scholarly journals Water-soluble organic compounds in biomass burning aerosols over Amazonia 2. Apportionment of the chemical composition and importance of the polyacidic fraction

2002 ◽  
Vol 107 (D20) ◽  
Author(s):  
O. L. Mayol-Bracero
Keyword(s):  
Chemical Composition ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Water Soluble

scholarly journals Analysis of CCN activity of Arctic aerosol and Canadian biomass burning during summer 2008

2013 ◽  
Vol 13 (5) ◽  
pp. 2735-2756 ◽  
Author(s):  
T. L. Lathem ◽  
A. J. Beyersdorf ◽  
K. L. Thornhill ◽  
E. L. Winstead ◽  
M. J. Cubison ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Biomass Burning ◽  
Industrial Pollution ◽  
Physical Aging ◽  
Volume Fraction ◽  
Cloud Condensation Nuclei ◽  
Water Soluble ◽  
The Arctic ◽  
High Concentration ◽  
Air Masses

Abstract. The NASA DC-8 aircraft characterized the aerosol properties, chemical composition, and cloud condensation nuclei (CCN) concentrations of the summertime Arctic during the 2008 NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. Air masses characteristic of fresh and aged biomass burning, boreal forest, Arctic background, and anthropogenic industrial pollution were sampled. Observations were spatially extensive (50–85° N and 40–130° W) and exhibit significant variability in aerosol and CCN concentrations. The chemical composition was dominated by highly oxidized organics (66–94% by volume), with a water-soluble mass fraction of more than 50%. The aerosol hygroscopicity parameter, κ, ranged between κ = 0.08–0.32 for all air mass types. Industrial pollution had the lowest κ of 0.08 ± 0.01, while the Arctic background had the highest and most variable κ of 0.32 ± 0.21, resulting from a lower and more variable organic fraction. Both fresh and aged (long-range transported) biomass burning air masses exhibited remarkably similar κ (0.18 ± 0.13), consistent with observed rapid chemical and physical aging of smoke emissions in the atmosphere, even in the vicinity of fresh fires. The organic hygroscopicity (κorg) was parameterized by the volume fraction of water-soluble organic matter (εWSOM), with a κ = 0.12, such that κorg = 0.12εWSOM. Assuming bulk (size-independent) composition and including the κorg parameterization enabled CCN predictions to within 30% accuracy for nearly all environments sampled. The only exception was for industrial pollution from Canadian oil sands exploration, where an external mixture and size-dependent composition was required. Aerosol mixing state assumptions (internal vs. external) in all other environments did not significantly affect CCN predictions; however, the external mixing assumption provided the best results, even though the available observations could not determine the true degree of external mixing and therefore may not always be representative of the environments sampled. No correlation was observed between κorg and O : C. A novel correction of the CCN instrument supersaturation for water vapor depletion, resulting from high concentrations of CCN, was also employed. This correction was especially important for fresh biomass burning plumes where concentrations exceeded 1.5×104 cm−3 and introduced supersaturation depletions of ≥25%. Not accounting for supersaturation depletion in these high concentration environments would therefore bias CCN closure up to 25% and inferred κ by up to 50%.

scholarly journals Chemical composition and source apportionment of atmospheric aerosols on the Namibian coast

2020 ◽  
Vol 20 (24) ◽  
pp. 15811-15833
Author(s):  
Danitza Klopper ◽  
Paola Formenti ◽  
Andreas Namwoonde ◽  
Mathieu Cazaunau ◽  
Servanne Chevaillier ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Biomass Burning ◽  
Mineral Dust ◽  
Open Ocean ◽  
Sea Salt ◽  
Water Soluble ◽  
Marine Phytoplankton ◽  
Fugitive Dust ◽  
The South ◽  
North West

Abstract. The chemical composition of aerosols is of particular importance to assess their interactions with radiation, clouds and trace gases in the atmosphere and consequently their effects on air quality and the regional climate. In this study, we present the results of the first long-term dataset of the aerosol chemical composition at an observatory on the coast of Namibia, facing the south-eastern Atlantic Ocean. Aerosol samples in the mass fraction of particles smaller than 10 µm in aerodynamic diameter (PM10) were collected during 26 weeks between 2016 and 2017 at the ground-based Henties Bay Aerosol Observatory (HBAO; 22∘6′ S, 14∘30′ E; 30 m above mean sea level). The resulting 385 filter samples were analysed by X-ray fluorescence and ion chromatography for 24 inorganic elements and 15 water-soluble ions. Statistical analysis by positive matrix factorisation (PMF) identified five major components, sea salt (mass concentration: 74.7±1.9 %), mineral dust (15.7±1.4 %,), ammonium neutralised (6.1±0.7 %), fugitive dust (2.6±0.2 %) and industry (0.9±0.7 %). While the contribution of sea salt aerosol was persistent, as the dominant wind direction was south-westerly and westerly from the open ocean, the occurrence of mineral dust was episodic and coincided with high wind speeds from the south-south-east and the north-north-west, along the coastline. Concentrations of heavy metals measured at HBAO were higher than reported in the literature from measurements over the open ocean. V, Cd, Pb and Nd were attributed to fugitive dust emitted from bare surfaces or mining activities. As, Zn, Cu, Ni and Sr were attributed to the combustion of heavy oils in commercial ship traffic across the Cape of Good Hope sea route, power generation, smelting and other industrial activities in the greater region. Fluoride concentrations up to 25 µg m−3 were measured, as in heavily polluted areas in China. This is surprising and a worrisome result that has profound health implications and deserves further investigation. Although no clear signature for biomass burning could be determined, the PMF ammonium-neutralised component was described by a mixture of aerosols typically emitted by biomass burning, but also by other biogenic activities. Episodic contributions with moderate correlations between NO3-, nss-SO42- (higher than 2 µg m−3) and nss-K+ were observed, further indicative of the potential for an episodic source of biomass burning. Sea salt accounted for up to 57 % of the measured mass concentrations of SO42-, and the non-sea salt fraction was contributed mainly by the ammonium-neutralised component and small contributions from the mineral dust component. The marine biogenic contribution to the ammonium-neutralised component is attributed to efficient oxidation in the moist marine atmosphere of sulfur-containing gas phase emitted by marine phytoplankton in the fertile waters offshore in the Benguela Upwelling System. The data presented in this paper provide the first ever information on the temporal variability of aerosol concentrations in the Namibian marine boundary layer. This data also provide context for intensive observations in the area.

scholarly journals Characterization of the organic composition of aerosols from Rondônia, Brazil, during the LBA-SMOCC 2002 experiment and its representation through model compounds

2006 ◽  
Vol 6 (2) ◽  
pp. 375-402 ◽  
Author(s):  
S. Decesari ◽  
S. Fuzzi ◽  
M. C. Facchini ◽  
M. Mircea ◽  
L. Emblico ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Biomass Burning ◽  
Functional Group ◽  
Group Analysis ◽  
Water Soluble ◽  
Total Carbon ◽  
Individual Compound ◽  
Model Compounds ◽  
Functional Group Analysis

Abstract. The chemical composition of carbonaceous aerosols collected during the LBA-SMOCC field experiment, conducted in Rondônia, Brazil, in 2002 during the transition from the dry to the wet season, was investigated by a suite of state-of-the-art analytical techniques. The period of most intense biomass burning was characterized by high concentrations of submicron particles rich in carbonaceous material and water-soluble organic compounds (WSOC). At the onset of the rainy period, submicron total carbon (TC) concentrations decreased by about 20 times. In contrast, the concentration of supermicron TC was fairly constant throughout the experiment, pointing to a constant emission of coarse particles from the natural background. About 6–8% of TC (9–11% of WSOC) was speciated at the molecular level by GC-MS and liquid chromatography. Polyhydroxylated compounds, aliphatic and aromatic acids were the main classes of compounds accounted for by individual compound analysis. Functional group analysis by proton NMR and chromatographic separation on ion-exchange columns allowed characterization of ca. 50–90% of WSOC into broad chemical classes (neutral species/light acids/humic-like substances). In spite of the significant change in the chemical composition of tracer compounds from the dry to the wet period, the functional groups and the general chemical classes of WSOC changed only to a small extent. Model compounds representing size-resolved WSOC chemical composition for the different periods of the campaign are then proposed in this paper, based on the chemical characterization by both individual compound analysis and functional group analysis deployed during the LBA-SMOCC experiment. Model compounds reproduce quantitatively the average chemical structure of WSOC and can be used as best-guess surrogates in microphysical models involving organic aerosol particles over tropical areas affected by biomass burning.

scholarly journals Characterization of the organic composition of aerosols from Rondônia, Brazil, during the LBA-SMOCC 2002 experiment and its representation through model compounds

2005 ◽  
Vol 5 (4) ◽  
pp. 5687-5749 ◽  
Author(s):  
S. Decesari ◽  
S. Fuzzi ◽  
M. C. Facchini ◽  
M. Mircea ◽  
L. Emblico ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Biomass Burning ◽  
Functional Group ◽  
Group Analysis ◽  
Water Soluble ◽  
Total Carbon ◽  
Individual Compound ◽  
Model Compounds ◽  
Functional Group Analysis

Abstract. The chemical composition of carbonaceous aerosols collected during the LBA-SMOCC field experiment, conducted in Rondônia, Brazil, in 2002 during the transition from the dry to the wet season, was investigated by a suite of advanced analytical techniques. The period of most intense biomass burning was characterized by high concentrations of submicron particles rich in carbonaceous material and water-soluble organic compounds (WSOC). At the onset of the rainy period, submicron total carbon (TC) concentrations had decreased by about 20 times. In contrast, the concentration of supermicron TC was fairly constant throughout the experiment, pointing to a constant emission of coarse particles from the natural background. About 6–8% of TC (9–11% of WSOC) was speciated at the molecular level by GC-MS and liquid chromatography. Poly-hydroxylated compounds, aliphatic and aromatic acids were the main classes of compounds accounted for by individual compound analysis. Functional group analysis by proton NMR and chromatographic separation on ion-exchange columns allowed characterization of ca. 50–90% of WSOC into broad chemical classes (neutral species/light acids/humic-like substances). In spite of the significant change in the chemical composition of tracer compounds from the dry to the wet period, the functional groups and the general chemical classes of WSOC changed only to a lesser extent. Model compounds representing size-resolved WSOC chemical composition for the different periods of the campaign are then proposed in this paper, based on the chemical characterization by both individual compound analysis and functional group analysis deployed during the LBA-SMOCC experiment. Model compounds reproduce quantitatively the average chemical structure of WSOC and can be used as best-guess surrogates in microphysical models involving organic aerosol particles over tropical areas affected by biomass burning.

scholarly journals Chemical composition and source apportionment of atmospheric aerosols on the Namibian coast

2020 ◽  
Author(s):  
Danitza Klopper ◽  
Paola Formenti ◽  
Andreas Namwoonde ◽  
Mathieu Cazaunau ◽  
Servanne Chevaillier ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Chemical Composition ◽  
Biomass Burning ◽  
Mineral Dust ◽  
Open Ocean ◽  
Sea Salt ◽  
Water Soluble ◽  
Marine Phytoplankton ◽  
Back Trajectory ◽  
Secondary Products

Abstract. The chemical composition of aerosols is of particular importance to assess their interactions with radiation, clouds and trace gases in the atmosphere, and consequently their effects on air quality and the regional climate. In this study, we present the results of the first long-term dataset of the aerosol chemical composition at an observatory on the coast of Namibia, facing the southeast Atlantic Ocean. Aerosol samples in the mass fraction of particles smaller than 10 µm in aerodynamic diameter (PM10) were collected during 26 weeks between 2016 and 2017 at the ground-based Henties Bay Aerosol Observatory (HBAO; 22°6’ S, 14°30’ E, 30 m above mean sea level). The resulting 385 filter samples were analysed by X-ray fluorescence and ion-chromatography for 24 inorganic elements and 15 water-soluble ions. Statistical analysis by positive matrix factorization and back-trajectory modelling identified five major sources, sea salt (mass concentration: 70.8 ± 0.2 %), marine biogenic (13.5 ± 0.8 %), mineral dust (9.9 ± 0.1 %), secondary products (3.2 ± 1.0 %) and heavy metals (2.3 ± 2.5 %). While the contribution of sea salt aerosol was persistent, as the dominant wind direction was south-westerly and westerly from the open ocean, the occurrence of mineral dust was episodic and coincided with high wind speeds from the south-southeast and the north-northwest, along the coastline. Concentrations of heavy metals measured at HBAO were higher than reported in the literature from measurements over the open ocean. The heavy metals (V, Cr, Nd and Mn) measured at the site were attributed to mining activities and the combustion of heavy fuels in commercial ship traffic across the Cape of Good Hope sea route. Fluoride concentrations up to 25 µg m−3 were measured, as in heavily polluted areas in China. This is surprising and a worrisome result that has profound health implications and deserves further investigation. Although no clear signature for biomass burning could be determined, the source of secondary products identified by PMF was described by a mixture of aerosols typically emitted by biomass burning, but also by other biogenic activities. Episodic contributions with moderate correlations between NO3−, nss-SO42− (higher than 2 µg m−3) and nss-K+, were observed, further indicative of the potential for an episodic source of biomass burning. Sea salt accounted for up to 57 % of the measured mass concentrations of SO42− and the non-sea salt fraction contributed mainly to the secondary product and marine biogenic sources identified by PMF. The marine biogenic contribution is attributed to efficient oxidation in the moist marine atmosphere of sulphur-containing gas-phase emitted by marine phytoplankton in the fertile waters offshore in the Benguela Upwelling System. The data presented in this paper provide first-ever information on the temporal variability of aerosol concentrations in the Namibian marine boundary layer and the links to meteorological conditions shaping the transport patterns of aerosols from different sources. This data can be used to provide context for intensive observations in the area.

scholarly journals Chemical characterisation of humic-like substances from urban, rural and tropical biomass burning environments using liquid chromatography with UV/vis photodiode array detection and electrospray ionisation mass spectrometry

2012 ◽  
Vol 9 (3) ◽  
pp. 273 ◽  
Author(s):  
Magda Claeys ◽  
Reinhilde Vermeylen ◽  
Farhat Yasmeen ◽  
Yadian Gómez-González ◽  
Xuguang Chi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Water Soluble ◽  
Photodiode Array Detection ◽  
Ionisation Mass Spectrometry ◽  
Photodiode Array ◽  
Array Detection ◽  
Ionisation Mass

Environmental contextOne of the most important classes of water-soluble organic compounds in continental fine and tropical biomass burning aerosol is humic-like substances (HULIS), which contain components with strong polar, acidic and chromophoric properties. We focus on the chemical characterisation of HULIS and provide evidence that nitro-aromatic catecholic compounds are among the major species of HULIS. This indicates that volatile aromatic hydrocarbons emitted during biomass burning are important gas-phase precursors for HULIS. AbstractHumic-like substances (HULIS) are ubiquitously present in the troposphere and make up a major fraction of continental fine-sized water-soluble organic compounds. They are regarded as material with strong polar, acidic and chromophoric properties; however, structural information at the individual component level is rather limited. In the present study, we have characterised HULIS from different locations using liquid chromatography coupled to photodiode array detection and negative ion electrospray ionisation mass spectrometry. Aerosol samples with particles less than 2.5 μm in diameter (PM2.5) were collected in Budapest and K-puszta, Hungary, during 2007 and 2008 spring and summer periods, and in Rondônia, Brazil, during a 2002 biomass burning experiment. Major components of the Budapest 2007 and Brazil 2002 HULIS corresponded to chromophoric substances, of which 4-nitrocatechol (molecular weight (MW) 155) was identified as the most abundant organic species and less abundant ones were attributed to mono- and dimethyl nitrocatechols (MWs 169 and 183). The mass concentrations of 4-nitrocatechol in the water-soluble organic carbon (WSOC) of the Budapest 2007 and day- and night-time Brazil 2002 HULIS were 0.46, 0.50 and 1.80 %. Abundant components of K-puszta 2008 HULIS were assigned to α-pinene secondary organic aerosol (SOA) tracers, i.e. 3-methyl-1,2,3-butanetricarboxylic acid and terpenylic acid; their mass concentrations in the HULIS WSOC were 0.75 and 0.40 %. Tere- and ortho-phthalic acids (MW 166) were major components of the Budapest and K-puszta HULIS, but only minor ones of the Brazil 2002 biomass burning HULIS, consistent with a source that is different from biomass burning and likely related to open waste burning of phthalate ester-containing material such as plastic.

Chemical composition and light absorption of brown carbon emitted from residential coal combustion in China

2020 ◽  
Author(s):  
Jianzhong Song ◽  
Meiju Li ◽  
Xingjun Fan ◽  
Peng'an Peng
Keyword(s):  
Organic Carbon ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Light Absorption ◽  
Coal Combustion ◽  
Extraction Methods ◽  
Water Soluble ◽  
Brown Carbon ◽  
Smoke Particles ◽  
Soluble Organic Carbon

<p>Brown carbon (BrC) is a type of light-absorbing organic compounds with a high capacity to absorb light in the low-wavelength visible and near-ultraviolet regions, which is ubiquitous in atmospheric aerosols, rainwater, and cloudwater samples. BrC can not only alter the light absorption and radiative forcing of aerosols but can also influence the formation of cloud condensation nuclei; therefore, it has a potential impact on atmospheric chemistry and climate change. Numerous studies have demonstrated that combustion processes are significant sources of atmospheric BrC, however most of these studies were focused on the emissions of biomass burning. Knowledge of primary BrC from coal combustion is still limited. In the study, smoke particles emitted from the combustion of residential coals with different geological maturity were collected in a combustion system. Then BrC fractions, including water soluble organic carbon (WSOC), water soluble humic-like substances (HULIS<sub>w</sub>), alkaline soluble organic carbon (ASOC) and methanol soluble organic carbon (MSOC) were extracted and characterized for their abundances, chemical, and light absorption properties.</p><p> </p><p>Our results showed that the abundance and light absorption of the coal combustion-derived BrC fractions were strongly dependent on the extraction methods used and the coal maturity. The abundances of MSOC fraction was significantly higher than WSOC and ASOC fractions and even higher than the sum of WSOC and ASOC, indicating that most organic compounds in smoke particles were soluble in pure methanol. The WSOC and MSOC fractions from the combustion of low maturity coal had relatively low SUVA<sub>254</sub> and MAE<sub>365</sub> values, indicated that they had relatively low levels of aromatic structures and light absorption.</p><p> </p><p>The WSOC and MSOC fractions were characterized by ultrahigh-resolution mass spectrometry. The results showed that S-containing compounds (CHOS and CHONS) are found to be the dominant components of the WSOC, whereas CHO and CHON compounds make a great contribution to the MSOC samples. Noted that a greater abundance of S-containing compounds was found in the smoke produced from coal combustion compared to biomass burning and atmospheric samples, indicated that coal combustion could be an important source of atmospheric S-containing compounds in certain areas. The findings also suggest that organic molecules with a high aromaticity index and low polarity showed stronger light absorption. In summary, our study indicated that coal combustion is a potential source of atmospheric BrC and their abundance, chemical, and light absorption were strongly dependent on the extraction methods used and the coal maturity.</p>

scholarly journals Adhesive Droplets of Glowworm Snares (Keroplatidae: Arachnocampa spp.) Are a Complex Mix of Organic Compounds

2021 ◽  
Vol 7 ◽  
Author(s):  
Jonas O. Wolff ◽  
Janek von Byern ◽  
Dakota Piorkowski ◽  
Jian Fang ◽  
Xungai Wang ◽  
...  
Keyword(s):  
New Zealand ◽  
Chemical Composition ◽  
Organic Compounds ◽  
High Performance ◽  
Prey Capture ◽  
Polar Compounds ◽  
Water Soluble ◽  
High Humidity ◽  
Adhesive Properties ◽  
Spider Webs

Adhesive snares built from silks are fascinating adaptations that have rarely evolved outside spiders. Glowworms (Arachnocampa spp.) are an iconic part of the fauna of Australia and New Zealand that combine the construction of a sticky snare with a bioluminescent lure. Recently, the structure and biomechanical properties of glowworm silk have been studied in detail, but the chemical composition of its adhesive coating, and how it varies between species of Arachnocampa remained unclear, limiting an understanding of the glue function. Here, we studied the chemical composition of the water-soluble fraction of the adhesive droplets from the snares in cave and epigaeic populations of three species of Arachnocampa from mainland Australia, Tasmania, and New Zealand, using a combination of nuclear magnetic resonance and mass spectrometry. We found that glowworm glues comprise a large variety of small organic compounds, with organic acids, amino acids, amino acid derivates, alcohols, urea, and urea derivates being the major fraction, supplemented by small amounts of sugars, fatty acids, and other organic compounds. While there was a general overlap in the compounds detected in the adhesives of all tested Arachnocampa species and populations, the relative amounts differed considerably. We expect that these differences are a product of diet rather than an adaptive response to different environments, but experiments are needed for clarification. The high amount of polar substances and compounds that are hygroscopic at high humidity explains the adhesive properties of the viscous solution and its stability in damp environments. These results contribute to our understanding of the unique prey capture strategy of glowworms. Further, the comparison with convergent spider webs highlights the use of small polar compounds as plasticizers of macro-molecular bioadhesives as a general principle. This may inspire the biomimetic design of novel pressure sensitive adhesives with high performance under high humidity conditions.

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