Abstract
We introduce the pollen calendar of important allergenic pollens in Japan, monitored from 2002 to, at longest 2018 at sites in Sapporo (Hokkaido), Sendai (Tohoku), Sagamihara (Kanto), Hamamatsu (Tokai), Wakayama (Kinki) and Fukuoka (Kyushu). The airborne pollen count was investigated using the gravitational method, Durham’s sampler, with samples counted every ten days and mean pollen count per day calculated to create the calendar. The tree pollen counts were Cupressaceae (Japanese Cedar and Cypress family), Betulaceae (Alder and Birch), with grass pollen counted in early summer, and Asteraceae (Ambrosia and Artemisia) and Cannabacear (Humulus japonicus, Japanese Hop) as the weed allergenic pollen in autumn.
Alder and Japanese Cedar pollen grains were observed from January, and in February Japanese Cedar pollen grains were overwhelmingly in the preponderance in all parts of Japan except Sapporo and were collected in Sagamihara City (Kanto) until May. Cypress family was observed for one month from March to April. In Hokkaido and Tohoku the birch pollination season stretches from April to June. From October to December a few of autumnal Japanese Cedar pollen grains were counted each year, except in Hokkaido.
Herbaceous grasses allergenic pollen grains were monitored mainly from April to June, but mostly in May, more in Kanto and Tohoku than in other regions. Ambrosia, Artemisiaand Japanese Hop pollen grains were counted at almost all sites in September.
