How does the upgraded domestic emission control area policy affect PM2.5 concentrations in port cities of China?

Abstract

Ship emissions are significant sources of air pollution in coastal areas. To mitigate the impacts of these emissions, China implemented the Domestic Emission Control Area (DECA) policy, which was upgraded to DECA 2.0 in late 2018, aiming at improving air quality in port cities. Quantitating the effectiveness of DECA 2.0 is therefore crucial for future air quality management in these cities. This study employs the Synthetic Control Method (SCM) to assess the impact of the DECA 2.0 policy on PM_2.5 concentrations in port cities in the Bohai Rim Area (BRA), Yangtze River Delta (YRD) and Pearl River Delta (PRD) of China from 2010 to 2021. Spatial heterogeneity was found in the effects of DECA 2.0 on PM_2.5 concentrations: the effect is generally greater in port cities of the YRD. These findings provide valuable insights for air quality management and policy formulation in China's coastal port cities.