide, NO2 Nitrogen Dioxide, PM10 Inhalable Particles
Note: Standard errors are in brackets; *** p < 0.01, ** p < 0.05, * p < 0.1. The model controls for both the year and individual effects to consider the influence of unobservable factors