Results of a Survey of Ammonium Sulfate and Ammonium Bisulfate in Ambient PM_2.5 in Tokyo

Abstract

A study was conducted to investigate the concentrations of ammonium sulfate ((NH₄)₂SO₄) and ammonium bisulfate (NH₄HSO₄) in ambient particulate matter (PM_2.5) at a single location in Tokyo over a one-year period, from August 2022 to August 2023. Following 52 consecutive weeks of one-week samplings, the detection rate of (NH₄)₂SO₄ was 100% with the annual average concentration of 1.2 µg/m³. Its maximum concentration was 3.8 µg/m³. The annual concentration of the (NH₄)₂SO₄ trends were higher during the spring and summer (March to August) and lower during the fall and winter (September to February). The detection rate for NH₄HSO₄ was approximately 27% with an average concentration of 0.6 µg/m³, and the detection period was from April to August. Also, an analysis of the relationship with air pollutant concentrations showed a correlation with the oxidants.