Rewrite the following paragraphBoth Chen et al 2013 and Ebenstein et al 2017 focus on PM25’s long-term impact by using a regression discontinuity RD approach based on the Huai River heating policy in

Chen et al. (2013) and Ebenstein et al. (2017) both examine the long-term effects of PM2.5 using a regression discontinuity (RD) approach. They focus on the Huai River heating policy in China, which creates varying levels of air pollution due to differences in central heating policy. This allows for a purely cross-sectional analysis of air pollution. On the other hand, He et al. (2016) assess the short-term impact of air pollution using data from the 2008 Olympic games in Beijing. While informative, this study does not provide insights into long-term exposure