Candidates to Provide a Specific Concentration Difference for Ambient Sulfur and Nitrogen Compounds Near the Coastal and Roadside Sites of Japan

Abstract

The concentrations of atmospheric gases and aerosols were measured using the four-stage filter-pack method to study the atmospheric chemistry and the representativeness of a site established near an expressway and a national road with heavy traffic in a coastal as well as an urbanized area. The clear seasonal difference in the concentrations of nitrate species (HNO3 and NO3−) between the two sites was observed, and the difference was correlated with, but not quantitative, the atmospheric oxidation reaction from NO2 to HNO3. The concentrations of ammoniacal nitrogen (NH3 and NH4+) were determined on a regional scale; in other words, their concentrations were not determined by specific emission sources, differently from the case of nitrate species. The temporal variation of the concentration of total sulfur (SO2 + SO42−) was largely controlled by the concentration of SO2, which, in turn, would be controlled by emission sources other than roads, differently from the cases of nitrate species and ammoniacal nitrogen. It was strongly suggested that there was an existence of the important sulfur emission sources: one candidate is sea traffic lane.