Reaction of Criegee Intermediates with Water VaporAn Additional Source of OH Radicals in Alkene Ozonolysis?

2003 ◽  
Vol 107 (32) ◽  
pp. 6176-6182 ◽  
Author(s):  
Alam S. Hasson ◽  
Myeong Y. Chung ◽  
Keith T. Kuwata ◽  
Amber D. Converse ◽  
Debra Krohn ◽  
...  
Keyword(s):  
Oh Radicals ◽  
Additional Source ◽  
Criegee Intermediates

scholarly journals Role of Criegee intermediates in the formation of sulfuric acid at a Mediterranean (Cape Corsica) site under influence of biogenic emissions

2021 ◽  
Vol 21 (17) ◽  
pp. 13333-13351
Author(s):  
Alexandre Kukui ◽  
Michel Chartier ◽  
Jinhe Wang ◽  
Hui Chen ◽  
Sébastien Dusanter ◽  
...  
Keyword(s):  
Steady State ◽  
Sulfuric Acid ◽  
Organic Compounds ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Additional Source ◽  
So2 Oxidation ◽  
Criegee Intermediates ◽  
Volatile Organic

Abstract. Reaction of stabilized Criegee intermediates (SCIs) with SO2 was proposed as an additional pathway of gaseous sulfuric acid (H2SO4) formation in the atmosphere, supplementary to the conventional mechanism of H2SO4 production by oxidation of SO2 in reaction with OH radicals. However, because of a large uncertainty in mechanism and rate coefficients for the atmospheric formation and loss reactions of different SCIs, the importance of this additional source is not well established. In this work, we present an estimation of the role of SCIs in H2SO4 formation at a western Mediterranean (Cape Corsica) remote site, where comprehensive field observations including gas-phase H2SO4, OH radicals, SO2, volatile organic compounds (VOCs) and aerosol size distribution measurements were performed in July–August 2013 as a part of the project ChArMEx (Chemistry-Aerosols Mediterranean Experiment). The measurement site was under strong influence of local emissions of biogenic volatile organic compounds, including monoterpenes and isoprene generating SCIs in reactions with ozone, and, hence, presenting an additional source of H2SO4 via SO2 oxidation by the SCIs. Assuming the validity of a steady state between H2SO4 production and its loss by condensation on existing aerosol particles with a unity accommodation coefficient, about 90 % of the H2SO4 formation during the day could be explained by the reaction of SO2 with OH. During the night the oxidation of SO2 by OH radicals was found to contribute only about 10 % to the H2SO4 formation. The accuracy of the derived values for the contribution of OH + SO2 reaction to the H2SO4 formation is limited mostly by a large, at present factor of 2, uncertainty in the OH + SO2 reaction rate coefficient. The contribution of the SO2 oxidation by SCIs to the H2SO4 formation was evaluated using available measurements of unsaturated VOCs and steady-state SCI concentrations estimated by adopting rate coefficients for SCI reactions based on structure–activity relationships (SARs). The estimated concentration of the sum of SCIs was in the range of (1–3) × 103 molec. cm−3. During the day the reaction of SCIs with SO2 was found to account for about 10 % and during the night for about 40 % of the H2SO4 production, closing the H2SO4 budget during the day but leaving unexplained about 50 % of the H2SO4 formation during the night. Despite large uncertainties in used kinetic parameters, these results indicate that the SO2 oxidation by SCIs may represent an important H2SO4 source in VOC-rich environments, especially during nighttime.

scholarly journals Role of Criegee intermediates in the formation of sulfuric acid at a Mediterranean (Cape Corsica) site under influence of biogenic emissions

2021 ◽  
Author(s):  
Alexandre Kukui ◽  
Michel Chartier ◽  
Jinhe Wang ◽  
Hui Chen ◽  
Sébastien Dusanter ◽  
...  
Keyword(s):  
Steady State ◽  
Sulfuric Acid ◽  
Organic Compounds ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Additional Source ◽  
So2 Oxidation ◽  
Criegee Intermediates ◽  
Volatile Organic

Abstract. Reaction of stabilized Criegee Intermediates (SCIs) with SO2 was proposed as an additional pathway of gaseous sulfuric acid (H2SO4) formation in the atmosphere, supplementary to the conventional mechanism of H2SO4 production by oxidation of SO2 in reaction with OH radicals. However, because of a large uncertainty in mechanism and rate coefficients for the atmospheric formation and loss reactions of different SCIs, the importance of this additional source is not well established. In this work, we present an estimation of the role of SCIs in H2SO4 formation at a western Mediterranean (Cape Corsica) remote site, where a comprehensive field observations including gas phase H2SO4, OH radicals, SO2, volatile organic compounds (VOCs) and aerosol size distribution measurements have been performed in July–August 2013 as a part of the project ChArMEx. The measurement site was under strong influence of local emissions of biogenic volatile organic compounds including monoterpenes and isoprene generating SCIs in reactions with ozone and, hence, presenting an additional source of H2SO4 via SO2 oxidation by the SCIs. Assuming the validity of a steady state between H2SO4 production and its loss by condensation on existing aerosol particles with a unity accommodation coefficient, about 90 % of the H2SO4 formation during the day could be explained by the reaction of SO2 with OH. During the night the oxidation of SO2 by OH radicals was found to contribute only about 10 % to the H2SO4 formation. The accuracy of the derived values for the contribution of OH+SO2 reaction to the H2SO4 formation is limited mostly by a large, presently of a factor of 2, uncertainty in OH+SO2 reaction rate coefficient. The contribution of the SO2 oxidation by SCIs to the H2SO4 formation was evaluated using available measurements of unsaturated VOCs and steady state SCIs concentrations estimated by adopting rate coefficients for SCIs reactions based on structure–activity relationships (SARs). The estimated concentration of the sum of SCIs was in the range of (1–3) × 103 molecule cm−3. During the day the reaction of SCIs with SO2 was found to account for about 10 % and during the night for about 40 % of the H2SO4 production, closing the H2SO4 budget during the day but leaving unexplained about 50 % of the H2SO4 formation during the night. Despite large uncertainties in used kinetic parameters, these results indicate that the SO2 oxidation by SCIs may represent an important H2SO4 source in VOCs-rich environments, especially during night-time.

scholarly journals The oxidation regime and SOA composition in limonene ozonolysis: roles of different double bonds, radicals, and water

2018 ◽  
Vol 18 (20) ◽  
pp. 15105-15123 ◽  
Author(s):  
Yiwei Gong ◽  
Zhongming Chen ◽  
Huan Li
Keyword(s):  
Mass Fraction ◽  
Reaction Pathway ◽  
Performic Acid ◽  
Oh Radicals ◽  
Double Bonds ◽  
Criegee Intermediates ◽  
Volatile Organic ◽  
Partitioning Coefficients ◽  
Reaction With Water ◽  
Partitioning Behavior

Abstract. Volatile organic compounds play an important role in air quality and climate change, largely because they contribute to the formation of oxidizing compounds and secondary organic aerosol (SOA). In this study, a series of products, including peroxides and carbonyl compounds in both gaseous and particulate phases, were simultaneously detected to investigate the oxidation regime and SOA composition in limonene ozonolysis. The roles of different double bonds (DBs), radicals, and water were also examined. In our first investigation, we focused on representative oxidizing compounds produced in limonene ozonolysis, including stabilized Criegee intermediates (SCIs), OH radicals, and peroxides. The dependence of H2O2 and hydroxymethyl hydroperoxide (HMHP) formation on RH demonstrates that the reaction with water is an important reaction pathway for limonene SCIs, and the lower limit SCI yields of endocyclic and exocyclic DBs were estimated to be ∼0.24 and ∼0.43, respectively. The OH yield was determined by adding sufficient amounts of an OH scavenger, and the OH yields of endocyclic and exocyclic DBs were ∼0.65 and ∼0.24, respectively. These results indicate that in limonene ozonolysis the endocyclic DB is inclined to generate OH radicals through the hydroperoxide channel, while the exocyclic DB has a higher fraction of forming SCIs. Additionally, other gas-phase and particle-phase peroxides were also studied in this work. The formation of performic acid (PFA) and peracetic acid (PAA) was promoted significantly by increasing RH and the degree of oxidation, and the discrepancy between the experimental and model results suggested some missing formation pathways. Considerable generation of H2O2 from SOA in the aqueous phase was observed, especially at a high [O3] ∕ [limonene] ratio, which was mainly attributed to the hydration and decomposition of unstable peroxides in SOA such as peroxycarboxylic acids and peroxyhemiacetals. Different DBs and OH scavengers had a large impact on the particulate peroxides, and their stability indicated that the types of peroxides in SOA changed under different conditions. As for the contribution of peroxides to SOA, the results demonstrated that the mass fraction of particulate peroxides in limonene SOA was less than 0.2 at a low [O3] ∕ [limonene] ratio, while the mass fraction was 0.4–0.6 at a high [O3] ∕ [limonene] ratio. The partitioning behavior of peroxides showed that multi-generation oxidation helped produce more low-volatility peroxides, which partially explained the higher SOA yield. The partitioning behavior of carbonyls was also examined and the experimental partitioning coefficients (Kp) were found to be typically several orders of magnitude higher than the theoretical values. This study provided new insights into the oxidation regime and SOA composition in limonene ozonolysis, and limonene showed its specificity in many aspects when both endocyclic and exocyclic DBs were ozonated. We suggest that the atmospheric implications of terpenes containing more than one DB and the SOA composition, especially particulate peroxides, need further study.

scholarly journals Formation of secondary aerosols from gasoline vehicle exhaust when mixing with SO<sub>2</sub>

2016 ◽  
Vol 16 (2) ◽  
pp. 675-689 ◽  
Author(s):  
T. Liu ◽  
X. Wang ◽  
Q. Hu ◽  
W. Deng ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Production Factor ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Vehicle Exhaust ◽  
High Concentration ◽  
Molar Ratios ◽  
Criegee Intermediates ◽  
Positive Linear Correlation ◽  
Secondary Aerosols ◽  
Photochemical Aging

Abstract. Sulfur dioxide (SO2) can enhance the formation of secondary aerosols from biogenic volatile organic compounds (VOCs), but its influence on secondary aerosol formation from anthropogenic VOCs, particularly complex mixtures like vehicle exhaust, remains uncertain. Gasoline vehicle exhaust (GVE) and SO2, a typical pollutant from coal burning, are directly co-introduced into a smog chamber, in this study, to investigate the formation of secondary organic aerosols (SOA) and sulfate aerosols through photooxidation. New particle formation was enhanced, while substantial sulfate was formed through the oxidation of SO2 in the presence of high concentration of SO2. Homogenous oxidation by OH radicals contributed a negligible fraction to the conversion of SO2 to sulfate, and instead the oxidation by stabilized Criegee intermediates (sCIs), formed from alkenes in the exhaust reacting with ozone, dominated the conversion of SO2. After 5 h of photochemical aging, GVE's SOA production factor revealed an increase by 60–200 % in the presence of high concentration of SO2. The increase could principally be attributed to acid-catalyzed SOA formation as evidenced by the strong positive linear correlation (R2 = 0.97) between the SOA production factor and in situ particle acidity calculated by the AIM-II model. A high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) resolved OA's relatively lower oxygen-to-carbon (O : C) (0.44 ± 0.02) and higher hydrogen-to-carbon (H : C) (1.40 ± 0.03) molar ratios for the GVE / SO2 mixture, with a significantly lower estimated average carbon oxidation state (OSc) of −0.51 ± 0.06 than −0.19 ± 0.08 for GVE alone. The relative higher mass loading of OA in the experiments with SO2 might be a significant explanation for the lower SOA oxidation degree.

Direct production of OH radicals upon CH overtone activation of (CH3)2COO Criegee intermediates

2014 ◽  
Vol 141 (23) ◽  
pp. 234312 ◽  
Author(s):  
Fang Liu ◽  
Joseph M. Beames ◽  
Marsha I. Lester
Keyword(s):  
Oh Radicals ◽  
Direct Production ◽  
Criegee Intermediates

scholarly journals Direct observation of OH formation from stabilised Criegee intermediates

2014 ◽  
Vol 16 (37) ◽  
pp. 19941-19951 ◽  
Author(s):  
A. Novelli ◽  
L. Vereecken ◽  
J. Lelieveld ◽  
H. Harder
Keyword(s):  
Direct Observation ◽  
Tropospheric Chemistry ◽  
Oh Radicals ◽  
Criegee Intermediates

The first direct observation of OH radicals from syn-CH3CHOO Criegee intermediates decomposition suggests it affects tropospheric chemistry and ambient OH measurements.

scholarly journals Formation of nighttime sulfuric acid from the ozonolysis of alkenes in Beijing

2021 ◽  
Vol 21 (7) ◽  
pp. 5499-5511
Author(s):  
Yishuo Guo ◽  
Chao Yan ◽  
Chang Li ◽  
Wei Ma ◽  
Zemin Feng ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
High Frequency ◽  
Particle Formation ◽  
Vapor Condensation ◽  
Urban Environments ◽  
Oh Radicals ◽  
Strongly Correlated ◽  
So2 Oxidation ◽  
Criegee Intermediates ◽  
Main Driver

Abstract. Gaseous sulfuric acid (SA) has received a lot of attention for its crucial role in atmospheric new particle formation (NPF). And for this reason, studies until now have mainly focused on daytime SA when most NPF events occur. While daytime SA production is driven by SO2 oxidation of OH radicals of photochemical origin, the formation of SA during nighttime and its potential influence on particle formation remains poorly understood. Here we present evidence for significant nighttime SA production in urban Beijing during winter, yielding concentrations between 1.0 and 3.0 × 106 cm−3. We found a high frequency (∼ 30 %) of nighttime SA events, which are defined by the appearance of a distinct SA peak observed between 20:00 and 04:00 local time, with the maximum concentration exceeding 1.0 × 106 cm−3. These events mostly occurred during unpolluted nights with a low vapor condensation sink. Furthermore, we found that under very clean conditions (visibility > 16.0 km) with abundant ozone (concentration > 2.0 × 1011 cm−3, ∼ 7 ppb), the overall sink of SA was strongly correlated with the products of O3, alkenes and SO2 concentrations, suggesting that the ozonolysis of alkenes played a major role in nighttime SA formation under such conditions. This is in light of previous studies showing that the ozonolysis of alkenes can form OH radicals and stabilized Criegee intermediates (SCIs), both of which are able to oxidize SO2 and thus lead to SA formation. However, we also need to point out that there exist additional sources of SA under more polluted conditions, which are not investigated in this study. Moreover, there was a strong correlation between SA concentration and the number concentration of sub-3 nm particles on both clean and polluted nights. Different from forest environments, where oxidized biogenic vapors are the main driver of nighttime clustering, our study demonstrates that the formation of nighttime cluster mode particles in urban environments is mainly driven by nighttime SA production.

scholarly journals Enhancement of atmospheric H<sub>2</sub>SO<sub>4</sub> / H<sub>2</sub>O nucleation: organic oxidation products versus amines

2014 ◽  
Vol 14 (2) ◽  
pp. 751-764 ◽  
Author(s):  
T. Berndt ◽  
M. Sipilä ◽  
F. Stratmann ◽  
T. Petäjä ◽  
J. Vanhanen ◽  
...  
Keyword(s):  
First Generation ◽  
Oxidation Products ◽  
Oh Radicals ◽  
Flow Tube ◽  
Experimental Conditions ◽  
Criegee Intermediates ◽  
Wide Range ◽  
Independent Process ◽  
Oxidant Production ◽  
Organic Oxidation

Abstract. Atmospheric H2SO4 / H2O nucleation influencing effects have been studied in the flow tube IfT-LFT (Institute for Tropospheric Research – Laminar Flow Tube) at 293 ± 0.5 K and a pressure of 1 bar using synthetic air as the carrier gas. The presence of a possible background amine concentration in the order of 107–108 molecule cm−3 throughout the experiments has to be taken into account. In a first set of investigations, ozonolysis of olefins (tetramethylethylene, 1-methyl-cyclohexene, α-pinene and limonene) for close to atmospheric concentrations, served as the source of OH radicals and possibly other oxidants initiating H2SO4 formation starting from SO2. The oxidant generation is inevitably associated with the formation of organic oxidation products arising from the parent olefins. These products (first generation mainly) showed no clear effect on the number of nucleated particles within a wide range of experimental conditions for H2SO4 concentrations higher than ~107 molecule cm−3. Also the early growth process of the nucleated particles was not significantly influenced by the organic oxidation products in line with the expected growth by organic products using literature data. An additional, H2SO4-independent process of particle (nano-CN) formation was observed in the case of α-pinene and limonene ozonolysis for H2SO4 concentrations smaller than ~107 molecule cm−3. Furthermore, the findings confirm the appearance of an additional oxidant for SO2 beside OH radicals, very likely stabilized Criegee Intermediates (sCI). A second set of experiments has been performed in the presence of added amines in the concentrations range of a few 107–1010 molecule cm−3 applying photolytic OH radical generation for H2SO4 production without addition of other organics. All amines showed significant nucleation enhancement with increasing efficiency in the order pyridine < aniline < dimethylamine < trimethylamine. This result supports the idea of H2SO4 cluster stabilization by amines due to strong H2SO4↔amine interactions. On the other hand, this study indicates that for organic oxidation products (in presence of the possible amine background as stated) a distinct H2SO4 / H2O nucleation enhancement can be due to increased H2SO4 formation caused by additional organic oxidant production (sCI) rather than by stabilization of H2SO4 clusters due to H2SO4↔organics interactions.

scholarly journals Estimation of mechanistic parameters in the gas-phase reactions of ozone with alkenes for use in automated mechanism construction

2022 ◽  
Author(s):  
Mike J. Newland ◽  
Camille Mouchel-Vallon ◽  
Richard Valorso ◽  
Bernard Aumont ◽  
Luc Vereecken ◽  
...  
Keyword(s):  
Theoretical Data ◽  
Closed Shell ◽  
Atmospheric Composition ◽  
Critical Parameters ◽  
Initial Reaction ◽  
Oh Radicals ◽  
Unimolecular Decomposition ◽  
Criegee Intermediates ◽  
Automatic Mechanism ◽  
The Impact

Abstract. Reaction with ozone is an important atmospheric removal process for alkenes. The ozonolysis reaction produces carbonyls, and carbonyl oxides (Criegee intermediates, CI), which can rapidly decompose to yield a range of closed shell and radical products, including OH radicals. Consequently, it is essential to accurately represent the complex chemistry of Criegee intermediates in atmospheric models in order to fully understand the impact of alkene ozonolysis on atmospheric composition. A mechanism construction protocol is presented which is suitable for use in automatic mechanism generation. The protocol defines the critical parameters for describing the chemistry following the initial reaction, namely: the primary carbonyl / CI yields from the primary ozonide fragmentation; the amount of stabilisation of the excited CI (CI*); the unimolecular decomposition pathways, rates and products of the CI; the bimolecular rates and products of atmospherically important reactions of the stabilised CI (SCI). This analysis implicitly predicts the yield of OH from the alkene-ozone reaction. A comprehensive database of experimental OH, SCI and carbonyl yields has been collated using reported values in the literature and used to assess the reliability of the protocol. The protocol provides estimates OH, SCI and carbonyl yields with a root mean square error of 0.13 and 0.12 and 0.14, respectively. Areas where new experimental and theoretical data would improve the protocol and its assessment are identified and discussed.

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