Seasonal variation and origins of dicarboxylic acids in the marine atmosphere over the western North Pacific

Abstract

[1] Concentrations of homologous (C 2 -C 11 ) dicarboxylic acids were measured in the atmosphere over Chichi-jima Island (27°04 0 N, 142°13 0 E), western North Pacific, from April 1990 to November 1993. The monthly averaged concentrations of straight-chain C 2 -C 7 dicarboxylic acids, and some branched, keto-, and unsaturated dicarboxylic acids showed a maximum in winter to spring and a minimum in the summer season. In contrast, straight-chain C 8 -C 11 dicarboxylic acids showed an opposite trend with a maximum in spring to summer. Principal component analysis revealed that there is a source characterized by a strong contribution of C 2 -C 7 dicarboxylic acids, phthalic acid, some keto-dicarboxylic acids, and unsaturated-dicarboxylic acids, whereas there seems to be another source(s) for the C 8 -C 11 dicarboxylic acids. A combined model of backward trajectories and emission inventories was used to better understand the sources and source regions of the dicarboxylic acids. The results show that concentrations of various C 2 -C 7 dicarboxylic acids in the western North Pacific atmosphere are largely controlled by their emissions and/or their precursor emissions from anthropogenic sources in the Asian continent, followed by long-range atmospheric transport. On the other hand, longer-chain dicarboxylic acids cannot be explained by long-range atmospheric transport from a continental region, which implies emissions and/or formation from natural sources, possibly from the ocean.

Contribution of Selected Dicarboxylic and ω-Oxocarboxylic Acids in Ambient Aerosol to them/z44 Signal of an Aerodyne Aerosol Mass Spectrometer

“…Oxalic acid is found as a dominant diacids species. This feature has been observed in various locations in previous studies (Kawamura and Ikushima 1993;Kawamura and Yasui 2005;Mochida et al 2003). Figure 1 shows the time series of OA and M 44 observed by the AMS and the mass concentrations of oxalic acid (C 2 ), total diacids, and total ω-oxoacids measured by the filter sampling technique.…”

“…Dicarboxylic acids (diacids), which contain two carboxyl groups, are the major constituents of WSOC and can be found in various locations in the troposphere (Saxena and Hildemann 1996;Kawamura and Ikushima 1993;Kawamura and Yasui 2005;Mochida et al 2003). Kawamura and Ikushima (1993) suggested that oxidation of volatile organic compounds (VOCs) is the major source of low molecular weight (C 2 -C 6 ) diacids observed at an urban site in Tokyo, based on the seasonal variation of these diacids.…”

Marine aerosol production: a review of the current knowledge

“…Further, despite a large number of studies on the occurrence of individual compounds or classes of compounds, e.g. carboxylic acids (Kawamura & Sakaguchi 1999;Mochida et al 2003), a comprehensive characterization of the chemical nature of organic matter in marine aerosols is currently not available.…”

Characterization of Atmospheric Iron Speciation and Acid Processing at Metropolitan Newark on the US East Coast

“…Though they comprise a minor fraction of the total aerosol mass, these acids, in particular oxalate, play significant roles in atmospheric chemistry through complexion with metal ions (such as Fe) and in the acidity of cloud droplets and precipitation. They often exhibit different mass size distributions [33][34][35], and their concentrations peaked in the accumulation mode either at 0.24-0.40 or 0.40-0.80 µm aerodynamic diameters [32]. Maudlin et al (2015) [36] conducted aerosol composition measurements at a coastal site in central California, they found that during wildfire periods, the mass size distribution of most dicarboxylic acids changed from unimodal to bimodal with peaks at 0.32 µm and 1.0-1.8 µm and Fe in sub-micrometer range was strongly enhanced.…”