HR: 1340h
AN: GP53B-1214    [Abstracts]
TI: A magnetic quantification of anthropogenic pollution for Asian dust
AU: * Kim, W
EM: wnkim@korea.ac.kr
AF: Department of Earth and Environmental Sciences, Korea University, Seoul, 136-713, Korea, Republic of
AU: Doh, S
EM: sjdoh@korea.ac.kr
AF: Department of Earth and Environmental Sciences, Korea University, Seoul, 136-713, Korea, Republic of
AU: Yu, Y
EM: yongjaeyu@naver.com
AF: Department of Earth and Environmental Sciences, Korea University, Seoul, 136-713, Korea, Republic of
AB: It was previously found that significant amounts of iron-oxides had been incorporated into the Asian dust during its transportation. Intensive electron microscopic observations identified that the added materials were carbon- bearing anthropogenic iron-oxides (resulting from fossil fuel combustion). To quantify magnetic concentration, values of saturation magnetization (M_s) were determined from the hysteresis measurements for 33 Asian dust samples and 22 dust source region samples. Then, observed values of M_s were divided by the M_s of magnetite (92.36 Am² kg^-1), yielding an apparent magnetic concentration, AMC (= observed M_s / M_s of magnetite). The AMC conceptually represents the lower limit of the net concentration of magnetic materials, because thermomagnetic analyses found magnetite and other less magnetic iron-oxides as a dominant magnetic phase in samples. Apparent magnetic concentrations were 0.06~1.22 × 10³ ppm and 0.77~2.65 × 10⁴ ppm for the source region and Asian dust samples, respectively. This result suggests that more than 90 % of magnetic materials were added in the Asian dust during its transportation. This study reveals that the AMC can be used as a powerful magnetic concentration parameter in environmental magnetism.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 1512 Environmental magnetism
DE: 1519 Magnetic mineralogy and petrology
DE: 1540 Rock and mineral magnetism
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting