Self-protection investment exacerbates air pollution exposure inequality in urban China

Urban China's high level of ambient air pollution lowers quality of life and raises mortality risk. China's wealthy can purchase private products such as portable room air filters that offset some of their pollution exposure risk. Using a unique data set of Internet purchases, we document that households invest more in masks and air filter products when ambient pollution levels exceed key alert thresholds. Richer people are more likely to invest in air filters, which are much more expensive and more effective than masks. Our findings have implications for trends in quality of life inequality in urban China.