Influences of Ship Emissions from an Asian Seaport on Ambient PM2.5 of Nearby Metropolitan Area: Field Sampling and Model Simulation

This study explored the inter-transport of PM_2.5 between the Kaohsiung Harbor and the neighboring Metro Kaohsiung. PM_2.5 was sampled at four sites for analyzing its chemical composition including water-soluble ions, metallic elements, carbons, anhydrosugars, and organic acids to characterize PM_2.5’s chemical fingerprints. Furthermore, an air dispersion model, CALPUFF, was applied to simulate the spatiotemporal distribution of PM_2.5 in the Kaohsiung Harbor and neighboring urban areas. Additionally, PM_2.5 concentrations at nighttime were commonly higher than those in the daytime in winter, spring, and fall, while an opposite trend was observed in summer. High correlation of PM_2.5 at the port and urban areas at nighttime implied the inter-transport phenomena of PM_2.5 between these two areas. Sea salt spray, ship emissions, secondary aerosols, and heavy fuel-oil boilers were higher in the port area than those in the urban area. Mobile sources, fugitive dust, and waste incinerators were the major sources in the Metro Kaohsiung. Moreover, sea breeze significantly influenced the dispersion of PM_2.5 from the Kaohsiung Harbor to the Metro Kaohsiung, particularly in the afternoon. The average contribution of PM_2.5 from main engines of ships in the Kaohsiung Harbor was 2.9-5.3%, while the auxiliary engines contributed 3.8-8.3% of PM_2.5 to the Metro Kaohsiung.