Table 1.
Summary statistics
| Variable | South (1) | North (2) | Difference in means (3) | Adjusted difference in means (4) | P value (5) |
| Panel 1: Air pollution exposure at China's Disease Surveillance Points | |||||
| TSPs, µg/m3 | 354.7 | 551.6 | 196.8*** | 199.5*** | <0.001/0.002 |
| SO2, µg/m3 | 91.2 | 94.5 | 3.4 | −3.1 | 0.812/0.903 |
| NOx, µg/m3 | 37.9 | 50.2 | 12.3*** | −4.3 | <0.001/0.468 |
| Panel 2: Climate at the Disease Surveillance Points | |||||
| Heating degree days | 2,876 | 6,220 | 3,344*** | 482 | <0.001/0.262 |
| Cooling degree days | 2,050 | 1,141 | −910*** | −183 | <0.001/0.371 |
| Panel 3: Demographic features of China's Disease Surveillance Points | |||||
| Years of education | 7.23 | 7.57 | 0.34 | −0.65 | 0.187/0.171 |
| Share in manufacturing | 0.14 | 0.11 | −0.03 | −0.15*** | 0.202/0.002 |
| Share minority | 0.11 | 0.05 | −0.05 | 0.04 | 0.132/0.443 |
| Share urban | 0.42 | 0.42 | 0.00 | −0.20* | 0.999/0.088 |
| Share tap water | 0.50 | 0.51 | 0.02 | −0.32** | 0.821/0.035 |
| Rural, poor | 0.21 | 0.23 | 0.01 | −0.33* | 0.879/0.09 |
| Rural, average income | 0.34 | 0.33 | 0.00 | 0.24 | 0.979/0.308 |
| Rural, high income | 0.21 | 0.19 | −0.02 | 0.27 | 0.772/0.141 |
| Urban site | 0.24 | 0.25 | 0.01 | −0.19 | 0.859/0.241 |
| Predicted life expectancy | 74.0 | 75.5 | 1.54*** | −0.24 | <0.001/0.811 |
| Actual life expectancy | 74.0 | 75.5 | 1.55 | −5.04** | 0.158/0.044 |
The sample (n = 125) is restricted to DSP locations within 150 km of an air quality monitoring station. TSP (µg/m3) in the years 1981–2000 before the DSP period is used to calculate city-specific averages. Degree days are the deviation of each day’s average temperature from 65°F, averaged over the years 1981–2000 before the DSP period. The results in column (4) are adjusted for a cubic in degrees of latitude north of the Huai River boundary. Predicted life expectancy is calculated by OLS using all of the demographic and meteorological covariates shown. All results are weighted by the population at the DSP location. One DSP location is excluded due to invalid mortality data. *Significant at 10%, **significant at 5%, ***significant at 1%. Sources: China Disease Surveillance Points (1991–2000), China Environment Yearbook (1981–2000), and World Meteorological Association (1980–2000).