抄録
We previously reported that the airborne fine allergenic particles of Japanese cedar pollen were high in concentration during sunny days after rainfall. In this study, we investigated the morphological change of Japanese cedar pollen grains due to the contact with raindrops, and the elution behavior of major pollen allergenic Cry j 1, based on the assumption that rainfall may promote the release of fine allergenic particles from airborne pollen grains.
The observation of raindrops showed that a great number of pollens were scavenged at the initial stage of precipitation and that many burst pollen grains were contained in the rainwater. Therefore, it was suspected that the fine allergenic particles included in fragment of cell wall and ingredients of pollen were released from the burst of pollen grains.
On the other hand, the elution of allergenic Cry j 1 was found to increase when the solution contained high concentrations of ionic species. Especially, elution of allergenic Cry j 1 was significantly increased when the pollens were soaked with a weak basic solution containing Ca2+ ion. It was also found that high ionic concentration and high pH values appeared in rainfall water during the rainfall after long range transportation events of Asian dust. Therefore, we think that one of the important factors for releasing fine allergenic particles is the contact with the rainfall which scavenged Asian dust experienced a long range transportation.
