Sulfur Chemistry at the Air-Water Interface

TY - JOUR

T1 - Sulfur Chemistry at the Air-Water Interface

AU - Liu, Pai

AU - Huang, Qishen

AU - Lei, Ting

AU - Zhang, Yun Hong

AU - Wang, Weigang

AU - Ge, Maofa

N1 - Publisher Copyright: Copyright © 2026 by the author(s). This work is licensed under a https://creativecommons.org/licenses/by-nc-nd/4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0), which permits any noncommercial use, sharing, distribution, and reproduction in any medium or format, provided the original author(s) and source are credited; this license does not permit sharing adapted material derived from this article or parts of it. Images or other third-party material in this article are included in the article's Creative Commons license unless indicated otherwise; see credit lines for license information.

PY - 2026

Y1 - 2026

N2 - The oxidation of gas-phase SO2 to sulfate aerosols has been a driver of urban air pollution since the Great Smog of London in 1952. Traditionally, this reaction has been perceived as a quintessential atmospheric aqueous reaction, occurring within condensed water such as cloud and fog droplets. This established view has been challenged by recent studies showing that, in urban air pollution, sulfate aerosols form predominantly through a heterogeneous SO2 conversion at aerosol surfaces. This review summarizes recent advances in understanding this heterogeneous process, focusing on (a) why S(IV) oxidation is faster at the air-water interface, (b) how to experimentally determine the reaction location with the scaling relationships of apparent reaction kinetics, and (c) how to predict, or retrieve, the localized surface reaction kinetics with multiscale models. We conclude by discussing open questions and remaining challenges, with the central theme of how the interfacial heterogeneous process may redefine our understanding of atmospheric sulfur chemistry.

AB - The oxidation of gas-phase SO2 to sulfate aerosols has been a driver of urban air pollution since the Great Smog of London in 1952. Traditionally, this reaction has been perceived as a quintessential atmospheric aqueous reaction, occurring within condensed water such as cloud and fog droplets. This established view has been challenged by recent studies showing that, in urban air pollution, sulfate aerosols form predominantly through a heterogeneous SO2 conversion at aerosol surfaces. This review summarizes recent advances in understanding this heterogeneous process, focusing on (a) why S(IV) oxidation is faster at the air-water interface, (b) how to experimentally determine the reaction location with the scaling relationships of apparent reaction kinetics, and (c) how to predict, or retrieve, the localized surface reaction kinetics with multiscale models. We conclude by discussing open questions and remaining challenges, with the central theme of how the interfacial heterogeneous process may redefine our understanding of atmospheric sulfur chemistry.

KW - SOoxidation

KW - air-water interface

KW - chemical kinetics

KW - haze chemistry

KW - heterogeneous reactions

KW - microdroplets

UR - https://www.scopus.com/pages/publications/105036327813

U2 - 10.1146/annurev-physchem-082324-095359

DO - 10.1146/annurev-physchem-082324-095359

M3 - Review article

C2 - 41223416

AN - SCOPUS:105036327813

SN - 0066-426X

VL - 77

SP - 17

EP - 41

JO - Annual Review of Physical Chemistry

JF - Annual Review of Physical Chemistry

IS - 1

ER -