Chemical significance and source apportionment of fine particles (PM2.5) in an industrial port area in East Asia

Abstract

This study explored the chemical significance, seasonal variation, spatial distribution, and source apportionment of fine particles (PM2.5) in an industrial port area. 24-h PM2.5 was simultaneously sampled at three port sites. Five chemical contents in PM2.5 including water-soluble ions (WSIs), metallic elements, carbonaceous content, anhydrosugars, and organic acids were then analyzed. The source apportionment of PM2.5 was further resolved by trajectory simulation, principal component analysis (PCA), and chemical mass balance (CMB) receptor model. Both local sources and long-range transport contributed to the rise-up of PM2.5 levels. Secondary inorganic aerosols (SIAs) dominated WSIs in PM2.5. Crustal elements (Mg, Al, Ca, Fe, and K) dominated the metallic content of PM2.5, while trace elements (Ni, V, Cr, Zn, and Pb) were originated from anthropogenic sources. Ship emissions in the seaport and offshores caused high V/Ni ratios in summer. High OC/EC (2.04–2.23) and SOC/OC (28–34%) ratios were observed in fall and winter, implying the potential formation of secondary organic aerosols (SOAs) in atmosphere. High correlation of levoglucosan and K+ indicated that PM2.5 was greatly influenced by biomass burning (BB) in winter. Polluted air masses with high PM2.5 levels of 43.33 ± 11.84 μg/m3 in winter were blown from the norths by Asian Northeastern Monsoons (ANMs), while clean air masses with low PM2.5 levels of 9.13 ± 2.75 μg/m3 in summer came mainly from the oceans via Asian Southwestern Monsoons (ASMs). Source apportionment resolution showed that the dominant sources of PM2.5 in the Kaohsiung Seaport were industrial emissions, secondary aerosols (SIAs/SOAs), ship/vehicular exhausts, oceanic spray, and soil dust.