2004 Volume 39 Issue 2 Pages 77-88
The denuder/filter-pack sampling system has been used for three years since September 1998, in order to measure daily concentrations of nitrate, chloride and ammonium in the gas and fine-and coarse-aerosol phases in Tokyo.
Total nitrate concentration does not vary seasonally, but its partitioning ratio shows remarkable seasonality with increases in the gas phase in summertime and in the fine-aerosol phase in wintertime. Total chloride concentration is high in wintertime due to non-sea-salt chloride in the fine-aerosol phase. Total ammonium concentration varies a little with season as well as its partitioning ratio.
Those measurements are analyzed for the partitioning of nitrate, ammonium and chloride between the gas and fine-aerosol phases. It was found that estimates based on equilibrium reactions in a multi-component system are very comparable to measured concentration products of gaseous components. This suggests that the gaseous components are in equilibrium with corresponding components in internally-mixed fine aerosol. In wintertime, however, the concentration products are also well predicted by equilibrium coefficients in a single component system, which implies that external mixture of fine aerosol can be applied.
