A Theoretical Perspective of the Structure and Thermodynamics of Secondary Organic Aerosols from Toluene: Molecular Hierarchical Synergistic Effects

2022 ◽  
Author(s):  
Xianli Duan ◽  
Xianyu Song ◽  
Shi Ruifang ◽  
Wang Xuan ◽  
Suhang Chen ◽  
...  
Keyword(s):  
Liquid Fuel ◽  
Secondary Organic Aerosols ◽  
Secondary Organic Aerosol ◽  
Synergistic Effects ◽  
Theoretical Perspective ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Underlying Mechanism ◽  
Important Constituent

Toluene is an important constituent of liquid fuel, and it contributes to the formation of secondary organic aerosol (SOA) under photochemical conditions. However, the underlying mechanism of toluene SOA is...

scholarly journals Influence of NO<sub>2</sub> on secondary organic aerosol formation from ozonolysis of limonene

2017 ◽  
Author(s):  
Changjin Hu ◽  
Qiao Ma ◽  
Zhi Liu ◽  
Yue Cheng ◽  
Liqing Hao ◽  
...  
Keyword(s):  
Experimental Data ◽  
Secondary Organic Aerosols ◽  
Secondary Organic Aerosol ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Chemical Mechanism ◽  
Aerosol Formation ◽  
Model Simulations ◽  
Negative Effect ◽  
Master Chemical Mechanism

Abstract. Limonene has a strong tendency to undergo ozonolysis to form semi-volatile and low-volatility compounds that contribute to secondary organic aerosols (SOAs) both outdoors and indoors. The influence of NO2 on SOA formation from ozonolysis of limonene has been evaluated using chamber experiments and the Master Chemical Mechanism (MCM) coupled with a gas-particle partitioning model in this work. A series of 21 indoor chamber experiments were carried out with or without NO2 under different [O3]0 / [VOC]0 ratios, and these experimental data were compared with the model simulations. Agreement in SOA yields was observed between the experimental observations and model simulations under varying conditions. Generally, SOA mass yields are positively dependent on [O3]0 / [VOC]0 without the presence of NO2. However, the introduction of NO2 leads to a more complicated change in SOA yield, which is shown to be related to initial [O3] / [VOC] ratios. When [O3]0 / [VOC]0 > 2, the introduction of NO2 results in an increase of SOA yield in the range of NO2 studied in this work; whereas a weak negative effect was found for SOA formation according to the introduction of ~ 250 ppbv NO2 under [O3]0 / [VOC]0 

scholarly journals Physico-chemical characterization of secondary organic aerosol derived from catechol and guaiacol as a model substance for atmospheric humic-like substances

2010 ◽  
Vol 10 (7) ◽  
pp. 17369-17405 ◽  
Author(s):  
J. Ofner ◽  
H.-U. Krüger ◽  
H. Grothe ◽  
P. Schmitt-Kopplin ◽  
K. Whitmore ◽  
...  
Keyword(s):  
Functional Groups ◽  
Mass Spectroscopy ◽  
Secondary Organic Aerosols ◽  
Secondary Organic Aerosol ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Chemical Diversity ◽  
Spherical Particles ◽  
Aerosol Formation ◽  
Vis Spectroscopy

Abstract. Secondary organic aerosol was produced from the aromatic precursors catechol and guaiacol by reaction with ozone in the presence and absence of simulated sunlight and humidity and investigated for its properties as a proxy for humic-like substances (HULIS). Beside a small particle size, a relatively low molecular weight and typical optical features in the UV/VIS spectral range, HULIS contain a typical aromatic and/or olefinic chemical structure and highly oxidized functional groups within a high chemical diversity. Various methods were used to characterize the secondary organic aerosols obtained: Fourier transform infrared spectroscopy (FTIR) demonstrated the formation of different carbonyl containing functional groups as well as structural and functional differences between aerosols formed at different environmental conditions. UV/VIS spectroscopy of filter samples showed that the particulate matter absorbs far into the visible range up to more than 500 nm. Ultrahigh resolved mass spectroscopy (ICR-FT/MS) determined O/C-ratios between 0.3 and 1 and main molecular weights between 200 and 500 Da. Temperature-programmed-pyrolysis mass spectroscopy identified carboxylic acids and lactones as major functional groups. Particle sizing using CNC-DMPS demonstrated the formation of small particles during a secondary organic aerosol formation process. Particle imaging using field-emission-gun scanning electron microscopy (FEG-SEM) showed spherical particles, forming clusters and chains. Hence, secondary organic aerosols from catechol and guaiacol are appropriate model substances for studies of the processing of aromatic secondary organic aerosols and atmospheric HULIS on the laboratory scale.

scholarly journals Formation of secondary organic aerosols from the ozonolysis of dihydrofurans

2017 ◽  
Vol 17 (3) ◽  
pp. 2347-2357 ◽  
Author(s):  
Yolanda Diaz-de-Mera ◽  
Alfonso Aranda ◽  
Larisa Bracco ◽  
Diana Rodriguez ◽  
Ana Rodriguez
Keyword(s):  
Relative Humidity ◽  
Particle Number ◽  
Secondary Organic Aerosols ◽  
Secondary Organic Aerosol ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Reaction Conditions ◽  
Criegee Intermediates ◽  
Rate Constant Ratio ◽  
Computational Calculations

Abstract. In this work we report the study of the ozonolysis of 2,5-dihydrofuran and 2,3-dihydrofuran and the reaction conditions leading to the formation of secondary organic aerosols. The reactions have been carried out in a Teflon chamber filled with synthetic air mixtures at atmospheric pressure and room temperature. The ozonolysis only produced particles in the presence of SO2. Rising relative humidity from 0 to 40 % had no effect on the production of secondary organic aerosol in the case of 2,5-dihydrofuran, while it reduced the particle number and particle mass concentrations from the 2,3-dihydrofuran ozonolysis. The water-to-SO2 rate constant ratio for the 2,3-dihydrofuran Criegee intermediate was derived from the secondary organic aerosol (SOA) yields in experiments with different relative humidity values, kH2O/kSO2 =  (9.8 ± 3.7) × 10−5. The experimental results show that SO3 may not be the only intermediate involved in the formation or growth of new particles in contrast to the data reported for other Criegee intermediate–SO2 reactions. For the studied reactions, SO2 concentrations remained constant during the experiments, behaving as a catalyst in the production of condensable products. Computational calculations also show that the stabilised Criegee intermediates from the ozonolysis reaction of both 2,5-dihydrofuran and 2,3-dihydrofuran may react with SO2, resulting in the regeneration of SO2 and the formation of low-volatility organic acids.

scholarly journals Modeling organic aerosols in a megacity: comparison of simple and complex representations of the volatility basis set approach

2010 ◽  
Vol 10 (12) ◽  
pp. 30205-30277 ◽  
Author(s):  
M. Shrivastava ◽  
J. Fast ◽  
R. Easter ◽  
W. I. Gustafson ◽  
R. A. Zaveri ◽  
...  
Keyword(s):  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Computational Cost ◽  
Organic Aerosols ◽  
Field Measurements ◽  
Organic Aerosol ◽  
Basis Set ◽  
Aerosol Formation ◽  
Secondary Organic Aerosol Formation ◽  
The City

Abstract. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is modified to include a volatility basis set (VBS) treatment of secondary organic aerosol formation. The VBS approach, coupled with SAPRC-99 gas-phase chemistry mechanism, is used to model gas-particle partitioning and multiple generations of gas-phase oxidation of organic vapors. In addition to the detailed 9-species VBS, a simplified mechanism using 2 volatility species (2-species VBS) is developed and tested for similarity to the 9-species VBS in terms of both mass and oxygen-to-carbon ratios of organic aerosols in the atmosphere. WRF-Chem results are evaluated against field measurements of organic aerosols collected during the MILAGRO 2006 campaign in the vicinity of Mexico City. The simplified 2-species mechanism reduces the computational cost by a factor of 2 as compared to 9-species VBS. Both ground site and aircraft measurements suggest that the 9-species and 2-species VBS predictions of total organic aerosol mass as well as individual organic aerosol components including primary, secondary, and biomass burning are comparable in magnitude. In addition, oxygen-to-carbon ratio predictions from both approaches agree within 25%, providing evidence that the 2-species VBS is well suited to represent the complex evolution of organic aerosols. Model sensitivity to amount of anthropogenic semi-volatile and intermediate volatility (S/IVOC) precursor emissions is also examined by doubling the default emissions. Both the emission cases significantly under-predict primary organic aerosols in the city center and along aircraft flight transects. Secondary organic aerosols are predicted reasonably well along flight tracks surrounding the city, but are consistently over-predicted downwind of the city. Also, oxygen-to-carbon ratio predictions are significantly improved compared to prior studies by adding 15% oxygen mass per generation of oxidation; however, all modeling cases still under-predict these ratios downwind as compared to measurements, suggesting a need to further improve chemistry parameterizations of secondary organic aerosol formation.

scholarly journals Synergetic formation of secondary inorganic and organic aerosol: Influence of SO<sub>2</sub> and/or NH<sub>3</sub> in the heterogeneous process

2016 ◽  
Author(s):  
Biwu Chu ◽  
Xiao Zhang ◽  
Yongchun Liu ◽  
Hong He ◽  
Yele Sun ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Synergistic Effects ◽  
Particle Growth ◽  
Organic Aerosol ◽  
Interactive Effects ◽  
Aerosol Formation ◽  
Secondary Aerosol ◽  
Heterogeneous Process ◽  
So2 Concentration ◽  
Inorganic And Organic

Abstract. The effects of SO2 and NH3 on secondary organic aerosol formation have rarely been investigated together, while the interactive effects between inorganic and organic species under highly complex pollution conditions remain uncertain. Here we studied the effects of SO2 and NH3 on secondary aerosol formation in the photooxidation system of toluene/NOx in the presence or absence of Al2O3 seed aerosols in a 2 m3 smog chamber. The presence of SO2 increased new particle formation and particle growth significantly, regardless of whether NH3 was present or not. Sulfate, organic aerosol, nitrate and ammonium were all found to increase linearly with increasing SO2 concentrations. The increases in these four species were more obvious under NH3-rich conditions, and the generation of nitrate, ammonium and organic aerosol increased more significantly than sulfate with respect to SO2 concentration, while sulfate was the most sensitive species under NH3-poor conditions. The synergistic effects between SO2 and NH3 in the heterogeneous process contributed greatly to secondary aerosol formation. Specifically, the generation of NH4NO3 was found to be highly dependent on the surface area concentration of suspended particles, and increased most significantly among the four species with respect to SO2 concentration under ammonia-rich conditions. Meanwhile, the absorbed NH3 might provide a liquid surface layer for the absorption and subsequent reaction of SO2 and organic products, and therefore, enhance sulfate and secondary organic aerosol (SOA) formation. This effect mainly occurred in the heterogeneous process and resulted in a significantly higher growth rate of seed aerosols compared to that without NH3. By applying positive matrix factorization (PMF) analysis to the AMS data, two factors were identified for the generated SOA. One factor, assigned to less-oxidized organic aerosol and some oligomers, increased with increasing SO2 under NH3-poor conditions, mainly due to the well-known acid catalytic effect of the acid products on SOA formation in the heterogeneous process. The other factor, assigned to the highly oxidized organic component and some nitrogen-containing organics (NOC), increased with SO2 under a NH3-rich environment, with NOC (organonitrates and NOC with reduced N) contributing most of the increase.

scholarly journals Modeling organic aerosols in a megacity: comparison of simple and complex representations of the volatility basis set approach

2011 ◽  
Vol 11 (13) ◽  
pp. 6639-6662 ◽  
Author(s):  
M. Shrivastava ◽  
J. Fast ◽  
R. Easter ◽  
W. I. Gustafson ◽  
R. A. Zaveri ◽  
...  
Keyword(s):  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Computational Cost ◽  
Organic Aerosols ◽  
Field Measurements ◽  
Organic Aerosol ◽  
Basis Set ◽  
Aerosol Formation ◽  
Secondary Organic Aerosol Formation ◽  
The City

Abstract. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is modified to include a volatility basis set (VBS) treatment of secondary organic aerosol formation. The VBS approach, coupled with SAPRC-99 gas-phase chemistry mechanism, is used to model gas-particle partitioning and multiple generations of gas-phase oxidation of organic vapors. In addition to the detailed 9-species VBS, a simplified mechanism using 2 volatility species (2-species VBS) is developed and tested for similarity to the 9-species VBS in terms of both mass and oxygen-to-carbon ratios of organic aerosols in the atmosphere. WRF-Chem results are evaluated against field measurements of organic aerosols collected during the MILAGRO 2006 campaign in the vicinity of Mexico City. The simplified 2-species mechanism reduces the computational cost by a factor of 2 as compared to 9-species VBS. Both ground site and aircraft measurements suggest that the 9-species and 2-species VBS predictions of total organic aerosol mass as well as individual organic aerosol components including primary, secondary, and biomass burning are comparable in magnitude. In addition, oxygen-to-carbon ratio predictions from both approaches agree within 25 %, providing evidence that the 2-species VBS is well suited to represent the complex evolution of organic aerosols. Model sensitivity to amount of anthropogenic semi-volatile and intermediate volatility (S/IVOC) precursor emissions is also examined by doubling the default emissions. Both the emission cases significantly under-predict primary organic aerosols in the city center and along aircraft flight transects. Secondary organic aerosols are predicted reasonably well along flight tracks surrounding the city, but are consistently over-predicted downwind of the city. Also, oxygen-to-carbon ratio predictions are significantly improved compared to prior studies by adding 15 % oxygen mass per generation of oxidation; however, all modeling cases still under-predict these ratios downwind as compared to measurements, suggesting a need to further improve chemistry parameterizations of secondary organic aerosol formation.

Effect of hydrophobic primary organic aerosols on secondary organic aerosol formation from ozonolysis ofα-pinene

2007 ◽  
Vol 34 (20) ◽  
Author(s):  
Chen Song ◽  
Rahul A. Zaveri ◽  
M. Lizabeth Alexander ◽  
Joel A. Thornton ◽  
Sasha Madronich ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Secondary Organic Aerosol Formation

scholarly journals Novel Pathway of SO<sub>2</sub> Oxidation in the Atmosphere: Reactions with Monoterpene Ozonolysis Intermediates and Secondary Organic Aerosol

2017 ◽  
Author(s):  
Jianhuai Ye ◽  
Jonathan P. D. Abbatt ◽  
Arthur W. H. Chan
Keyword(s):  
Secondary Organic Aerosol ◽  
Synergistic Effects ◽  
Organic Aerosol ◽  
Experimental Chamber ◽  
Organic Peroxides ◽  
So2 Oxidation ◽  
Loss Mechanism ◽  
Alpha Pinene ◽  
Criegee Intermediates ◽  
Dry Conditions

Abstract. Ozonolysis of monoterpenes is an important source of atmospheric biogenic secondary organic aerosol (BSOA). While enhanced BSOA formation has been associated with sulfate-rich conditions, the underlying mechanisms remain poorly understood. In this work, the interactions between SO2 and reactive intermediates from monoterpene ozonolysis were investigated under different humidity conditions (10 % vs. 50 %). Chamber experiments were conducted with ozonolysis of alpha-pinene or limonene in the presence of SO2. Limonene SOA formation was enhanced in the presence of SO2, while no significant changes in SOA yields were observed during alpha-pinene ozonolysis. Under dry conditions, SO2 primarily reacted with stabilized Criegee Intermediates (sCI) produced from ozonolysis, but at 50 % RH, heterogeneous uptake of SO2 onto organic aerosol was found to be the dominant sink of SO2, likely owing to reactions between SO2 and organic peroxides. This SO2 loss mechanism to organic peroxides in SOA has not previously been identified in experimental chamber study. Organosulfates were detected and identified using electrospray ionization-ion mobility time of flight mass spectrometer (ESI-IMS-TOF) when SO2 was present in the experiments. Our results demonstrate the synergistic effects between BSOA formation and SO2 oxidation through sCI chemistry and SO2 uptake onto organic aerosol and illustrate the importance of considering the chemistry of organic and sulfur-containing compounds holistically to properly account for their reactive sinks.

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