Optical Properties of Secondary Organic Aerosol from Nitrate Radical Oxidation of Biogenic Volatile Organic Compounds: The Role of Highly Oxygenated Organic Nitrates  

2020 ◽  
Author(s):  
Yinon Rudich ◽  
Quanfu He ◽  
Alexander Laskin ◽  
Steve Brown
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
High Resolution ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Organic Nitrates ◽  
Nitrate Radical ◽  
Biogenic Volatile Organic Compounds ◽  
Radical Oxidation ◽  
Volatile Organic

<p>Nitrate radical (NO<sub>3</sub>) oxidation of biogenic volatile organic compounds (BVOCs) represents one of the most important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. The functionalization process during this oxidation process leads to the formation of multifunctional compounds such as organic nitrates (ON). ON account for a significant fraction of total organic aerosols (OA) in ambient air, which influence atmospheric chemistry process, air quality, and climate through regional and global budgets for reactive nitrogen (particularly ON), ozone, and OA formation. Despite the significance of this process in atmospheric chemistry, the climatic effect of SOA from this process is undefined, largely due to a lack of knowledge about their optical properties with respect to their chemical composition. In this study, we generated SOA from NO<sub>3</sub> radical oxidation of a series BVOCs including isoprene, monoterpenes, and sesquiterpenes followed by photo-chemically aging in oxidation flow reactor (OFR/PAM). The chemical composition of the SOA was characterized online by high-resolution time-of-flight mass spectrometer (HR-Tof-AMS) and off-line by ultra-high-performance liquid chromatography (HPLC) coupled with photodiode array (PDA) detector coupled to a high-resolution Orbitrap mass spectrometer with a standard electrospray ionization (ESI) source (HPLC-PDA-HRMS). The UV-visible wavelength-resolved refractive index of the SOA, which is essential to understand their radiative forcing, was retrieved by measuring the light extinction using a novel broadband cavity-enhanced spectrometer (BBCES, 315-700 nm). We found that the SOA contain a large fraction of highly oxygenated ON, consisting of monomers and oligomers with single and multiple nitrate groups, which formed through bimolecular and unimolecular reactions. Strong absorption was detected in the UVA range which was attributed to the ON. The influence of the initial BVOCs/NO<sub>3</sub> ratio and the transition from nighttime oxidation to daytime aging on the SOA optical properties will be discussed. We will highlight the link between the SOA optical properties evolution and the chemical composition transformation with respect to the highly oxygenated ON formation and its atmospheric fate upon daytime photochemical aging.</p>

scholarly journals Importance of biogenic volatile organic compounds to acyl peroxy nitrates (APN) production in the southeastern US during SOAS 2013

2019 ◽  
Vol 19 (3) ◽  
pp. 1867-1880 ◽  
Author(s):  
Shino Toma ◽  
Steve Bertman ◽  
Christopher Groff ◽  
Fulizi Xiong ◽  
Paul B. Shepson ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Gas Phase ◽  
Organic Compounds ◽  
Model Simulation ◽  
Statistical Correlation ◽  
Organic Nitrates ◽  
Biogenic Volatile Organic Compounds ◽  
The North ◽  
Southeastern Us ◽  
Volatile Organic

Abstract. Gas-phase atmospheric concentrations of peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), and peroxymethacryloyl nitrate (MPAN) were measured on the ground using a gas chromatograph electron capture detector (GC-ECD) during the Southern Oxidants and Aerosols Study (SOAS) 2013 campaign (1 June to 15 July 2013) in Centreville, Alabama, in order to study biosphere–atmosphere interactions. Average levels of PAN, PPN, and MPAN were 169, 5, and 9 pptv, respectively, and the sum accounts for an average of 16 % of NOy during the daytime (10:00 to 16:00 local time). Higher concentrations were seen on average in air that came to the site from the urban NOx sources to the north. PAN levels were the lowest observed in ground measurements over the past two decades in the southeastern US. A multiple regression analysis indicates that biogenic volatile organic compounds (VOCs) account for 66 % of PAN formation during this study. Comparison of this value with a 0-D model simulation of peroxyacetyl radical production indicates that at least 50 % of PAN formation is due to isoprene oxidation. MPAN has a statistical correlation with isoprene hydroxynitrates (IN). Organic aerosol mass increases with gas-phase MPAN and IN concentrations, but the mass of organic nitrates in particles is largely unrelated to MPAN.

scholarly journals Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms and organic aerosol

2016 ◽  
Author(s):  
N. L. Ng ◽  
S. S. Brown ◽  
A. T. Archibald ◽  
E. Atlas ◽  
R. C. Cohen ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Climate Models ◽  
Large Body ◽  
Organic Aerosol ◽  
Organic Nitrate ◽  
Biogenic Volatile Organic Compounds ◽  
Volatile Organic

Abstract. Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than three decades, during which time a large body of research has emerged from laboratory, field and modeling studies. NO3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms and organic aerosol yields for NO3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO3 within the poorly mixed nocturnal atmosphere and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry-climate models. This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first section summarizes the current literature on NO3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models.

scholarly journals Global high-resolution emissions of soil NOx, sea salt aerosols, and biogenic volatile organic compounds

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Hongjian Weng ◽  
Jintai Lin ◽  
Randall Martin ◽  
Dylan B. Millet ◽  
Lyatt Jaeglé ◽  
...  
Keyword(s):  
High Resolution ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Sea Salt ◽  
Biogenic Volatile Organic Compounds ◽  
Sea Salt Aerosols ◽  
Volatile Organic

scholarly journals Seasonal and diurnal variations of biogenic volatile organic compounds in highland and lowland ecosystems in southern Kenya

2021 ◽  
Author(s):  
Yang Liu ◽  
Simon Schallhart ◽  
Ditte Taipale ◽  
Toni Tykkä ◽  
Matti Räsänen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Daily Maximum ◽  
Mixing Ratio ◽  
Biogenic Volatile Organic Compounds ◽  
Mixing Ratios ◽  
Seasonal And Diurnal Variations ◽  
Volatile Organic ◽  
Dry Seasons

Abstract. The East African lowland and highland areas consist of water-limited and humid ecosystems. The magnitude and seasonality of biogenic volatile organic compounds (BVOCs) emissions from these functionally contrasting ecosystems are limited due to a scarcity of direct observations. We measured mixing ratios of BVOCs from two contrasting ecosystems, humid highlands with agroforestry and dry lowlands with bushland, grassland, and agriculture mosaics, during both the rainy and dry seasons of 2019 in southern Kenya. We present the diurnal and seasonal characteristics of BVOC mixing ratios and their reactivity, and estimated emission factors (EFs) for certain BVOCs from the African lowland ecosystem based on field measurements. The most abundant BVOCs were isoprene and monoterpenoids (MTs), with isoprene contributing > 70 % of the total BVOC mixing ratio during daytime, while MTs accounted for > 50 % of the total BVOC mixing ratio during nighttime at both sites. The contributions of BVOCs to the local atmospheric chemistry were estimated by calculating the reactivity towards the hydroxyl radical (OH), ozone (O3), and the nitrate radical (NO3). Isoprene and MTs contributed the most to the reactivity of OH and NO3, while sesquiterpenes dominated the contribution of organic compounds to the reactivity of O3. The mixing ratio of isoprene measured in this study was lower to that measured in the relevant ecosystems in west and south Africa, while that of monoterpenoids was similar. Isoprene mixing ratios peaked daily between 16:00 and 20:00 with a maximum mixing ratio of 809 parts per trillion by volume (pptv) and 156 pptv in the highlands, and 115 pptv and 25 pptv in the lowlands, during the rainy and dry seasons, respectively. MT mixing ratios reached their daily maximum between midnight and early morning (usually 04:00 to 08:00) with mixing ratios of 254 pptv and 56 pptv in the highlands, and 89 pptv and 7 pptv in the lowlands, in the rainy and dry seasons, respectively. The dominant species within the MT group were limonene, α-pinene, and β-pinene. EFs for isoprene, MTs, and 2-methyl-3-buten-2-ol (MBO) were estimated using an inverse modeling approach. The estimated EFs for isoprene and β-pinene agreed very well with what is currently assumed in the world’s most extensively used biogenic emissions model, the Model of Emissions of Gases and Aerosols from Nature (MEGAN), for warm C4 grass, but the estimated EFs for MBO, α-pinene, and especially limonene, were significantly higher than that assumed in MEGAN for the relevant plant functional type. Additionally, our results indicate that the EF for limonene might be seasonally dependent in savanna ecosystems.

scholarly journals Simulations of atmospheric OH, O<sub>3</sub> and NO<sub>3</sub> reactivities within and above the boreal forest

2015 ◽  
Vol 15 (7) ◽  
pp. 3909-3932 ◽  
Author(s):  
D. Mogensen ◽  
R. Gierens ◽  
J. N. Crowley ◽  
P. Keronen ◽  
S. Smolander ◽  
...  
Keyword(s):  
Steady State ◽  
Volatile Organic Compounds ◽  
Boreal Forest ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Inorganic Compounds ◽  
Spectral Irradiance ◽  
Biogenic Volatile Organic Compounds ◽  
Short Period ◽  
Volatile Organic

Abstract. Using the 1-D atmospheric chemistry transport model SOSAA, we have investigated the atmospheric reactivity of a boreal forest ecosystem during the HUMPPA-COPEC-10 campaign (summer 2010, at SMEAR~II in southern Finland). For the very first time, we present vertically resolved model simulations of the NO3 and O3 reactivity (R) together with the modelled and measured reactivity of OH. We find that OH is the most reactive oxidant (R ∼ 3 s-1) followed by NO3 (R ∼ 0.07 s-1) and O3 (R ∼ 2 × 10-5s-1). The missing OH reactivity was found to be large in accordance with measurements (∼ 65%) as would be expected from the chemical subset described in the model. The accounted OH radical sinks were inorganic compounds (∼ 41%, mainly due to reaction with CO), emitted monoterpenes (∼ 14%) and oxidised biogenic volatile organic compounds (∼ 44%). The missing reactivity is expected to be due to unknown biogenic volatile organic compounds and their photoproducts, indicating that the true main sink of OH is not expected to be inorganic compounds. The NO3 radical was found to react mainly with primary emitted monoterpenes (∼ 60%) and inorganic compounds (∼ 37%, including NO2). NO2 is, however, only a temporary sink of NO3 under the conditions of the campaign (with typical temperatures of 20–25 °C) and does not affect the NO3 concentration. We discuss the difference between instantaneous and steady-state reactivity and present the first boreal forest steady-state lifetime of NO3 (113 s). O3 almost exclusively reacts with inorganic compounds (∼ 91%, mainly NO, but also NO2 during night) and less with primary emitted sesquiterpenes (∼ 6%) and monoterpenes (∼ 3%). When considering the concentration of the oxidants investigated, we find that OH is the oxidant that is capable of removing organic compounds at a faster rate during daytime, whereas NO3 can remove organic molecules at a faster rate during night-time. O3 competes with OH and NO3 during a short period of time in the early morning (around 5 a.m. local time) and in the evening (around 7–8 p.m.). As part of this study, we developed a simple empirical parameterisation for conversion of measured spectral irradiance into actinic flux. Further, the meteorological conditions were evaluated using radiosonde observations and ground-based measurements. The overall vertical structure of the boundary layer is discussed, together with validation of the surface energy balance and turbulent fluxes. The sensible heat and momentum fluxes above the canopy were on average overestimated, while the latent heat flux was underestimated.

scholarly journals Organic Gases Released and Taken Up by Soil Lack Quantification

Eos ◽  
2019 ◽  
Vol 100 ◽  
Author(s):  
Jing Tang ◽  
Guy Schurgers ◽  
Riikka Rinnan
Keyword(s):  
Chemical Composition ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Global Climate ◽  
Biogenic Volatile Organic Compounds ◽  
Volatile Organic ◽  
Organic Gases

Soils both emit and take up different biogenic volatile organic compounds, altering the chemical composition of the atmosphere and influencing local, regional, and global climate.

scholarly journals Seasonal characteristics of organic aerosol chemical composition and volatility in Stuttgart, Germany

2019 ◽  
Author(s):  
Wei Huang ◽  
Harald Saathoff ◽  
Xiaoli Shen ◽  
Ramakrishna Ramisetty ◽  
Thomas Leisner ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Time Of Flight ◽  
Organic Aerosol ◽  
Molecular Composition ◽  
Resolution Time ◽  
Volatile Organic

Abstract. Chemical composition and volatility of organic aerosol (OA) particles were investigated during July–August 2017 and February–March 2018 in the city of Stuttgart, one of the most polluted cities in Germany. Total non-refractory particle mass was measured with a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS; hereafter AMS). Aerosol particles were collected on filters and analyzed in the laboratory with a filter inlet for gases and aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-HR-ToF-CIMS; hereafter CIMS), yielding the molecular composition of oxygenated OA (OOA) compounds. While the average organic mass loadings are lower in the summer period (5.1 ± 3.2 µg m−3) than in the winter period (8.4 ± 5.6 µg m−3), we find relatively larger mass contributions of organics measured by AMS in summer (68.8 ± 13.4 %) compared to winter (34.8 ± 9.5 %). CIMS mass spectra show OOA compounds in summer have O : C ratios of 0.82 ± 0.02 and are more influenced by biogenic emissions, while OOA compounds in winter have O : C ratios of 0.89 ± 0.06 and are more influenced by biomass burning emissions. Volatility parametrization analysis shows that OOA in winter is less volatile with higher contributions of low volatile organic compounds (LVOC) and extremely low volatile organic compounds (ELVOC). We partially explain this by the higher contributions of compounds with shorter carbon chain lengths and higher number of oxygen atoms, i.e. higher O : C ratios in winter. Organic compounds desorbing from the particles deposited on the filter samples also exhibit a shift of signal to higher desorption temperatures (i.e. lower apparent volatility) in winter. This is consistent with the relatively higher O : C ratios in winter, but may also be related to higher particle viscosity due to the higher contributions of larger molecular-weight LVOC and ELVOC, interactions between different species and/or particles (particle matrix), and/or thermal decomposition of larger molecules. The results suggest that whereas lower temperature in winter may lead to increased partitioning of semi-volatile organic compounds (SVOC) into the particle phase, this does not result in a higher overall volatility of OOA in winter, and that the difference in sources and/or chemistry between the seasons plays a more important role. Our study provides insights into the seasonal variation of molecular composition and volatility of ambient OA particles, and into their potential sources.

scholarly journals The atmospheric potential of biogenic volatile organic compounds from needles of white pine (<i>Pinus strobus</i>) in Northern Michigan

2012 ◽  
Vol 12 (4) ◽  
pp. 2245-2252 ◽  
Author(s):  
S. Toma ◽  
S. Bertman
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Large Scale ◽  
Pinus Strobus ◽  
Biogenic Volatile Organic Compounds ◽  
White Pine ◽  
Volatile Organic ◽  
Pine Trees ◽  
Large Scale Screening

Abstract. The key role that biogenic volatile organic compounds (BVOC) play in atmospheric chemistry requires a detailed understanding of how BVOC concentrations will be affected by environmental change. Large-scale screening of BVOC emissions from whole forest ecosystems is difficult with enclosure methods. Leaf composition of BVOC, as a surrogate for direct emissions, can more easily reflect the distribution of BVOC compounds in a forest. In this study, BVOC composition in needles of 92 white pine trees (Pinus strobus), which are becoming a large part of Midwest forests, are tracked for three summers at the University of Michigan Biological Station (UMBS). α-Pinene, the dominant terpene in all samples, accounts for 30–50% of all terpenes on a mole basis. The most abundant sesquiterpenoid was a C15 alcohol identified as germacrene D-4-ol. The relationship between limonene and total other monoterpenes shows two distinct trends in the population of these forests. About 14% (n = 13) of the trees showed high levels of limonene (up to 36% of the total BVOC) in the same trees every year. Assuming that needle concentrations scale with emission rate, we estimate that hydroxyl radical reactivity due to reaction with monoterpenes from white pine increases approximately 6% at UMBS when these elevated concentrations are included. We suggest that chemotypic variation within forests has the potential to affect atmospheric chemistry and that large-scale screening of BVOC can be used to study the importance of BVOC variation.

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