Investigating monoterpene ozonolysis reactions in the mobile DouAir atmospheric simulation chamber: field and laboratory experiments

2021 ◽  
Author(s):  
Ahmad Lahib ◽  
Hichem Bouzidi ◽  
Nina Reijrink ◽  
Marius Duncianu ◽  
Emilie Perraudin ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Laboratory Experiments ◽  
Peroxy Radical ◽  
Chemical Transformations ◽  
Peroxy Radicals ◽  
Model Simulations ◽  
Chemical Mechanisms ◽  
Volatile Organic ◽  
Biogenic Compounds

<p>The chemistry of the atmosphere is usually studied using three different approaches, i.e. field measurements, laboratory studies and chemical model calculations. All three are complementary and powerful means to investigate chemical transformations of pollutants and improve our understanding of the atmosphere. Atmospheric simulation chambers are one of the most direct and critical approaches to mimic and examine chemical transformations under controlled experimental conditions. In combination with box model simulations, they allow assessment of the accuracy of chemical mechanisms implemented in atmospheric models.</p><p>During the CERVOLAND field campaign (Characterisation of Emissions and Reactivity of Volatile Organic compounds in the LANDes forest) we deployed a new mobile atmospheric chamber (DouAir) to probe the oxidation of biogenic volatile organic compounds (BVOCs) in real air masses. Biogenic compounds emitted by the surrounding forest (mainly pines - (Maritime pine, Pinus pinaster Ait) were trapped in DouAir and their transformations were probed using state-of-the-art online instrumentation, including PTR-ToF-MS (VOCs), PERCA (peroxy radicals), O<sub>3</sub> and NO<sub>x</sub> analysers, and SMPS (aerosols).</p><p>The objectives of the present study were to (1) reproduce in the laboratory selected field experiments performed during CERVOLAND, the chemical composition of the air mass being simplified, and (2) compare both the field and laboratory results to 0-D box model simulations using the Master Chemical Mechanisms (MCM). Comparing field observations, laboratory experiments and model simulations provides a critical test of our understanding of atmospheric oxidation processes involving biogenic compounds.</p><p>Here, we present ozonolysis experiments of primary biogenic VOCs (mainly monoterpenes) under dark conditions. Initial conditions used for the laboratory experiments were derived from reactant concentrations trapped in DouAir during CERVOLAND. The results show the capability of the model to reproduce oxidation rates of primary VOCs within uncertainty, although the model considerably overestimates measured peroxy radical concentrations. The addition of rapid self- and cross-reactions of monoterpene-derived peroxy radicals in the MCM improves the agreement with the measured peroxy radical concentrations.</p>

scholarly journals Radical chemistry at night: comparisons between observed and modelled HO<sub>x</sub>, NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> during the RONOCO project

2014 ◽  
Vol 14 (3) ◽  
pp. 1299-1321 ◽  
Author(s):  
D. Stone ◽  
M. J. Evans ◽  
H. Walker ◽  
T. Ingham ◽  
S. Vaughan ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Limit Of Detection ◽  
Chain Model ◽  
Peroxy Radicals ◽  
Model Simulations ◽  
Airborne Measurements ◽  
Heterogeneous Processes ◽  
Volatile Organic ◽  
The Uk

Abstract. The RONOCO (ROle of Nighttime chemistry in controlling the Oxidising Capacity of the AtmOsphere) aircraft campaign during July 2010 and January 2011 made observations of OH, HO2, NO3, N2O5 and a number of supporting measurements at night over the UK, and reflects the first simultaneous airborne measurements of these species. We compare the observed concentrations of these short-lived species with those calculated by a box model constrained by the concentrations of the longer lived species using a detailed chemical scheme. OH concentrations were below the limit of detection, consistent with model predictions. The model systematically underpredicts HO2 by ~200% and overpredicts NO3 and N2O5 by around 80 and 50%, respectively. Cycling between NO3 and N2O5 is fast and thus we define the NO3x (NO3x=NO3+N2O5) family. Production of NO3x is overwhelmingly dominated by the reaction of NO2 with O3, whereas its loss is dominated by aerosol uptake of N2O5, with NO3+VOCs (volatile organic compounds) and NO3+RO2 playing smaller roles. The production of HOx and ROx radicals is mainly due to the reaction of NO3 with VOCs. The loss of these radicals occurs through a combination of HO2+RO2 reactions, heterogeneous processes and production of HNO3 from OH+NO2, with radical propagation primarily achieved through reactions of NO3 with peroxy radicals. Thus NO3 at night plays a similar role to both OH and NO during the day in that it both initiates ROx radical production and acts to propagate the tropospheric oxidation chain. Model sensitivity to the N2O5 aerosol uptake coefficient (γN2O5) is discussed and we find that a value of γN2O5=0.05 improves model simulations for NO3 and N2O5, but that these improvements are at the expense of model success for HO2. Improvements to model simulations for HO2, NO3 and N2O5 can be realised simultaneously on inclusion of additional unsaturated volatile organic compounds, however the nature of these compounds is extremely uncertain.

scholarly journals OH and HO<sub>2</sub> radical chemistry during PROPHET 2008 and CABINEX 2009 – Part 1: Measurements and model comparison

2013 ◽  
Vol 13 (11) ◽  
pp. 5403-5423 ◽  
Author(s):  
S. M. Griffith ◽  
R. F. Hansen ◽  
S. Dusanter ◽  
P. S. Stevens ◽  
M. Alaghmand ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Model Comparison ◽  
Peroxy Radical ◽  
Box Model ◽  
Peroxy Radicals ◽  
Inorganic Species ◽  
Key Species ◽  
Volatile Organic

Abstract. Hydroxyl (OH) and hydroperoxyl (HO2) radicals are key species driving the oxidation of volatile organic compounds that can lead to the production of ozone and secondary organic aerosols. Previous measurements of these radicals in forest environments with high isoprene, low NOx conditions have shown serious discrepancies with modeled concentrations, bringing into question the current understanding of isoprene oxidation chemistry in these environments. During the summers of 2008 and 2009, OH and peroxy radical concentrations were measured using a laser-induced fluorescence instrument as part of the PROPHET (Program for Research on Oxidants: PHotochemistry, Emissions, and Transport) and CABINEX (Community Atmosphere-Biosphere INteractions EXperiment) campaigns at a forested site in northern Michigan. Supporting measurements of photolysis rates, volatile organic compounds, NOx (NO + NO2 and other inorganic species were used to constrain a zero-dimensional box model based on the Regional Atmospheric Chemistry Mechanism, modified to include the Mainz Isoprene Mechanism (RACM-MIM). The CABINEX model OH predictions were in good agreement with the measured OH concentrations, with an observed-to-modeled ratio near one (0.70 ± 0.31) for isoprene mixing ratios between 1–2 ppb on average. The measured peroxy radical concentrations, reflecting the sum of HO2 and isoprene-based peroxy radicals, were generally lower than predicted by the box model in both years.

scholarly journals OH and HO<sub>2</sub> radical chemistry during PROPHET 2008 and CABINEX 2009 – Part 1: Measurements and model comparison

2012 ◽  
Vol 12 (12) ◽  
pp. 33165-33218
Author(s):  
S. M. Griffith ◽  
R. F. Hansen ◽  
S. Dusanter ◽  
P. S. Stevens ◽  
M. Alaghmand ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Model Comparison ◽  
Peroxy Radical ◽  
Box Model ◽  
Peroxy Radicals ◽  
Inorganic Species ◽  
Key Species ◽  
Volatile Organic

Abstract. Hydroxyl (OH) and hydroperoxyl (HO2) radicals are key species driving the oxidation of volatile organic compounds that can lead to the production of ozone and secondary organic aerosols. Previous measurements of these radicals in forest environments with high isoprene, low NOx conditions have shown serious discrepancies with modeled concentrations, bringing into question the current understanding of isoprene oxidation chemistry in these environments. During the summers of 2008 and 2009, OH and peroxy radical concentrations were measured using a laser-induced fluorescence instrument as part of the PROPHET (Program for Research on Oxidants: PHotochemistry, Emissions, and Transport) and CABINEX (Community Atmosphere-Biosphere INteractions EXperiment) campaigns at a forested site in northern Michigan. Supporting measurements of photolysis rates, volatile organic compounds, NOx (NO + NO2) and other inorganic species were used to constrain a zero-dimensional box model based on the Regional Atmospheric Chemistry Mechanism, modified to include the Mainz Isoprene Mechanism (RACM-MIM). The CABINEX model OH predictions were in good agreement with the measured OH concentrations, with an observed-to-modeled ratio near one (0.70 ± 0.31) for isoprene mixing ratios between 1–2 ppb on average. The measured peroxy radical concentrations, reflecting the sum of HO2 and isoprene-based peroxy radicals, were generally lower than predicted by the box model in both years.

scholarly journals Mapping Asian anthropogenic emissions of non-methane volatile organic compounds to multiple chemical mechanisms

2013 ◽  
Vol 13 (12) ◽  
pp. 32649-32701 ◽  
Author(s):  
M. Li ◽  
Q. Zhang ◽  
D. G. Streets ◽  
K. B. He ◽  
Y. F. Cheng ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Individual Species ◽  
Chemical Mechanisms ◽  
Mixing Ratios ◽  
Wide Range ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Species Mapping ◽  
Multiple Chemical

Abstract. An accurate speciation mapping of non-methane volatile organic compounds (NMVOC) emissions has an important impact on the performance of chemical transport models (CTMs) in simulating ozone mixing ratios and secondary organic aerosols. In this work, we developed an improved speciation framework to generate model-ready anthropogenic Asian NMVOC emissions for various gas-phase chemical mechanisms commonly used in CTMs by using an explicit assignment approach and updated NMVOC profiles, based on the total NMVOC emissions in the INTEX-B Asian inventory for the year 2006. NMVOC profiles were selected and aggregated from a wide range of new measurements and the SPECIATE database. To reduce potential uncertainty from individual measurements, composite profiles were developed by grouping and averaging source profiles from the same category. The fractions of oxygenated volatile organic compounds (OVOC) were corrected during the compositing process for those profiles which used improper sampling and analyzing methods. Emissions of individual species were then lumped into species in different chemical mechanisms used in CTMs by applying mechanism-dependent species mapping tables, which overcomes the weakness of inaccurate mapping in previous studies. Gridded emissions for eight chemical mechanisms are developed at 30 min × 30 min resolution using various spatial proxies and are provided through the website: http://mic.greenresource.cn/intex-b2006. Emission estimates for individual NMVOC species differ between one and three orders of magnitude for some species when different sets of profiles are used, indicating that source profile is the most important source of uncertainties of individual species emissions. However, those differences are diminished in lumped species as a result of the lumping in the chemical mechanisms.

scholarly journals Mapping Asian anthropogenic emissions of non-methane volatile organic compounds to multiple chemical mechanisms

2014 ◽  
Vol 14 (11) ◽  
pp. 5617-5638 ◽  
Author(s):  
M. Li ◽  
Q. Zhang ◽  
D. G. Streets ◽  
K. B. He ◽  
Y. F. Cheng ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Individual Species ◽  
Chemical Mechanisms ◽  
Mixing Ratios ◽  
Wide Range ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Species Mapping ◽  
Multiple Chemical

Abstract. An accurate speciation mapping of non-methane volatile organic compounds (NMVOC) emissions has an important impact on the performance of chemical transport models (CTMs) in simulating ozone mixing ratios and secondary organic aerosols. Taking the INTEX-B Asian NMVOC emission inventory as the case, we developed an improved speciation framework to generate model-ready anthropogenic NMVOC emissions for various gas-phase chemical mechanisms commonly used in CTMs in this work, by using an explicit assignment approach and updated NMVOC profiles. NMVOC profiles were selected and aggregated from a wide range of new measurements and the SPECIATE database v.4.2. To reduce potential uncertainty from individual measurements, composite profiles were developed by grouping and averaging source profiles from the same category. The fractions of oxygenated volatile organic compounds (OVOC) were corrected during the compositing process for those profiles which used improper sampling and analyzing methods. Emissions of individual species were then lumped into species in different chemical mechanisms used in CTMs by applying mechanism-dependent species mapping tables, which overcomes the weakness of inaccurate mapping in previous studies. Emission estimates for individual NMVOC species differ between one and three orders of magnitude for some species when different sets of profiles are used, indicating that source profile is the most important source of uncertainties of individual species emissions. However, those differences are diminished in lumped species as a result of the lumping in the chemical mechanisms. Gridded emissions for eight chemical mechanisms at 30 min × 30 min resolution as well as the auxiliary data are available at http://mic.greenresource.cn/intex-b2006. The framework proposed in this work can be also used to develop speciated NMVOC emissions for other regions.

Rate Coefficients and Mechanisms for the Atmospheric Oxidation of the N-Atom-Containing Oxygenates

2011 ◽  
Author(s):  
Jack Calvert ◽  
Abdelwahid Mellouki ◽  
John Orlando ◽  
Michael Pilling ◽  
Timothy Wallington
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Photochemical Reactions ◽  
Rate Coefficients ◽  
Peroxy Radicals ◽  
Alkyl Nitrates ◽  
Volatile Organic ◽  
Peroxyacyl Nitrates ◽  
Alkyl Peroxy Radicals ◽  
The Many

The many different nitrogen-containing oxygenated volatile organic compounds that are present in the troposphere play important roles in the chemistry of our atmosphere. They can be emitted directly into the atmosphere, such as in the case of amides that are widely used as organic solvents, starting materials, or intermediates in different industries (e.g., synthetic polymers, manufacture of dyes, and synthesis of pesticides). Amides are formed in situ as intermediate products in the degradation of amines (e.g., see Tuazon et al., 1994; Finlayson-Pitts and Pitts, 2000). Nitrogen-containing oxygenated organic compounds are formed in the atmosphere also via reactions of alkoxy (RO) and alkyl peroxy radicals (RO2) with NO or NO2 leading to alkyl nitrates, alkyl nitrites, and peroxy acetyl nitrates. However, primary sources of these organic species have also been suggested such as diesel and other engines and biomass burning (e.g., see Simpson et al., 2002). Alkyl nitrates (RONO2) have been detected in both the urban and the remote troposphere (e.g., see Roberts, 1990; Walega et al., 1992; Atlas et al., 1992; Ridley et al., 1997; and Stroud et al., 2001; see also section I-D). Nitrates are formed as minor products in the reaction of peroxy radicals with NO. The nitrate yield increases with the size of peroxy radicals and can be as high as 20–30% for large (>C6) radicals (Calvert et al., 2008). Peroxyacyl nitrates (RC(O)O2NO2) are important constituents of urban air pollution. They have been identified in ambient air (e.g., see Bertman and Roberts, 1991; Williams et al., 1997, 2000; Nouaime et al., 1998; Hansel and Wisthaler, 2000; also see section I-D). They are formed from photochemical reactions via RC(O)O2 + NO2. A major role of these compounds is their capacity to act as a reservoir for NOx that can be transported from polluted urban to remote regions that are poor NOx regions and where their presence can increase NOx levels (Roberts, 1990). As with other volatile organic compounds (VOCs), once released to the atmosphere, nitrogen-containing organic compounds are expected to undergo degradation primarily via reaction with hydroxyl and nitrate radicals, reaction with ozone, and photolysis. Thermal decomposition is an important loss process for the peroxyacyl nitrates.

scholarly journals Production of fungal volatile organic compounds in bedding materials

1997 ◽  
Vol 6 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Saana Lappalainen ◽  
Anna-Liisa Pasanen ◽  
Pentti Pasanen ◽  
Pentti Kalliokoski
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Laboratory Experiments ◽  
Fungal Growth ◽  
Co2 Production ◽  
Growth Media ◽  
Emission Rates ◽  
Potential Growth ◽  
Volatile Organic ◽  
Bedding Materials

The high relative humidity of the air and many potential growth media, such as bedding materials, hay and grains in the horse stable, for example, provide suitable conditions for fungal growth. Metabolic activity of four common agricultural fungi incubated in peat and wood shavings at 25°C and 4°C was characterized in this study using previously specified volatile metabolites of micro-organisms and CO2 production as indicators. The volatile organic compounds were collected into Tenax resin and analysed by gas chromatography. Several microbial volatile organic compounds (MVOCs), e.g. 1-butanol, 2-hexanone, 2-heptanone, 3-octanone, 1-octen-3-ol and 1-octanol were detected in laboratory experiments; however, these accounted for only 0.08-1.5% of total volatile organic compounds (TVOCs). Emission rates of MVOCs were 0,001-0.176 μg/kg of bedding materials per hour. Despite some limitations of the analytical method, certain individual MVOCs, 2-hexanone, 2-heptanone and 3-octanone, were also detected in concentrations of less than 4.6 μg/m3 (0.07-0.31% of TVOC) in a horse stable where peat and shavings were used as bedding materials. MVOC emission rate was estimated to be 0.2-2.0 μg/kg x h-1 from bedding materials in the stable, being about ten times higher than the rates found in the laboratory experiments. Some compounds, e.g. 3-octanone and 1-octen-3-ol, can be assumed to originate mainly from microbial metabolisms.

Development of a Personal Aerosol Sampler for Monitoring the Particle–Vapour Fractionation of SVOCs in Workplaces

2020 ◽  
Vol 64 (8) ◽  
pp. 903-908
Author(s):  
George C Dragan ◽  
Vesta Kohlmeier ◽  
Juergen Orasche ◽  
Juergen Schnelle-Kreis ◽  
Patricia B C Forbes ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Laboratory Experiments ◽  
Particle Separation ◽  
Reference Laboratory ◽  
Average Difference ◽  
Toxicological Effects ◽  
Volatile Organic ◽  
Particle Fractionation

Abstract Semi-volatile organic compounds (SVOCs), partitioned between particulates and vapours of an aerosol, require special attention. The toxicological effects caused by the inhalation of such aerosols may depend on the concentration and in which phase the organic compounds are found. A personal denuder-gas–particle separation aerosol sampler was developed to provide information about the partitioning of aerosols from organic compounds. The sampler was tested in a series of controlled laboratory experiments, which confirmed the capability and accuracy of the sampler to measure gas–particle mixtures. An average difference of 14.8 ± 4.8% was found between sampler and reference laboratory instruments. The obtained results showed that our sampler enables a more accurate measurement of the SVOC aerosols’ gas–particle fractionation, compared with that of conventional samplers.

scholarly journals Formation of condensable organic vapors from anthropogenic and biogenic volatile organic compounds (VOCs) is strongly perturbed by NO<sub><i>x</i></sub> in eastern China

2021 ◽  
Vol 21 (19) ◽  
pp. 14789-14814
Author(s):  
Yuliang Liu ◽  
Wei Nie ◽  
Yuanyuan Li ◽  
Dafeng Ge ◽  
Chong Liu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Eastern China ◽  
Carbon Number ◽  
Decisive Role ◽  
Organic Nitrates ◽  
Ionization Mass ◽  
Peroxy Radicals ◽  
Related Factors ◽  
Volatile Organic

Abstract. Oxygenated organic molecules (OOMs) are the crucial intermediates linking volatile organic compounds (VOCs) to secondary organic aerosols (SOAs) in the atmosphere, but comprehensive understanding of the characteristics of OOMs and their formation from VOCs is still missing. Ambient observations of OOMs using recently developed mass spectrometry techniques are still limited, especially in polluted urban atmospheres where VOCs and oxidants are extremely variable and complex. Here, we investigate OOMs, measured by a nitrate-ion-based chemical ionization mass spectrometer at Nanjing in eastern China, through performing positive matrix factorization on binned mass spectra (binPMF). The binPMF analysis reveals three factors about anthropogenic VOC (AVOC) daytime chemistry, three isoprene-related factors, three factors about biogenic VOC (BVOC) nighttime chemistry, and three factors about nitrated phenols. All factors are influenced by NOx in different ways and to different extents. Over 1000 non-nitro molecules have been identified and then reconstructed from the selected solution of binPMF, and about 72 % of the total signals are contributed by nitrogen-containing OOMs, mostly regarded as organic nitrates formed through peroxy radicals terminated by nitric oxide or nitrate-radical-initiated oxidations. Moreover, multi-nitrates account for about 24 % of the total signals, indicating the significant presence of multiple generations, especially for isoprene (e.g., C5H10O8N2 and C5H9O10N3). Additionally, the distribution of OOM concentration on the carbon number confirms their precursors are driven by AVOCs mixed with enhanced BVOCs during summer. Our results highlight the decisive role of NOx in OOM formation in densely populated areas, and we encourage more studies on the dramatic interactions between anthropogenic and biogenic emissions.

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