Secondary Organic Aerosol Reduced by Mixture of Atmospheric Vapours

Biogenic volatile organic compounds (VOC) are important secondary organic aerosol (SOA) precursors. Whilst isoprene dominates VOC plant emissions globally, its yield of SOA mass is found to be modest in comparison to that of monoterpenes (MT). Tracers from isoprene oxidation have been observed in particles showing that they condense from the gas phase and yet new particle formation is suppressed by the presence of isoprene in mixtures of plant emissions containing MT.Experiments were performed in the JPAC chamber in J&#252;lich. We showed that isoprene can suppress both the instantaneous mass formation and overall yield of monoterpenes in mixtures by two effects: oxidant and product scavenging. Isoprene scavenged OH radicals from reacting with MT (oxidant scavenging). Subsequently, the resulting isoprene peroxy radicals reacted with highly oxygenated peroxy radicals from MT oxidation (product scavenging). These effects from isoprene, also demonstrated using CO or CH4, reduced the yield of low-volatility, highly oxygenated molecules (HOM) from MT that would otherwise form SOA.Our results show that in mixtures changes in particle mass and number are not additive, and yields from single precursor experiments cannot simply be linearly combined. Reactive, modest SOA yield compounds are not necessarily net SOA producers and isoprene oxidation can suppress both SOA number and mass. Global model calculations support that OH scavenging and product scavenging can also operate in the real atmosphere. Our results highlight a need for more realistic consideration of SOA formation in the atmosphere analogous to the treatment of ozone formation, where interactions between the mechanistic pathways involving peroxy radicals are recognised to be essential.

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Composition and volatility of secondary organic aerosol (SOA) formed from oxidation of real tree emissions compared to simplified volatile organic compound (VOC) systems

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-5629-2020 ◽

2020 ◽

Vol 20 (9) ◽

pp. 5629-5644 ◽

Cited By ~ 3

Author(s):

Arttu Ylisirniö ◽

Angela Buchholz ◽

Claudia Mohr ◽

Zijun Li ◽

Luis Barreira ◽

...

Keyword(s):

Chemical Composition ◽

Scots Pine ◽

Flow Reactor ◽

Secondary Organic Aerosol ◽

Organic Aerosol ◽

Oxidation Products ◽

Mass Yield ◽

Chemical Complexity ◽

Volatile Organic ◽

Plant Emissions

Abstract. Secondary organic aerosol (SOA) is an important constituent of the atmosphere where SOA particles are formed chiefly by the condensation or reactive uptake of oxidation products of volatile organic compounds (VOCs). The mass yield in SOA particle formation, as well as the chemical composition and volatility of the particles, is determined by the identity of the VOC precursor(s) and the oxidation conditions they experience. In this study, we used an oxidation flow reactor to generate biogenic SOA from the oxidation of Scots pine emissions. Mass yields, chemical composition and volatility of the SOA particles were characterized and compared with SOA particles formed from oxidation of α-pinene and from a mixture of acyclic–monocyclic sesquiterpenes (farnesenes and bisabolenes), which are significant components of the Scots pine emissions. SOA mass yields for Scots pine emissions dominated by farnesenes were lower than for α-pinene but higher than for the artificial mixture of farnesenes and bisabolenes. The reduction in the SOA yield in the farnesene- and bisabolene-dominated mixtures is due to exocyclic C=C bond scission in these acyclic–monocyclic sesquiterpenes during ozonolysis leading to smaller and generally more volatile products. SOA particles from the oxidation of Scots pine emissions had similar or lower volatility than SOA particles formed from either a single precursor or a simple mixture of VOCs. Applying physical stress to the Scots pine plants increased their monoterpene, especially monocyclic β-phellandrene, emissions, which further decreased SOA particle volatility and increased SOA mass yield. Our results highlight the need to account for the chemical complexity and structure of real-world biogenic VOC emissions and stress-induced changes to plant emissions when modelling SOA production and properties in the atmosphere. These results emphasize that a simple increase or decrease in relative monoterpene and sesquiterpene emissions should not be used as an indicator of SOA particle volatility.

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Chemical characterization of biogenic secondary organic aerosol generated from plant emissions under baseline and stressed conditions: inter- and intra-species variability for six coniferous species

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-3629-2015 ◽

2015 ◽

Vol 15 (7) ◽

pp. 3629-3646 ◽

Cited By ~ 8

Author(s):

C. L. Faiola ◽

M. Wen ◽

T. M. VanReken

Keyword(s):

Mass Spectra ◽

Secondary Organic Aerosol ◽

Plant Stress ◽

Chemical Characterization ◽

Organic Aerosol ◽

Aerosol Mass ◽

Treatment Conditions ◽

Volatile Organic ◽

Plant Emissions ◽

Pre Treatment

Abstract. The largest global source of secondary organic aerosol (SOA) in the atmosphere is derived from the oxidation of biogenic emissions. Plant stressors associated with a changing environment can alter both the quantity and composition of the compounds that are emitted. Alterations to the biogenic volatile organic compound (BVOC) profile could impact the characteristics of the SOA formed from those emissions. This study investigated the impacts of one global change stressor, increased herbivory, on the composition of SOA derived from real plant emissions. Herbivory was simulated via application of methyl jasmonate (MeJA), a proxy compound. Experiments were repeated under pre- and post-treatment conditions for six different coniferous plant types. Volatile organic compounds (VOCs) emitted from the plants were oxidized to form SOA via dark ozone-initiated chemistry. The SOA chemical composition was measured using a Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS). The aerosol mass spectra of pre-treatment biogenic SOA from all plant types tended to be similar with correlations usually greater than or equal to 0.90. The presence of a stressor produced characteristic differences in the SOA mass spectra. Specifically, the following m/z were identified as a possible biogenic stress AMS marker with the corresponding HR ion(s) shown in parentheses: m/z 31 (CH3O+), m/z 58 (C2H2O2+, C3H6O+), m/z 29 (C2H5+), m/z 57 (C3H5O+), m/z 59 (C2H3O2+, C3H7O+), m/z 71 (C3H3O2+, C4H7O+), and m/z 83 (C5H7O+). The first aerosol mass spectrum of SOA generated from the oxidation of the plant stress hormone, MeJA, is also presented. Elemental analysis results demonstrated an O : C range of baseline biogenic SOA between 0.3 and 0.47. The O : C of standard MeJA SOA was 0.52. Results presented here could be used to help identify a biogenic plant stress marker in ambient data sets collected in forest environments.

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Isoprene-derived secondary organic aerosol in the global aerosol–chemistry–climate model ECHAM6.3.0–HAM2.3–MOZ1.0

Geoscientific Model Development ◽

10.5194/gmd-11-3235-2018 ◽

2018 ◽

Vol 11 (8) ◽

pp. 3235-3260 ◽

Cited By ~ 8

Author(s):

Scarlet Stadtler ◽

Thomas Kühn ◽

Sabine Schröder ◽

Domenico Taraborrelli ◽

Martin G. Schultz ◽

...

Keyword(s):

Climate Model ◽

Secondary Organic Aerosol ◽

Ph Value ◽

Organic Aerosol ◽

Chemical Mechanism ◽

Vapor Pressures ◽

Model Framework ◽

Aerosol Model ◽

Single Precursor ◽

Isoprene Oxidation

Abstract. Within the framework of the global chemistry climate model ECHAM–HAMMOZ, a novel explicit coupling between the sectional aerosol model HAM-SALSA and the chemistry model MOZ was established to form isoprene-derived secondary organic aerosol (iSOA). Isoprene oxidation in the chemistry model MOZ is described by a semi-explicit scheme consisting of 147 reactions embedded in a detailed atmospheric chemical mechanism with a total of 779 reactions. Semi-volatile and low-volatile compounds produced during isoprene photooxidation are identified and explicitly partitioned by HAM-SALSA. A group contribution method was used to estimate their evaporation enthalpies and corresponding saturation vapor pressures, which are used by HAM-SALSA to calculate the saturation concentration of each iSOA precursor. With this method, every single precursor is tracked in terms of condensation and evaporation in each aerosol size bin. This approach led to the identification of dihydroxy dihydroperoxide (ISOP(OOH)2) as a main contributor to iSOA formation. Further, the reactive uptake of isoprene epoxydiols (IEPOXs) and isoprene-derived glyoxal were included as iSOA sources. The parameterization of IEPOX reactive uptake includes a dependency on aerosol pH value. This model framework connecting semi-explicit isoprene oxidation with explicit treatment of aerosol tracers leads to a global annual average isoprene SOA yield of 15 % relative to the primary oxidation of isoprene by OH, NO3 and ozone. With 445.1 Tg (392.1 Tg C) isoprene emitted, an iSOA source of 138.5 Tg (56.7 Tg C) is simulated. The major part of iSOA in ECHAM–HAMMOZ is produced by IEPOX at 42.4 Tg (21.0 Tg C) and ISOP(OOH)2 at 78.0 Tg (27.9 Tg C). The main sink process is particle wet deposition, which removes 133.6 (54.7 Tg C). The average iSOA burden reaches 1.4 Tg (0.6 Tg C) in the year 2012.

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Modeling Biogenic and Anthropogenic Secondary Organic Aerosol in China

10.5194/acp-2016-687 ◽

2016 ◽

Cited By ~ 1

Author(s):

Jianlin Hu ◽

Peng Wang ◽

Qi Ying ◽

Hongliang Zhang ◽

Jianjun Chen ◽

...

Keyword(s):

Urban Areas ◽

Secondary Organic Aerosol ◽

Temporal Distribution ◽

Organic Aerosol ◽

Sensitivity Analyses ◽

Biogenic Emissions ◽

Anthropogenic Emissions ◽

Volatile Components ◽

Volatile Organic ◽

Isoprene Oxidation

Abstract. A revised Community Multiscale Air Quality (CMAQ) model with updated secondary organic aerosol (SOA) yields and more detailed description of SOA formation from isoprene oxidation was applied to study the spatial and temporal distribution of SOA in China in the entire year of 2013. Predicted organic carbon (OC), elemental carbon and volatile organic compounds agreed favorably with observations at several urban areas, although the high OC concentrations in wintertime in Beijing were under-predicted. Predicted summer SOA was generally higher (10–15 µg m−3) due to large contributions of isoprene (country average, 61 %). Wintertime SOA was slightly lower and was mostly due to emissions of alkane and aromatic compounds (51 %). Contributions of monoterpenes SOA were relatively constant (8–10 %). Overall, biogenic SOA accounted for approximately 75 % of total SOA in summer, 50–60 % in autumn and spring, and 24 % in winter. Sichuan Basin had the highest predicted SOA concentrations in the country in all seasons, with hourly concentrations up to 50 µg m−3. Approximately half of the SOA in all seasons was due to the traditional equilibrium partitioning of semi-volatile components followed by oligomerization, while the remaining SOA was mainly due to reactive surface uptake of isoprene epoxide (5–14 %), glyoxal (14–25 %) and methylglyoxal (23–28 %). Sensitivity analyses showed that formation of SOA from biogenic emissions was significantly enhanced due to anthropogenic emissions. Removing all anthropogenic emissions while keeping the biogenic emissions unchanged led to total SOA concentrations of less than 1 µg m−3, which suggests that manmade emissions facilitated biogenic SOA formation and controlling anthropogenic emissions would result in reduction of both anthropogenic and biogenic SOA.

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Isoprene derived secondary organic aerosol in a global aerosol chemistry climate model

10.5194/gmd-2017-244 ◽

2017 ◽

Cited By ~ 2

Author(s):

Scarlet Stadtler ◽

Thomas Kühn ◽

Sabine Schröder ◽

Domenico Taraborrelli ◽

Martin G. Schultz ◽

...

Keyword(s):

Climate Model ◽

Secondary Organic Aerosol ◽

Ph Value ◽

Organic Aerosol ◽

Chemical Mechanism ◽

Vapor Pressures ◽

Model Framework ◽

Aerosol Model ◽

Single Precursor ◽

Isoprene Oxidation

Abstract. Within the framework of the global chemistry climate model ECHAM-HAMMOZ a novel explicit coupling between the sectional aerosol model HAM-SALSA and the chemistry model MOZ was established to form isoprene derived secondary organic aerosol (iSOA). Isoprene oxidation in the chemistry model MOZ is described by a semi-explicit scheme consisting of 147 reactions, embedded in a detailed atmospheric chemical mechanism with a total of 779 reactions. Low volatile compounds (LVOC) produced during isoprene photooxidation are identified and explicitly partitioned by HAM-SALSA. A group contribution method was used to estimate their evaporation enthalpies and corresponding saturation vapor pressures, which are used by HAM-SALSA to calculate the saturation concentration of each LVOC. With this method, every single precursor is tracked in terms of condensation and evaporation in each aerosol size bin. This approach lead to the identification of ISOP(OOH)2 as a main contributor to iSOA formation. Further, reactive uptake of isoprene epoxidiols (IEPOX) and isoprene derived glyoxal were included as iSOA sources. The parameterization of IEPOX reactive uptake includes a dependency on aerosol pH value. This model framework connecting semi-explicit isoprene oxidation with explicit treatment of aerosol tracers leads to a global, annual isoprene SOA yield of 16 % relative to the primary oxidation of isoprene by OH, NO3, and ozone. With 445 Tg (392 TgC) isoprene emitted, an iSOA source of 148 Tg (61 TgC) is simulated. The major part of iSOA in ECHAM-HAMMOZ is produced by IEPOX (24.4 TgC) and ISOP(OOH)2 (28.3 TgC). The main sink process is particle wet deposition which removes 143 Tg (59 TgC). The iSOA burden reaches 1.6 Tg (0.7 TgC) in the year 2012.

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Secondary organic aerosol formation from biomass burning emissions

10.5194/acp-2019-326 ◽

2019 ◽

Cited By ~ 2

Author(s):

Christopher Y. Lim ◽

David H. Hagan ◽

Matthew M. Coggon ◽

Abigail R. Koss ◽

Kanako Sekimoto ◽

...

Keyword(s):

Biomass Burning ◽

Secondary Organic Aerosol ◽

Total Concentration ◽

Organic Aerosol ◽

Oh Radicals ◽

Aerosol Formation ◽

Atmospheric Aging ◽

Aerosol Mass ◽

Photochemical Aging ◽

Organic Gases

Abstract. Biomass burning is an important source of aerosol and trace gases to the atmosphere, but how these emissions change chemically during their lifetimes is not fully understood. As part of the Fire Influence on Regional and Global Environments Experiment (FIREX 2016), we investigated the effect of photochemical aging on biomass burning organic aerosol (BBOA), with a focus on fuels from the western United States. Emissions were sampled into a small (150 L) environmental chamber and photochemically aged via the addition of ozone and irradiation by 254 nm light. While some fraction of species undergoes photolysis, the vast majority of aging occurs via reaction with OH radicals, with total OH exposures corresponding to the equivalent of up to 10 days of atmospheric oxidation. For all fuels burned, large and rapid changes are seen in the ensemble chemical composition of BBOA, as measured by an aerosol mass spectrometer (AMS). Secondary organic aerosol (SOA) formation is seen for all aging experiments and continues to grow with increasing OH exposure, but the magnitude of the SOA formation is highly variable between experiments. This variability can be explained well by a combination of experiment-to-experiment differences in OH exposure and the total concentration of non-methane organic gases (NMOGs) in the chamber before oxidation, measured by PTR-ToF-MS (r2 values from 0.64 to 0.83). From this relationship, we calculate the fraction of carbon from biomass burning NMOGs that is converted to SOA as a function of equivalent atmospheric aging time, with carbon yields ranging from 24 ± 4 % after 6 hours to 56 ± 9 % after 4 days.

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Aging of atmospheric aerosols and the role of iron in catalyzing brown carbon formation

Environmental Science: Atmospheres ◽

10.1039/d1ea00038a ◽

2021 ◽

Author(s):

Hind A. A. Al-Abadleh

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Atmospheric Aerosols ◽

Secondary Organic Aerosol ◽

Organic Aerosol ◽

Atmospheric Oxidation ◽

Carbon Formation ◽

Brown Carbon ◽

Volatile Organic

Extensive research has been done on the processes that lead to the formation of secondary organic aerosol (SOA) including atmospheric oxidation of volatile organic compounds (VOCs) from biogenic and anthropogenic...

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Large contribution to secondary organic aerosol from isoprene cloud chemistry

Science Advances ◽

10.1126/sciadv.abe2952 ◽

2021 ◽

Vol 7 (13) ◽

pp. eabe2952

Author(s):

Houssni Lamkaddam ◽

Josef Dommen ◽

Ananth Ranjithkumar ◽

Hamish Gordon ◽

Günther Wehrle ◽

...

Keyword(s):

Radiative Forcing ◽

Flow Reactor ◽

Secondary Organic Aerosol ◽

Cloud Droplet ◽

Organic Aerosol ◽

Global Scale ◽

Oxidation Products ◽

Oh Radicals ◽

Large Contribution ◽

Cloud Processing

Aerosols still present the largest uncertainty in estimating anthropogenic radiative forcing. Cloud processing is potentially important for secondary organic aerosol (SOA) formation, a major aerosol component: however, laboratory experiments fail to mimic this process under atmospherically relevant conditions. We developed a wetted-wall flow reactor to simulate aqueous-phase processing of isoprene oxidation products (iOP) in cloud droplets. We find that 50 to 70% (in moles) of iOP partition into the aqueous cloud phase, where they rapidly react with OH radicals, producing SOA with a molar yield of 0.45 after cloud droplet evaporation. Integrating our experimental results into a global model, we show that clouds effectively boost the amount of SOA. We conclude that, on a global scale, cloud processing of iOP produces 6.9 Tg of SOA per year or approximately 20% of the total biogenic SOA burden and is the main source of SOA in the mid-troposphere (4 to 6 km).

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Constraining condensed-phase formation kinetics of secondary organic aerosol components from isoprene epoxydiols

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-1245-2016 ◽

2016 ◽

Vol 16 (3) ◽

pp. 1245-1254 ◽

Cited By ~ 31

Author(s):

T. P. Riedel ◽

Y.-H. Lin ◽

Z. Zhang ◽

K. Chu ◽

J. A. Thornton ◽

...

Keyword(s):

Aqueous Phase ◽

Atmospheric Aerosols ◽

Rate Constants ◽

Reaction Rate ◽

Secondary Organic Aerosol ◽

Organic Aerosol ◽

Heterogeneous Reactions ◽

Model Calculations ◽

Reaction Rate Constants ◽

Aerosol Mass

Abstract. Isomeric epoxydiols from isoprene photooxidation (IEPOX) have been shown to produce substantial amounts of secondary organic aerosol (SOA) mass and are therefore considered a major isoprene-derived SOA precursor. Heterogeneous reactions of IEPOX on atmospheric aerosols form various aerosol-phase components or "tracers" that contribute to the SOA mass burden. A limited number of the reaction rate constants for these acid-catalyzed aqueous-phase tracer formation reactions have been constrained through bulk laboratory measurements. We have designed a chemical box model with multiple experimental constraints to explicitly simulate gas- and aqueous-phase reactions during chamber experiments of SOA growth from IEPOX uptake onto acidic sulfate aerosol. The model is constrained by measurements of the IEPOX reactive uptake coefficient, IEPOX and aerosol chamber wall losses, chamber-measured aerosol mass and surface area concentrations, aerosol thermodynamic model calculations, and offline filter-based measurements of SOA tracers. By requiring the model output to match the SOA growth and offline filter measurements collected during the chamber experiments, we derive estimates of the tracer formation reaction rate constants that have not yet been measured or estimated for bulk solutions.

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