This study investigated the spatiotemporal variation, chemical characteristics, and source resolution of PM2.5 in an East Asian seaport adjacent to industrial complex and urban area. Three representative harbor sites were selected to simultaneously sample 24-h PM2.5 once every 13 days in four seasons. A significant seasonal variation was observed with the highest and the lowest PM2.5 concentration in February (winter) and May (summer), respectively. High contribution of secondary inorganic aerosols (SIAs) showed that SO2 and NOx emitted from neighboring combustion sources burning coal and heavy fuel oil (HFO) were the major precursors forming secondary inorganic PM2.5. High ratios of V/Ni and V/Cu were observed in summer (June~August) since the prevailing west and southwest winds from outer port carried ship emissions to inter port. The correlation of chemical fingerprints (V, Ni, V/Ni, Zn, nss-SO42−, OC) and the number of ships were high at the Zhung-He Site and moderate at the Qi-Ho Site. The Cl−, Na+, V, Ni, nss-SO42−, OC, and V/Ni of PM2.5 were co-influenced by ship missions and oceanic spray in the Kaohsiung Harbor. The influences were relatively higher for winds blown from the harbor areas than those blown from the industrial areas. Oppositely, the Fe, Mn, Cr, Cu, Ca, Zn, and Al in PM2.5 were higher for winds blown from the industrial areas than those from the harbor areas. The CMB receptor modelling resolved that the major sources of PM2.5 were industrial missions, secondary aerosols, mobile sources, ship emissions, oceanic spray, fugitive dust, biomass burning, and organic carbon. Similar to Busan (South Korea), Brindisi (Italy), Lampedusa (Italy), and Barcelona (Spain), the contributions of ship emissions in the Kaohsiung Harbor were in the range of 7.4–7.8 %. Meanwhile, Kaohsiung Harbor was highly influenced by emissions from industrial areas and urban areas.
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