scholarly journals Biomass burning emissions disturbances on the isoprene oxidation in a tropical forest

2017 ◽  
Author(s):  
Fernando C. Santos ◽  
Karla M. Longo ◽  
Alex B. Guenther ◽  
Saewung Kim ◽  
Dasa Gu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Biomass Burning ◽  
Oxidative Capacity ◽  
Oxidation Products ◽  
Amazon Forest ◽  
South American ◽  
Range Transport ◽  
Isoprene Oxidation ◽  
Emission Tracers

Abstract. We present a characterization of the chemical composition of the atmosphere of the Brazilian Amazon rainforest based on trace gases measurements carried out during the South American Biomass Burning Analysis (SAMBBA) airborne experiment in September 2012. We analyzed the observations of primary biomass burning emission tracers, i.e., carbon monoxide (CO) and nitrogen oxides (NOx), ozone (O3), isoprene, and its main oxidation products, methyl vinyl ketone (MVK), methacrolein (MACR), and hydroxyhydroperoxides (ISOPOOH). The focus of SAMBBA was primarily on biomass burning emissions, but there were also several flights in areas of the Amazon forest not directly affected by biomass burning, revealing a background with a signature of biomass burning in the chemical composition due to long-range transport of biomass burning tracers from both Africa and the eastern part of Amazonia. We used the [MVK + MACR + ISOPOOH] / [Isoprene] ratio and the hydroxyl radical (OH) indirect calculation to assess the oxidative capacity of the Amazon forest atmosphere. We compared the background regions (CO 

scholarly journals Biomass burning emission disturbances of isoprene oxidation in a tropical forest

2018 ◽  
Vol 18 (17) ◽  
pp. 12715-12734 ◽  
Author(s):  
Fernando Santos ◽  
Karla Longo ◽  
Alex Guenther ◽  
Saewung Kim ◽  
Dasa Gu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Biomass Burning ◽  
Oxidative Capacity ◽  
Oxidation Products ◽  
Amazon Rainforest ◽  
Amazon Forest ◽  
Oxidation Reactions ◽  
Smoke Plumes ◽  
Isoprene Oxidation ◽  
The Impact

Abstract. We present a characterization of the chemical composition of the atmosphere of the Brazilian Amazon rainforest based on trace gas measurements carried out during the South AMerican Biomass Burning Analysis (SAMBBA) airborne experiment in September 2012. We analyzed the observations of primary biomass burning emission tracers, i.e., carbon monoxide (CO), nitrogen oxides (NOx), ozone (O3), isoprene, and its main oxidation products, methyl vinyl ketone (MVK), methacrolein (MACR), and isoprene hydroxy hydroperoxide (ISOPOOH). The focus of SAMBBA was primarily on biomass burning emissions, but there were also several flights in areas of the Amazon forest not directly affected by biomass burning, revealing a background with a signature of biomass burning in the chemical composition due to long-range transport of biomass burning tracers from both Africa and the eastern part of Amazonia. We used the [MVK + MACR + ISOPOOH] ∕ [isoprene] ratio and the hydroxyl radical (OH) indirect calculation to assess the oxidative capacity of the Amazon forest atmosphere. We compared the background regions (CO < 150 ppbv), fresh and aged smoke plumes classified according to their photochemical age ([O3] ∕ [CO]), to evaluate the impact of biomass burning emissions on the oxidative capacity of the Amazon forest atmosphere. We observed that biomass burning emissions disturb the isoprene oxidation reactions, especially for fresh plumes ([MVK + MACR + ISOPOOH] ∕ [isoprene] =  7) downwind. The oxidation of isoprene is higher in fresh smoke plumes at lower altitudes (∼ 500 m) than in aged smoke plumes, anticipating near the surface a complex chain of oxidation reactions which may be related to secondary organic aerosol (SOA) formation. We proposed a refinement of the OH calculation based on the sequential reaction model, which considers vertical and horizontal transport for both biomass burning regimes and background environment. Our approach for the [OH] estimation resulted in values on the same order of magnitude of a recent observation in the Amazon rainforest [OH] ≅ 106 (molecules cm−3). During the fresh plume regime, the vertical profile of [OH] and the [MVK + MACR + ISOPOOH] ∕ [isoprene] ratio showed evidence of an increase in the oxidizing power in the transition from planetary boundary layer to cloud layer (1000–1500 m). These high values of [OH] (1.5 × 106 molecules cm−3) and [MVK + MACR + ISOPOOH] ∕ [isoprene] (7.5) indicate a significant change above and inside the cloud decks due to cloud edge effects on photolysis rates, which have a major impact on OH production rates.

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 Assessment of fire emission inventories during the South American Biomass Burning Analysis (SAMBBA) experiment

2016 ◽  
Vol 16 (11) ◽  
pp. 6961-6975 ◽  
Author(s):  
Gabriel Pereira ◽  
Ricardo Siqueira ◽  
Nilton E. Rosário ◽  
Karla L. Longo ◽  
Saulo R. Freitas ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Aerosol ◽  
Trace Gases ◽  
Correlation Coefficients ◽  
Amazon Forest ◽  
South American ◽  
Emission Model ◽  
Emission Inventories ◽  
Emission Fluxes ◽  
Co Emission

Abstract. Fires associated with land use and land cover changes release large amounts of aerosols and trace gases into the atmosphere. Although several inventories of biomass burning emissions cover Brazil, there are still considerable uncertainties and differences among them. While most fire emission inventories utilize the parameters of burned area, vegetation fuel load, emission factors, and other parameters to estimate the biomass burned and its associated emissions, several more recent inventories apply an alternative method based on fire radiative power (FRP) observations to estimate the amount of biomass burned and the corresponding emissions of trace gases and aerosols. The Brazilian Biomass Burning Emission Model (3BEM) and the Fire Inventory from NCAR (FINN) are examples of the first, while the Brazilian Biomass Burning Emission Model with FRP assimilation (3BEM_FRP) and the Global Fire Assimilation System (GFAS) are examples of the latter. These four biomass burning emission inventories were used during the South American Biomass Burning Analysis (SAMBBA) field campaign. This paper analyzes and inter-compared them, focusing on eight regions in Brazil and the time period of 1 September–31 October 2012. Aerosol optical thickness (AOT550 nm) derived from measurements made by the Moderate Resolution Imaging Spectroradiometer (MODIS) operating on board the Terra and Aqua satellites is also applied to assess the inventories' consistency. The daily area-averaged pyrogenic carbon monoxide (CO) emission estimates exhibit significant linear correlations (r, p  >  0.05 level, Student t test) between 3BEM and FINN and between 3BEM_ FRP and GFAS, with values of 0.86 and 0.85, respectively. These results indicate that emission estimates in this region derived via similar methods tend to agree with one other. However, they differ more from the estimates derived via the alternative approach. The evaluation of MODIS AOT550 nm indicates that model simulation driven by 3BEM and FINN typically underestimate the smoke particle loading in the eastern region of Amazon forest, while 3BEM_FRP estimations to the area tend to overestimate fire emissions. The daily regional CO emission fluxes from 3BEM and FINN have linear correlation coefficients of 0.75–0.92, with typically 20–30 % higher emission fluxes in FINN. The daily regional CO emission fluxes from 3BEM_FRP and GFAS show linear correlation coefficients between 0.82 and 0.90, with a particularly strong correlation near the arc of deforestation in the Amazon rainforest. In this region, GFAS has a tendency to present higher CO emissions than 3BEM_FRP, while 3BEM_FRP yields more emissions in the area of soybean expansion east of the Amazon forest. Atmospheric aerosol optical thickness is simulated by using the emission inventories with two operational atmospheric chemistry transport models: the IFS from Monitoring Atmospheric Composition and Climate (MACC) and the Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modelling System (CCATT-BRAMS). Evaluation against MODIS observations shows a good representation of the general patterns of the AOT550 nm time series. However, the aerosol emissions from fires with particularly high biomass consumption still lead to an underestimation of the atmospheric aerosol load in both models.

scholarly journals Sensitivity of tropospheric loads and lifetimes of short lived pollutants to fire emissions

2015 ◽  
Vol 15 (6) ◽  
pp. 3543-3563 ◽  
Author(s):  
N. Daskalakis ◽  
S. Myriokefalitakis ◽  
M. Kanakidou
Keyword(s):  
Biomass Burning ◽  
Atmospheric Transport ◽  
Feedback Mechanism ◽  
Oxidation Products ◽  
Atmospheric Composition ◽  
Secondary Aerosol ◽  
Fire Emissions ◽  
Calculated Load ◽  
Isoprene Oxidation ◽  
Aerosol Emissions

Abstract. The capability of global chemistry and transport models (CTMs) to simulate atmospheric composition and its spatial and temporal changes highly relies on the input data used by the models, in particular the emission inventories. Biomass burning emissions show large spatial, diurnal, seasonal and year-to-year variability. In the present study, we applied a global 3-D CTM to evaluate uncertainties in the computed atmospheric composition associated with the use of different biomass burning emissions and identify areas where observational data can help to reduce these uncertainties. We find the emission inventory choice to lead to regional differences in the calculated load of aerosols up to a factor of 4. Assumptions on the injection height of the biomass burning emissions are found to produce regionally up to 30% differences in the calculated tropospheric lifetimes of pollutants. Computed changes in lifetimes point to a strong chemical feedback mechanism between emissions from biomass burning and isoprene emissions from vegetation that are linked via NOx-driven oxidant chemistry, NOx-dependent changes in isoprene oxidation products, aerosol emissions and atmospheric transport. These interactions reduce isoprene load in the presence of biomass burning emissions by 15%, calculated for the same amount of isoprene emitted into the troposphere. Thus, isoprene load and lifetime are inversely related to the quantities of pollutants emitted by biomass burning. These interactions are shown to be able to increase the global annual secondary aerosol yield from isoprene emissions, defined as the ratio of tropospheric loads of secondary aerosol from isoprene oxidation to isoprene emissions, by up to 18%.

scholarly journals Assessment of fire emissions inventories during the South American Biomass Burning Analysis (SAMBBA) experiment

2016 ◽  
Author(s):  
G. Pereira ◽  
R. Siqueira ◽  
N. E. Rosário ◽  
K.L. Longo ◽  
S .R. Freitas ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Correlation Coefficient ◽  
Biomass Burning ◽  
Trace Gases ◽  
Amazon Forest ◽  
South American ◽  
Emission Model ◽  
The South ◽  
Fire Emissions ◽  
Emissions Inventories

Abstract. Fires associated with land use and land cover changes release into the atmosphere large amounts of aerosols and trace gases. Although there are several inventories of biomass burning emissions covering Brazil, there are still considerable uncertainties and differences among these. While most fire emissions inventories still utilize the parameters of vegetation fuel load, emission factors and other parameters to estimate the biomass burned and its associated emissions, certain more recent inventories tend to apply an alternative method based on fire radiative power (FRP) observations to estimate the amount of biomass burned and the corresponding emissions of trace gases and aerosols. The Brazilian Biomass Burning Emission Model (3BEM) and Fire Inventory from NCAR (FINN) are examples of the first, while Brazilian Biomass Burning Emission Model with FRP assimilation (3BEM_FRP) and Global Fire Assimilation System (GFAS) are examples of the latter method mentioned. In this paper, the output of four biomass burning emission inventories used during the South American Biomass Burning Analysis (SAMBBA) field campaign are analyzed and intercompared, focusing on eight predefined grids. Aerosol optical thickness derived from measurements made by the MODIS sensor operating onboard the Aqua satellite is applied to assess the inventories consistency. Significant correlation coefficients (r, p>0.05 level, Student t-test) were found between 3BEM and FINN, and between 3BEM_FRP and GFAS, with approximately 0.86 and 0.85, respectively. These results indicate that emissions estimates in this region derived via similar methods tend to agree with one other, but differ more from the estimates derived via the alternative approach. However, correlations in specific grids indicate that 3BEM and FINN typically underestimated the smoke emission loading in the eastern region of Amazon Forest, whilst 3BEM_FRP presents a tendency to overestimate fire emissions in the same area. The relationship between the 3BEM and FINN fire inventories present a correlation coefficient of 0.75-0.92, with a tendency of FINN to overestimate the emission of carbon monoxide by 20-30%. Moreover, 3BEM and GFAS shows a correlation coefficient of between 0.75-0.85, with higher values near the arc of deforestation in Amazon Rainforest. However, GFAS has a tendency to present higher carbon monoxide emissions in this region, and 3BEM_FRP tends to overestimate the emissions in soybean expansion (east of Amazon forest).

scholarly journals Ground based aerosol characterization during the South American Biomass Burning Analysis (SAMBBA) field experiment

2014 ◽  
Vol 14 (8) ◽  
pp. 12279-12322 ◽  
Author(s):  
J. Brito ◽  
L. V. Rizzo ◽  
W. T. Morgan ◽  
H. Coe ◽  
B. Johnson ◽  
...  
Keyword(s):  
Surface Layer ◽  
Field Experiment ◽  
Biomass Burning ◽  
Weather Prediction ◽  
Organic Aerosol ◽  
Average Concentration ◽  
Amazon Forest ◽  
South American ◽  
The South ◽  
A Site

Abstract. This paper investigates the physical and chemical characteristics of aerosols at ground level at a site heavily impacted by biomass burning. The site is located near Porto Velho, Rondônia, in the Southwestern part of the Brazilian Amazon forest, and was selected for the deployment of a large suite of instruments, among them an Aerosol Chemical Speciation Monitor. Our measurements were made during the South American Biomass Burning Analysis (SAMBBA) field experiment, which consisted of a combination of aircraft and ground based measurements over Brazil, aiming to investigate the impacts of biomass burning emissions on climate, air quality, and numerical weather prediction over South America. The campaign took place during the dry season and the transition to the wet season in September/October 2012. During most of the campaign, the site was impacted by regional biomass burning pollution (average CO mixing ratio of 0.6 ppm), occasionally superimposed by intense (up to 2 ppm of CO), freshly emitted biomass burning plumes. Aerosol number concentrations ranged from ∼1000 cm−3 to peaks of up to 35 000 cm−3 during biomass burning (BB) events, corresponding to an average submicron mass mean concentrations of 13.7 μg m−3 and peak concentrations close to 100 μg m−3. Organic aerosol strongly dominated the submicron non-refractory composition, with an average concentration of 11.4 μg m−3. The inorganic species, NH4, SO4, NO3, and Cl, were observed on average at concentrations of 0.44, 0.34, 0.19, and 0.01 μg m−3, respectively. Equivalent Black Carbon (BCe) ranged from 0.2 to 5.5 μg m−3, with an average concentration of 1.3 μg m−3. During BB peaks, organics accounted for over 90% of total mass (submicron non-refractory plus BCe), among the highest values described in the literature. We examined the ageing of Biomass Burning Organic Aerosol (BBOA) using the changes in the H : C and O : C ratios, and found that throughout most of the aerosol processing (O : C ≅ 0.25 to O : C ≅ 0.6), no remarkable change is observed in the H : C ratio (∼1.35). Such a result contrasts strongly with previous observations of chemical ageing of both urban and Amazonian biogenic aerosols. At higher levels of processing (O : C>0.6), the H : C ratio changes with a H : C / O : C slope of −0.5, possibly due to the development of a combination of BB (H : C / O : C slope = 0) and biogenic (H : C / O : C slope = −1) OA. An analysis of the ΔOA / ΔCO mass ratios yields very little enhancement in the OA loading with atmospheric processing, consistent with previous observations. These results indicate that negligible Secondary Organic Aerosol (SOA) formation occurs throughout the observed BB plume processing, or that SOA formation is almost entirely balanced by OA volatilization. Positive Matrix Factorization of the organic aerosol spectra resulted in three factors: Fresh BBOA, Aged BBOA and Low-Volatility Oxygenated Organic Aerosol (LV-OOA). Analysis of the diurnal patterns and correlation with external markers indicates that during the first part of the campaign OA concentrations are impacted by local fire plumes with some chemical processing occurring in the near-surface layer. During the second part of the campaign, long-range transport of BB plumes above the surface layer, as well as potential SOAs formed aloft, dominates OA concentrations at our ground-based sampling site. This manuscript describes the first ground-based deployment of aerosol mass spectrometry at a site heavily impacted by biomass burning in the Amazon region, allowing a deeper understanding of aerosol life cycle in this important ecosystem.

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