Simple Analysis of Atmospheric NO₂, SO₂, and O₃ in Mountains by Using Passive Samplers

Abstract

A simple analysis of atmospheric NO2, SO2, and O3 in mountains by passive samplers was investigated and applied to the spatial analysis of air pollutants at Mt. Hiei in Kyoto City. Passive samplers were exposed for 30 days. Yanagisawa-type samplers were used for NO2 determination. The absorbed NO2 was measured as nitrite ion spectrophotometrically by the Saltzman method. On the other hand, SO2 samplers comprising an absorbent filter containing sodium carbonate solution were made. The absorbed SO2 was oxidized to SO42- with an H2O2 solution and determined by ion chromatography. For O3 determination, Ogawa ozone samplers were used. The O3 reacted with nitrite ion to produce nitrate ion, which was measured by ion chromatography. The relative standard deviations for NO2, SO2, and O3 samplers were 1.4%, 3−10%, and 2−5%, respectively. Samplers were set up in 13 locations at Mt. Hiei. The NO2 concentration and its distribution along the slope of Mt. Hiei changed considerably both daily and seasonally. The seasonal variation of atmospheric NO2 showed a winter maximum and a summer minimum. The concentration of atmospheric SO2 at Mt. Hiei was lower than that of NO2 and scarcely changed. Atmospheric O3 increased gradually with an increase of the altitude, exhibiting a regular pattern with a maximum in spring and a minimum in winter.