Observation of Atmospheric Particle Electrostatic Charging States in Urban and Rural Regions

YUTO ISHII, Tatsuhiro Mori, Ayumi Iwata, Atsushi Matsuki, Tomoaki Okuda, Keio University

     Abstract Number: 50
     Working Group: Aerosol Physics

Abstract
Atmospheric particulate matters emitted from various sources on the earth have adverse on human health by deposition on the lungs. In particular, particles with a diameter of 2.5μm or less, called PM2.5 have more adverse effects because they can be breathed deeper into the lungs. However, how the various characteristic of the particles act on human health is a complicated process and not yet fully understood. Several laboratory experiments and numerical simulations have reported that the charging state of the particles influences their deposition on the human airway. Regarding outdoor research, it has been suggested that the presence of ions and charged particles may be linked to several adverse health effects such as respiratory and cardiological conditions. In order to clarify the relationship between the electrostatic charging state of atmospheric hundreds nanometer particles and human health effects, we developed the parallel-plate particle separate device (Keio Measurement system of Aerosol Charging State; K-MACS) for separating particles according to their charging state. We confirmed by comparison with stationary charge distributions that the distributions obtained by our method can be used to easily determine the relative variation of particle charging states, although the proportion of particles with a small charge number was quantitatively underestimated. The K-MACS was utilized in Yokohama city (urban area) and Suzu city (rural area) to recode the temporal variation of the particle charging state constantly for approximately two months. Then we compared whether the human and urban environments affect atmospheric particle charging characteristics. The developed K-MACS system and the findings of this study provide useful information on charging characteristics of atmospheric particles in urban and rural regions and may contribute to a new perspective for the prevention and control of air pollution.