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 Laboratory investigation of photochemical oxidation of organic aerosol from wood fires 1: measurement and simulation of organic aerosol evolution

2009 ◽  
Vol 9 (4) ◽  
pp. 1263-1277 ◽  
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 ◽  
Photochemical Oxidation ◽  
Basis Set ◽  
Aerosol Model ◽  
Wood Stove ◽  
Pollutant Concentrations ◽  
Small Wood

Abstract. Experiments were conducted to investigate the effects of photo-oxidation on organic aerosol (OA) emissions from flaming and smoldering hard- and soft-wood fires under plume-like conditions. This was done by exposing the dilute emissions from a small wood stove to UV light in a smog chamber and measuring the gas- and particle-phase pollutant concentrations with a suite of instruments including a Proton Transfer Reaction Mass Spectrometer (PTR-MS), an Aerosol Mass Spectrometer (AMS) and a thermodenuder. The measurements highlight how atmospheric 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 a state-of-the-art secondary organic aerosol model and the measured decay of traditional SOA precursors. The thermodenuder data indicate that the primary OA is semivolatile; at 50°C between 50 and 80% of the fresh primary OA evaporated. Aging reduced the volatility of the OA; at 50°C only 20 to 40% of aged OA evaporated. The predictions of a volatility basis-set model that explicitly tracks the partitioning and aging of low-volatility organics was compared to the chamber data. The OA production can be explained by the oxidation of low-volatility organic vapors; the model can also reproduce observed changes in OA volatility and composition. The model was used to investigate the competition between photochemical processing and dilution on OA concentrations in plumes.

scholarly journals Laboratory investigation of photochemical oxidation of organic aerosol from wood fires – Part 2: Analysis of aerosol mass spectrometer data

2008 ◽  
Vol 8 (5) ◽  
pp. 17095-17130 ◽  
Author(s):  
A. P. Grieshop ◽  
N. M. Donahue ◽  
A. L. Robinson
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Explicit Knowledge ◽  
Uv Light ◽  
Organic Aerosol ◽  
Photochemical Oxidation ◽  
Wood Smoke ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Spectrometer Data

Abstract. Experiments were conducted to investigate the effects of photo-oxidation on organic aerosol (OA) in dilute wood smoke by exposing emissions from soft- and hard-wood fires to UV light in a smog chamber. This paper focuses on changes in OA composition measured using a unit mass resolution quadrupole Aerosol Mass Spectrometer (AMS). The results highlight how photochemical processing can lead to considerable evolution of the mass, the volatility and the level of oxygenation of biomass-burning OA. Photochemical oxidation produced substantial new OA, more than doubling the primary contribution after a few hours of aging under typical summertime conditions. Aging decreased the OA volatility of the total OA as measured with a thermodenuder; it also made the OA progressively more oxygenated in every experiment. With explicit knowledge of the condensed-phase mass spectrum (MS) of the primary emissions from each fire, each MS can be decomposed into primary and residual spectra throughout the experiment. The residual spectra provide an estimate of the composition of the photochemically produced OA. These spectra are also very similar to those of the oxygenated OA that dominates ambient AMS datasets. In addition, aged wood smoke spectra are shown to be similar to those from OA created by photo-oxidized dilute diesel exhaust and aged biomass-burning OA measured in urban and remote locations. This demonstrates that the oxygenated OA observed in the atmosphere can be produced by photochemical aging of dilute emissions from combustion of fuels containing both modern and fossil carbon.

scholarly journals Primary and secondary organic aerosol origin by combined gas-particle phase source apportionment

2013 ◽  
Vol 13 (3) ◽  
pp. 8537-8583 ◽  
Author(s):  
M. Crippa ◽  
F. Canonaco ◽  
J. G. Slowik ◽  
I. El Haddad ◽  
P. F. DeCarlo ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Proton Transfer Reaction ◽  
Anthropogenic Sources ◽  
Particle Phase ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Formation And Evolution

Abstract. Secondary organic aerosol (SOA), a predominant fraction of particulate organic mass (OA), remains poorly constrained. Its formation involves several unknown precursors, formation and evolution pathways and multiple natural and anthropogenic sources. Here a combined gas-particle phase source apportionment is applied to wintertime and summertime data collected in the megacity of Paris in order to investigate SOA origin during both seasons. This was possible by combining the information provided by an aerosol mass spectrometer (AMS) and a proton transfer reaction mass spectrometer (PTR-MS). A better constrained apportionment of primary OA (POA) sources is also achieved using this methodology, making use of gas-phase tracers. These tracers allowed distinguishing between biogenic and continental/anthropogenic sources of SOA. We found that continental SOA was dominant during both seasons (24–50% of total OA), while contributions from photochemistry-driven SOA (9% of total OA) and marine emissions (13% of total OA) were also observed during summertime. A semi-volatile nighttime component was also identified (up to 18% of total OA during wintertime). This approach was successfully applied here and implemented in a new source apportionment toolkit.

scholarly journals Laboratory investigation of photochemical oxidation of organic aerosol from wood fires 2: analysis of aerosol mass spectrometer data

2009 ◽  
Vol 9 (6) ◽  
pp. 2227-2240 ◽  
Author(s):  
A. P. Grieshop ◽  
N. M. Donahue ◽  
A. L. Robinson
Keyword(s):  
Source Apportionment ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Motor Vehicle ◽  
Organic Aerosol ◽  
Photochemical Oxidation ◽  
Wood Smoke ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Spectrometer Data

Abstract. Experiments were conducted to investigate the effects of photo-oxidation on organic aerosol (OA) in dilute wood smoke by exposing emissions from soft- and hard-wood fires to UV light in a smog chamber. This paper focuses on changes in OA composition measured using a unit-mass-resolution quadrupole Aerosol Mass Spectrometer (AMS). The results highlight how photochemical processing can lead to considerable evolution of the mass, volatility and level of oxygenation of biomass-burning OA. Photochemical oxidation produced substantial new OA, more than doubling the OA mass after a few hours of aging under typical summertime conditions. Aging also decreased the volatility of the OA and made it progressively more oxygenated. The results also illustrate strengths of, and challenges with, using AMS data for source apportionment analysis. For example, the mass spectra of fresh and aged BBOA are distinct from fresh motor-vehicle emissions. The mass spectra of the secondary OA produced from aging wood smoke are very similar to those of the oxygenated OA (OOA) that dominates ambient AMS datasets, further reinforcing the connection between OOA and OA formed from photo-chemistry. In addition, aged wood smoke spectra are similar to those from OA created by photo-oxidizing dilute diesel exhaust. This demonstrates that the OOA observed in the atmosphere can be produced by photochemical aging of dilute emissions from different types of combustion systems operating on fuels with modern or fossil carbon. Since OOA is frequently the dominant component of ambient OA, the similarity of spectra of aged emissions from different sources represents an important challenge for AMS-based source apportionment studies.

scholarly journals Primary and secondary organic aerosol origin by combined gas-particle phase source apportionment

2013 ◽  
Vol 13 (16) ◽  
pp. 8411-8426 ◽  
Author(s):  
M. Crippa ◽  
F. Canonaco ◽  
J. G. Slowik ◽  
I. El Haddad ◽  
P. F. DeCarlo ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Proton Transfer Reaction ◽  
Anthropogenic Sources ◽  
Particle Phase ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Formation And Evolution

Abstract. Secondary organic aerosol (SOA), a prominent fraction of particulate organic mass (OA), remains poorly constrained. Its formation involves several unknown precursors, formation and evolution pathways and multiple natural and anthropogenic sources. Here a combined gas-particle phase source apportionment is applied to wintertime and summertime data collected in the megacity of Paris in order to investigate SOA origin during both seasons. This was possible by combining the information provided by an aerosol mass spectrometer (AMS) and a proton transfer reaction mass spectrometer (PTR-MS). A better constrained apportionment of primary OA (POA) sources is also achieved using this methodology, making use of gas-phase tracers. These tracers made possible the discrimination between biogenic and continental/anthropogenic sources of SOA. We found that continental SOA was dominant during both seasons (24–50% of total OA), while contributions from photochemistry-driven SOA (9% of total OA) and marine emissions (13% of total OA) were also observed during summertime. A semi-volatile nighttime component was also identified (up to 18% of total OA during wintertime). This approach was successfully applied here and implemented in a new source apportionment toolkit.

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.

scholarly journals Characterization of a real-time tracer for isoprene epoxydiols-derived secondary organic aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

2015 ◽  
Vol 15 (20) ◽  
pp. 11807-11833 ◽  
Author(s):  
W. W. Hu ◽  
P. Campuzano-Jost ◽  
B. B. Palm ◽  
D. A. Day ◽  
A. M. Ortega ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Transport Model ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Chemical Transport Model ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Multiple Field

Abstract. Substantial amounts of secondary organic aerosol (SOA) can be formed from isoprene epoxydiols (IEPOX), which are oxidation products of isoprene mainly under low-NO conditions. Total IEPOX-SOA, which may include SOA formed from other parallel isoprene oxidation pathways, was quantified by applying positive matrix factorization (PMF) to aerosol mass spectrometer (AMS) measurements. The IEPOX-SOA fractions of organic aerosol (OA) in multiple field studies across several continents are summarized here and show consistent patterns with the concentration of gas-phase IEPOX simulated by the GEOS-Chem chemical transport model. During the Southern Oxidant and Aerosol Study (SOAS), 78 % of PMF-resolved IEPOX-SOA is accounted by the measured IEPOX-SOA molecular tracers (2-methyltetrols, C5-Triols, and IEPOX-derived organosulfate and its dimers), making it the highest level of molecular identification of an ambient SOA component to our knowledge. An enhanced signal at C5H6O+ (m/z 82) is found in PMF-resolved IEPOX-SOA spectra. To investigate the suitability of this ion as a tracer for IEPOX-SOA, we examine fC5H6O (fC5H6O= C5H6O+/OA) across multiple field, chamber, and source data sets. A background of ~ 1.7 ± 0.1 ‰ (‰ = parts per thousand) is observed in studies strongly influenced by urban, biomass-burning, and other anthropogenic primary organic aerosol (POA). Higher background values of 3.1 ± 0.6 ‰ are found in studies strongly influenced by monoterpene emissions. The average laboratory monoterpene SOA value (5.5 ± 2.0 ‰) is 4 times lower than the average for IEPOX-SOA (22 ± 7 ‰), which leaves some room to separate both contributions to OA. Locations strongly influenced by isoprene emissions under low-NO levels had higher fC5H6O (~ 6.5 ± 2.2 ‰ on average) than other sites, consistent with the expected IEPOX-SOA formation in those studies. fC5H6O in IEPOX-SOA is always elevated (12–40 ‰) but varies substantially between locations, which is shown to reflect large variations in its detailed molecular composition. The low fC5H6O (< 3 ‰) reported in non-IEPOX-derived isoprene-SOA from chamber studies indicates that this tracer ion is specifically enhanced from IEPOX-SOA, and is not a tracer for all SOA from isoprene. We introduce a graphical diagnostic to study the presence and aging of IEPOX-SOA as a triangle plot of fCO2 vs. fC5H6O. Finally, we develop a simplified method to estimate ambient IEPOX-SOA mass concentrations, which is shown to perform well compared to the full PMF method. The uncertainty of the tracer method is up to a factor of ~ 2, if the fC5H6O of the local IEPOX-SOA is not available. When only unit mass-resolution data are available, as with the aerosol chemical speciation monitor (ACSM), all methods may perform less well because of increased interferences from other ions at m/z 82. This study clarifies the strengths and limitations of the different AMS methods for detection of IEPOX-SOA and will enable improved characterization of this OA component.

scholarly journals A Black Carbon‐Tracer Method for Estimating Cooking Organic Aerosol From Aerosol Mass Spectrometer Measurements

2019 ◽  
Vol 46 (14) ◽  
pp. 8474-8483 ◽  
Author(s):  
Yao He ◽  
Yele Sun ◽  
Qingqing Wang ◽  
Wei Zhou ◽  
Weiqi Xu ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Tracer Method ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

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 Relating hygroscopicity and composition of organic aerosol particulate matter

2011 ◽  
Vol 11 (3) ◽  
pp. 1155-1165 ◽  
Author(s):  
J. Duplissy ◽  
P. F. DeCarlo ◽  
J. Dommen ◽  
M. R. Alfarra ◽  
A. Metzger ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Field Experiments ◽  
Organic Aerosol ◽  
Photochemical Oxidation ◽  
Ionization Mass ◽  
Hygroscopic Growth ◽  
Atmospheric Models ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Organic Precursors

Abstract. A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44). m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "ϰorg" parameter, and f44 was determined and is given by ϰorg = 2.2 × f44 − 0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass.

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