SO2 is a common air pollutant, which is harmful to human physical and mental health. This study construct, an individual-family-province three-level linear regression model to reveal the heterogeneity effect of SO2 pollution and household health care expense on depression. The findings are as follows: (1) 28.73% and 1.91% depression differences are caused by family and province differences. (2) At the family level, the higher the family health care expenditure, the greater the inequality of depression caused by the differences of social status and physical health. (3) At the province level, the depression difference between men and women was smaller under high SO2 concentration. The inequality in depression caused by education level disparity increased with the increase in SO2 concentration. The depression difference between individuals with and without chronic disease was larger under high SO2 concentration. The inequality in depression caused by relative income disparity increased with the increase in SO2 concentration. This study is helpful for the government to formulate relevant health service policies for depression and promote the equal development of public mental health.
Keywords SO2 pollution, depression, heterogeneity effect, hierarchical level model