scholarly journals Global-scale combustion sources of organic aerosols: sensitivity to formation and removal mechanisms

2017 ◽  
Vol 17 (12) ◽  
pp. 7345-7364 ◽  
Author(s):  
Alexandra P. Tsimpidi ◽  
Vlassis A. Karydis ◽  
Spyros N. Pandis ◽  
Jos Lelieveld
Keyword(s):  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Climate Model ◽  
Hybrid Approach ◽  
Model Performance ◽  
Organic Aerosols ◽  
Global Scale ◽  
Emission Rates ◽  
Combustion Sources ◽  
Scavenging Efficiency

Abstract. Organic compounds from combustion sources such as biomass burning and fossil fuel use are major contributors to the global atmospheric load of aerosols. We analyzed the sensitivity of model-predicted global-scale organic aerosols (OA) to parameters that control primary emissions, photochemical aging, and the scavenging efficiency of organic vapors. We used a computationally efficient module for the description of OA composition and evolution in the atmosphere (ORACLE) of the global chemistry–climate model EMAC (ECHAM/MESSy Atmospheric Chemistry). A global dataset of aerosol mass spectrometer (AMS) measurements was used to evaluate simulated primary (POA) and secondary (SOA) OA concentrations. Model results are sensitive to the emission rates of intermediate-volatility organic compounds (IVOCs) and POA. Assuming enhanced reactivity of semi-volatile organic compounds (SVOCs) and IVOCs with OH substantially improved the model performance for SOA. The use of a hybrid approach for the parameterization of the aging of IVOCs had a small effect on predicted SOA levels. The model performance improved by assuming that freshly emitted organic compounds are relatively hydrophobic and become increasingly hygroscopic due to oxidation.

scholarly journals Global-scale combustion sources of organic aerosols: Sensitivity to formation and removal mechanisms

2017 ◽  
Author(s):  
Alexandra P. Tsimpidi ◽  
Vlassis A. Karydis ◽  
Spyros N. Pandis ◽  
Jos Lelieveld
Keyword(s):  
Organic Compounds ◽  
Climate Model ◽  
Hybrid Approach ◽  
Model Performance ◽  
Organic Aerosols ◽  
Global Scale ◽  
Emission Rates ◽  
Computationally Efficient ◽  
Combustion Sources ◽  
Scavenging Efficiency

Abstract. Organic compounds from combustion sources such as biomass burning and fossil fuel use are major contributors to the global atmospheric load of aerosols. We analyzed the sensitivity of model-predicted global-scale organic aerosols (OA) to parameters that control primary emissions, photochemical aging and the scavenging efficiency of organic vapors. We used a computationally efficient module for the description of OA composition and evolution in the atmosphere (ORACLE) of the global chemistry-climate model EMAC. A global dataset of aerosol mass spectrometer measurements was used to evaluate simulated primary (POA) and secondary OA (SOA) concentrations. Model results are sensitive to the emission rates of intermediate volatility organic compounds (IVOCs) and POA. Assuming enhanced reactivity of semi-volatile organic compounds (SVOCs) and IVOCs with OH substantially improved the model performance for SOA. Use of a hybrid approach for the parameterization of the aging of IVOCs had a small effect on predicted SOA levels. The model performance improved by assuming that freshly emitted organic compounds are relatively hydrophobic and become increasingly hygroscopic due to oxidation.

Carbon monoxide emissions by phytoplankton: evidence from laboratory experiments

2009 ◽  
Vol 6 (5) ◽  
pp. 369 ◽  
Author(s):  
Valérie Gros ◽  
Ilka Peeken ◽  
Katrin Bluhm ◽  
Eckart Zöllner ◽  
Roland Sarda-Esteve ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Atmospheric Chemistry ◽  
Laboratory Experiments ◽  
Euphotic Zone ◽  
Global Scale ◽  
Emission Rates ◽  
Direct Production ◽  
Diurnal Cycles

Environmental context. Carbon monoxide (CO) is a key component for atmospheric chemistry and its production in the ocean, although minor at the global scale, could play a significant role in the remote marine atmosphere. Up to now, CO production in the ocean was considered to mainly originate from the photo-production of dissolved organic matter (mainly under UV radiation). In this paper, we show evidence for direct production of CO by phytoplankton and we suggest it as a significant mechanism for CO production in the ocean. Abstract. In order to investigate carbon monoxide (CO) emissions by phytoplankton organisms, a series of laboratory experiments was conducted in Kiel (Germany). Nine monocultures, including diatoms, coccolithophorids, chlorophytes and cyanobacteria have been characterised. This was done by following the CO variations from monoculture aliquots exposed to photosynthetically active radiation during one or two complete diurnal cycles. All the studied cultures have shown significant CO production when illuminated. Emission rates have been estimated to range from 1.4 × 10–5 to 8.7 × 10–4 μg of CO μg chlorophyll–1 h–1 depending on the species. When considering the magnitude of the emission rates from the largest CO emitters (cyanobacteria and diatoms), this biotic source could represent up to 20% of the CO produced in oceanic waters. As global models currently mainly consider CO production from the photo-degradation of dissolved organic matter, this study suggests that biotic CO production should also be taken into account. Whether this biological production might also contribute to some degree to the previous observed non-zero CO production below the euphotic zone (dark CO production) cannot be deduced here and needs to be further investigated.

Variation of atmospheric volatile organic compounds over the Southern Indian Ocean (30 - 49°S)

2009 ◽  
Vol 6 (1) ◽  
pp. 70 ◽  
Author(s):  
Aurélie Colomb ◽  
Valérie Gros ◽  
Séverine Alvain ◽  
Roland Sarda-Esteve ◽  
Bernard Bonsang ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Indian Ocean ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Marine Boundary Layer ◽  
Global Scale ◽  
Climate Impacts ◽  
Southern Indian Ocean ◽  
Oceanic Fronts ◽  
Volatile Organic

Environmental context. Oceans represent 70% of the blue planet, and surprisingly, ocean emission in term of volatile organic compounds is poorly understood. The potential climate impacts on a global scale of various trace organic gases have been established, and the terrestrial inputs are well studied, but little is known about which of these can be emitted from oceanic sources. In the present study, atmospheric samples were taken over the Southern Indian Ocean, while crossing some oceanic fronts and different phytoplankton species. Such a study should aid in understanding oceanic emission, especially from phytoplankton, and will help modellers to determine concentrations of organic traces in the remote marine troposphere. Abstract. Considering its size and potential importance, the ocean is poorly characterised in terms of volatile organic compounds (VOC) that play important roles in global atmospheric chemistry. In order to better understand their potential sources and sinks over the Southern Indian Austral Ocean, shipborne measurements of selected species were made during the MANCHOT campaign during December 2004, on board the research vessel Marion Dufresne. Along the transect La Réunion to Kerguelen Island, air measurements of selected VOC (including dimethylsulfide (DMS) isoprene, carbonyls and organohalogens), carbon monoxide and ozone were performed, crossing subtropical, temperate and sub-Antarctic waters as well as pronounced subtropical and sub-Antarctic oceanic fronts. The remote marine boundary layer was characterised at latitudes 45–50°S. Oceanic fronts were associated with enhanced chlorophyll and biological activity in the seawater and elevated DMS and organohalogens in the atmosphere. These were compared with a satellite-derived phytoplankton distribution (PHYSAT). Diurnal variation for isoprene, terpenes, acetone and acetaldehyde was observed, analogously to recent results observed in mesocosm experiments.

scholarly journals Fluxes and concentrations of volatile organic compounds from a South-East Asian tropical rainforest

2010 ◽  
Vol 10 (17) ◽  
pp. 8391-8412 ◽  
Author(s):  
B. Langford ◽  
P. K. Misztal ◽  
E. Nemitz ◽  
B. Davison ◽  
C. Helfter ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Tropical Forests ◽  
Atmospheric Chemistry ◽  
Carbon Flux ◽  
Tropical Rainforest ◽  
East Asian ◽  
Emission Rates ◽  
Reactive Carbon ◽  
Volatile Organic

Abstract. As part of the OP3 field study of rainforest atmospheric chemistry, above-canopy fluxes of isoprene, monoterpenes and oxygenated volatile organic compounds were made by virtual disjunct eddy covariance from a South-East Asian tropical rainforest in Malaysia. Approximately 500 hours of flux data were collected over 48 days in April–May and June–July 2008. Isoprene was the dominant non-methane hydrocarbon emitted from the forest, accounting for 80% (as carbon) of the measured emission of reactive carbon fluxes. Total monoterpene emissions accounted for 18% of the measured reactive carbon flux. There was no evidence for nocturnal monoterpene emissions and during the day their flux rate was dependent on both light and temperature. The oxygenated compounds, including methanol, acetone and acetaldehyde, contributed less than 2% of the total measured reactive carbon flux. The sum of the VOC fluxes measured represents a 0.4% loss of daytime assimilated carbon by the canopy, but atmospheric chemistry box modelling suggests that most (90%) of this reactive carbon is returned back to the canopy by wet and dry deposition following chemical transformation. The emission rates of isoprene and monoterpenes, normalised to 30 °C and 1000 μmol m−2 s−1 PAR, were 1.6 mg m−2 h−1 and 0.46mg m−2 h−1 respectively, which was 4 and 1.8 times lower respectively than the default value for tropical forests in the widely-used MEGAN model of biogenic VOC emissions. This highlights the need for more direct canopy-scale flux measurements of VOCs from the world's tropical forests.

scholarly journals From emissions to ambient mixing ratios: on-line seasonal field measurements of volatile organic compounds over a Norway spruce dominated forest in central Germany

2013 ◽  
Vol 13 (11) ◽  
pp. 30187-30232 ◽  
Author(s):  
E. Bourtsoukidis ◽  
J. Williams ◽  
J. Kesselmeier ◽  
S. Jacobi ◽  
B. Bonn
Keyword(s):  
Volatile Organic Compounds ◽  
Norway Spruce ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Temperature Dependency ◽  
Emission Rates ◽  
Temperature Dependent ◽  
Central Germany ◽  
Mixing Ratios ◽  
Volatile Organic

Abstract. Biogenic volatile organic compounds (BVOC) are substantial contributors to atmospheric chemistry and physics and demonstrate the close relationship between biosphere and atmosphere. Their emission rates are highly sensitive to meteorological and environmental changes with concomitant impacts on atmospheric chemistry. We have investigated seasonal isoprenoid and oxygenated VOC (oxVOC) fluxes from a Norway spruce (Picea abies) tree in Central Germany and explored the emission responses under various atmospheric conditions. Emission rates were quantified by using dynamic branch enclosure and Proton Transfer Reaction–Mass Spectrometry (PTR-MS) techniques. Additionally, ambient mixing ratios were derived through application of a new box model treatment on the dynamic chamber measurements. These are compared in terms of abundance and origin with the corresponding emissions. Isoprenoids govern the BVOC emissions from Norway spruce, with monoterpenes and sesquiterpenes accounting for 50.8 ± 7.2% and 19.8 ± 8.1% respectively of the total emissions. Normalizing the VOC emission rates, we have observed a trend of reduction of carbon containing emissions from April to November, with an enhancement of oxVOC. Highest emission rates were observed in June for all measured species, with the exception of sesquiterpenes that were emitted most strongly in April. We exploit the wide range of conditions experienced at the site to filter the dataset with a combination of temperature, ozone and absolute humidity values in order to derive the emission potential and temperature dependency development for the major chemical species investigated. A profound reduction of monoterpene emission potential (E30) and temperature dependency (β) was found under low temperature regimes, combined with low ozone levels (E30MT, LTLO3=56 ± 9.1 ng g(dw)−1 h−1, βMT,LTLO3=0.03±0.01 K−1) while a combination of both stresses was found to alter their emissions responses with respect to temperature substantially (E30MT,HTHO3=1420.1 ± 191.4 ng g(dw)−1 h−1, βMT,HTHO3=0.15 ± 0.02 K−1). Moreover, we have explored compound relationships under different atmospheric condition sets, addressing possible co-occurrence of emissions under specific conditions. Finally, we evaluate the temperature dependent algorithm that seems to describe the temperature dependent emissions. Highest emission deviations were observed for monoterpenes and these emission fluctuations were attributed to a fraction which is triggered by an additional light dependency.

scholarly journals Tropospheric Ozone Assessment Report: Assessment of global-scale model performance for global and regional ozone distributions, variability, and trends

Elem Sci Anth ◽  
2018 ◽  
Vol 6 ◽  
Author(s):  
P. J. Young ◽  
V. Naik ◽  
A. M. Fiore ◽  
A. Gaudel ◽  
J. Guo ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Tropospheric Ozone ◽  
Model Performance ◽  
Temporal Distribution ◽  
Temporal Variations ◽  
Global Scale ◽  
Scale Model ◽  
Significant Information ◽  
Assessment Report ◽  
Spatio Temporal

The goal of the Tropospheric Ozone Assessment Report (TOAR) is to provide the research community with an up-to-date scientific assessment of tropospheric ozone, from the surface to the tropopause. While a suite of observations provides significant information on the spatial and temporal distribution of tropospheric ozone, observational gaps make it necessary to use global atmospheric chemistry models to synthesize our understanding of the processes and variables that control tropospheric ozone abundance and its variability. Models facilitate the interpretation of the observations and allow us to make projections of future tropospheric ozone and trace gas distributions for different anthropogenic or natural perturbations. This paper assesses the skill of current-generation global atmospheric chemistry models in simulating the observed present-day tropospheric ozone distribution, variability, and trends. Drawing upon the results of recent international multi-model intercomparisons and using a range of model evaluation techniques, we demonstrate that global chemistry models are broadly skillful in capturing the spatio-temporal variations of tropospheric ozone over the seasonal cycle, for extreme pollution episodes, and changes over interannual to decadal periods. However, models are consistently biased high in the northern hemisphere and biased low in the southern hemisphere, throughout the depth of the troposphere, and are unable to replicate particular metrics that define the longer term trends in tropospheric ozone as derived from some background sites. When the models compare unfavorably against observations, we discuss the potential causes of model biases and propose directions for future developments, including improved evaluations that may be able to better diagnose the root cause of the model-observation disparity. Overall, model results should be approached critically, including determining whether the model performance is acceptable for the problem being addressed, whether biases can be tolerated or corrected, whether the model is appropriately constituted, and whether there is a way to satisfactorily quantify the uncertainty.

scholarly journals Surface–atmosphere fluxes of volatile organic compounds in Beijing

2020 ◽  
Author(s):  
W. Joe F. Acton ◽  
Zhonghui Huang ◽  
Brian Davison ◽  
Will S. Drysdale ◽  
Pingqing Fu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Emission Inventory ◽  
Central Area ◽  
High Reactivity ◽  
Emission Rates ◽  
Formation Potential ◽  
Volatile Organic

Abstract. Air pollution in Beijing has a major impact on public health and is therefore of concern to both policy makers and the general public. Volatile organic compounds (VOCs) are emitted from both anthropogenic and biogenic sources in urban environments and play an important role in atmospheric chemistry and hence atmospheric pollution through the formation of secondary organic aerosol and tropospheric ozone. Fluxes and mixing ratios of VOCs were recorded in two field campaigns as part of the Air Pollution and Human Health in a Chinese Megacity (APHH) project at the Institute of Atmospheric Physics (IAP) meteorological tower in central Beijing. These measurements represent the first eddy covariance flux measurements of VOCs in Beijing giving a top down estimation of VOC emissions from a central area of the city. These were then used to validate the Multi-resolution Emission Inventory for China (MEIC). The APHH winter and summer campaigns took place in November and December 2016 and May and June 2017 respectively. The largest VOC fluxes observed were of small oxygenated compounds such as methanol, ethanol + formic acid and acetaldehyde, with average emission rates of 8.02, 3.88 and 1.76 nmol m−2 s−1 respectively recorded in the summer campaign. In addition a large flux of isoprene was observed in the summer with an average flux of 4.63 nmol m−2 s−1. While oxygenated VOCs made up 60 % of the molar VOC flux measured, when fluxes were scaled by ozone formation potential and peroxyacyl nitrate (PAN) formation potential the high reactivity of isoprene and monoterpenes meant that these species represented 30 and 28 % of the flux contribution to ozone and PAN formation potential respectively. Comparison of measured fluxes with the emission inventory showed that the inventory failed to capture VOC emission at the local scale.

scholarly journals Fluxes and concentrations of volatile organic compounds from a South-East Asian tropical rainforest

2010 ◽  
Vol 10 (5) ◽  
pp. 11975-12021 ◽  
Author(s):  
B. Langford ◽  
P. K. Misztal ◽  
E. Nemitz ◽  
B. Davison ◽  
C. Helfter ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Tropical Forests ◽  
Atmospheric Chemistry ◽  
Carbon Flux ◽  
Tropical Rainforest ◽  
East Asian ◽  
Emission Rates ◽  
Reactive Carbon ◽  
Volatile Organic

Abstract. As part of the OP3 field study of rainforest atmospheric chemistry, above-canopy fluxes of isoprene, monoterpenes and oxygenated volatile organic compounds were made by virtual disjunct eddy covariance from a South-East Asian tropical rainforest in Malaysia. Approximately 500 hours of flux data were collected over 48 days in April–May and June–July 2008. Isoprene was the dominant non-methane hydrocarbon emitted from the forest, accounting for 80% (as carbon) of the measured emission of reactive carbon fluxes. Total monoterpene emissions accounted for 18% of the measured reactive carbon flux. Monoterpenes were not emitted at night, and during the day their flux rate was dependent on both light and temperature. The oxygenated compounds, including methanol, acetone and acetaldehyde, contributed less than 2% of the total measured reactive carbon flux. The sum of the VOC fluxes measured represents a 0.4% loss of daytime assimilated carbon by the canopy, but atmospheric chemistry box modelling suggests that most (90%) of this reactive carbon is returned back to the canopy by wet and dry deposition following chemical transformation. The emission rates of isoprene and monoterpenes, normalised to 30 °C and 1000 μmol m−2 s−1 PAR, were 1.6 mg m−2 h−1 and 0.46 mg m−2 h−1 respectively, which was 4 and 1.7 times lower respectively than the default value for tropical forests in the widely-used MEGAN model of biogenic VOC emissions. This highlights the need for more direct canopy-scale flux measurements of VOCs from the world's tropical forests.

Investigating the sensitivity in production of SOA from its precursor VOCs with different sources of emissions using an interactive chemistry climate model

2020 ◽  
Author(s):  
Pawan Vats ◽  
Dilip Ganguly ◽  
Anushree Biswas
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Organic Aerosols ◽  
Global Climate Models ◽  
Indian Region ◽  
Anthropogenic Sources ◽  
Computational Time

<p>The organic aerosols (OA) contribute significantly to fine particulate mass in the atmosphere, however, most global climate models do not include elaborate treatment associated with the production of secondary organic aerosols (SOA) involving complex chemical processes to save computational time. As a result, the concentrations of SOA simulated by these climate models are often highly uncertain. Moreover, very limited research has been done on SOA and its precursors, particularly on the contribution of individual sources towards the SOA concentrations across India. In this study, we investigate the sensitivity of the production of SOA from different VOC sources and different atmospheric oxidants by the Community Atmospheric Model version 4 coupled with an extensive interactive atmospheric chemistry module (CAM4-Chem). The main objective of our present research is to understand the contribution of individual sources of VOCs towards the production and distribution of SOA across the Indian region. We carried out a series of systematically designed simulations using the CAM4-Chem model to understand the sensitivity of simulated SOA over the Indian region to changes in only emissions of VOCs from anthropogenic, biogenic, and biomass burning emissions from preindustrial (PI) to present-day (PD) period. In order to avoid the influence of changes in meteorology from PI to PD on the production of SOA, all simulations are performed for the same period from 2004 to 2014 with identical meteorology prescribed to the model based on MERRA2 data, while the VOC emissions from anthropogenic, biogenic, and biomass burning sources are allowed to change from PI to PD in different simulations. Our results show that the simulated distribution of SOA over the Indian region in PD is linked to the significant changes in the emissions of VOCs from anthropogenic, biogenic, and biomass burning emissions sources from PI to PD. We find that the changes in emissions of VOCs from biogenic sources from PI to PD associated with land use and land cover changes contribute significantly along with the changes in emissions from anthropogenic sources towards the total changes in SOA distribution over the Indian region over the same period.  The global annual mean burden of SOA from our sensitivity simulations vary in the range of 0.65Tg to 0.80Tg due to variations in emission of different VOCs that are precursors to the production of SOA in the atmosphere. These sensitivity simulations improve our understanding of atmospheric chemistry and specifically about the formation of SOA from different precursor gases originating from diverse anthropogenic, biogenic, and biomass burning emissions sources. More results with greater detail will be presented.</p>

scholarly journals From emissions to ambient mixing ratios: online seasonal field measurements of volatile organic compounds over a Norway spruce-dominated forest in central Germany

2014 ◽  
Vol 14 (13) ◽  
pp. 6495-6510 ◽  
Author(s):  
E. Bourtsoukidis ◽  
J. Williams ◽  
J. Kesselmeier ◽  
S. Jacobi ◽  
B. Bonn
Keyword(s):  
Volatile Organic Compounds ◽  
Norway Spruce ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Environmental Changes ◽  
Emission Rates ◽  
Temperature Dependent ◽  
Central Germany ◽  
Mixing Ratios ◽  
Volatile Organic

Abstract. Biogenic volatile organic compounds (BVOCs) are substantial contributors to atmospheric chemistry and physics and demonstrate the close relationship between biosphere and atmosphere. Their emission rates are highly sensitive to meteorological and environmental changes with concomitant impacts on atmospheric chemistry. We have investigated seasonal isoprenoid and oxygenated VOC (oxVOC) fluxes from a Norway spruce (Picea abies) tree in central Germany and explored the emission responses under various atmospheric conditions. Emission rates were quantified by using dynamic branch enclosure and proton-transfer-reaction mass spectrometry (PTR-MS) techniques. Additionally, ambient mixing ratios were derived through application of a new box model treatment on the dynamic chamber measurements. These are compared in terms of abundance and origin with the corresponding emissions. Isoprenoids dominate the BVOC emissions from Norway spruce, with monoterpenes and sesquiterpenes accounting for 50.8 ± 7.2% and 19.8 ± 8.1% respectively of the total emissions. Normalizing the VOC emission rates, we have observed a trend of reduction of carbon-containing emissions from April to November, with an enhancement of oxVOC. Highest emission rates were observed in June for all measured species, with the exception of sesquiterpenes, which were emitted most strongly in April. Finally, we evaluate the temperature-dependent algorithm that seems to describe the temperature-dependent emissions of methanol, acetaldehyde and monoterpenes but only with the use of the monthly derived values for emission potential, Es, and temperature dependency, β factor.

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