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 Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions

2017 ◽  
Author(s):  
Alex K. Y. Lee ◽  
Chia-Li Chen ◽  
Jun Liu ◽  
Derek J. Price ◽  
Raghu Betha ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Spectral Characteristics ◽  
Organic Aerosol ◽  
Vehicular Emissions ◽  
Aerosol Mass Spectrometer ◽  
Diurnal Cycles ◽  
Aerosol Mass ◽  
Inorganic Species

Abstract. Black carbon (BC) emitted from incomplete combustion can result in significant impacts on air quality and climate. Understanding the mixing state of ambient BC and the chemical characteristics of its associated coatings are particularly important to evaluate BC fate and environmental impacts. In this study, we investigate the formation of organic coatings on BC particles in an urban environment (Fontana, California) under hot and dry conditions using a Soot-Particle Aerosol Mass Spectrometer (SP-AMS). The SP-AMS was operated in a configuration that can detect refractory BC (rBC) particles and their coatings exclusively. Using the −log(NOx/NOy) ratio as a proxy for photochemical age of air masses, substantial formation of secondary organic aerosol (SOA) coatings on rBC particles was observed due to active photochemistry in the afternoon, whereas primary organic aerosol (POA) components were strongly associated with rBC from fresh vehicular missions in the morning rush hours. There is also evidence that cooking related organic aerosols were externally mixed from rBC. Positive matrix factorization and elemental analysis illustrate that most of the observed SOA coatings were freshly formed, providing an opportunity to examine SOA coating formation on rBC near vehicular emissions. Approximately 7–20 wt % of secondary organic and inorganic species were estimated to be internally mixed with rBC on average, implying that rBC is unlikely the major condensation sinks of SOA in this study. Diurnal cycles of oxygenated organic aerosol (OOA) observed by a co-located standard high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-MS) correlated well with that of SOA coatings on rBC, but their mass spectral characteristics were different from each other. Our results suggest that at least a portion of SOA materials condensed on rBC surface were chemically different from OOA particles that were externally mixed with rBC, although they are both generated from local photochemistry.

scholarly journals Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions

2017 ◽  
Vol 17 (24) ◽  
pp. 15055-15067 ◽  
Author(s):  
Alex K. Y. Lee ◽  
Chia-Li Chen ◽  
Jun Liu ◽  
Derek J. Price ◽  
Raghu Betha ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Vehicular Emissions ◽  
Aerosol Mass Spectrometer ◽  
Carbon Particles ◽  
Aerosol Mass ◽  
Inorganic Species ◽  
Dry Conditions

Abstract. Black carbon (BC) emitted from incomplete combustion can result in significant impacts on air quality and climate. Understanding the mixing state of ambient BC and the chemical characteristics of its associated coatings is particularly important to evaluate BC fate and environmental impacts. In this study, we investigate the formation of organic coatings on BC particles in an urban environment (Fontana, California) under hot and dry conditions using a soot-particle aerosol mass spectrometer (SP-AMS). The SP-AMS was operated in a configuration that can exclusively detect refractory BC (rBC) particles and their coatings. Using the −log(NOx ∕ NOy) ratio as a proxy for photochemical age of air masses, substantial formation of secondary organic aerosol (SOA) coatings on rBC particles was observed due to active photochemistry in the afternoon, whereas primary organic aerosol (POA) components were strongly associated with rBC from fresh vehicular emissions in the morning rush hours. There is also evidence that cooking-related organic aerosols were externally mixed from rBC. Positive matrix factorization and elemental analysis illustrate that most of the observed SOA coatings were freshly formed, providing an opportunity to examine SOA coating formation on rBCs near vehicular emissions. Approximately 7–20 wt % of secondary organic and inorganic species were estimated to be internally mixed with rBC on average, implying that rBC is unlikely the major condensation sink of SOA in this study. Comparison of our results to a co-located standard high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) measurement suggests that at least a portion of SOA materials condensed on rBC surfaces were chemically different from oxygenated organic aerosol (OOA) particles that were externally mixed with rBC, although they could both be generated from local photochemistry.

scholarly journals Measurements of the aerosol chemical composition and mixing state in the Po Valley using multiple spectroscopic techniques

2014 ◽  
Vol 14 (22) ◽  
pp. 12109-12132 ◽  
Author(s):  
S. Decesari ◽  
J. Allan ◽  
C. Plass-Duelmer ◽  
B. J. Williams ◽  
M. Paglione ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Black Carbon ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Spectroscopic Techniques ◽  
Mixing State ◽  
Mass Spectrometers ◽  
Aerosol Mass Spectrometer ◽  
Po Valley ◽  
Aerosol Mass

Abstract. The use of co-located multiple spectroscopic techniques can provide detailed information on the atmospheric processes regulating aerosol chemical composition and mixing state. So far, field campaigns heavily equipped with aerosol mass spectrometers have been carried out mainly in large conurbations and in areas directly affected by their outflow, whereas lesser efforts have been dedicated to continental areas characterised by a less dense urbanisation. We present here the results obtained at a background site in the Po Valley, Italy, in summer 2009. For the first time in Europe, six state-of-the-art spectrometric techniques were used in parallel: aerosol time-of-flight mass spectrometer (ATOFMS), two aerosol mass spectrometers (high-resolution time-of-flight aerosol mass spectrometer – HR-ToF-AMS and soot particle aerosol mass spectrometer – SP-AMS), thermal desorption aerosol gas chromatography (TAG), chemical ionisation mass spectrometry (CIMS) and (offline) proton nuclear magnetic resonance (1H-NMR) spectroscopy. The results indicate that, under high-pressure conditions, atmospheric stratification at night and early morning hours led to the accumulation of aerosols produced by anthropogenic sources distributed over the Po Valley plain. Such aerosols include primary components such as black carbon (BC), secondary semivolatile compounds such as ammonium nitrate and amines and a class of monocarboxylic acids which correspond to the AMS cooking organic aerosol (COA) already identified in urban areas. In daytime, the entrainment of aged air masses in the mixing layer is responsible for the accumulation of low-volatility oxygenated organic aerosol (LV-OOA) and also for the recycling of non-volatile primary species such as black carbon. According to organic aerosol source apportionment, anthropogenic aerosols accumulating in the lower layers overnight accounted for 38% of organic aerosol mass on average, another 21% was accounted for by aerosols recirculated in residual layers but still originating in northern Italy, while a substantial fraction (41%) was due to the most aged aerosols imported from transalpine areas. The different meteorological regimes also affected the BC mixing state: in periods of enhanced stagnation and recirculation of pollutants, the number fraction of the BC-containing particles determined by ATOFMS was 75% of the total, while in the days of enhanced ventilation of the planetary boundary layer (PBL), such fraction was significantly lower (50%) because of the relative greater influence of non-BC-containing aerosol local sources in the Po Valley. Overall, a full internal mixing between BC and the non-refractory aerosol chemical components was not observed during the experiment in this environment.

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 Collection efficiency of the soot-particle aerosol mass spectrometer (SP-AMS) for internally mixed particulate black carbon

2014 ◽  
Vol 7 (12) ◽  
pp. 4507-4516 ◽  
Author(s):  
M. D. Willis ◽  
A. K. Y. Lee ◽  
T. B. Onasch ◽  
E. C. Fortner ◽  
L. R. Williams ◽  
...  
Keyword(s):  
Laser Beam ◽  
Black Carbon ◽  
Mass Spectrometer ◽  
Soot Particle ◽  
Collection Efficiency ◽  
Particle Beam ◽  
Aerosol Mass Spectrometer ◽  
Coated Particles ◽  
Aerosol Mass ◽  
Wide Range

Abstract. The soot-particle aerosol mass spectrometer (SP-AMS) uses an intra-cavity infrared laser to vaporize refractory black carbon (rBC) containing particles, making the particle beam–laser beam overlap critical in determining the collection efficiency (CE) for rBC and associated non-refractory particulate matter (NR-PM). This work evaluates the ability of the SP-AMS to quantify rBC and NR-PM mass in internally mixed particles with different thicknesses of organic coating. Using apparent relative ionization efficiencies for uncoated and thickly coated rBC particles, we report measurements of SP-AMS sensitivity to NR-PM and rBC, for Regal Black, the recommended particulate calibration material. Beam width probe (BWP) measurements are used to illustrate an increase in sensitivity for highly coated particles due to narrowing of the particle beam, which enhances the CE of the SP-AMS by increasing the laser beam–particle beam overlap. Assuming complete overlap for thick coatings, we estimate CE for bare Regal Black particles of 0.6 ± 0.1, which suggests that previously measured SP-AMS sensitivities to Regal Black were underestimated by up to a factor of 2. The efficacy of the BWP measurements is highlighted by studies at a busy road in downtown Toronto and at a non-roadside location, which show particle beam widths similar to, but greater than that of bare Regal Black and coated Regal Black, respectively. Further BWP measurements at field locations will help to constrain the range of CE for fresh and aged rBC-containing particles. The ability of the SP-AMS to quantitatively assess the composition of internally mixed particles is validated through measurements of laboratory-generated organic coated particles, which demonstrate that the SP-AMS can quantify rBC and NR-PM over a wide range of particle compositions and rBC core sizes.

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 Elemental composition and oxidation of chamber organic aerosol

2011 ◽  
Vol 11 (17) ◽  
pp. 8827-8845 ◽  
Author(s):  
P. S. Chhabra ◽  
N. L. Ng ◽  
M. R. Canagaratna ◽  
A. L. Corrigan ◽  
L. M. Russell ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Mass Spectrometer ◽  
Graphical Representation ◽  
Laboratory Data ◽  
Chemical Characterization ◽  
Organic Aerosol ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Triangular Region ◽  
Van Krevelen Diagram

Abstract. Recently, graphical representations of aerosol mass spectrometer (AMS) spectra and elemental composition have been developed to explain the oxidative and aging processes of secondary organic aerosol (SOA). It has been shown previously that oxygenated organic aerosol (OOA) components from ambient and laboratory data fall within a triangular region in the f44 vs. f43 space, where f44 and f43 are the ratios of the organic signal at m/z 44 and 43 to the total organic signal in AMS spectra, respectively; we refer to this graphical representation as the "triangle plot." Alternatively, the Van Krevelen diagram has been used to describe the evolution of functional groups in SOA. In this study we investigate the variability of SOA formed in chamber experiments from twelve different precursors in both "triangle plot" and Van Krevelen domains. Spectral and elemental data from the high-resolution Aerodyne aerosol mass spectrometer are compared to offline species identification analysis and FTIR filter analysis to better understand the changes in functional and elemental composition inherent in SOA formation and aging. We find that SOA formed under high- and low-NOx conditions occupy similar areas in the "triangle plot" and Van Krevelen diagram and that SOA generated from already oxidized precursors allows for the exploration of areas higher on the "triangle plot" not easily accessible with non-oxidized precursors. As SOA ages, it migrates toward the top of the triangle along a path largely dependent on the precursor identity, which suggests increasing organic acid content and decreasing mass spectral variability. The most oxidized SOA come from the photooxidation of methoxyphenol precursors which yielded SOA O/C ratios near unity. α-pinene ozonolysis and naphthalene photooxidation SOA systems have had the highest degree of mass closure in previous chemical characterization studies and also show the best agreement between AMS elemental composition measurements and elemental composition of identified species within the uncertainty of the AMS elemental analysis. In general, compared to their respective unsaturated SOA precursors, the elemental composition of chamber SOA follows a slope shallower than −1 on the Van Krevelen diagram, which is indicative of oxidation of the precursor without substantial losss of hydrogen, likely due to the unsaturated nature of the precursors. From the spectra of SOA studied here, we are able to reproduce the triangular region originally constructed with ambient OOA compents with chamber aerosol showing that SOA becomes more chemically similar as it ages. Ambient data in the middle of the triangle represent the ensemble average of many different SOA precursors, ages, and oxidative processes.

scholarly journals Elemental analysis of chamber organic aerosol using an aerodyne high-resolution aerosol mass spectrometer

2010 ◽  
Vol 10 (9) ◽  
pp. 4111-4131 ◽  
Author(s):  
P. S. Chhabra ◽  
R. C. Flagan ◽  
J. H. Seinfeld
Keyword(s):  
High Resolution ◽  
Elemental Composition ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Uptake System ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Single Ring ◽  
Spectrometer Data ◽  
Ambient Measurements

Abstract. The elemental composition of laboratory chamber secondary organic aerosol (SOA) from glyoxal uptake, α-pinene ozonolysis, isoprene photooxidation, single-ring aromatic photooxidation, and naphthalene photooxidation is evaluated using Aerodyne high-resolution time-of-flight mass spectrometer data. SOA O/C ratios range from 1.13 for glyoxal uptake experiments to 0.30–0.43 for α-pinene ozonolysis. The elemental composition of α-pinene and naphthalene SOA is also confirmed by offline mass spectrometry. The fraction of organic signal at m/z 44 is generally a good measure of SOA oxygenation for α-pinene/O3, isoprene/high-NOx, and naphthalene SOA systems. The agreement between measured and estimated O/C ratios tends to get closer as the fraction of organic signal at m/z 44 increases. This is in contrast to the glyoxal uptake system, in which m/z 44 substantially underpredicts O/C. Although chamber SOA has generally been considered less oxygenated than ambient SOA, single-ring aromatic- and naphthalene-derived SOA can reach O/C ratios upward of 0.7, well within the range of ambient PMF component OOA, though still not as high as some ambient measurements. The spectra of aromatic and isoprene-high-NOx SOA resemble that of OOA, but the spectrum of glyoxal uptake does not resemble that of any ambient organic aerosol PMF component.

scholarly journals Investigations of primary and secondary particulate matter of different wood combustion appliances with a high-resolution time-of-flight aerosol mass spectrometer

2011 ◽  
Vol 11 (12) ◽  
pp. 5945-5957 ◽  
Author(s):  
M. F. Heringa ◽  
P. F. DeCarlo ◽  
R. Chirico ◽  
T. Tritscher ◽  
J. Dommen ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Smog Chamber ◽  
Resolution Time ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Wood Burning ◽  
Primary Emissions ◽  
Stable Burning

Abstract. A series of photo-oxidation smog chamber experiments were performed to investigate the primary emissions and secondary aerosol formation from two different log wood burners and a residential pellet burner under different burning conditions: starting and flaming phase. Emissions were sampled from the chimney and injected into the smog chamber leading to primary organic aerosol (POA) concentrations comparable to ambient levels. The composition of the aerosol was measured by an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and black carbon (BC) instrumentation. The primary emissions were then exposed to xenon light to initiate photo-chemistry and subsequent secondary organic aerosol (SOA) production. After correcting for wall losses, the average increase in organic matter (OM) concentrations by SOA formation for the starting and flaming phase experiments with the two log wood burners was found to be a factor of 4.1±1.4 after five hours of aging. No SOA formation was observed for the stable burning phase of the pellet burner. The startup emissions of the pellet burner showed an increase in OM concentration by a factor of 3.3. Including the measured SOA formation potential, average emission factors of BC+POA+SOA, calculated from CO2 emission, were found to be in the range of 0.04 to 3.9 g/kg wood for the stable burning pellet burner and an old log wood burner during startup respectively. SOA contributed significantly to the ion C2H4O2+ at mass to charge ratio m/z 60, a commonly used marker for primary emissions of wood burning. This contribution at m/z 60 can overcompensate for the degradation of levoglucosan leading to an overestimation of the contribution of wood burning or biomass burning to the total OM. The primary organic emissions from the three different burners showed a wide range in O:C atomic ratio (0.19−0.60) for the starting and flaming conditions, which also increased during aging. Primary wood burning emissions have a rather low relative contribution at m/z 43 (f 43) to the total organic mass spectrum. The non-oxidized fragment C3H7+ has a considerable contribution at m/z 43 for the fresh OA with an increasing contribution of the oxygenated ion C2H3O+ during aging. After five hours of aging, the OA has a rather low C2H3O+ signal for a given CO2+ fraction, possibly indicating a higher ratio of acid to non-acid oxygenated compounds in wood burning OA compared to other oxygenated organic aerosol (OOA).

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