Air pollutant deposition effect and morphological change of Cryptomeria japonica pollen during its transport in urban and mountainous areas of Japan

摘要

Morbidity due to Cryptomeria japonica pollinosis is increasing, especially in the urban areas of Japan. It represents a major health problem for most modern societies. The reasons for this increase might be the association of pollen with air pollutants. Hyper-reactivity tests are being conducted on mice and rats for allergic immune response. However, such tests cannot evaluate the deposition of pollen to the respiratory tract, because they force the animals to be immunized to pollen allergen mixed with air pollutants separately. The purpose of this study is to investigate how air pollutants deposit onto airborne Cryptomeria japonica pollen grains during the pollen-flying season between urban and mountainous areas, and to aid further bioreactivity and hypersensitive research. Suspended particulate matter (SPM), Cryptomeria japonica perigonium and pollen grains were collected to identify the deposition of air pollutants in an urban area, Saitama City, and in a mountainous area, Okuchichibu, during the pollen flying seasons. Ionic and metallic components of SPM and perigonium and pollen grains were analyzed. We found that crustal components (Al, Fe and Ti) tended to deposit on pollen perigonium. The amount of ionic components of particles (NO_3~- SO_4~(2-) and NH_4~+) and gaseous pollutants (NO_2, SO_2 and NH_3) deposited on the perigonium and pollen grains were higher in the urban than in the mountainous areas, the results of which was proven by determination of gaseous pollutants exposed to Cryptomeria japonica pollen. It is suggested that these phenomena may affect the pollinosis and therefore it is necessary to investigate implications on further bioreactivity and hypersensitive research.