A Survey of Airborne Japanese Cedar Pollen in the Kansai Region

Abstract

Japan Abstract Based on a survey of airborne Japanese cedar pollen carried out in Hyogo prefecture over 10 years (1998-2007), we performed a comparative study of yearly, weekly and daily changes in Japanese cedar pollen counts in the large metropolitan areas of Kyoto, Osaka and Kobe in the Kansai region. Airborne pollen counts were found to have a bi-annual cycle in each of the cities. Fluctuations in the quantity of male cedar flowers and temperatures during the previous summer season are thought to have an effect. Pollen scattering tended to begin earlier in Kobe than in Kyoto. Weekly and daily changes in pollen counts were found to follow the same rise and fall patterns in all three cities at certain times; but to vary between the cities at other times. The position and distance of cedar trees, forest flowering stages and wind speed and direction are also thought to have an