Stability of Monoterpene-Derived α-Hydroxyalkyl-Hydroperoxides in Aqueous Organic Media: Relevance to the Fate of Hydroperoxides in Aerosol Particle Phases

Abstract

The -hydroxyalkyl-hydroperoxides [R-(H)C(-OH)(-OOH), -HH] produced in the ozonolysis of unsaturated organic compounds may contribute to SOA aging. -HHs inherent instability, however, hampers their detection and a positive assessment of their actual role. Here we report, for the first time, the rates and products of the decomposition of the -HHs generated in the ozonolysis of atmospherically important monoterpenes -pinene (-P), dlimonene (d-L), -terpinene (-Tn) and -terpineol (-Tp) in water:acetonitrile (W:AN) mixtures. We detect -HHs and multifunctional decomposition products as chloride-adducts by online electrospray ionization mass spectrometry. Experiments involving D 2 O and H 2 18 O instead of H 2 16 O, and an OH-radical scavenger show that -HHs decompose into gem-diols + H 2 O 2 rather than free radicals. -HHs decay mono-or bi-exponentially depending on molecular structure and solvent composition. e-fold times,  1/e , in water-rich solvent mixtures range from  1/e = 15-45 min for monoterpene-derived -HHs to  1/e > 10 3 min for the -Tp

Heterogeneous interactions between SO<sub>2</sub> and organic peroxides in submicron aerosol

“…Solute strength may change the pH dependence of γ SO 2 in two ways. First, the solubility of SO 2 may decrease and become less dependent on pH as ionic strength increases (Rodríguez-Sevilla et al, 2002). A former study (Leng et al, 2015) has shown that the effective Henry's law of triethylamine decreases with increased ionic strength.…”

Reactive species formed upon interaction of water with fine particulate matter from remote forest and polluted urban air

“…The mean RF of  OH, ordered from lowest to highest are: 21% (Hyytiälä) < 38% (Mainz) < 53% (Beijing). The presence of  OH is related to multiple formation pathways, such as Fenton-like reactions, thermal or hydrolytic decomposition of peroxide-containing HOMs, and redox chemistry of environmentally persistent free radicals or aromatic compounds-containing humic-like substances (Chevallier et al, 2004;Valavanidis et al, 2005;Li et al, 2008;Page et al, 2012;Gehling et al, 2014;Tong et al, 2016a;Tong et al, 2017;Tong et al, 2018;Tong et al, 2019;Qiu et al, 2020). The mean RF of O2 only varies slightly in the range of 2-6%, showing no clear trend and within the range of standard errors in 3.2 Mass-specific and air sample volume-specific yields of RS from ambient PM2.5 Figure 3 shows the mass-specific and air sample volume-specific yields of reactive species (RS) including radicals, H2O2, and the sum of radicals and H2O2 by PM2.5 from Hyytiälä, Mainz, and Beijing.…”

“…(HOMs) (Chen et al, 2010;Wang et al, 2011b;Tong et al, 2016a;Tong et al, 2018;Tong et al, 2019;Fang et al, 2020;Qiu et al, 2020). Moreover, the humic-like substances and other multifunctional compounds containing carboxyl, carboxylate, phenolic, and quinoid groups may influence the redox activity of PM via chelating transition metals (Laglera and van den Berg, 2009;Kostić et al, 2011;Catrouillet et al, 2014;Gonzalez et al, 2017;Wang et al, 2018c;Win et al, 2018;Wei et al, 2019).…”

Heterogeneous Interactions between SO&lt;sub&gt;2&lt;/sub&gt; and Organic Peroxides in Submicron Aerosol

“…Organic peroxides generated from both biogenic and anthropogenic hydrocarbon emissions are abundant in submicron aerosol. Given that they are highly reactive with relatively short lifetimes (Bonn et al, 2004;Krapf et al, 2016;Qiu et al, 2020), these species could serve as important condensed phase oxidants for gas phase SO2. Combining laboratory measurements and model predictions, the current study investigated heterogeneous reactions between SO2 and particulate organic peroxide.…”