Theoretical investigation of the gas phase oxidation mechanism of dimethyl sulfoxide by OH radical

Abstract. The aim of this study was to investigate oxidation of SOA formed from ozonolysis of α-pinene and limonene by hydroxyl radicals. This paper focuses on changes of particle volatility, using a Volatility Tandem DMA (VTDMA) set-up, in order to explain and elucidate the mechanism behind atmospheric ageing of the organic aerosol. The experiments were conducted at the AIDA chamber facility of Karlsruhe Institute of Technology (KIT) in Karlsruhe and at the SAPHIR chamber of Forchungzentrum Jülich (FZJ) in Jülich. A fresh SOA was produced from ozonolysis of α-pinene or limonene and then aged by enhanced OH exposure. As an OH radical source in the AIDA-chamber the ozonolysis of tetramethylethylene (TME) was used while in the SAPHIR-chamber the OH was produced by natural light photochemistry. A general feature is that SOA produced from ozonolysis of α-pinene and limonene initially was rather volatile and becomes less volatile with time in the ozonolysis part of the experiment. Inducing OH chemistry or adding a new portion of precursors made the SOA more volatile due to addition of new semi-volatile material to the aged aerosol. The effect of OH chemistry was less pronounced in high concentration and low temperature experiments when lower relative amounts of semi-volatile material were available in the gas phase. Conclusions drawn from the changes in volatility were confirmed by comparison with the measured and modelled chemical composition of the aerosol phase. Three quantified products from the α-pinene oxidation; pinonic acid, pinic acid and methylbutanetricarboxylic acid (MBTCA) were used to probe the processes influencing aerosol volatility. A major conclusion from the work is that the OH induced ageing can be attributed to gas phase oxidation of products produced in the primary SOA formation process and that there was no indication on significant bulk or surface reactions. The presented results, thus, strongly emphasise the importance of gas phase oxidation of semi- or intermediate-volatile organic compounds (SVOC and IVOC) for atmospheric aerosol ageing.

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An experimental, theoretical and kinetic-modeling study of the gas-phase oxidation of ammonia

Reaction Chemistry & Engineering ◽

10.1039/c9re00429g ◽

2020 ◽

Vol 5 (4) ◽

pp. 696-711 ◽

Cited By ~ 10

Author(s):

Alessandro Stagni ◽

Carlo Cavallotti ◽

Suphaporn Arunthanayothin ◽

Yu Song ◽

Olivier Herbinet ◽

...

Keyword(s):

Kinetic Model ◽

Gas Phase ◽

Theoretical Investigation ◽

Kinetic Modeling ◽

Ammonia Gas ◽

Wide Range ◽

Phase Oxidation ◽

Detailed Kinetic Model ◽

Gas Phase Oxidation ◽

Modeling Study

A wide-range experimental and theoretical investigation of ammonia gas-phase oxidation is performed, and a predictive, detailed kinetic model is developed.

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Volatility of secondary organic aerosol during OH radical induced ageing

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-19507-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 19507-19543

Author(s):

K. Salo ◽

M. Hallquist ◽

Å. M. Jonsson ◽

H. Saathoff ◽

K.-H. Naumann ◽

...

Keyword(s):

Gas Phase ◽

Organic Aerosol ◽

Oh Radical ◽

High Concentration ◽

Volatile Material ◽

Volatile Organic ◽

Phase Oxidation ◽

Gas Phase Oxidation ◽

Set Up ◽

Pinic Acid

Abstract. The aim of this study was to investigate oxidation of SOA formed from ozonolysis of α-pinene and limonene by hydroxyl radicals. This paper focuses on changes of particle volatility, using a Volatility Tandem DMA (VTDMA) set-up, in order to explain and elucidate the mechanism behind atmospheric ageing of the organic aerosol. The experiments were conducted at the AIDA chamber facility of KIT in Karlsruhe and at the SAPHIR chamber of FZJ in Jülich. A fresh SOA was produced from ozonolysis of α-pinene or limonene and then aged by enhanced OH exposure. As an OH-radical source in the AIDA-chamber the ozonolysis of tetramethylethylene (TME) was used while in the SAPHIR-chamber the OH was produced by natural light photochemistry. A general feature is that SOA produced from ozonolysis of α-pinene and limonene initially were rather volatile and becomes less volatile with time in the ozonolysis part of the experiment. Inducing OH chemistry or adding a new portion of precursors made the SOA more volatile due to addition of new semi-volatile material to the aged aerosol. The effect of OH chemistry was less pronounced in high concentration and low temperature experiments when lower relative amounts of semi-volatile material were available in the gas phase. Conclusions drawn from the changes in volatility were confirmed by comparison with the measured and modelled chemical composition of the aerosol phase. Three quantified products from the α-pinene oxidation; pinonic acid, pinic acid and methylbutanetricarboxylic acid (MBTCA) were used to probe the processes influencing aerosol volatility. A major conclusion from the work is that the OH induced ageing can be attributed to gas phase oxidation of products produced in the primary SOA formation process and that there was no indication on significant bulk or surface reactions. The presented results, thus, strongly emphasise the importance of gas phase oxidation of semi- or intermediate-volatile organic compounds (SVOC and IVOC) for atmospheric aerosol ageing processing.

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