HR: 0800h
AN: A31A-0807    [Abstracts]
TI: Observation of Asian Mineral Dust Particles in Japan by a Single-Particle Mass Spectrometer
AU: * Matsumoto, J
EM: mjun@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Labo., Nagoya Univ., 3-13 Honohara, Toyokawa, Aichi, 442-8507 Japan
AU: Takahashi, K
EM: kent@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Labo., Nagoya Univ., 3-13 Honohara, Toyokawa, Aichi, 442-8507 Japan
AU: Matsumi, Y
EM: matsumi@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Labo., Nagoya Univ., 3-13 Honohara, Toyokawa, Aichi, 442-8507 Japan
AU: Sugimoto, N
EM: nsugimot@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506 Japan
AU: Matsui, I
EM: i-matsui@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506 Japan
AU: Shimizu, A
EM: shimizua@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506 Japan
AB: The Asian mineral dust (Kosa) particles, emitted from the desert area of inland China, are characteristic of East Asian aerosols. The Kosa particles are important as regional carriers of various materials, especially in spring when the stormy dusts are transported to Japan and Pacific Ocean. In this study, the chemical mixing state of each atmospheric aerosol was measured individually by a laser-based time-of-flight mass spectrometer (TOFMS) to discuss chemical changes of Kosa particles during the transport. Observation was conducted at Tsukuba (36.05°N, 140.12°E) in April and May 2004. The LIDAR measurement was also carried out to determine the Kosa events. To classify the source of the air mass, the NOAA-HYSPLIT backward trajectory was applied. For the TOFMS instrument, particles with μm and sub-μm diameters were detected. The polarity of ion detection was altered every minute. During 30 days, the numbers of logged mass spectra (MS) were 5993 and 4382 for positive and negative ions, respectively. When the MS of ambient aerosols were compared with that of the standard Kosa sample, sulfate- and nitrate-mixed Kosa particles were found. To explore the mixing state of particles further, classification of the particles by the ART-2a algorithm was adopted. NO₂^-, NO₃^-, HSO₄^-, SiO₂^-, SiO₃^-, Cl^- and NaCl₂^- were focused. Finally, particles were classified to 4 categories as A: sulfate and sulfate-rich mineral; B: sulfate-poor mineral; C: sea salt; D: unidentified. The relative fractions of A were 30 % and 1 % for a Kosa event and a maritime air mass, respectively. Note that the air mass for Kosa event case passed over the coast region of China, where SOx emission was intensive. It was reasonable that sulfate was internally mixed with Kosa particles and transported to Japan. Consequently, it was confirmed experimentally that Kosa particles are important as carriers of pollutants in the rim region of Pacific Ocean. Comparison with the observation in 2005 is also shown.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005