Long term measurements of atmospheric gaseous and aerosol species using an annular denuder system in Nara, Japan

During the period from June 1994 to May 1995 a three-line annular denuder filter system was used to sample atmospheric gas phase SO2, HNO3, HNO2, HCl, and NH3 and aerosol phase SO2-4, NO-3, Cl-, NH+4, Na+, K+, Ca2+, and Mg2+ in Nara, Japan. The average annual concentrations of these species were determined together with their seasonal variations. It was found that even in a medium-sized city such as Nara HNO3 and HNO2 concentrations were fairly high. The present system also enabled the determination of the percent loss of aerosol components NO-3, Cl- and NH+4 collected on filters.