[Relationship between birch pollen counts and meteorological factors for 8 years in Sapporo].

Occurrence of airborne pollen in Sapporo was studied for the 8 years between 1995 and 2002. Observations on pollen seasons of cedar, birch, grass, and mugwort are presented. There are wide year-to-year variations in quantities of birch pollens. Simple linear regression by the least squares method was used for studying correlations between annual quantities of birch pollen and the meteorological factors. A highly significant (P = 0.00004) positive correlation was found between precipitation in February of the preceding year and annual birch pollen concentrations with the coefficient of determination, R2 = 0.950. These results suggest that atmospheric birch pollen counts can be predicted from the meteorological factor in the preceding year.