Inter-comparison of Seasonal Variation, Chemical Characteristics, and Source Identification of Atmospheric Fine Particles on Both Sides of the Taiwan Strait

The spatiotemporal distribution and chemical composition of atmospheric fine particles in areas around the Taiwan Strait were firstly investigated. Fine particles (PM(2.5)) were simultaneously collected at two sites on the west-side, one site at an offshore island, and three sites on the east-side of the Taiwan Strait in 2013–2014. Field sampling results indicated that the average PM(2.5) concentrations at the west-side sampling sites were generally higher than those at the east-side sampling sites. In terms of chemical composition, the most abundant water-soluble ionic species of PM(2.5) were SO(4)(2−), NO(3)(−), and NH(4)(+), while natural crustal elements dominated the metallic content of PM(2.5), and the most abundant anthropogenic metals of PM(2.5) were Pb, Ni and Zn. Moreover, high OC/EC ratios of PM(2.5) were commonly observed at the west-side sampling sites, which are located at the downwind of major stationary sources. Results from CMB receptor modeling showed that the major sources of PM(2.5) were anthropogenic sources and secondary aerosols at the both sides, and natural sources dominated PM(2.5) at the offshore site. A consistent decrease of secondary sulfate and nitrate contribution to PM(2.5) suggested the transportation of aged particles from the west-side to the east-side of the Taiwan Strait.