Fig. 5: Temporal variation of water-soluble Mn, total Mn, and sulfate concentration in PM2.5 in the North China Plain (Baoding and Tianjin) from January 1–12, 2015.
a Refers to Baoding, and b refers to Tianjin. Metal ions and sulfate concentration were measured by inductively coupled plasma mass spectrometry and ion chromatography, respectively.
