Impact of sulfur dioxide oxidation by Stabilized Criegee Intermediate on sulfate

Sarwar, Golam; Simon, Heather; Fahey, Kathleen M.; Mathur, Rohit; Goliff, W. S.; Stockwell, William R.

doi:10.1016/j.atmosenv.2013.12.013

Cited by 57 publications

(60 citation statements)

References 38 publications

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“…Overall, the calculated peak sCI levels are higher than the maximum sCI levels (∼1 × 10 4 molecules cm −3 ) predicted by a regional model for the summer season. 21 It should be noted that the direct comparison between the short-term observationally based estimation and the seasonal estimate of the regional model (12-km resolution) should be cautiously interpreted.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment

Kim

Lefer

Flynn

et al. 2015

Environ. Sci. Technol.

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We present field observations made in June 2011 downwind of Dallas−Fort Worth, TX, and evaluate the role of stabilized Criegee radicals (sCIs) in gaseous sulfuric acid (H 2 SO 4 ) production. Zerodimensional model calculations show that sCI from biogenic volatile organic compounds composed the majority of the sCIs. The main uncertainty associated with an evaluation of H 2 SO 4 production from the sCI reaction channel is the lack of experimentally determined reaction rates for sCIs formed from isoprene ozonolysis with SO 2 along with systematic discrepancies in experimentally derived reaction rates between other sCIs and SO 2 and water vapor. In general, the maximum of H 2 SO 4 production from the sCI channel is found in the late afternoon as ozone increases toward the late afternoon. The sCI channel, however, contributes minor H 2 SO 4 production compared with the conventional OH channel in the mid-day. Finally, the production and the loss rates of H 2 SO 4 are compared. The application of the recommended mass accommodation coefficient causes significant overestimation of H 2 SO 4 loss rates compared with H 2 SO 4 production rates. However, the application of a lower experimental value for the mass accommodation coefficient provides good agreement between the loss and production rates of H 2 SO 4 . The results suggest that the recommended coefficient for the H 2 O surface may not be suitable for this relatively dry environment. ■ INTRODUCTIONMost sulfur compounds emitted to the atmosphere are in a reduced form (e.g., sulfur dioxide, SO 2 (IV)). Atmospheric gasphase oxidation processes sulfur throughout the troposphere and the stratosphere and transforms these emitted sulfur compounds into the most oxidized form of gas-phase sulfuric acid (H 2 SO 4 ), unless heterogeneous uptake transforms the sulfur into condensed-phase forms. The discussion in this paper will focus exclusively on gas-phase H 2 SO 4 formation from gas-phase SO 2 oxidation. Although sulfur compounds contribute a relatively minor fraction of the chemical composition of the troposphere, 1 the critical role of H 2 SO 4 in determining acidity in precipitation 2 and forming particles that influence regional and global climate has been highlighted. 3−5 Anthropogenic sulfur emission in the form of SO 2 is currently estimated to dominate global sulfur emissions, followed by oceanic dimethylsulfide (CH 3 SCH 3 ). 6 The gas-phase atmospheric oxidation processes of SO 2 were thought previously to be driven mostly by hydroxyl radical (OH), as shown in R1−R3. 7The potential role of stabilized Criegee biradicals (sCIs) 8 in SO 2 oxidation has been discussed since the 1970s. Cox and Penkett 9 reported significant SO 3 formation rates from chamber experiments with various alkene compounds, ozone (O 3 ), and SO 2 . They speculated sCIs prompted SO 2 oxidation because the reaction between SO 2 and O 3 is insignificant under atmospheric conditions. Calvert and Stockwell 2 presented comprehensive zero-dimensional model calculation results examining atmosp...

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Section: ■ Results and Discussionmentioning

confidence: 99%

Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment

Kim

Lefer

Flynn

et al. 2015

Environ. Sci. Technol.

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“…However, recent studies have revived an interest in the formation and fate of atmospheric Criegee intermediates (radical species produced from reactions of ozone with alkenes; Calvert et al, 2000;Criegee, 1975), which to this day have eluded direct measurements in the atmosphere since Cox and Penkett (1971) first suggested their potentially important role. Field and laboratory measurements (Berndt et al, , 2014Stone et al, 2014;Taatjes et al, 2014;Mauldin III et al, 2012;Welz et al, 2012) as well as theoretical and modeling studies (Sarwar et al, 2014;Boy et al, 2013;Vereecken et al, 2012) now suggest that the reactivity of these types of radicals towards compounds such as SO 2 may have been underestimated by at least 2 orders of magnitude. Therefore, in addition to OH -or possibly even rivalling OH chemistry -Criegee intermediates may, under certain conditions, be significant contributors to atmospheric sulfuric acid formation and the production of hygroscopic sulfate particles, which can be activated as cloud condensation nuclei (CCN).…”

Section: H Berresheim Et Al: Missing So 2 Oxidant In the Coastal Atmentioning

confidence: 99%

Missing SO<sub>2</sub> oxidant in the coastal atmosphere? – observations from high-resolution measurements of OH and atmospheric sulfur compounds

et al. 2014

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Abstract. Diurnal and seasonal variations of gaseous sulfuric acid (H 2 SO 4 ) and methane sulfonic acid (MSA) were measured in NE Atlantic air at the Mace Head atmospheric research station during the years 2010 and 2011. The measurements utilized selected-ion chemical ionization mass spectrometry (SI/CIMS) with a detection limit for both compounds of 4.3 × 10 4 cm −3 at 5 min signal integration. The H 2 SO 4 and MSA gas-phase concentrations were analyzed in conjunction with the condensational sink for both compounds derived from 3 nm to 10 µm (aerodynamic diameter) aerosol size distributions. Accommodation coefficients of 1.0 for H 2 SO 4 and 0.12 for MSA were assumed, leading to estimated atmospheric lifetimes on the order of 7 and 25 min, respectively. With the SI/CIMS instrument in OH measurement mode alternating between OH signal and background (non-OH) signal, evidence was obtained for the presence of one or more unknown oxidants of SO 2 in addition to OH. Depending on the nature of the oxidant(s), its ambient concentration may be enhanced in the CIMS inlet system by additional production. The apparent unknown SO 2 oxidant was additionally confirmed by direct measurements of SO 2 in conjunction with calculated H 2 SO 4 concentrations. The calculated H 2 SO 4 concentrations were consistently lower than the measured concentrations by a factor of 4.7 ± 2.4 when considering the oxidation of SO 2 by OH as the only source of H 2 SO 4 . Both the OH and the background signal were also observed to increase significantly during daytime aerosol nucleation events, independent of the ozone photolysis frequency, J (O 1 D), and were followed by peaks in both H 2 SO 4 and MSA concentrations. This suggests a strong relation between the unknown oxidant(s), OH chemistry, and the atmospheric photolysis and photooxidation of biogenic iodine compounds. As to the identity of the atmospheric SO 2 oxidant(s), we have been able to exclude ClO, BrO, IO, and OIO as possible candidates based on ab initio calculations. Nevertheless, IO could contribute significantly to the observed CIMS background signal. A detailed analysis of this CIMS background signal in context with recently published kinetic data currently suggests that Criegee intermediates (CIs) produced from ozonolysis of alkenes play no significant role for SO 2 oxidation in the marine atmosphere at Mace Head. On the other hand, SO 2 oxidation by small CIs such as CH 2 OO produced photolytically or possibly in the photochemical degradation of methane is consistent with our observations. In addition, H 2 SO 4 formation from dimethyl sulfide oxidation via SO 3 as an intermediate instead of SO 2 also appears to be a viable explanation. Both pathways need to be further explored.

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“…SO 2 oxidation in the gas phase is simulated using mechanisms previously reported in the literature (Byun and Schere, 2006;Sarwar et al, 2013Sarwar et al, , 2014Binkowski and Roselle, 2003) (Table S1 in the Supplement).…”

Section: Amar Model Descriptionmentioning

confidence: 99%

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO<sub>2</sub>

Jang

Park

2017

Atmos. Chem. Phys.

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Abstract. The photocatalytic ability of airborne mineral dust particles is known to heterogeneously promote SO 2 oxidation, but prediction of this phenomenon is not fully taken into account by current models. In this study, the Atmospheric Mineral Aerosol Reaction (AMAR) model was developed to capture the influence of air-suspended mineral dust particles on sulfate formation in various environments. In the model, SO 2 oxidation proceeds in three phases including the gas phase, the inorganic-salted aqueous phase (non-dust phase), and the dust phase. Dust chemistry is described as the absorption-desorption kinetics of SO 2 and NO x (partitioning between the gas phase and the multilayer coated dust). The reaction of absorbed SO 2 on dust particles occurs via two major paths: autoxidation of SO 2 in open air and photocatalytic mechanisms under UV light. The kinetic mechanism of autoxidation was first leveraged using controlled indoor chamber data in the presence of Arizona Test Dust (ATD) particles without UV light, and then extended to photochemistry. With UV light, SO 2 photooxidation was promoted by surface oxidants (OH radicals) that are generated via the photocatalysis of semiconducting metal oxides (electron-hole theory) of ATD particles. This photocatalytic rate constant was derived from the integration of the combinational product of the dust absorbance spectrum and wave-dependent actinic flux for the full range of wavelengths of the light source. The predicted concentrations of sulfate and nitrate using the AMAR model agreed well with outdoor chamber data that were produced under natural sunlight. For seven consecutive hours of photooxidation of SO 2 in an outdoor chamber, dust chemistry at the low NO x level was attributed to 55 % of total sulfate (56 ppb SO 2 , 290 µg m −3 ATD, and NO x less than 5 ppb). At high NO x (> 50 ppb of NO x with low hydrocarbons), sulfate formation was also greatly promoted by dust chemistry, but it was suppressed by the competition between NO 2 and SO 2 , which both consume the dust-surface oxidants (OH radicals or ozone).

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Impact of sulfur dioxide oxidation by Stabilized Criegee Intermediate on sulfate

Cited by 57 publications

References 38 publications

Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment

Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment

Missing SO<sub>2</sub> oxidant in the coastal atmosphere? – observations from high-resolution measurements of OH and atmospheric sulfur compounds

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO<sub>2</sub>

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Impact of sulfur dioxide oxidation by Stabilized Criegee Intermediate on sulfate

Cited by 57 publications

References 38 publications

Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment

Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment

Missing SO&lt;sub&gt;2&lt;/sub&gt; oxidant in the coastal atmosphere? – observations from high-resolution measurements of OH and atmospheric sulfur compounds

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO&lt;sub&gt;2&lt;/sub&gt;

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Missing SO<sub>2</sub> oxidant in the coastal atmosphere? – observations from high-resolution measurements of OH and atmospheric sulfur compounds

Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO<sub>2</sub>