09:00 〜 09:15
[HGG01-01] Preliminary magnetic biomonitoring of the spatial distribution of atmospheric particulate matter in Toyama city, Toyama, Japan
キーワード：環境磁気、大気磁性粒子、交通量、桜、富山
Magnetic biomonitoring techniques have been shown to be rapid, cost-effective and useful methods for investigating spatial distribution of urban air pollution. Here environmental magnetic results are reported for the materials deposited on the Japanese flowering cherries (Prunus subgenus Cerasus) at 81 sites in 2022 in Toyama city, Toyama, Japan. About three leaves were collected from each flowering cherry at the height of ~2.0 m from the ground, and then the collected leaves were put into 7 cm3 non-magnetic plastic cubes for magnetic analyses. Also the materials deposited on the top of the leaves were wiped off and analyzed by low temperature experiments. Detailed rock magnetic analyses show that there are measurable magnetic particles on leaves. It also indicates that the main magnetic minerals in the dust on the leaves are single-domain partially oxidized magnetite, and the magnetic mineralogy on leaves’ surface is likely consistent throughout the study area. Higher saturation isothermal remanent magnetization (SIRM) intensities are observed at the urban area than the rural area. Traffic volumes near the studied sites are roughly estimated by an image analysis of photos taken by 57 traffic monitoring cameras in the Toyama city, and the observed SIRM intensities show a weak positive correlation with the estimated traffic volume. These results indicate that magnetic biomonitoring using the leaves of the Japanese flowering cherry can be a rapid and cost-effective method for studying the spatial distribution of atmospheric particulate matter derived from local traffic and/or industrial activities, and therefore it should be considered for application elsewhere in the country.