Abstract
Mass concentrations and chemical compositions of PM2.5 were measured continuously for over five years from the year 2000 at Kisai in the North Saitama region. Kisai is located in the outer suburbs of the Tokyo metropolitan area. PM2.5 was collected weekly a PM2.5 sampler (R & P, Partisol Plus 2025).
PM2.5 mass concentrations did not decrease clearly for the five yearperiod. Water soluble inorganic ions and carbons, which are major chemical compositions of suspended fine particles, involved in PM2.5 were analyzed. The total concentrations of chloride (C1-), nitrate (NO3-), sulfate (SO42-) and ammonium (NH4+) accounted for over 90 percent of all the water soluble inorganic ions. Concentrations of Cl-, NO3- and SO42- changed seasonally. Concentrations of Cl- and total carbon (TC), especially elemental carbon (Cel), decreased clearly, and those of NO3-decreased gradually. On the other hand, SO42- did not decrease but increased from the year 2003 through the year 2005, except in winter.
TEOM was operating for the same period and mass concentrations were compared with filter collections from the PM2.5 sampler. Annual mean conentrations of TEOM were the same as those of the filter collections from the PM2.5 sampler; however, there were discrepancies in the seasonal average concentrations. The measured weight differences of Semi-volatile compositions between TEOM and the collection filter in the+PM2.5 sampler indicated distinctive trends.
