open access

https://hdl.handle.net/2115/45169

Distributions and stable carbon isotope ratios of low molecular weight dicarboxylic acids in the atmospheric aerosols

日本語

2010-03-31

Institute of Low Temperature Science, Hokkaido University

Low Temperature Science

68

101-106

Stable carbon isotopic composition (δ13C) has been studied for C2-C9 diacids in the remote marine aerosols (n＝32) collected from the Pacific Ocean including tropics (34°N-14°S, 140°E-150°W). Their isotopic compositions showed a diverse variation with the highest values in oxalic (C2) acid (range: ＋4.1 to ＋15.3‰,av.＋10.3‰), followed by malonic (C3) acid (－11.2 to －3.1‰, av.－7.3‰) and succinic (C4) acid (－29.9 to －11.2‰, av.－17.6‰). The isotope ratios generally decrease with an increase in their carbon chain length, showing the lowest value of azelaic (C9) acid (av. －22.4‰). Although a significant enrichment of 13C in oxalic acid was found in all the remote marine aerosol samples, highest δ13C values were observed in the samples collected in the equatorial Pacific. We found that the δ13C values sharply increased as a function of ambient temperature and relative abundance of diacid-carbon in TC at a latitudinal transect in the western (0-35°N) and central equatorial Pacific (18°S to 20°N). This study suggests that photochemically induced degradation may be responsible to the enrichment of 13C in the C2-C4 diacids in the remote marine atmosphere. We propose that δ13C values of small diacids can be used as potential tracer of photochemical aging of organic aerosols.

紀要論文

Version of Record

1880-7593