Record of Pre-neutralized H2SO4 Implied in the Results of Four-Stage and Five-Stage Paralleled Filter Pack Observations on the Western Edge of Japan
2022
Nguyen, Khanh Linh | Aikawa, Masahide
Particulate sulfate (SO₄²⁻) usually exists in the atmosphere in the chemical form of (NH₄)₂SO₄ and/or NH₄HSO₄. In contrast, we could successfully detect particulate sulfuric acid (H₂SO₄) without neutralization by ammonia in the monitoring campaign by filter pack methods. The presence of ambient H₂SO₄ was revealed from the concentration difference in a nitric acid gas (HNO₃) determined by a four-stage filter pack and a five-stage filter pack. Ambient H₂SO₄ could exist more frequently in summer (August) than in winter (January). Trajectory analysis identified the attribution of ambient H₂SO₄ as follows: in summer, SO₂ released from a domestic volcano in Japan was responsible for the ambient H₂SO₄, while in other seasons, SO₂ was carried to the survey site by northwestern air masses from the Asian continent.
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