Deposition of air pollutants on airborne Cryptomeria japonica pollen in urban areas of Kanto Plain, Japan

The morbidity due to Cryptomeria japonica pollinosis so-called ‘Japanese Cedar Pollinosis’ is increasing, especially in the urban areas of Kanto Plain in Japan. The reasons of this increase might have been associated with airborne pollutants from the biomedical tests conducted on mice and rats. The overall purposes of this study were to investigate whether air pollutants may deposit onto airborne Cryptomeria japonica pollen or not during the pollen flying season, and thereby also try to find out the influence of airborne pollutants on the pollinosis, the results of which may advance the further biomedical researching. We investigated deposition of air pollutants on Cryptomeria japonica perigonium pollen and what pollutants may deposit together with the airborne pollen to respiratory tract between urban and mountainous areas. Metallic, ionic and carbonic components of suspended particulate matter (SPM) and perigonium pollen collected at the urban of Saitama City and the mountainous areas of Okuchichibu during the season were analyzed to identify their relationship. We found that crustal particles (Al, Fe and Ti) tended to deposit on the perigonium pollen. The amount of ionic components of anthropogenic secondary particles (NO3 -, SO4 2- and NH4 +) deposited on the perigonium pollen were higher in the urban than in the mountainous areas. It suggested that these airborne pollutants may affect the pollinosis, and it is important to determine airborne Cryptomeria japonica pollen and its major allergen (Cry j I), and investigate the chemical, physical and biomedical combination effects on it in our further study