Organic and inorganic compositions of marine aerosols from East Asia: Seasonal variations of water-soluble dicarboxylic acids, major ions, total carbon and nitrogen, and stable C and N isotopic composition

Abstract

Atmospheric particles were collected for one year (2001)(2002) at a site Gosan on Jeju Island, South Korea. The samples were analyzed for water-soluble dicarboxylic acids and related compounds using a capillary GC and GC/MS. Total carbon and nitrogen contents, as well as their stable isotopic ratios, were also determined using elemental analyzer (EA) and EA/IR/MS, respectively. Elemental and isotopic analyses were also performed after the HCl vapor treatment of aerosol samples. The results demonstrate that calcium carbonate of dust origin was not a significant component, except for a few dust event samples. Carbonates most likely reacted with acidic species (such as H 2 SO 4 , HNO 3 and organic acids) in the atmosphere during a long-range transport, and did not contribute to the total aerosol carbon, except for few strong dust episodes that occurred in spring. This study also demonstrates that nitrate and ammonium largely contribute to aerosol nitrogen and organic nitrogen is minor component in the Asian aerosols. Acidic aerosols enriched with sulfate likely adsorb NH 3 gas that is emitted from soils in Asia whereas mineral dust particles containing carbonate may adsorb HNO 3 and volatile organic acids.Homologous series of dicarboxylic acids (C 2 -C 12 ) including unsaturated structures as well as ketocarboxylic acids (C 2 -C 9 ) were detected in the aerosol samples with oxalic (C 2 ) acid being the most abundant species followed by malonic (C 3 ) or succinic (C 4 ) acids. Total concentrations of diacids (130-2070 ng m -3 ) are one or two orders of magnitude greater than those reported for remote marine aerosols in the North Pacific, but are equivalent to those reported for urban aerosols. Very high concentrations of dusts (up to 880 µg m -3 ) and watersoluble dicarboxylic acids were often observed in early spring. However, their correlation (r=0.27) is not strong throughout the campaign. Although both mineral dusts and diacids are derived from the Asian continent, they originate from different sources and source regions.Diacids are probably emitted from urban sources in East Asia and produced by secondary photochemical oxidation of their precursors, whereas dusts are derived from the arid interior regions. This study provides evidence for photochemical production of water-soluble organic acids in East Asia and the western North Pacific rim.3

Water-Soluble dicarboxylic acids, ketoacids and dicarbonyls in the atmospheric aerosols over the southern ocean and western pacific ocean

“…Concentrations of the organics detected in the marine aerosols over the western Pacific are comparable to those reported previously over the Pacific Ocean (Kawamura and Usukura, 1993;Kawamura and Sakaguchi, 1999), but significantly lower than those over the East China Sea and the Sea of Japan (Mochida et al, 2003a;Kawamura et al, 2004). This indicates that continental air masses over the Asian Continent have a great impact on the occurrence of the water-soluble organics in the marine atmosphere over the North Pacific.…”

Diurnal and temporal variations of water-soluble dicarboxylic acids and related compounds in aerosols from the northern vicinity of Beijing: Implication for photochemical aging during atmospheric transport

“…The concentrations of total oxoacids are equivalent to those from Gosan site (av. 53 ng m -3 ) in Jeju Island in the East China Sea (Kawamura et al, 2004) and slightly more abundant than those from urban sites in China (45 ng m -3 ) (Ho et al, 2007).…”

Diurnal changes in the distribution of dicarboxylic acids, ketocarboxylic acids and dicarbonyls in the urban Tokyo atmosphere

“…In order to evaluate a possible contribution of inorganic carbon (such as CaCO 3 ) to TC, filter samples were exposed to HCl fume and analyzed for carbon isotopic ratios. The δ 13 C values (-23.1 ‰ to -26.2 ‰) did not show any serious changes before and after the HCl treatment, indicating a negligible contribution of CaCO 3 (whose δ 13 C is around 0 ‰) to TC (Kawamura et al, 2004). Here, we used the TC data that were obtained without HCl treatment to normalize organic acid-carbon by TC.…”