Effects of comprehensive smoke-free legislation on smoking behaviours and macroeconomic outcomes in Shanghai, China: a difference-in-differences analysis and modelling study

China has one of the highest levels of tobacco consumption globally, and there is no national smoke-free legislation. Although more than 20 Chinese cities have passed local smoke-free laws since 2008, evidence on their effectiveness in reducing smoking behaviours and their economic benefits is scarce. By exploiting a natural quasi-experiment, whereby a comprehensive public smoking ban was implemented in Shanghai in March, 2017, this study aims to assess the impact of the policy on individual smoking behaviours and quantify its effect on macroeconomic outcomes.