scholarly journals The influences of ammonia on aerosol formation in the ozonolysis of styrene: roles of Criegee intermediate reactions

2018 ◽  
Vol 5 (5) ◽  
pp. 172171 ◽  
Author(s):  
Qiao Ma ◽  
Xiaoxiao Lin ◽  
Chengqiang Yang ◽  
Bo Long ◽  
Yanbo Gai ◽  
...  
Keyword(s):  
Gas Phase ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Gas Phase Reactions ◽  
Aerosol Composition ◽  
Theoretical Methods ◽  
Criegee Intermediates ◽  
Secondary Ozonide

The influences of ammonia (NH 3 ) on secondary organic aerosol (SOA) formation from ozonolysis of styrene have been investigated using chamber experiments and quantum chemical calculations. With the value of [O 3 ] 0 /[styrene] 0 ratios between 2 and 4, chamber experiments were carried out without NH 3 or under different [NH 3 ]/[styrene] 0 ratios. The chamber experiments reveal that the addition of NH 3 led to significant decrease of SOA yield. The overall SOA yield decreased with the [NH 3 ] 0 /[styrene] 0 increasing. In addition, the addition of NH 3 at the beginning of the reaction or several hours after the reaction occurs had obviously different influence on the yield of SOA. Gas phase reactions of Criegee intermediates (CIs) with aldehydes and NH 3 were studied in detail by theoretical methods to probe into the mechanisms behind these phenomena. The calculated results showed that 3,5-diphenyl-1,2,4-trioxolane, a secondary ozonide formed through the reactions of C 6 H 5 ĊHOO· with C 6 H 5 CHO, could make important contribution to the aerosol composition. The addition of excess NH 3 may compete with aldehydes, decreasing the secondary ozonide yield to some extent and thus affect the SOA formation.

scholarly journals Secondary organic aerosol formation from photooxidation of naphthalene and alkylnaphthalenes: implications for oxidation of intermediate volatility organic compounds (IVOCs)

2009 ◽  
Vol 9 (1) ◽  
pp. 1873-1905
Author(s):  
A. W. H. Chan ◽  
K. E. Kautzman ◽  
P. S. Chhabra ◽  
J. D. Surratt ◽  
M. N. Chan ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Gas Phase ◽  
Aromatic Hydrocarbons ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Atmospheric Models ◽  
Gas Phase Reactions ◽  
Aerosol Mass ◽  
Polycyclic Aromatic

Abstract. Current atmospheric models do not include secondary organic aerosol (SOA) production from gas-phase reactions of polycyclic aromatic hydrocarbons (PAHs). Recent studies have shown that primary semivolatile emissions, previously assumed to be inert, undergo oxidation in the gas phase, leading to SOA formation. This opens the possibility that low-volatility gas-phase precursors are a potentially large source of SOA. In this work, SOA formation from gas-phase photooxidation of naphthalene, 1-methylnaphthalene (1-MN), 2-methylnaphthalene (2-MN), and 1,2-dimethylnaphthalene (1,2-DMN) is studied in the Caltech dual 28-m3 chambers. Under high-NOx conditions and aerosol mass loadings between 10 and 40 μg m

scholarly journals Secondary organic aerosol formation from photooxidation of naphthalene and alkylnaphthalenes: implications for oxidation of intermediate volatility organic compounds (IVOCs)

2009 ◽  
Vol 9 (9) ◽  
pp. 3049-3060 ◽  
Author(s):  
A. W. H. Chan ◽  
K. E. Kautzman ◽  
P. S. Chhabra ◽  
J. D. Surratt ◽  
M. N. Chan ◽  
...  
Keyword(s):  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Diesel Emissions ◽  
Aerosol Formation ◽  
Gas Phase Reactions ◽  
Large Source ◽  
Aerosol Mass ◽  
Polycyclic Aromatic ◽  
Primary Emissions

Abstract. Current atmospheric models do not include secondary organic aerosol (SOA) production from gas-phase reactions of polycyclic aromatic hydrocarbons (PAHs). Recent studies have shown that primary emissions undergo oxidation in the gas phase, leading to SOA formation. This opens the possibility that low-volatility gas-phase precursors are a potentially large source of SOA. In this work, SOA formation from gas-phase photooxidation of naphthalene, 1-methylnaphthalene (1-MN), 2-methylnaphthalene (2-MN), and 1,2-dimethylnaphthalene (1,2-DMN) is studied in the Caltech dual 28-m3 chambers. Under high-NOx conditions and aerosol mass loadings between 10 and 40 μg m−3, the SOA yields (mass of SOA per mass of hydrocarbon reacted) ranged from 0.19 to 0.30 for naphthalene, 0.19 to 0.39 for 1-MN, 0.26 to 0.45 for 2-MN, and constant at 0.31 for 1,2-DMN. Under low-NOx conditions, the SOA yields were measured to be 0.73, 0.68, and 0.58, for naphthalene, 1-MN, and 2-MN, respectively. The SOA was observed to be semivolatile under high-NOx conditions and essentially nonvolatile under low-NOx conditions, owing to the higher fraction of ring-retaining products formed under low-NOx conditions. When applying these measured yields to estimate SOA formation from primary emissions of diesel engines and wood burning, PAHs are estimated to yield 3–5 times more SOA than light aromatic compounds over photooxidation timescales of less than 12 h. PAHs can also account for up to 54% of the total SOA from oxidation of diesel emissions, representing a potentially large source of urban SOA.

scholarly journals Different roles of water in secondary organic aerosol formation from toluene and isoprene

2018 ◽  
Vol 18 (11) ◽  
pp. 8137-8154 ◽  
Author(s):  
Long Jia ◽  
YongFu Xu
Keyword(s):  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Chemical Components ◽  
Smog Chamber ◽  
Aerosol Formation ◽  
Model Simulations ◽  
Criegee Intermediates ◽  
Dry Conditions ◽  
Major Chemical

Abstract. Roles of water in the formation of secondary organic aerosol (SOA) from the irradiations of toluene-NO2 and isoprene-NO2 were investigated in a smog chamber. Experimental results show that the yield of SOA from toluene almost doubled as relative humidity increased from 5 to 85 %, whereas the yield of SOA from isoprene under humid conditions decreased by 2.6 times as compared to that under dry conditions. The distinct difference of RH effects on SOA formation from toluene and isoprene is well explained with our experiments and model simulations. The increased SOA from humid toluene-NO2 irradiations is mainly contributed by O–H-containing products such as polyalcohols formed from aqueous reactions. The major chemical components of SOA in isoprene-NO2 irradiations are oligomers formed from the gas phase. SOA formation from isoprene-NO2 irradiations is controlled by stable Criegee intermediates (SCIs) that are greatly influenced by water. As a result, high RH can obstruct the oligomerization reaction of SCIs to form SOA.

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 Identifying precursors and aqueous organic aerosol formation pathways during the SOAS campaign

2016 ◽  
Vol 16 (22) ◽  
pp. 14409-14420 ◽  
Author(s):  
Neha Sareen ◽  
Annmarie G. Carlton ◽  
Jason D. Surratt ◽  
Avram Gold ◽  
Ben Lee ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Aqueous Phase ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Negative Ion ◽  
Anthropogenic Sources ◽  
Ionization Mass ◽  
Aqueous Mixtures ◽  
Aerosol Formation

Abstract. Aqueous multiphase chemistry in the atmosphere can lead to rapid transformation of organic compounds, forming highly oxidized, low-volatility organic aerosol and, in some cases, light-absorbing (brown) carbon. Because liquid water is globally abundant, this chemistry could substantially impact climate, air quality, and health. Gas-phase precursors released from biogenic and anthropogenic sources are oxidized and fragmented, forming water-soluble gases that can undergo reactions in the aqueous phase (in clouds, fogs, and wet aerosols), leading to the formation of secondary organic aerosol (SOAAQ). Recent studies have highlighted the role of certain precursors like glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone, and epoxides in the formation of SOAAQ. The goal of this work is to identify additional precursors and products that may be atmospherically important. In this study, ambient mixtures of water-soluble gases were scrubbed from the atmosphere into water at Brent, Alabama, during the 2013 Southern Oxidant and Aerosol Study (SOAS). Hydroxyl (OH⚫) radical oxidation experiments were conducted with the aqueous mixtures collected from SOAS to better understand the formation of SOA through gas-phase followed by aqueous-phase chemistry. Total aqueous-phase organic carbon concentrations for these mixtures ranged from 92 to 179 µM-C, relevant for cloud and fog waters. Aqueous OH-reactive compounds were primarily observed as odd ions in the positive ion mode by electrospray ionization mass spectrometry (ESI-MS). Ultra high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) spectra and tandem MS (MS–MS) fragmentation of these ions were consistent with the presence of carbonyls and tetrols. Products were observed in the negative ion mode and included pyruvate and oxalate, which were confirmed by ion chromatography. Pyruvate and oxalate have been found in the particle phase in many locations (as salts and complexes). Thus, formation of pyruvate/oxalate suggests the potential for aqueous processing of these ambient mixtures to form SOAAQ.

Quantum Chemical Calculations on the Reaction of Zinc and Water in Gas Phase

2013 ◽  
Vol 186 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Weijuan Yang ◽  
Zhijiang Han ◽  
Junhu Zhou ◽  
Jianzhong Liu ◽  
Kefa Cen
Keyword(s):  
Gas Phase ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical
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