Article

# Evidence for Organosulfates in Secondary Organic Aerosol

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University of Antwerp, Antwerpen, Flemish, Belgium
(Impact Factor: 5.33). 02/2007; 41(2):517-27. DOI: 10.1021/es062081q
Source: PubMed

ABSTRACT

Recent work has shown that particle-phase reactions contribute to the formation of secondary organic aerosol (SOA), with enhancements of SOA yields in the presence of acidic seed aerosol. In this study, the chemical composition of SOA from the photooxidations of alpha-pinene and isoprene, in the presence or absence of sulfate seed aerosol, is investigated through a series of controlled chamber experiments in two separate laboratories. By using electrospray ionization-mass spectrometry, sulfate esters in SOA produced in laboratory photooxidation experiments are identified for the first time. Sulfate esters are found to account for a larger fraction of the SOA mass when the acidity of seed aerosol is increased, a result consistent with aerosol acidity increasing SOA formation. Many of the isoprene and alpha-pinene sulfate esters identified in these chamber experiments are also found in ambient aerosol collected at several locations in the southeastern U.S. It is likely that this pathway is important for other biogenic terpenes, and may be important in the formation of humic-like substances (HULIS) in ambient aerosol.

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Available from: Edward O. Edney,
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• "Analysis of filter extracts is commonly performed by liquid chromatography (LC) and gas chromatography (GC), coupled to mass spectrometry with the use of electron ionization (EI), chemical ionization (CI), electrospray ionization (ESI), and atmospheric pressure chemical ionization (APCI) (Dye and Yttri, 2005; Simpson et al., 2005; Surratt et al., 2006 and 2007a, b; Lavrich and Hays, 2007; Szmigielski et al., 2007; Lin et al., 2012). Major organic classes in SOA that have been identified from filter-based analysis include (nitrooxy)organosulfates (Surratt et al., 2007a, b and 2008; Iinuma et al., 2007; Chan et al., 2011), dimers, trimers, and oligomers (Jang et al., 2002; Limbeck et al., 2003; Gao et al., 2004; Kalberer et al., 2004; Fahnestock et al., 2014), and humic-like substances (Gelencser et al., 2002; Graham et al., 2002). A limitation of filterbased analysis is low time resolution and, consequently, the inability to track particle-phase kinetics. "
##### Article: Time-resolved molecular characterization of organic aerosols by PILS + UPLC/ESI-Q-TOFMS

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• "The effects of acid enhancement on BSOA formation were examined by comparing paired samples collected under high and low SO 2 or NH 3 scenarios. Even though some of these BSOA tracers have been previously characterized from PM 2.5 samples collected from the SEARCH network in a time-integrated manner (Chan et al., 2010b; Gao et al., 2006; Surratt et al., 2007a, 2008), using conditional sampling approaches to collect PM 2.5 in this study is to our knowledge one of the first attempts to systematically examine if BSOA formation is enhanced or suppressed due to anthropogenic emissions in this region. "
##### Article: Investigating the influences of SO2 and NH3 levels on isoprene-derived secondary organic aerosol formation using conditional sampling approaches
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ABSTRACT: Filter-based PM2.5 samples were chemically analyzed to investigate secondary organic aerosol (SOA) formation from isoprene in a rural atmosphere of the southeastern US influenced by both anthropogenic sulfur dioxide (SO2) and ammonia (NH3) emissions. Daytime PM2.5 samples were collected during summer 2010 using conditional sampling approaches based on pre-defined high and low SO2 or NH3 thresholds. Known molecular-level tracers for isoprene SOA formation, including 2-methylglyceric acid, 3-methyltetrahydrofuran-3,4-diols, 2-methyltetrols, C5-alkene triols, dimers, and organosulfate derivatives, were identified and quantified by gas chromatography coupled to electron ionization mass spectrometry (GC/EI-MS) and ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS). Mass concentrations of six isoprene low-NOx SOA tracers contributed to 12-19% of total organic matter (OM) in PM2.5 samples collected during the sampling period, indicating the importance of the hydroxyl radical (OH)-initiated oxidation (so-called photooxidation) of isoprene under low-NOx conditions that leads to SOA formation through reactive uptake of gaseous isoprene epoxydiols (IEPOX) in this region. IEPOX-derived SOA tracers were enhanced under high-SO2 sampling scenarios, suggesting that SO2 oxidation increases aerosol acidity of sulfate aerosols needed for enhancing heterogeneous oxirane ring-opening reactions of IEPOX. No clear associations between isoprene SOA formation and high and low NH3 conditional samples were found. Furthermore, weak correlations between aerosol acidity and mass of IEPOX SOA tracers suggests that IEPOX-derived SOA formation might be modulated by other factors as well in addition to aerosol acidity. Positive correlations between sulfate aerosol loadings and IEPOX-derived SOA tracers for samples collected under all conditions indicates that sulfate aerosol could be a surrogate for surface area in the uptake of IEPOX onto preexisting aerosols.
Atmospheric Chemistry and Physics 08/2013; 13:8457-8470. DOI:10.5194/acp-13-8457-2013 · 4.88 Impact Factor
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• "Radical reactions involve a variety of atmospheric oxidants, including OH radicals, NO 3 radicals, O 3 , H 2 O 2 , and can be initiated by photolysis (Lim et al., 2010). Non-radical reactions include hemiacetal formation (Liggio et al., 2005b; Loeffler et al., 2006), esterification via condensation reactions (Gao et al., 2004; Surratt et al., 2006; Surratt et al., 2007; Altieri et al., 2008), imine formation (De Haan et al., 2009a; De Haan et al., 2009c), anhydride formation (Gao et al., 2004), aldol condensation (Jang et al., 2002; Kalberer et al., 2004; Noziere and Cordova, 2008; Shapiro et al., 2009), and organosulfate formation (Liggio et al., 2005a; Surratt et al., 2007). Presently only a few studies have attempted to quantitatively explore the factors that contribute to the formation of cloud SOA. "
##### Article: Evaluation of factors controlling global secondary organic aerosol production from cloud processes
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ABSTRACT: Secondary organic aerosols (SOA) exert a significant influence on ambient air quality and regional climate. Recent field, laboratorial and modeling studies have confirmed that in-cloud processes contribute to a large fraction of SOA production with large space-time heterogeneity. This study evaluates the key factors that govern the production of cloud-process SOA (SOAcld) on a global scale based on the GFDL coupled chemistry-climate model AM3 in which full cloud chemistry is employed. The association between SOAcld production rate and six factors (i.e., liquid water content (LWC), total carbon chemical loss rate (TCloss), temperature, VOC/NOx, OH, and O3) is examined. We find that LWC alone determines the spatial pattern of SOAcld production, particularly over the tropical, subtropical and temperate forest regions, and is strongly correlated with SOAcld production. TCloss ranks the second and mainly represents the seasonal variability of vegetation growth. Other individual factors are essentially uncorrelated spatiotemporally to SOAcld production. We find that the rate of SOAcld production is simultaneously determined by both LWC and TCloss, but responds linearly to LWC and nonlinearly (or concavely) to TCloss. A parameterization based on LWC and TCloss can capture well the spatial and temporal variability of the process-based SOAcld formation (R2 = 0.5) and can be easily applied to global three dimensional models to represent the SOA production from cloud processes.
ATMOSPHERIC CHEMISTRY AND PHYSICS 02/2013; 13(4):1913-1926. DOI:10.5194/acp-13-1913-2013 · 5.05 Impact Factor