[Prediction of the dispersion of birch pollen in Asahikawa]

A birch pollen survey was carried out for 11 years from 1993 to 2003 in Asahikawa. An analysis was made of how the various meteorological factors related to the total birch pollen counts and the day when such pollen release started, and the correlation with and prediction of birch pollen dispersal were examined. The simple regression analysis provided evidence that the total birch pollen counts were related to the mean temperature in June of the preceding year. Also, the day on which birch pollen release commenced showed a correlation with the cumulative highest temperature of each day between March 21 and 31. These findings suggest that it is possible to predict both the total birch pollen counts and the first day of birch pollen release according to these meteorological factors.