Anthropogenic contribution of magnetic particulates in urban roadside dust: Fid-Bau Portal

Anthropogenic contribution of magnetic particulates in urban roadside dust

Kim, Wonnyon / Doh, Seong-Jae / Yu, Yongjae

AbstractEnvironmental magnetism parameters have been optimized as qualitative proxy indicators of the distribution of anthropogenic particulates, heavy metals and/or organic materials. In the present study, we propose a quantitative magnetic proxy which is suitable for the monitoring of spatial and temporal pollution patterns in urban areas. A total of 1353 roadside dust samples were collected from Seoul, Korea for 13 months. Thermomagnetic data and intensive electron microscopy identified a predominance of carbon-bearing iron-oxides, indicating that anthropogenic particulates mostly originated from fossil fuel combustions. To quantify anthropogenic particulates, an apparent magnetic concentration $[{AMC}_{{Fe}_{3} O_{4}} = observed saturation magnetization (M_{s}) / M_{s} of {Fe}_{3} O_{4} (= 92.36 {Am}^{2} {kg}^{- 1})]$ was calculated. ${AMC}_{{Fe}_{3} O_{4}}$ showed distinctive spatial and seasonal dependences: highest in industrial areas and lowest in park areas; and maximum in winter and minimum in summer. Seasonal mapping using ${AMC}_{{Fe}_{3} O_{4}}$ illustrated that industries in southwestern Seoul were the major pollution source. In addition, dominant westerly winds possibly transported pollutants along topographically lower areas in Seoul.