Extended Data Fig. 8: Chemical regimes for SIA formation in summer and winter. | Nature Geoscience

Extended Data Fig. 8: Chemical regimes for SIA formation in summer and winter.

From: Regime shift in secondary inorganic aerosol formation and nitrogen deposition in the rural United States

Extended Data Fig. 8

Panels (a)–(e) show the summer chemical regimes of (NH4)2SO4 formation. The lines in panels (a–e) indicate the condition that NH4T explicitly balances SO42− to form (NH4)2SO4 (1:2 line) for a system that is only consist of NH4T and SO42−. Above the line, reducing NH4T only removes NH3g from the system, such that\(\Delta {c}_{{\rm{SIA}}}/\Delta {c}_{{{\rm{NH}}}_{4}^{{\rm{T}}}}=0\). Panels (f)–(o) show NH4NO3 evaporation plays a major role. The framework of using aerosol pH and aerosol water content to determine NH4NO3 regime developed by Nenes et al.38 is used here (Text S3)20,21. The four regimes shown in panel (f)–(o) are relatively consistent when aerosol composition changes. The colour of the markers and the lines in panels (f)–(o) indicate the year.

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