Importing air pollution? Evidence from China’s plastic waste imports
研究了中国进口塑料垃圾对城市空气污染的影响，发现进口增加了PM2.5浓度，而2018年的进口禁令显著改善了空气质量，主要原因是减少了非回收垃圾的焚烧。
Plastic waste trade has grown considerably in the last decades and has led to severe environmental problems in recipient countries. Being the largest recipient, China has permanently banned the imports of plastic waste since 2018. This paper examines the causal effect of plastic waste imports on air pollution by exploiting China’s experience of importing plastic waste and the recent import ban. By combining data on plastic waste imports with PM2.5 data at the city level for the years 2000-2011, we find that plastic waste imports increased PM2.5 density significantly in recipient cities. To evaluate the impact of the import ban on air quality, we employ daily data on air pollution between 2015 and 2020. Our difference-in-differences results show that affected cities, relative to other cities, experienced considerable improvement in air quality following the ban. Further analysis reveals that increased incineration of non-recycled waste is the main channel. These findings provide insights into the costs of importing plastic waste and the potential environmental gains from banning such imports in other countries.