Opinion: Atmospheric Multiphase Chemistry: Past, Present, and Future

Abstract

Abstract. Multiphase chemistry occurs between chemicals in different atmospheric phases, typically involving gas-solid and gas-liquid interactions. The importance of atmospheric multiphase chemistry has long been recognized. Its central role extends from acid precipitation and stratospheric ozone depletion, to its impact on the oxidizing capacity of the troposphere, and to the roles that aerosol particles play in driving chemistry-climate interactions and affecting human health. This opinion article briefly introduces the subject of multiphase chemistry and tracks its development before and after the start of Atmospheric Chemistry and Physics. Most of the article focuses on research opportunities and challenges in the field. Central themes are that a fundamental understanding of the chemistry at the molecular level underpins the ability of atmospheric chemistry to accurately predict environmental change, and that the discipline of multiphase chemistry is strongest when tightly connected to atmospheric modeling and field observations.

Atmospheric aging modifies the redox potential and toxicity of humic-like substances (HULIS) from biomass burning

“…A recent opinion review has emphasized the necessity of a better understanding of multiphase chemistry triggered by respirable particles at the lung–air interface to address the health impacts of harmful particles. 74 We acknowledge the limitations of the current investigation on HULIS aerosol, including the lack of speciation and quantification of the target organic toxicant/redox-active compounds, as well as the exact reaction pathways following atmospheric transformation and aging in the lung fluid environment. The simplified lung fluid mimics of PBS and SLF cannot fully replicate the conditions in the respiratory system, which is a complicated chemical environment incorporating antioxidants, surfactants, and proteins and involving biological interactions with the alveoli epithelial cells.…”

Key Factors Determining the Formation of Sulfate Aerosols Through Multiphase Chemistry—A Kinetic Modeling Study Based on Beijing Conditions

“…The famous London Fog and Beijing Haze were attributed to the rapid sulfate formation (Cheng et al., 2016; Wang et al., 2016, 2020a). As normally classified, secondary sulfate originates from the oxidation of sulfur dioxide (SO 2 ) via the gas‐phase oxidation in gaseous environments (Mauldin III et al., 2012) and the multiphase oxidation associated with aerosol particles (Abbatt & Ravishankara, 2023; Burkholder et al., 2017; Liu et al., 2021a; Pöschl & Shiraiwa, 2015; Seinfeld & Pandis, 2016; Tilgner et al., 2021). Nowadays, one of the critical problems is the unexplainable gap between the simulated and observed sulfate concentrations (Cheng et al., 2016; Su et al., 2020), and another one is the enhanced oxidation of SO 2 against its decreasing concentration (Liu et al., 2021b).…”

Distinct Temperature Trends in the Uptake of Gaseous n-Butylamine on Two Solid Diacids

“…The atmospheric impacts of SOA are determined by their formation and transformation processes. , Among those processes, reactive uptake of gas species can significantly alter the physiochemical properties of particles, e.g., through changes in mass, composition, and morphology of particles, thus impacting their light scattering and absorption. ,, Multiphase reaction products from reactive uptake may have different hygroscopicity, volatility, phase transition temperatures, and toxicity compared to the original components, altering the CCN activity, viscosity, interactions with gases, and health effects of SOA. − Moreover, reactive uptake by aerosol particles can alter the abundance and distribution of gases, representing an important sink for many trace gases in the atmosphere …”