Impacts of ship emissions and sea-land breeze on urban air quality using chemical characterization, source contribution and dispersion model simulation of PM at Asian seaport.

Fine particulate matter (PM) emitted from marine transportation, bulk materials handling at the docks, and dust dispersion has garnered increased attention, particularly in the interface between port and urban areas. This study explored the inter-transport of PM between Kaohsiung Harbor and neighboring Metro Kaohsiung. Chemical analyses of PM samples from four sites include water-soluble ions, metallic elements, carbons, anhydrosugars, and organic acids to establish PM's chemical fingerprints. The CALPUFF air dispersion model is employed to simulate the spatiotemporal distribution of PM in Kaohsiung Harbor and adjacent urban areas. A clear seasonal and diurnal variation of PM concentrations and chemical composition was observed in both harbor and urban areas. The high correlation of nighttime PM levels between the port and urban areas suggests inter-transport phenomena. Sea salt spray, ship emissions, secondary aerosols, and heavy fuel-oil boilers exhibit higher levels in the port area than in the urban area. In Metro Kaohsiung, mobile sources, fugitive dust, and waste incinerators emerge as major PM contributors. Furthermore, sea breeze significantly influences PM dispersion from Kaohsiung Harbor to Metro Kaohsiung, particularly in the afternoon. The average contribution of PM from ships' main engines in Kaohsiung Harbor ranges from 2.9% to 5.3%, while auxiliary engines contribute 3.8%-8.3% of PM in Metro Kaohsiung.