scholarly journals Molecular composition of fresh and aged secondary organic aerosol from a mixture of biogenic volatile compounds: a high-resolution mass spectrometry study

2015 ◽  
Vol 15 (10) ◽  
pp. 5683-5695 ◽  
Author(s):  
I. Kourtchev ◽  
J.-F. Doussin ◽  
C. Giorio ◽  
B. Mahon ◽  
E. M. Wilson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Radical Reaction ◽  
Organic Aerosol ◽  
Molecular Composition ◽  
Oh Radicals ◽  
Oh Radical ◽  
High Resolution Mass ◽  
Resolution Mass

Abstract. Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidized molecules. Aerosol processing or further oxidation (aging) of organic aerosol has been suggested to be responsible for their formation through heterogeneous reaction with oxidants and multigenerational oxidation of vapours by OH radicals. In this study we investigated the influence of several aging processes on the molecular composition of secondary organic aerosols (SOA) using direct infusion and liquid chromatography high-resolution mass spectrometry. SOA was formed in simulation chamber experiments from ozonolysis of a mixture of four biogenic volatile organic compounds (BVOC): α-pinene, β-pinene, Δ3-carene and isoprene. The SOA was subsequently aged under three different sets of conditions: in the dark in the presence of residual ozone, with UV irradiation and OH radicals, and using UV light only. Among all studied conditions, only OH radical-initiated aging was found to influence the molecular composition of the aerosol and showed an increase in carbon oxidation state (OSC) and elemental O / C ratios of the SOA components. None of the aging processes produced an observable effect on the oligomers formed from ozonolysis of the BVOC mixture, which were found to be equally abundant in both "fresh" and "aged" SOA. Additional experiments using α-pinene as the sole precursor demonstrated that oligomers are an important group of compounds in SOA produced from both ozonolysis and OH radical-initiated oxidation processes; however, a completely different set of oligomers is formed under these two oxidation regimes. SOA from the OH-initiated oxidation of α-pinene had a significantly higher overall OSC and O / C compared to that from pure ozonolysis experiments confirming that the OH radical reaction is more likely to be responsible for the occurrence of highly oxidized species in ambient biogenic SOA.

scholarly journals Impact of anthropogenic and biogenic sources on the seasonal variation of the molecular composition of urban organic aerosols: a field and laboratory study using ultra-high resolution mass spectrometry

2018 ◽  
Author(s):  
Kaspar R. Daellenbach ◽  
Ivan Kourtchev ◽  
Alexander L. Vogel ◽  
Emily A. Bruns ◽  
Jianhui Jiang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Secondary Organic Aerosol ◽  
High Resolution Mass Spectrometry ◽  
Organic Aerosol ◽  
Molecular Composition ◽  
Wood Burning ◽  
High Resolution Mass ◽  
Alpine Valleys ◽  
Resolution Mass

Abstract. This study presents the molecular composition of OA using ultra-high resolution mass spectrometry (Orbitrap) at an urban site in Central Europe (Zurich, Switzerland). Specific source spectra were also analysed, including samples representative of wood burning emissions from Alpine valleys during wood burning pollution episodes and chamber investigations of wood smoke as well as samples from Hyytiälä strongly influenced by biogenic secondary organic aerosol. While samples collected during winter in Alpine valleys have a molecular composition remarkably similar to fresh laboratory wood burning emissions, winter samples from Zurich are influenced by more aged wood burning emissions. In addition, other organic aerosol emission or formation pathways seem to be important at the latter location in winter. Samples from Zurich during summer are similar to those collected in Hyytiälä, predominantly impacted by oxygenated compounds with an H / C ratio of 1.5, indicating the importance of biogenic precursors for SOA formation at this location. We could explain the strong seasonality of the molecular composition at a typical European site by primary and aged wood burning emissions and biogenic secondary organic aerosol formation during winter and summer, respectively. Results presented here likely explain the seasonally rather constant predominance of non-fossil organic carbon at European locations.

scholarly journals Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry

2015 ◽  
Vol 15 (4) ◽  
pp. 5359-5389 ◽  
Author(s):  
I. Kourtchev ◽  
J.-F. Doussin ◽  
C. Giorio ◽  
B. Mahon ◽  
E. M. Wilson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Uv Light ◽  
Radical Reaction ◽  
Organic Aerosol ◽  
Molecular Composition ◽  
Oh Radicals ◽  
Oh Radical ◽  
Ultrahigh Resolution ◽  
Ageing Processes ◽  
Resolution Mass

Abstract. Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidised molecules. Aerosol processing or further oxidation (ageing) of organic aerosol has been suggested to be responsible for their formation through heterogeneous uptake of oxidants and multigenerational oxidation of vapours by OH radicals. In this study we investigated the influence of several ageing processes on the molecular composition of secondary organic aerosols (SOA) using direct infusion and liquid chromatography ultrahigh resolution mass spectrometry. SOA was formed in simulation chamber experiments from ozonolysis of a mixture of four biogenic volatile organic compounds (BVOC): α-pinene, β-pinene, Δ3-carene and isoprene. The SOA was subsequently aged under three different sets of conditions: in the dark in the presence of residual ozone, with UV irradiation and OH radicals, and using UV light only. Among all studied conditions, only OH radical-initiated ageing was found to influence the molecular composition of the aerosol and showed an increase in carbon oxidation state (OSC) and elemental O/C ratios of the SOA components. None of the ageing processes produced an observable effect on the oligomers formed from ozonolysis of the BVOC mixture, which were found to be equally abundant in both "fresh" and "aged" SOA. Additional experiments using α-pinene as the sole precursor demonstrated that oligomers are an important group of compounds in SOA produced from both ozonolysis and OH radical-initiated oxidation processes; however, a completely different set of oligomers is formed under these two oxidation regimes. SOA from the OH radical-initiated α-pinene oxidation had a significantly higher overall OSC and O/C compared to that from pure ozonolysis experiments confirming that the OH radical reaction is more likely to be responsible for the occurrence of highly oxidised species in ambient biogenic SOA.

scholarly journals Secondary Organic Aerosol from Atmospheric Photooxidation of Indole

2017 ◽  
Author(s):  
Julia Montoya ◽  
Jeremy R. Horne ◽  
Mallory L. Hinks ◽  
Lauren T. Fleming ◽  
Veronique Perraud ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Air Quality ◽  
Chemical Composition ◽  
High Resolution ◽  
Secondary Organic Aerosol ◽  
High Resolution Mass Spectrometry ◽  
Organic Aerosol ◽  
Scanning Mobility Particle Sizer ◽  
High Resolution Mass ◽  
Resolution Mass

Abstract. Indole is a heterocyclic compound emitted by various plant species under stressed conditions or during flowering events. The formation, optical properties, and chemical composition of secondary organic aerosol (SOA) formed by low-NOx photooxidation of indole were investigated. The SOA yield (1.1 ± 0.3) was estimated from measuring the particle mass concentration with a scanning mobility particle sizer (SMPS) and correcting it for the wall loss effects. The SOA particles were collected on filters and analysed offline with UV-Vis spectrophotometry to measure the mass absorption coefficient (MAC) of the bulk sample. The samples were visibly brown and had MAC values of ~7 m2/g at λ = 300 nm and ~2 m2/g at λ = 400 nm, comparable to strongly absorbing brown carbon emitted from biomass burning. The chemical composition of SOA was examined with several mass spectrometry methods. The direct analysis in real time mass spectrometry (DART-MS) and nanospray desorption electrospray high resolution mass spectrometry (nano-DESI-HRMS) were used to provide information about the overall distribution of SOA compounds. High performance liquid chromatography, coupled to photodiode array spectrophotometry and high resolution mass spectrometry (HPLC-PDA-HRMS) was used to identify chromophoric compounds. Indole derivatives, such as tryptanthrin, indirubin, indigo dye, and indoxyl red were found to contribute significantly to the visible absorption spectrum of indole SOA. The potential effect of indole SOA on air quality was explored with the airshed model, which found elevated concentrations of indole SOA during the afternoon hours contributing considerably to the total organic aerosol under selected scenarios. Because of its high MAC values, indole SOA can contribute to decreased visibility and poor air quality.

scholarly journals Molecular Composition of Particulate Matter Emissions from Dung and Brushwood Burning Household Cookstoves in Haryana, India

2017 ◽  
Author(s):  
Lauren T. Fleming ◽  
Peng Lin ◽  
Alexander Laskin ◽  
Julia Laskin ◽  
Robert Weltman ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Particulate Matter ◽  
High Resolution ◽  
Biomass Burning ◽  
High Resolution Mass Spectrometry ◽  
Molecular Composition ◽  
High Resolution Mass ◽  
Organic Particles ◽  
Resolution Mass ◽  
Pm2.5 Emissions

Abstract. Emissions of airborne particles from biomass-burning are a significant source of black carbon (BC) and brown carbon (BrC) in rural areas of developing countries where biomass is the predominant energy source for cooking and heating. This study explores the molecular composition of organic particles from household cooking emissions, with a focus on identifying fuel-specific compounds and BrC chromophores. Traditional meals were prepared by a local cook with dung and brushwood-fueled cookstoves in a village of Palwal district, Haryana, India. The cooking events were carried out in a village kitchen while controlling for variables including stove type, fuel moisture content, and meal. The particulate matter (PM2.5) emissions were collected on filters, and then analyzed via nanospray desorption electrospray ionization/high resolution mass spectrometry (nano-DESI-HRMS) and high performance liquid chromatography/photodiode array/high resolution mass spectrometry (HPLC-PDA-HRMS) techniques. The nano-DESI-HRMS analysis provided an inventory of compounds present in the particle phase. Although several compounds observed in this study have been previously characterized using gas chromatography methods, a majority of species in nano-DESI spectra were newly observed biomass-burning compounds. Both the stove (chulha or angithi) and the fuel (brushwood or dung) affected the composition of organic particles. The geometric mean PM2.5 emissions factor and the molecular complexity of PM2.5 emissions increased in the following order: brushwood/chulha (4.9 ± 1.7 g kg-1 dry fuel, 93 compounds), dung/chulha (12.3 ± 2.5 g kg-1 dry fuel, 212 compounds), and dung/angithi (16.7 ± 6.7 g kg-1 dry fuel, 262 compounds). The lower limit for the mass absorption coefficient (MAC) at 365 nm and 405 nm for brushwood PM2.5 was 3.4 m2 g-1 and 1.8 m2 g-1, respectively, which was approximately a factor of two higher than that for dung PM2.5. The HPLC-PDA-HRMS analysis showed that, regardless of fuel type, the main chromophores were CxHyOz lignin fragments. The main chromophores accounting for the higher MAC values of brushwood PM2.5 were C8H10O3 (tentatively assigned syringol), possible nitrophenol species C8H9NO4, and C10H10O3 (tentatively assigned methoxycinnamic acid).

scholarly journals Impact of anthropogenic and biogenic sources on the seasonal variation in the molecular composition of urban organic aerosols: a field and laboratory study using ultra-high-resolution mass spectrometry

2019 ◽  
Vol 19 (9) ◽  
pp. 5973-5991 ◽  
Author(s):  
Kaspar R. Daellenbach ◽  
Ivan Kourtchev ◽  
Alexander L. Vogel ◽  
Emily A. Bruns ◽  
Jianhui Jiang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Secondary Organic Aerosol ◽  
High Resolution Mass Spectrometry ◽  
Carbon Number ◽  
Organic Aerosol ◽  
Molecular Composition ◽  
Wood Burning ◽  
Alpine Valleys ◽  
Resolution Mass

Abstract. This study presents the molecular composition of organic aerosol (OA) using ultra-high-resolution mass spectrometry (Orbitrap) at an urban site in Central Europe (Zurich, Switzerland). Specific source spectra were also analysed, including samples representative of wood-burning emissions from Alpine valleys during wood-burning pollution episodes and smog chamber investigations of woodsmoke, as well as samples from Hyytiälä, which were strongly influenced by biogenic secondary organic aerosol. While samples collected during winter in Alpine valleys have a molecular composition remarkably similar to fresh laboratory wood-burning emissions, winter samples from Zurich are influenced by more aged wood-burning emissions. In addition, other organic aerosol emissions or formation pathways seem to be important at the latter location in winter. Samples from Zurich during summer are similar to those collected in Hyytiälä and are predominantly impacted by oxygenated compounds with an H∕C ratio of 1.5, indicating the importance of biogenic precursors for secondary organic aerosol (SOA) formation at this location (summertime Zurich – carbon number 7.6, O:C 0.7; Hyytiälä – carbon number 10.5, O:C 0.57). We could explain the strong seasonality of the molecular composition at a typical European site by primary and aged wood-burning emissions and biogenic secondary organic aerosol formation during winter and summer, respectively. Results presented here likely explain the rather constant seasonal predominance of non-fossil organic carbon at European locations.

Sign in / Sign up

Export Citation Format

Share Document