Increasing Isoprene Epoxydiol-to-Inorganic Sulfate Aerosol (IEPOX:Sulf inorg ) Ratio Results in Extensive Conversion of Inorganic Sulfate to Organosulfur Forms: Implications for Aerosol Physicochemical Properties

Riva, Matthieu; Chen, Yuzhi; Zhang, Yue; Lei, Ziying; Olson, Nicole; Boyer, Hallie C.; Narayan, Shweta; Yee, Lindsay D.; Green, Hilary; Cui, Tianqu; Zhang, Zhenfa; Baumann, Karsten D; Fort, Michael; Edgerton, Eric S.; Budisulistiorini, Sri; Rose, Caitlin A; Ribeiro, Igor; e Oliveira, Rafael L.; Santos, Erickson; Szopa, Sophie; Machado, Cristine; Zhao, Yue; Alves, Eliane; de Sa, Suzane; Hu, Weiwei; Knipping, Eladio; Shaw, Stephanie; Duvoisin Junior, Sergio; Souza, Rodrigo Augusto; Palm, Brett B; Jimenez, Jose L.; Glasius, Marianne; Goldstein, Allen H.; Pye, Havala Olson; Gold, Avram; Turpin, Barbara J.; Vizuete, William; Martin, Scot T.; Thornton, Joel; Dutcher, Cari S.; Ault, Andrew P; Surratt, Jason Douglas

doi:10.1021/acs.est.9b01019

In order to examine the reaction products, kinetics, and implications of ISOPOOH with aqueous sulfite, ammonium bisulfate particles were injected into the UNC 10‐m3 indoor environmental chamber under humid (i.e., 72% RH) and dark conditions. After the inorganic sulfate concentration stabilized, selected concentrations of gas‐phase 1,2‐ISOPOOH were injected into the chamber, and aerosols showed a minimal mass increase. Gaseous SO2 was subsequently injected into the chamber and a significant amount of aerosol mass was produced. The gas‐phase ISOPOOH and particle‐phase species were sampled with online instruments, including a chemical ionization mass spectrometer (CIMS), an aerosol chemical speciation monitor (ACSM), a particle‐into‐liquid sampler (PILS) for analysis by ion chromatography analysis (IC), and filter samples were analyzed by an ultra‐performance liquid chromatography coupled to an electrospray ionization highresolution quadrupole time‐of‐flight mass spectrometry (UPLCESI‐ HR‐QTOFMS) to obtain offline molecular‐level information. Results show that a significant amount of inorganic sulfate and organosulfates were formed rapidly after injecting SO2, altering the chemical and physical properties of the particles including phase state, pH, reactivity, and composition. Multifunctional C5‐organic species that were previously measured in atmospheric fine aerosol samples were also reported here as reaction products, including 2‐methyletrols and 2‐methyltetrol sulfates that were previously thought to be only produced from the reactive uptake of isoprene‐derived epoxydiols (IEPOX). Such results indicate that the multiphase reactions of ISOPOOH could have significant impacts on the atmospheric lifecycle of organic aerosols and sulfur, as well as the physicochemical properties of ambient particles.

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