Chemical characterization of acid fog and rain in northern Japan using back trajectory and oblique rotational factor analysis

Fog/cloud and rain water were collected at the mountainside of Hachimantai range in northern Japan and rain water was also collected at Akita City in order to investigate the air pollutant scavenging mechanism. The concentrat ions of various ions in these samples were analyzed, and the fog drop size and the wind direction were measured at each fog event. The fog at Hachiman tai range had a very high total ion concentration, and was considerably aci dified by non sea salt (nss-) SO42- and NO3-, compared with the rain at Aki ta and all sites in Hachimantai range. Using the oblique rotational factor analysis, three factors were extracted as the air pollutants; A: (NH4)(2)SO 4+H2SO4, B: sea salts+HNO3+H2SO4, C: NH4NO3+OH-. These salts are well-known as the cloud condensation nuclei (CCN). Combining the factor analysis with the 72h back trajectory at 850hPa. level, the contribution of Factor A was closely connected to the long-range transportation of anthropogenic or nat ural aerosol in air masses of continental origin.