scholarly journals Highly-controlled, reproducible measurements of aerosol emissions from African biomass combustion

2017 ◽  
Author(s):  
Sophie L. Haslett ◽  
J. Chris Thomas ◽  
William T. Morgan ◽  
Rory Hadden ◽  
Dantong Liu ◽  
...  
Keyword(s):  
Black Carbon ◽  
Thermal Environment ◽  
Organic Aerosol ◽  
Biomass Combustion ◽  
Particulate Emissions ◽  
Radiative Balance ◽  
Mass Spectral ◽  
Aerosol Emission ◽  
Flaming Combustion ◽  
Aerosol Emissions

Abstract. Particulate emissions from biomass burning can both alter the atmosphere's radiative balance and cause significant harm to human health. However, due to the large effect on emissions caused by even small alterations to the way in which a fuel burns, it is difficult to study particulate production of biomass combustion mechanistically and in a repeatable manner. In order to address this gap, in this study, small wood samples sourced from Côte D'Ivoire in West Africa were burned in a highly-controlled laboratory environment. The shape and mass of samples, available airflow and surrounding thermal environment were carefully regulated. Organic aerosol and refractory black carbon emissions were measured in real time using an Aerosol Mass Spectrometer and a Single Particle Soot Photometer, respectively. This methodology produced remarkably repeatable results, allowing aerosol emissions to be mapped directly onto different phases of combustion. Emissions from pyrolysis were visible as a distinct phase before flaming was established. After flaming combustion was initiated, a black-carbon-dominant flame was observed during which very little organic aerosol was produced, followed by a period that was dominated by organic-carbon-producing smouldering combustion, despite the presence of residual flaming. During pyrolysis and smouldering, the two phases producing organic aerosol, distinct mass spectral signatures that correspond to previously-reported variations in biofuel emissions measured in the atmosphere are found. Organic aerosol emission factors averaged over an entire combustion event were found to be representative of the time spent in the pyrolysis and smouldering phases, rather than reflecting a coupling between emissions and the mass loss of the sample. Further exploration of aerosol yields from similarly carefully controlled fires and a careful comparison with data from macroscopic fires and real-world emissions will help to deliver greater constraints on variability of particulate emissions in atmospheric systems.

scholarly journals Highly controlled, reproducible measurements of aerosol emissions from combustion of a common African biofuel source

2018 ◽  
Vol 18 (1) ◽  
pp. 385-403 ◽  
Author(s):  
Sophie L. Haslett ◽  
J. Chris Thomas ◽  
William T. Morgan ◽  
Rory Hadden ◽  
Dantong Liu ◽  
...  
Keyword(s):  
Black Carbon ◽  
Thermal Environment ◽  
Organic Aerosol ◽  
Biomass Combustion ◽  
Particulate Emissions ◽  
Radiative Balance ◽  
Mass Spectral ◽  
Aerosol Emission ◽  
Flaming Combustion ◽  
Aerosol Emissions

Abstract. Particulate emissions from biomass burning can both alter the atmosphere's radiative balance and cause significant harm to human health. However, due to the large effect on emissions caused by even small alterations to the way in which a fuel burns, it is difficult to study particulate production of biomass combustion mechanistically and in a repeatable manner. In order to address this gap, in this study, small wood samples sourced from Côte D'Ivoire in West Africa were burned in a highly controlled laboratory environment. The shape and mass of samples, available airflow and surrounding thermal environment were carefully regulated. Organic aerosol and refractory black carbon emissions were measured in real time using an Aerosol Mass Spectrometer and a Single Particle Soot Photometer, respectively. This methodology produced remarkably repeatable results, allowing aerosol emissions to be mapped directly onto different phases of combustion. Emissions from pyrolysis were visible as a distinct phase before flaming was established. After flaming combustion was initiated, a black-carbon-dominant flame was observed during which very little organic aerosol was produced, followed by a period that was dominated by organic-carbon-producing smouldering combustion, despite the presence of residual flaming. During pyrolysis and smouldering, the two phases producing organic aerosol, distinct mass spectral signatures that correspond to previously reported variations in biofuel emissions measured in the atmosphere are found. Organic aerosol emission factors averaged over an entire combustion event were found to be representative of the time spent in the pyrolysis and smouldering phases, rather than reflecting a coupling between emissions and the mass loss of the sample. Further exploration of aerosol yields from similarly carefully controlled fires and a careful comparison with data from macroscopic fires and real-world emissions will help to deliver greater constraints on the variability of particulate emissions in atmospheric systems.

Investigating model nudging as a novel technique to isolate aerosol radiative adjustment mechanisms

2021 ◽  
Author(s):  
Max Coleman ◽  
William Collins ◽  
Keith Shine ◽  
Nicolas Bellouin ◽  
Fiona O'Connor
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
Potential Temperature ◽  
Atmospheric Temperature ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Aerosol Emission ◽  
Aerosol Emissions ◽  
Adjustment Mechanisms

<p>We investigate a novel use of model nudging to interrogate radiative rapid adjustment mechanisms and their magnitudes in response to aerosol emission perturbations in an earth system model. The radiative effects of a forcing agent can be quantified using the effective radiative forcing (ERF). ERF is the sum of the instantaneous radiative forcing, and radiative adjustments – changes in the atmosphere’s state in response to the initial forcing agent that cause a further radiative forcing. Radiative adjustments are particularly important for aerosols, which affect clouds both via microphysical interactions and changes in circulation, stratification and convection. Understanding the different adjustment mechanisms and their contribution to the total ERF of different aerosol emissions is necessary to better understand how their ERF may change with future changes in anthropogenic aerosol emissions. In this work we investigate radiative adjustments resulting from changes in atmospheric temperature (and the resulting changes in stratification and convection) due to anthropogenic sulphate and black carbon aerosol forcing.</p><p>We have conducted multiple global atmosphere-only time-slice experiments using the UK Earth System Model (UKESM1). Each experiment has either control, black carbon perturbed, or sulphur dioxide perturbed emissions; and either no nudging, nudged horizontal winds (uv), or nudged horizontal winds and potential temperature (uvθ). The difference between nudged uvθ minus nudged uv simulations determines the atmospheric temperature related adjustments arising from the aerosol perturbation. We have also conducted repeats of each simulation, varying the nudging setup to test sensitivity to different nudging parameters.</p><p>We find that nudging horizontal winds affects the resulting ERF very little, whereas nudging potential temperature as well can cause a significant difference from the non-nudged experiments, primarily in the cloud radiative effect. However, this difference is sensitive to the strength of the nudging applied, for which we consider the most appropriate value.</p>

scholarly journals Particulate emissions from residential wood combustion in Europe – revised estimates and an evaluation

2015 ◽  
Vol 15 (11) ◽  
pp. 6503-6519 ◽  
Author(s):  
H. A. C. Denier van der Gon ◽  
R. Bergström ◽  
C. Fountoukis ◽  
C. Johansson ◽  
S. N. Pandis ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Emission Inventory ◽  
Organic Aerosol ◽  
Carbonaceous Aerosol ◽  
Small Scale ◽  
Particulate Emissions ◽  
Wood Combustion ◽  
Fuel Prices ◽  
Aerosol Emission ◽  
Winter Time

Abstract. Currently residential wood combustion (RWC) is increasing in Europe because of rising fossil fuel prices but also due to climate change mitigation policies. However, especially in small-scale applications, RWC may cause high emissions of particulate matter (PM). Recently we have developed a new high-resolution (7 × 7 km) anthropogenic carbonaceous aerosol emission inventory for Europe. The inventory indicated that about half of the total PM2.5 emission in Europe is carbonaceous aerosol and identified RWC as the largest organic aerosol source in Europe. The inventory was partly based on national reported PM emissions. Use of this organic aerosol inventory as input for two chemical transport models (CTMs), PMCAMx and EMEP MSC-W, revealed major underestimations of organic aerosol in winter time, especially for regions dominated by RWC. Interestingly, this was not universal but appeared to differ by country. In the present study we constructed a revised bottom-up emission inventory for RWC accounting for the semivolatile components of the emissions. The revised RWC emissions are higher than those in the previous inventory by a factor of 2–3 but with substantial inter-country variation. The new emission inventory served as input for the CTMs and a substantially improved agreement between measured and predicted organic aerosol was found. The revised RWC inventory improves the model-calculated organic aerosol significantly. Comparisons to Scandinavian source apportionment studies also indicate substantial improvements in the modelled wood-burning component of organic aerosol. This suggests that primary organic aerosol emission inventories need to be revised to include the semivolatile organic aerosol that is formed almost instantaneously due to dilution and cooling of the flue gas or exhaust. Since RWC is a key source of fine PM in Europe, a major revision of the emission estimates as proposed here is likely to influence source–receptor matrices and modelled source apportionment. Since usage of biofuels in small combustion units is a globally significant source, the findings presented here are also relevant for regions outside of Europe.

Light Absorption by Organic Aerosol Emissions Rivals That of Black Carbon from Residential Biomass Fuels in South Asia

2020 ◽  
Vol 7 (4) ◽  
pp. 266-272 ◽  
Author(s):  
Apoorva Pandey ◽  
Alice Hsu ◽  
Suresh Tiwari ◽  
Shamsh Pervez ◽  
Rajan K. Chakrabarty
Keyword(s):  
South Asia ◽  
Black Carbon ◽  
Light Absorption ◽  
Organic Aerosol ◽  
Biomass Fuels ◽  
Aerosol Emissions

scholarly journals An Inventory on Black Carbon and Organic Carbon Emission by the Different Vegetative Ecosystem Over India

2020 ◽  
Author(s):  
Karthik Venkatraman ◽  
Vijay Bhaskar ◽  
Amit Kesarkar
Keyword(s):  
Organic Carbon ◽  
Black Carbon ◽  
Waste Utilization ◽  
Carbonaceous Aerosol ◽  
Fire Season ◽  
Deposition Flux ◽  
Carbonaceous Aerosols ◽  
Potential Threat ◽  
Aerosol Emission ◽  
Aerosol Emissions

Abstract Fires provoke land degradation, deforestation, imbalance in the ecosystem, and promote changes in land use. To add more vein aerosols such as Black Carbon (BC) and Organic Carbon (OC) were emitted during the combustion event which plays a major role in climate change, pollution, and health. Hence this study aims to estimate the emission, residence, dry deposition flux, and sequestering ability of deposited BC and OC from different vegetative fires across India using MODIS satellite data from 2013 to 2019. It was observed that the mean OC and BC emission were about 5.08 × 107 tonnes 4.48 × 106 tonnes during the fire season across India. On a national scale, cropland fires contributed the largest portion (80%) of total carbonaceous aerosol emissions from open fires. In co-emission of species, forest shares a maximum relationship (> 92 percent) among carbonaceous aerosols. Estimation of deposition flux of emitted species showed cropland has higher deposition rates with a residence period ranging between 7hours to 23days. From the observed results, it is evident that higher aerosol emission combined with negligible deposition will be a potential threat to the environment. Waste utilization promoting strategies has to be adopted in India since agriculture contributes to major aerosols emission.

scholarly journals Particulate emissions from residential wood combustion in Europe – revised estimates and an evaluation

2014 ◽  
Vol 14 (23) ◽  
pp. 31719-31765 ◽  
Author(s):  
H. A. C. Denier van der Gon ◽  
R. Bergström ◽  
C. Fountoukis ◽  
C. Johansson ◽  
S. N. Pandis ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Emission Inventory ◽  
Organic Aerosol ◽  
Carbonaceous Aerosol ◽  
Small Scale ◽  
Volatile Components ◽  
Particulate Emissions ◽  
Wood Combustion ◽  
Aerosol Emission ◽  
Winter Time

Abstract. Currently residential wood combustion (RWC) is increasing in Europe because of rising fossil fuel prices but also due to climate change mitigation policies. However, especially in small-scale applications, RWC may cause high emissions of particulate matter (PM). Recently we have developed a new high-resolution (7 km × 7 km) anthropogenic carbonaceous aerosol emission inventory for Europe. The inventory indicated that about half of the total PM2.5 emission in Europe is carbonaceous aerosol and identified RWC as the largest organic aerosol (OA) source in Europe. The inventory was partly based on national reported PM emissions. Use of this OA inventory as input for two Chemical Transport Models (CTMs), PMCAMx and EMEP MSC-W, revealed major underestimations of OA in winter time, especially for regions dominated by RWC. Interestingly, this was not universal but appeared to differ by country. In the present study we constructed a new bottom-up emission inventory for RWC accounting for the semi-volatile components of the emissions. The new RWC emissions are higher than those in the previous inventory by a factor of 2–3 but with substantial inter-country variation. The new emission inventory served as input for the CTMs and a substantially improved agreement between measured and predicted organic aerosol was found. The new RWC inventory improves the model calculated OA significantly. Comparisons to Scandinavian source apportionment studies also indicate substantial improvements in the modeled wood-burning component of OA. This suggests that primary organic aerosol emission inventories need to be revised to include the semi-volatile OA that is formed almost instantaneously due to cooling of the flue gas or exhaust. Since RWC is a key source of fine PM in Europe, a major revision of the emission estimates as proposed here is likely to influence source-receptor matrices and modelled source apportionment. Since usage of biofuels, such as wood, in small combustion units is a globally significant source, this insight may also dramatically change global estimates of organic aerosol emissions.

scholarly journals Study of Temporal Variations of Equivalent Black Carbon in a Coastal City in Northwest Spain Using an Atmospheric Aerosol Data Management Software

2021 ◽  
Vol 11 (2) ◽  
pp. 516
Author(s):  
María Piñeiro-Iglesias ◽  
Javier Andrade-Garda ◽  
Sonia Suárez-Garaboa ◽  
Soledad Muniategui-Lorenzo ◽  
Purificación López-Mahía ◽  
...  
Keyword(s):  
Data Management ◽  
Black Carbon ◽  
Light Absorption ◽  
Atmospheric Aerosol ◽  
Urban Areas ◽  
Radiative Properties ◽  
Anthropogenic Sources ◽  
Biomass Combustion ◽  
Management Support ◽  
Diurnal Variability

Light-absorbing carbonaceous aerosols (including black carbon (BC)) pose serious health issues and play significant roles in atmospheric radiative properties. Two-year measurements (2015–2016) of aerosol light absorption, combined with measurements of sub-micrometric particles, were continuously conducted in A Coruña (northwest (NW) Spain) to determine their light absorption properties: absorption coefficients (σabs) and the absorption Ångström exponent (AAE). The mean and standard deviation of equivalent black carbon (eBC) during the period of study were 0.85 ± 0.83 µg m−3, which are lower than other values measured in urban areas of Spain and Europe. High eBC concentrations found in winter are associated with an increase in emissions from anthropogenic sources in combination with lower mixing layer heights and frequent stagnant conditions. The pronounced diurnal variability suggests a strong influence from local sources. AAE had an average value of 1.26 ± 0.22 which implies that both fossil fuel combustion and biomass burning influenced optical aerosol properties. This also highlights biomass combustion in suburban areas, where the use of wood for domestic heating is encouraged, as an important source of eBC. All data treatment was gathered using SCALA© as atmospheric aerosol data management support software program.

scholarly journals Sensitivity of the Single Particle Soot Photometer to different black carbon types

2012 ◽  
Vol 5 (5) ◽  
pp. 1031-1043 ◽  
Author(s):  
M. Laborde ◽  
P. Mertes ◽  
P. Zieger ◽  
J. Dommen ◽  
U. Baltensperger ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Diesel Exhaust ◽  
Mass Analyzer ◽  
Human Beings ◽  
Radiative Balance ◽  
Ambient Particles ◽  
Fullerene Soot ◽  
Wood Burning ◽  
Incomplete Removal

Abstract. Black carbon (BC) is now mainly of anthropogenic origin. It is the dominant light absorbing component of atmospheric aerosols, playing an important role in the earth's radiative balance and therefore relevant to climate change studies. In addition, BC is known to be harmful to human beings making it relevant to policy makers. Nevertheless, the measurement of BC remains biased by the instrument-based definition of BC. The Single Particle Soot Photometer (SP2), allows the measurement of the refractory BC (rBC) mass of individual particles using laser-induced incandescence. However, the SP2 needs an empirical calibration to retrieve the rBC mass from the incandescence signal and the sensitivity of the SP2 differs between different BC types. Ideally, for atmospheric studies, the SP2 should be calibrated using ambient particles containing a known mass of ambient rBC. However, such "ambient BC" calibration particles cannot easily be obtained and thus commercially available BC particles are commonly used for SP2 calibration instead. In this study we tested the sensitivity of the SP2 to different BC types in order to characterize the potential error introduced by using non-ambient BC for calibration. The sensitivity of the SP2 was determined, using an aerosol particle mass analyzer, for rBC from thermodenuded diesel exhaust, wood burning exhaust and ambient particles as well as for commercially available products: Aquadag® and fullerene soot. Thermodenuded, fresh diesel exhaust has been found to be ideal for SP2 calibration for two reasons. First, the small amount of non-BC matter upon emission reduces the risk of bias due to incomplete removal of non-BC matter and second, it is considered to represent atmospheric rBC in urban locations where diesel exhaust is the main source of BC. The SP2 was found to be up to 16% less sensitive to rBC from thermodenuded ambient particles (≤15 fg) than rBC from diesel exhaust, however, at least part of this difference can be explained by incomplete removal of non-refractory components in the thermodenuder. The amount of remaining non-refractory matter was estimated to be below 30% by mass, according to a comparison of the scattering cross sections of the whole particles with that of the pure BC cores. The SP2 sensitivity to rBC from wood burning exhaust agrees with the SP2 sensitivity to rBC from diesel exhaust within an error of less than 14% (≤40 fg). If, due to experimental restrictions, diesel exhaust cannot be used, untreated fullerene soot was found to give an SP2 calibration curve similar to diesel exhaust and ambient rBC (within ±10% for a rBC mass ≤15 fg) and is therefore recommended although two different batches differed by ~14% between themselves. In addition, the SP2 was found to be up to 40% more sensitive to Aquadag® than to diesel exhaust rBC. Therefore Aquadag® cannot be recommended for atmospheric application without accounting for the sensitivity difference. These findings for fullerene soot and Aquadag® confirm results from previous literature.

The local and remote atmospheric impacts of Africa’s 21st century aerosol emission trajectory

2021 ◽  
Author(s):  
Chris Wells ◽  
Apostolos Voulgarakis
Keyword(s):  
Regional Climate ◽  
Emission Region ◽  
Anthropogenic Aerosol ◽  
Remote Locations ◽  
Aerosol Emission ◽  
Radiation Fluxes ◽  
The World ◽  
Aerosol Emissions ◽  
The Impact ◽  
Lower Biomass

<p>Aerosols are a major climate forcer, but their historical effect has the largest uncertainty of any forcing; their mechanisms and impacts are not well understood. Due to their short lifetime, aerosols have large impacts near their emission region, but they also have effects on the climate in remote locations. In recent years, studies have investigated the influences of regional aerosols on global and regional climate, and the mechanisms that lead to remote responses to their inhomogeneous forcing. Using the Shared Socioeconomic Pathway scenarios (SSPs), transient future experiments were performed in UKESM1, testing the effect of African emissions following the SSP3-RCP7.0 scenario as the rest of the world follows SSP1-RCP1.9, relative to a global SSP1-RCP1.9 control. SSP3 sees higher direct anthropogenic aerosol emissions, but lower biomass burning emissions, over Africa. Experiments were performed changing each of these sets of emissions, and both. A further set of experiments additionally accounted for changing future CO<sub>2</sub> concentrations, to investigate the impact of CO<sub>2</sub> on the responses to aerosol perturbations. Impacts on radiation fluxes, temperature, circulation and precipitation are investigated, both over the emission region (Africa), where microphysical effects dominate, and remotely, where dynamical influences become more relevant. </p>

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