Behaviors of Sulfate, Nitrate and Other Pollutants in Long-Range Transport of Air Pollutants

Abstract

Behaviors of sulfate, nitrate and other pollutants in long-range transport of airpollutants were investigated using the cooperative field observation data. The observation was conducted during 26-30 July 1983 in the wide area from the coastal region around Tokyo Bay to the northeastern part of Nagano prefecture which located in central mountainous region.
In the inland area, SO₄^2-, NO₃^- and NH₄⁺ in aerosol and gaseous HNO3concentrations increased notably by transport of the polluted air mass. Usually the ion balance in aerosol using SO₄^2-, NO₃^-, Cl^-, NH₄⁺, Na⁺, K⁺, Ca₂⁺ and Mg₂⁺ was in good in inland area, but when the polluted air mass was transported, the ion balance leaned toward anion side. From this, existence of the droplet of H₂SO₄ or NH₄HSO₄was suggested.
It was observed that the gaseous HNO₃ converted into the aerosol phase according o the equilibrium relationship between gaseous HNO₃, NH₃ and NH₄NO₃ which depended on temperature and relative humidity, when the polluted air mass transported to the central mountainous region in the late afternoon.
It was considered that the oxidation of NOR to HNO₃ or NO₃^- proceeded almost at the same time of generation of oxidants, but oxidation of SO₂ to SO₄^2- proceeded more slowly than that of NO_x.