Studies on Behaviors of Sulfur Compounds (SO₂, SO₃, and H₂S) in the Atmospheric Air

In the winter, 1975, measurements of the concentrations of sulfur compounds (SO₂, SO₃ and H₂S) in the atmospheric air were made in Yokohama area for the purpose to investigate the behaviors of these gases. The concentration of SO₂ was measured by the p-rosalinine-form-aldehyde modified method, that of SO₃ by turbidimetry with barium sulfate, and that of H₂S by fluorometric method which is highly sensitive and suitable for the measurement of H2S on environmental levels. The results of the measurement are shown in Table 2. The average values within this period were 43.6 ppb (SO₂), 10.9 ppb (SO₃), and 0.87ppb (H₂S). The relative concentration ratio of these sulfieds in the atmospheric air was 79: 19.2: 1.8. An interesting relation was observed between the concentration of SO₂ and that of H₂S; the concentration of H₂S decreased in the daytime while that of SO, increased (Table 3 and Fig. 1). In the morning (10; 00), SO₂/H₂S concentration ratio was almost constant (30), But, during daytime (13; 00 and 16; 00) SO₂/H₂S concentration ratio was high and the range was great (50~200), In the evening (19; 00), the concentration of SO, decreased and concentration ratio became 30~100 (Fig. 2 and 3) again. SO₂/SO₃ concentration ratio was almost the same for varied concentrations of SO₂ (Fig. 4) in the atmospheric air, while SO₂/H₂S concentration ratio increased with increasing concentration of SO₂. Therefore, it was presumed that H2S might be emitted from the natural sources despite SO₂ and SO₃ were emitted from the common industrial sources.