Impact of international Maritime Organization 2020 sulfur content regulations on port air quality at international hub port

Abstract

In this study, various characteristics of port air quality that are affected by harbor activities, including ship emissions, were assessed at an international hub port (Busan port) and other major ports in South Korea from November 2017 to December 2020. We conducted an in-depth analysis of aerosol characteristics to investigate the impact of ship emissions, harbor activities, and emission control measures (reinforced limits of sulfur content in fuel oil, from 3.5% to 0.5% mass fraction) on the air quality around the Busan port, South Korea. Our results demonstrate that the impact of ship emissions on port air quality varied significantly according to chemical species. The largest impact on port air quality from ship emissions and air mass pathways (e.g., port wind sector) was confirmed by significantly higher concentrations of SO2 at the port. Our results of regression discontinuity design, a quasi-experimental impact evaluation method, revealed that the implementation of reinforced regulations (i.e., International Maritime Organization 2020 policy) significantly reduced SO2 and NH4+ concentrations at the Busan port, but did not affect the concentrations of PM2.5 and NO2.