北陸地域の大気中PM0.1の季節変動特性と発生源の考察

Size fractionated airborne particulates including PM0.1 were simultaneously monitored at threedifferent sites in the Hokuriku region of Japan. These were Kanazawa, Suzu and Toyama. Research wasconducted over a three-year period between 2014 and 2016 in order to collect information concerningthe PM status and related seasonal patterns. Possible local emission sources of PM0.1 and the influenceof long-range transportation are discussed in relation to mass concentration and diagnostic parametersdefined by particle-bound carbonaceous components such as organic and elemental carbon, and theirratios. The influence of trans-boundary air mass transport from outside Japan is also discussed based onPM0.1 characteristics and air mass trajectory analyses. The seasonal behavior for PM concentrationswere similar between sites reflecting similar meteorological characteristics. Due to larger numbers ofemission sources, the PM at the Toyama site was the largest between the three sites while at theKanazawa site, precipitation in the spring and the summer was higher than in the autumn and winterseasons and this may have resulted in a decrease in PM levels. The concentration and influence ofsecondary organic carbon on the PM0.1 carbon content were largest at the Toyama site. The Py-OC/O4ratio was consistent with increases in the number of hotspots in the spring and autumn. Carbonaceouscomponents in the PM0.1 fraction could be largely explained by local emission sources. However,explaining the influence of the trans-boundary transportation of air pollutants only by the behavior ofcarbonaceous components in PM0.1 may not be sufficient, and a more detailed discussion of variouschemicals in different sizes of particles is needed.