Sulfur Dioxide Modifies Aerosol Particle Formation and Growth by Ozonolysis of Monoterpenes and Isoprene

Abstract

The effect of sulfur dioxide on particle formation and growth by ozonolysis of three monoterpenes (α‐pinene, β‐pinene, and limonene) and isoprene was investigated in the presence of monodisperse ammonium sulfate seed particles and an OH scavenger in a flow tube under dry conditions. Without sulfur dioxide, new particle formation was not observed, and seed particle growth was consistent with condensation of low‐volatility oxidation products produced from each organic precursor. With sulfur dioxide, new particle formation was observed from every precursor studied, consistent with sulfuric acid formation by reaction of sulfur dioxide with stabilized Criegee Intermediates. The presence of sulfur dioxide did not significantly affect seed particle growth rates from α‐pinene and limonene ozonolysis, although chemical composition measurements revealed the presence of organosulfates in the particles following SO2 exposure. Contrarily, the growth of seeds by β‐pinene and isoprene ozonolysis was considerably enhanced by sulfur dioxide, and chemical composition measurements revealed that the enhanced growth was not due to additional organic material, suggesting that inorganic sulfate was likely responsible. The results suggest that a previously unconsidered particle‐phase pathway to growth activated by sulfur dioxide may alter production of cloud condensation nuclei over regions with significant SO2‐alkene interactions.

Increased new particle yields with largely decreased probability of survival to CCN size at the summit of Mt. Tai under reduced SO<sub>2</sub> emissions

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New Particle Formation in the Atmosphere: From Molecular Clusters to Global Climate

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Temperature effects on sulfuric acid aerosol nucleation and growth: initial results from the TANGENT study

“…At present, there is still no clear evidence from atmospheric observations that demonstrates "causal effects" of temperature and RH on NPF (Lee et al, 2019). Recent CLOUD studies have shown that oxygenated organics formed from biogenic volatile organic compounds (BVOCs) can grow newly nucleated particles in a wide range of tropospheric temperatures (Stolzenburg et al, 2018). This is because gas-phase autooxidation reactions involved in the formation of highly oxidized molecules (HOMs) usually have strong temperature dependencies, with higher reaction rates at higher temperatures (Frege et al, 2018), whereas nucleation is favored at lower temperatures.…”