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

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 (HNO and NO ) between the two sites was observed, and the difference was correlated with, but not quantitative, the atmospheric oxidation reaction from NO to HNO. The concentrations of ammoniacal nitrogen (NH and NH ) 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 (SO + SO ) was largely controlled by the concentration of SO, 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. [ABSTRACT FROM AUTHOR]