Influence of sulfur emission control areas on particulate matter emission: A difference-in-differences analysis

Abstract As the shipping industry calls for a more sustainable development approach to minimize ecological footprints, emission control areas (ECAs) requiring low-sulfur fuel content have been established worldwide. Particulate matter (PM) is directly related to marine fuel quality; hence, based on classical emission calculation models, ECAs could theoretically reduce PM. However, empirical evidence and testing using econometric analyses are scarce. This retrospective study uses empirical meteorological data to examine whether China’s ECAs contribute to PM reduction using a difference-in-difference approach. Notably, China’s ECA policy has resulted in different outcomes in the country’s Yangtze River Delta, Pearl River Delta, and Bohai Rim regions. Only the Yangtze River Delta region has shown a significant PM reduction effect as a result of the ECA policy, while the Pearl River Delta and Bohai Rim regions have not recorded similar results. Possible explanations are proposed as well.