The morbidity of allergic rhinitis (AR) based on Japan National Health Insurance records was calculated from 1981 to 1990. The data shows a three-fold increase of the rate for AR patients in those 10 years. Additionally, Aichi Prefecture's morbidity of AR was analysed for May 1991. When cross-sectional methods were used for May 1991, it was found that the morbidity of AR showed little correlation with the pollen count for Japanese cedars and Japanese cypresses. However, the results suggested possible correlations between the morbidity of AR and the mean yearly levels of the pollutant components SPM and NO2.