The seasonal variation of airborne pollen grains that cause sugipollinosis in japan in the last three years

In Japan, the problems of Sugi (Cryptomeria japonica)-pollinosis have been much discussed in recent papers and journals. The author made an investigation on the airborne pollen grains from a scientific standpoint in connection with the incidence of pollinosis. By using the Cascade Impactor the author collected 600 liters of air sample a day, at the roof of the Pharmaceutical Science Building, Toho University, Funabashi, Chiba, Japan. Each air sampling for 2 hrs was repeated three times a week since 1969. The airborne pollen grains in each sample were counted under the microscope to identify the pollen types. The pollen grains were classified into six types according to the classification of pollen grains in Japan established by lkuse. The accumulated number of pollen of each species was analysed statistically by circular plot, Weibull plot, Edwards plot and semi-logarithmic plot. In this report mainly 3B type of pollen grains (Cryptomeria, Chamaecyparis), collected in the last three years are described. The total number of pollen grains in 1988 (2820 grains) was doubled in quantity as compared with that in 1987 (1177 grains) and in 1989 (1121 grains). The 3B type of pollen grains in 1988 (1450 grains) was 3.4 times as many as in 1987 (397 grains), and 12.9 times as in 1989 (112 grains). The 3B type of pollen grains represented the major portion of total pollen, and influenced the annual amount and the dispersal period.