Measurements of Secondary Organic Aerosol Formed from OH-initiated Photo-oxidation of Isoprene Using Online Photoionization Aerosol Mass Spectrometry

2012 ◽  
Vol 46 (7) ◽  
pp. 3898-3904 ◽  
Author(s):  
Wenzheng Fang ◽  
Lei Gong ◽  
Qiang Zhang ◽  
Maoqi Cao ◽  
Yuquan Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Photo Oxidation ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry

scholarly journals Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

2011 ◽  
Vol 11 (12) ◽  
pp. 5917-5929 ◽  
Author(s):  
J. F. Hamilton ◽  
M. Rami Alfarra ◽  
K. P. Wyche ◽  
M. W. Ward ◽  
A. C. Lewis ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Ion Cyclotron Resonance ◽  
Photo Oxidation ◽  
Seed Particles ◽  
Aerosol Mass ◽  
Seed Aerosol ◽  
Limonene Oxidation

Abstract. The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES) project to study the effect of seed particles on the formation of secondary organic aerosol (SOA) from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulfate or diesel particles, a method was developed to use in-situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m−3). Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8 %. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90 % RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC × GC) and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

scholarly journals Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

2010 ◽  
Vol 10 (10) ◽  
pp. 25117-25151
Author(s):  
J. F. Hamilton ◽  
M. Rami Alfarra ◽  
K. P. Wyche ◽  
M. W. Ward ◽  
A. C. Lewis ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Ion Cyclotron Resonance ◽  
Photo Oxidation ◽  
Seed Particles ◽  
Aerosol Mass ◽  
Seed Aerosol ◽  
Limonene Oxidation

Abstract. The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES) project to study the effect of seed particles on the formation of secondary organic aerosol (SOA) from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulphate or diesel particles, a method was developed to use in situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m-3). Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8%. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90% RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC×GC) and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

Identification of secondary organic aerosol based on aerosol mass spectrometry

2010 ◽  
Vol 40 (10) ◽  
pp. 1550-1557
Author(s):  
YuanHang ZHANG ◽  
Lian XUE ◽  
LingYan HE ◽  
QiJing BIAN ◽  
Min HU ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry

Evaluating the Mixing of Organic Aerosol Components Using High-Resolution Aerosol Mass Spectrometry

2011 ◽  
Vol 45 (15) ◽  
pp. 6329-6335 ◽  
Author(s):  
Lea Hildebrandt ◽  
Kaytlin M. Henry ◽  
Jesse H. Kroll ◽  
Douglas R. Worsnop ◽  
Spyros N. Pandis ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Organic Aerosol ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry

scholarly journals Rural continental aerosol properties and processes observed during the Hohenpeissenberg Aerosol Characterization Experiment (HAZE2002)

2007 ◽  
Vol 7 (3) ◽  
pp. 8617-8662 ◽  
Author(s):  
N. Hock ◽  
J. Schneider ◽  
S. Borrmann ◽  
A. Römpp ◽  
G. Moortgat ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Particle Number ◽  
Dicarboxylic Acids ◽  
Organic Aerosol ◽  
Particle Formation ◽  
Total Carbon ◽  
Submicron Particles ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Meteorological Observatory

Abstract. Detailed investigations of the chemical and microphysical properties of rural continental aerosols were performed during the HAZE2002 experiment, which was conducted in May 2002 at the Meteorological Observatory Hohenpeissenberg (DWD) in Southern Germany. The online measurement data and techniques included: size-resolved chemical composition of submicron particles by aerosol mass spectrometry (AMS); total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm (CPC, SMPS, OPC); monoterpenes determined by gas chromatography- ion trap mass spectrometry; OH and H2SO4 determined by atmospheric pressure chemical ionization mass spectrometry (CIMS). Filter sampling and offline analytical techniques were used to determine: fine particle mass (PM2.5), organic, elemental and total carbon in PM2.5 (OC2.5, EC2.5, TC2.5), and selected organic compounds (dicarboxylic acids, polycyclic aromatic hydrocarbons, proteins). Overall, the non-refractory components of submicron particles detected by aerosol mass spectrometry (PM1, 6.6±5.4 μg m−3, arithmetic mean and standard deviation) accounted for ~62% of PM2.5 determined by filter gravimetry (10.6±4.7 μg m−3). The relative proportions of non-refractory submicron particle components were: 11% ammonium, 19% nitrate, 20% sulfate, and 50% organics (OM1). In spite of strongly changing meteorological conditions and absolute concentration levels of particulate matter (3–13 μg m−3 PM1), OM1 was closely correlated with PM1 (r2=0.9) indicating a near-constant ratio of non-refractory organics and inorganics. In contrast, the ratio of nitrate to sulfate was highly dependent on temperature (14–32°C) and relative humidity (20–100%), which could be explained by thermodynamic model calculations of NH3/HNO3/NH4NO3 gas-particle partitioning. From the combination of optical and other sizing techniques (OPC, AMS, SMPS), an average refractive index of 1.40–1.45 was inferred for the measured rural aerosol particles. The average ratio of OM1 to OC2.5 was 2, indicating a high proportion of heteroelements in the organic fraction of the sampled rural aerosol. This is consistent with the high ratio of oxygenated organic aerosol (OOA) over hydrocarbon-like organic aerosol (HOA) inferred from the AMS results (4:1), and also with the high abundance of proteins (~3%) indicating a high proportion of primary biological material (~30%) in PM2.5. Moreover, the low abundance of PAHs (<1 ng m−3) and EC (<1 μg m−3) in PM2.5 confirm a low contribution of combustion emissions, which are usually also major sources for HOA. Slightly enhanced HOA concentrations indicating fresh anthropogenic emissions were observed during a period when air masses were advected from the densely populated Po Valley, Italy. Detection of several secondary organic aerosol compounds (dicarboxylic acids) and their precursors (monoterpenes) confirmed the finding that secondary aerosol from natural sources was an important aerosol constituent. A sharp decrease of the short lived monoterpenes indicated that during night-time the measurement station was isolated from ground emission sources by a stable inversion layer. Nighttime values can therefore be regarded to represent regional or long range transport. New particle formation was observed almost every day with particle number concentrations exceeding 104 cm−3 (nighttime background level 1000–2000 cm−3). Closer inspection of two major events indicated that ternary H2SO4/H2O/NH3 nucleation triggered particle formation and that condensation of both organic and inorganic species contributed to particle growth.

scholarly journals High formation of secondary organic aerosol from the photo-oxidation of toluene

2009 ◽  
Vol 9 (1) ◽  
pp. 693-733 ◽  
Author(s):  
L. Hildebrandt ◽  
N. M. Donahue ◽  
S. N. Pandis
Keyword(s):  
Air Quality ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Ambient Conditions ◽  
Dynamic Nature ◽  
Experimental Conditions ◽  
Quality Models ◽  
Photo Oxidation ◽  
Aerosol Mass ◽  
Photochemical Aging

Abstract. Toluene and other aromatics have long been viewed as the dominant anthropogenic secondary organic aerosol (SOA) precursors, but the SOA mass yields from toluene reported in previous studies vary widely. Experiments conducted in the Carnegie Mellon University environmental chamber to study SOA formation from the photo-oxidation of toluene show significantly larger SOA production than parameterizations employed in current air-quality models. Aerosol mass yields depend on experimental conditions: yields are higher under higher UV intensity, under low-NOx conditions and at lower temperatures. The extent of oxidation of the aerosol also varies with experimental conditions, consistent with ongoing, progressive photochemical aging of the toluene SOA. Measurements using a thermodenuder system suggest that the aerosol formed under high- and low-NOx conditions is semi-volatile. These results suggest that SOA formation from toluene depends strongly on ambient conditions. An approximate parameterization is proposed for use in air-quality models until a more thorough treatment accounting for the dynamic nature of this system becomes available.

scholarly journals Characterization of aerosol chemical composition with aerosol mass spectrometry in Central Europe: an overview

2010 ◽  
Vol 10 (21) ◽  
pp. 10453-10471 ◽  
Author(s):  
V. A. Lanz ◽  
A. S. H. Prévôt ◽  
M. R. Alfarra ◽  
S. Weimer ◽  
C. Mohr ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Composition ◽  
Organic Aerosol ◽  
Volatile Fraction ◽  
Aerosol Composition ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Field Campaigns ◽  
Alpine Valleys ◽  
Aerosol Chemical Composition

Abstract. Real-time measurements of non-refractory submicron aerosols (NR-PM1) were conducted within the greater Alpine region (Switzerland, Germany, Austria, France and Liechtenstein) during several week-long field campaigns in 2002–2009. This region represents one of the most important economic and recreational spaces in Europe. A large variety of sites was covered including urban backgrounds, motorways, rural, remote, and high-alpine stations, and also mobile on-road measurements were performed. Inorganic and organic aerosol (OA) fractions were determined by means of aerosol mass spectrometry (AMS). The data originating from 13 different field campaigns and the combined data have been utilized for providing an improved temporal and spatial data coverage. The average mass concentration of NR-PM1 for the different campaigns typically ranged between 10 and 30 μg m−3. Overall, the organic portion was most abundant, ranging from 36% to 81% of NR-PM1. Other main constituents comprised ammonium (5–15%), nitrate (8–36%), sulfate (3–26%), and chloride (0–5%). These latter anions were, on average, fully neutralized by ammonium. As a major result, time of the year (winter vs. summer) and location of the site (Alpine valleys vs. Plateau) could largely explain the variability in aerosol chemical composition for the different campaigns and were found to be better descriptors for aerosol composition than the type of site (urban, rural etc.). Thus, a reassessment of classifications of measurements sites might be considered in the future, possibly also for other regions of the world. The OA data was further analyzed using positive matrix factorization (PMF) and the multi-linear engine ME (factor analysis) separating the total OA into its underlying components, such as oxygenated (mostly secondary) organic aerosol (OOA), hydrocarbon-like and freshly emitted organic aerosol (HOA), as well as OA from biomass burning (BBOA). OOA was ubiquitous, ranged between 36% and 94% of OA, and could be separated into a low-volatility and a semi-volatile fraction (LV-OOA and SV-OOA) for all summer campaigns at low altitude sites. Wood combustion (BBOA) accounted for a considerable fraction during wintertime (17–49% OA), particularly in narrow Alpine valleys BBOA was often the most abundant OA component. HOA/OA ratios were comparatively low for all campaigns (6–16%) with the exception of on-road, mobile measurements (23%) in the Rhine Valley. The abundance of the aerosol components and the retrievability of SV-OOA and LV-OOA are discussed in the light of atmospheric chemistry and physics.

scholarly journals Gas-phase composition and secondary organic aerosol formation from standard and particle filter-retrofitted gasoline direct injection vehicles investigated in a batch and flow reactor

2018 ◽  
Vol 18 (13) ◽  
pp. 9929-9954 ◽  
Author(s):  
Simone M. Pieber ◽  
Nivedita K. Kumar ◽  
Felix Klein ◽  
Pierre Comte ◽  
Deepika Bhattu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Flow Reactor ◽  
Secondary Organic Aerosol ◽  
Matrix Effects ◽  
Direct Injection ◽  
Organic Aerosol ◽  
Gasoline Direct Injection ◽  
Particulate Filter ◽  
Aerosol Formation ◽  
Aerosol Mass

Abstract. Gasoline direct injection (GDI) vehicles have recently been identified as a significant source of carbonaceous aerosol, of both primary and secondary origin. Here we investigated primary emissions and secondary organic aerosol (SOA) from four GDI vehicles, two of which were also retrofitted with a prototype gasoline particulate filter (GPF). We studied two driving test cycles under cold- and hot-engine conditions. Emissions were characterized by proton transfer reaction time-of-flight mass spectrometry (gaseous non-methane organic compounds, NMOCs), aerosol mass spectrometry (sub-micron non-refractory particles) and light attenuation measurements (equivalent black carbon (eBC) determination using Aethalometers) together with supporting instrumentation. Atmospheric processing was simulated using the PSI mobile smog chamber (SC) and the potential aerosol mass oxidation flow reactor (OFR). Overall, primary and secondary particulate matter (PM) and NMOC emissions were dominated by the engine cold start, i.e., before thermal activation of the catalytic after-treatment system. Trends in the SOA oxygen to carbon ratio (O : C) for OFR and SC were related to different OH exposures, but divergences in the H : C remained unexplained. SOA yields agreed within experimental variability between the two systems, with a tendency for higher values in the OFR than in the SC (or, vice versa, lower values in the SC). A few aromatic compounds dominated the NMOC emissions, primarily benzene, toluene, xylene isomers/ethylbenzene and C3-benzene. A significant fraction of the SOA was explained by those compounds, based on comparison of effective SOA yield curves with those of toluene, o-xylene and 1,2,4-trimethylbenzene determined in our OFR, as well as others from literature. Remaining discrepancies, which were smaller in the SC and larger in the OFR, were up to a factor of 2 and may have resulted from diverse reasons including unaccounted precursors and matrix effects. GPF retrofitting significantly reduced primary PM through removal of refractory eBC and partially removed the minor POA fraction. At cold-started conditions it did not affect hydrocarbon emission factors, relative chemical composition of NMOCs or SOA formation, and likewise SOA yields and bulk composition remained unaffected. GPF-induced effects at hot-engine conditions deserve attention in further studies.

scholarly journals Characterization of urban aerosol in Cork city (Ireland) using aerosol mass spectrometry

2013 ◽  
Vol 13 (9) ◽  
pp. 4997-5015 ◽  
Author(s):  
M. Dall'Osto ◽  
J. Ovadnevaite ◽  
D. Ceburnis ◽  
D. Martin ◽  
R. M. Healy ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometer ◽  
Urban Areas ◽  
Time Of Flight ◽  
Organic Matrix ◽  
Organic Aerosol ◽  
Abundant Species ◽  
Urban Aerosol ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry

Abstract. Ambient wintertime background urban aerosol in Cork city, Ireland, was characterized using aerosol mass spectrometry. During the three-week measurement study in 2009, 93% of the ca. 1 350 000 single particles characterized by an Aerosol Time-of-Flight Mass Spectrometer (TSI ATOFMS) were classified into five organic-rich particle types, internally mixed to different proportions with elemental carbon (EC), sulphate and nitrate, while the remaining 7% was predominantly inorganic in nature. Non-refractory PM1 aerosol was characterized using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS) and was also found to comprise organic aerosol as the most abundant species (62%), followed by nitrate (15%), sulphate (9%) and ammonium (9%), and chloride (5%). Positive matrix factorization (PMF) was applied to the HR-ToF-AMS organic matrix, and a five-factor solution was found to describe the variance in the data well. Specifically, "hydrocarbon-like" organic aerosol (HOA) comprised 20% of the mass, "low-volatility" oxygenated organic aerosol (LV-OOA) comprised 18%, "biomass burning" organic aerosol (BBOA) comprised 23%, non-wood solid-fuel combustion "peat and coal" organic aerosol (PCOA) comprised 21%, and finally a species type characterized by primary \\textit{m/z}~peaks at 41 and 55, similar to previously reported "cooking" organic aerosol (COA), but possessing different diurnal variations to what would be expected for cooking activities, contributed 18%. Correlations between the different particle types obtained by the two aerosol mass spectrometers are also discussed. Despite wood, coal and peat being minor fuel types used for domestic space heating in urban areas, their relatively low combustion efficiencies result in a significant contribution to PM1 aerosol mass (44% and 28% of the total organic aerosol mass and non-refractory total PM1, respectively).

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