title: Transboundary secondary organic aerosol in western Japan indicated by the δ13C of water-soluble organic carbon and the m/z 44 signal in organic aerosol mass spectra.
abstract: The stable carbon isotope ratio (δ13C) of low-volatile water-soluble organic carbon (LV-WSOC) was measured in filter samples of total suspended particulate matter, collected every 24 h in the winter of 2010 at an urban site and two rural sites in western Japan. Concentrations of the major chemical species in fine aerosol (<1.0 μm) were also measured in real time by aerosol mass spectrometers. The oxidation state of organic aerosol was evaluated using f44; i.e., the proportion of the signal at m/z 44 (CO2+ ions from the carboxyl group) to the sum of all m/z signals in the organic mass spectra. A strong correlation between LV-WSOC and m/z 44 concentrations was observed, which suggested that LV-WSOC was likely to be associated with carboxylic acids in fine aerosol. Plots of δ13C of LV-WSOC versus f44 showed random variation at the urban site and systematic trends at the rural sites. The systematic trends qualitatively agreed with a simple binary mixture model of secondary organic aerosol with background LV-WSOC with an f44 of ∼0.08 and δ13C of -17‰ or higher. Comparison with reference values suggested that the source of background LV-WSOC was likely to be primary emissions associated with C4 plants.
authors.affiliation: National Institute for Environmental Studies , 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Irei
authors.forename: Akinori
authors.initials: A
authors.lastname: Takami
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hayashi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Sadanaga
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Hara
authors.forename: Naoki
authors.initials: N
authors.lastname: Kaneyasu
authors.forename: Kei
authors.initials: K
authors.lastname: Sato
authors.forename: Takemitsu
authors.initials: T
authors.lastname: Arakaki
authors.forename: Shiro
authors.initials: S
authors.lastname: Hatakeyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Bandow
authors.forename: Toshihide
authors.initials: T
authors.lastname: Hikida
authors.forename: Akio
authors.initials: A
authors.lastname: Shimono
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D007564:Japan; D013058:Mass Spectrometry; D009930:Organic Chemicals / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D002247:Carbon Isotopes; D009930:Organic Chemicals; D052638:Particulate Matter