scholarly journals Characterization of a thermodenuder- particle beam mass spectrometer system for the study of organic aerosol volatility and composition

2008 ◽  
Vol 1 (1) ◽  
pp. 21-65 ◽  
Author(s):  
A. E. Faulhaber ◽  
B. M. Thomas ◽  
J. L. Jimenez ◽  
J. T. Jayne ◽  
D. R. Worsnop ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Vapor Pressure ◽  
Pressure Distribution ◽  
Mass Spectrometer ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Particle Beam ◽  
Basis Set ◽  
Aerosol Mass ◽  
Dependent Mass

Abstract. This paper describes the development and evaluation of a method for measuring the vapor pressure distribution and volatility-dependent mass spectrum of organic aerosol particles using a thermodenuder-particle beam mass spectrometer. The method is well suited for use with the widely used Aerodyne Aerosol Mass Spectrometer (AMS) and other quantitative aerosol mass spectrometers. The data that can be obtained are valuable for modeling organic gas-particle partitioning and for gaining improved composition information from aerosol mass spectra. The method is based on an empirically determined relationship between the thermodenuder temperature at which 50% of the organic aerosol mass evaporates (T50) and the organic component vapor pressure at 25°C (P25). This approach avoids the need for complex modeling of aerosol evaporation, which normally requires detailed information on aerosol composition and physical properties. T50 was measured for a variety of monodisperse, single-component organic aerosols with known P25 values and the results used to create a log P25 vs. T50 calibration curve. Experiments and simulations were used to estimate the uncertainties in P25 introduced by variations in particle size and mass concentration as well as mixing with other components. A vapor pressure distribution and volatility-dependent mass spectrum were then measured for laboratory-generated secondary organic aerosol particles. Vaporization profiles from this method can easily be converted to a volatility basis set representation, which shows the distribution of mass vs. saturation concentration and the gas-particle partitioning of aerosol material. The experiments and simulations indicate that this method can be used to estimate organic aerosol component vapor pressures to within approximately an order of magnitude and that useful mass-spectral separation based on volatility can be achieved.

scholarly journals Characterization of a thermodenuder-particle beam mass spectrometer system for the study of organic aerosol volatility and composition

2009 ◽  
Vol 2 (1) ◽  
pp. 15-31 ◽  
Author(s):  
A. E. Faulhaber ◽  
B. M. Thomas ◽  
J. L. Jimenez ◽  
J. T. Jayne ◽  
D. R. Worsnop ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Vapor Pressure ◽  
Pressure Distribution ◽  
Mass Spectrometer ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Particle Beam ◽  
Basis Set ◽  
Aerosol Mass ◽  
Dependent Mass

Abstract. This paper describes the development and evaluation of a method for measuring the vapor pressure distribution and volatility-dependent mass spectrum of organic aerosol particles using a thermodenuder-particle beam mass spectrometer. The method is well suited for use with the widely used Aerodyne Aerosol Mass Spectrometer (AMS) and other quantitative aerosol mass spectrometers. The data that can be obtained are valuable for modeling organic gas-particle partitioning and for gaining improved composition information from aerosol mass spectra. The method is based on an empirically determined relationship between the thermodenuder temperature at which 50% of the organic aerosol mass evaporates (T50) and the organic component vapor pressure at 25°C (P25). This approach avoids the need for complex modeling of aerosol evaporation, which normally requires detailed information on aerosol composition and physical properties. T50 was measured for a variety of monodisperse, single-component organic aerosols with known P25 values and the results used to create a logP25 vs. T50 calibration curve. Experiments and simulations were used to estimate the uncertainties in P25 introduced by variations in particle size and mass concentration as well as mixing with other components. A vapor pressure distribution and volatility-dependent mass spectrum were then measured for laboratory-generated secondary organic aerosol particles. Vaporization profiles from this method can easily be converted to a volatility basis set representation, which shows the distribution of mass vs. saturation concentration and the gas-particle partitioning of aerosol material. The experiments and simulations indicate that this method can be used to estimate organic aerosol component vapor pressures to within approximately an order of magnitude and that useful mass-spectral separation based on volatility can be achieved.

scholarly journals Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

2010 ◽  
Vol 10 (18) ◽  
pp. 8933-8945 ◽  
Author(s):  
X.-F. Huang ◽  
L.-Y. He ◽  
M. Hu ◽  
M. R. Canagaratna ◽  
Y. Sun ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Olympic Games ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Organic Mass ◽  
Aerosol Mass Spectrometer ◽  
Beijing Olympic Games ◽  
Aerosol Mass ◽  
2008 Beijing Olympic Games

Abstract. As part of Campaigns of Air Quality Research in Beijing and Surrounding Region-2008 (CAREBeijing-2008), an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralympic Games (24 July to 20 September 2008). The campaign mean PM1 mass concentration was 63.1 ± 39.8 μg m−3; the mean composition consisted of organics (37.9%), sulfate (26.7%), ammonium (15.9%), nitrate (15.8%), black carbon (3.1%), and chloride (0.87%). The average size distributions of the species (except BC) were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF) analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA), cooking-related (COA), and two oxygenated organic aerosols (OOA-1 and OOA-2), which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum and diurnal pattern showed similar characteristics to that measured for cooking emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C) compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM1 pollution during the campaign. Aerosol particles in southern airmasses were especially rich in inorganic and oxidized organic species. Aerosol particles in northern airmasses contained a large fraction of primary HOA and COA species, probably due to stronger influences from local emissions. The lowest concentration levels for all major species were obtained during the Olympic game days (8 to 24 August 2008), possibly due to the effects of both strict emission controls and favorable meteorological conditions.

scholarly journals Secondary organic aerosol formation from idling gasoline passenger vehicle emissions investigated in a smog chamber

2013 ◽  
Vol 13 (12) ◽  
pp. 6101-6116 ◽  
Author(s):  
E. Z. Nordin ◽  
A. C. Eriksson ◽  
P. Roldin ◽  
P. T. Nilsson ◽  
J. E. Carlsson ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Mass Spectrometer ◽  
Urban Areas ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Smog Chamber ◽  
Aerosol Formation ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Gasoline Vehicles

Abstract. Gasoline vehicles have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from three passenger vehicles (EURO2–EURO4) were investigated with photo-oxidation experiments in a 6 m3 smog chamber. The experiments were carried out down to atmospherically relevant organic aerosol mass concentrations. The characterization instruments included a high-resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind of urban areas. After a cumulative OH exposure of ~5 × 106 cm−3 h, the formed SOA was 1–2 orders of magnitude higher than the primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f43 (mass fraction at m/z = 43), approximately two times higher than to the gasoline SOA. However O : C and H : C ratios were similar for the two cases. Classical C6–C9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher-order aromatic compounds such as C10 and C11 light aromatics, naphthalene and methyl-naphthalenes. We conclude that approaches using only light aromatic precursors give an incomplete picture of the magnitude of SOA formation and the SOA composition from gasoline exhaust.

scholarly journals Secondary organic aerosol formation from gasoline passenger vehicle emissions investigated in a smog chamber

2012 ◽  
Vol 12 (12) ◽  
pp. 31725-31765 ◽  
Author(s):  
E. Z. Nordin ◽  
A. C. Eriksson ◽  
P. Roldin ◽  
P. T. Nilsson ◽  
J. E. Carlsson ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Mass Spectrometer ◽  
Urban Areas ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Smog Chamber ◽  
Aerosol Formation ◽  
Characterization Methods ◽  
Aerosol Mass ◽  
Cold Starts

Abstract. Gasoline vehicles have elevated emissions of volatile organic compounds during cold starts and idling and have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from one Euro II, one Euro III and one Euro IV passenger vehicles were investigated using photo-oxidation experiments in a 6 m3 smog chamber. The experiments were carried out at atmospherically relevant organic aerosol mass concentrations. The characterization methods included a high resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind urban areas. After 4 h aging the formed SOA was 1–2 orders of magnitude higher than the Primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f43 (mass fraction at m/z = 4 3) approximately two times higher than to the gasoline SOA. However O : C and H : C ratios were similar for the two cases. Classical C6–C9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher order aromatic compounds such as C10, C11 light aromatics, naphthalene and methyl-naphthalenes.

scholarly journals Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

2010 ◽  
Vol 10 (5) ◽  
pp. 13219-13251 ◽  
Author(s):  
X.-F. Huang ◽  
L.-Y. He ◽  
M. Hu ◽  
M. R. Canagaratna ◽  
Y. Sun ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Olympic Games ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Organic Mass ◽  
Aerosol Mass Spectrometer ◽  
Beijing Olympic Games ◽  
Aerosol Mass ◽  
2008 Beijing Olympic Games

Abstract. As part of Campaigns of Air Quality Research in Beijing and Surrounding Region–2008 (CAREBeijing-2008), an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralytic Games (24 July to 20 September 2008). The campaign mean PM1 mass concentration was 63.1±39.8 μg m−3; the mean composition consisted of organics (37.9%), sulfate (26.7%), ammonium (15.9%), nitrate (15.8%), black carbon (3.1%), and chloride (0.87%). The average size distributions of the species (except BC) were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF) analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA), cooking-related (COA), and two oxygenated organic aerosols (OOA-1 and OOA-2), which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum showed high similarity to that measured from cooking aerosol emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C) compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM1 pollution during the campaign. This result is similar to observations made in the summer of 2006, although the average PM1 concentration level for the southerly air flows is 31% lower than for the 2008 campaign. Aerosol particles in southern airmasses were especially rich in inorganic and oxidized organic species. Aerosol particles in northern airmasses contained a large fraction of primary HOA and COA species, probably due to stronger influences from local emissions. The lowest concentration levels for all major species were obtained during the Olympic game days (8–24 August 2008), possibly due to the effects of both strict emission controls and favorable meteorological conditions.

scholarly journals Laboratory investigation of photochemical oxidation of organic aerosol from wood fires – Part 1: Measurement and simulation of organic aerosol evolution

2008 ◽  
Vol 8 (4) ◽  
pp. 15699-15737 ◽  
Author(s):  
A. P. Grieshop ◽  
J. M. Logue ◽  
N. M. Donahue ◽  
A. L. Robinson
Keyword(s):  
Mass Spectrometer ◽  
Uv Light ◽  
Organic Aerosol ◽  
Proton Transfer Reaction ◽  
Current Approach ◽  
Photochemical Oxidation ◽  
Basis Set ◽  
Organic Vapors ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

Abstract. Experiments were conducted to investigate the effects of photo-oxidation on organic aerosol (OA) in wood smoke by exposing diluted emissions from soft- and hard-wood fires to UV light in a smog chamber. Particle- and gas-phase concentrations were monitored with a suite of instruments including a Proton Transfer Reaction Mass Spectrometer (PTR-MS), an Aerosol Mass Spectrometer (AMS) and a thermodenuder to measure aerosol volatility. The measurements highlight how in-plume processing can lead to considerable evolution of the mass and volatility of biomass burning OA. Photochemical oxidation produced substantial new OA, increasing concentrations by a factor of 1.5 to 2.8 after several hours of exposure to typical summertime hydroxyl radical (OH) concentrations. Less than 20% of this new OA could be explained using the measured decay of traditional secondary organic aerosol (SOA) precursors and a state-of-the-art SOA model. Aging also created less volatile OA; at 50°C between 50 and 80% of the fresh primary OA evaporated but only 20 to 40% of aged OA. Therefore, the data provide additional evidence that primary OA is semivolatile. They also raise questions about the current approach used to simulate OA in chemical transport models, which assume that primary OA are non-volatile but that SOA is semivolatile. Predictions of a volatility basis-set model that explicitly tracks the partitioning and aging of low-volatile organics are compared to the chamber data. This model demonstrates that the OA production observed in these experiments can be explained by oxidation of low volatility organic vapors. The basis-set model can also simulate observed changes in OA volatility and composition, predicting the OA production and the increased oxygenation and decreased volatility of the OA.

scholarly journals Organic aerosol components observed in Northern Hemispheric datasets from Aerosol Mass Spectrometry

2010 ◽  
Vol 10 (10) ◽  
pp. 4625-4641 ◽  
Author(s):  
N. L. Ng ◽  
M. R. Canagaratna ◽  
Q. Zhang ◽  
J. L. Jimenez ◽  
J. Tian ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Organic Aerosol ◽  
Total Signal ◽  
Mass Spectral ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Wide Range ◽  
Triangular Region ◽  
Photochemical Aging ◽  
Spectral Diagnostic

Abstract. In this study we compile and present results from the factor analysis of 43 Aerosol Mass Spectrometer (AMS) datasets (27 of the datasets are reanalyzed in this work). The components from all sites, when taken together, provide a holistic overview of Northern Hemisphere organic aerosol (OA) and its evolution in the atmosphere. At most sites, the OA can be separated into oxygenated OA (OOA), hydrocarbon-like OA (HOA), and sometimes other components such as biomass burning OA (BBOA). We focus on the OOA components in this work. In many analyses, the OOA can be further deconvolved into low-volatility OOA (LV-OOA) and semi-volatile OOA (SV-OOA). Differences in the mass spectra of these components are characterized in terms of the two main ions m/z 44 (CO2+) and m/z 43 (mostly C2H3O+), which are used to develop a new mass spectral diagnostic for following the aging of OA components in the atmosphere. The LV-OOA component spectra have higher f44 (ratio of m/z 44 to total signal in the component mass spectrum) and lower f43 (ratio of m/z 43 to total signal in the component mass spectrum) than SV-OOA. A wide range of f44 and O:C ratios are observed for both LV-OOA (0.17±0.04, 0.73±0.14) and SV-OOA (0.07±0.04, 0.35±0.14) components, reflecting the fact that there is a continuum of OOA properties in ambient aerosol. The OOA components (OOA, LV-OOA, and SV-OOA) from all sites cluster within a well-defined triangular region in the f44 vs. f43 space, which can be used as a standardized means for comparing and characterizing any OOA components (laboratory or ambient) observed with the AMS. Examination of the OOA components in this triangular space indicates that OOA component spectra become increasingly similar to each other and to fulvic acid and HULIS sample spectra as f44 (a surrogate for O:C and an indicator of photochemical aging) increases. This indicates that ambient OA converges towards highly aged LV-OOA with atmospheric oxidation. The common features of the transformation between SV-OOA and LV-OOA at multiple sites potentially enable a simplified description of the oxidation of OA in the atmosphere. Comparison of laboratory SOA data with ambient OOA indicates that laboratory SOA are more similar to SV-OOA and rarely become as oxidized as ambient LV-OOA, likely due to the higher loadings employed in the experiments and/or limited oxidant exposure in most chamber experiments.

scholarly journals Secondary organic aerosol formation from reaction of tertiary amines with nitrate radical

2008 ◽  
Vol 8 (4) ◽  
pp. 16585-16608 ◽  
Author(s):  
M. E. Erupe ◽  
D. J. Price ◽  
P. J. Silva ◽  
Q. G. J. Malloy ◽  
L. Qi ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Nitrate Radical ◽  
Tertiary Amines ◽  
Aerosol Formation ◽  
Night Time ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Secondary Organic Aerosol Formation

Abstract. Secondary organic aerosol formation from the reaction of tertiary amines with nitrate radical was investigated in an indoor environmental chamber. Particle chemistry was monitored using a high resolution aerosol mass spectrometer while gas-phase species were detected using a proton transfer reaction mass spectrometer. Trimethylamine, triethylamine and tributylamine were studied. Results indicate that tributylamine forms the most aerosol mass followed by trimethylamine and triethylamine respectively. Spectra from the aerosol mass spectrometer indicate the formation of complex non-salt aerosol products. We propose a reaction mechanism that proceeds via abstraction of a proton by nitrate radical followed by RO2 chemistry. Rearrangement of the aminyl alkoxy radical through hydrogen shift leads to the formation of hydroxylated amides, which explain most of the higher mass ions in the mass spectra. These experiments show that oxidation of tertiary amines by nitrate radical may be an important night-time source of secondary organic aerosol.

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