Jernigan Christopher M, Cappa Christopher D, Bertram Timothy H
Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States.
Department of Civil and Environmental Engineering, University of California, Davis, 95616, California United States.
J Phys Chem A. 2022 Jul 14;126(27):4476-4481. doi: 10.1021/acs.jpca.2c03222. Epub 2022 Jun 28.
The oxidation products of dimethyl sulfide (DMS) contribute to the production and growth of cloud condensation nuclei (CCN) in the marine boundary layer. Recent work demonstrates that DMS is oxidized by OH radicals to the stable intermediate hydroperoxymethyl thioformate (HPMTF), which is both globally ubiquitous and efficiently lost to multiphase processes in the marine atmosphere. At present, there are no experimental measurements of the reactive uptake of HPMTF to aerosol particles, limiting model implementation of multiphase HPMTF chemistry. Using an entrained aerosol flow reactor combined with chemical ionization mass spectrometry (CIMS), we measured the reactive uptake coefficient (γ) of HPMTF to dry sodium chloride (NaCl), wet NaCl, and wet sodium iodide (NaI) particles to be (1.9 ± 1.3) × 10, (1.6 ± 0.6) × 10, and (9.2 ± 2.3) × 10, respectively. While we did not directly measure the condensed-phase products of HPMTF reactive uptake in this experiment, the ionization products observed in the CIMS instrument provide mechanistic insight on the reaction mechanism of HPMTF with halides.
二甲基硫醚（DMS）的氧化产物有助于海洋边界层中云凝结核（CCN）的产生和增长。近期研究表明，DMS被羟基自由基氧化为稳定的中间体氢过氧甲基硫代甲酸酯（HPMTF），这种物质在全球范围内普遍存在，并在海洋大气的多相过程中高效损耗。目前，尚无关于HPMTF在气溶胶颗粒上反应吸收的实验测量数据，这限制了多相HPMTF化学过程在模型中的应用。我们使用夹带气溶胶流动反应器结合化学电离质谱（CIMS），测量了HPMTF在干燥氯化钠（NaCl）、湿NaCl和湿碘化钠（NaI）颗粒上的反应吸收系数（γ），分别为(1.9 ± 1.3) × 10、(1.6 ± 0.6) × 10和(9.2 ± 2.3) × 10。虽然在本实验中我们没有直接测量HPMTF反应吸收的凝聚相产物，但CIMS仪器中观察到的电离产物为HPMTF与卤化物的反应机制提供了机理见解。
