Abstract
On 11 March 2011, the Great East Japan Earthquake has brought about significant damage in the Tohoku and Kanto areas. The greatest tsunami caused massive damage to coastal areas in the Tohoku region such as Miyagi Prefecture. There was a concern about the effects of particulate matter (PM) derived from tsunami sediment on human health. In this study, PM2.5, PM10, total suspended particles (TSP) and heavy metals in house dust collected from five evacuation centers and one high school were investigated in Miyagi prefecture during May to September 2011. The daytime average concentrations of PM2.5 were 18 to 31 μg/m3, which was bellow a 24-hour average standard of 35 μg/m3 in Japan. In addition, PM2.5, PM10, and TSP in most of the facilities tended to decrease over time. On the other hand, it should be careful about the health of the most vulnerable people including asthmatics, children and elderly in evacuation center because the daytime average concentration of PM2.5 sometimes exceeded 35 μg/m3. Based on obtained results, in order to reduce indoor PM2.5, PM10 and TSP, it is important to select evacuation center in the area outside of tsunami inundated area, to keep no outdoor shoes allowed in house, and to conduct periodic cleaning in evacuation center. For house dust, size fraction of <75 μm represented the greatest contribution of dust in evacuation center where people entered the house with shoes on while coarse particles and fibrous fraction (>75 μm) was the greatest portion of dust in evacuation center with lowest PM2.5, PM10 and TSP concentrations. Metal concentration level, except in the case of Cd, Co and Pb, in evacuation center dusts was substantially the same in household dust samples collected in Japan at normal times.
