Development of numerical tools for characterizing and quantifying biomass cookstove impact, The

2013 Summer.Includes bibliographical references.Biomass cookstove use can be damaging to both human health and the global climate. In an effort to minimize these impacts, numerous programs are working to disseminate improved biomass cookstoves. However, few programs have achieved extensive success towards improving either climate or health. One reason programs have only resulted in limited improvements has been the sector's inability to quantify cookstove performance. A numeric tool has been developed for characterizing biomass cookstove performance. This dissertation documents the development of that tool. The document is comprised of three components: (i) the critical analysis of the uncertainty associated with current methods for cookstove field-testing, (ii) the development and validation of a probabilistic impact model for biomass cookstoves, and (iii) the application of these numerical tools to quantify cookstove impact. Biomass cookstoves have traditionally been evaluated empirically. Cookstoves are tested in both the field and the laboratory, with each approach having advantages and limitations. Neither laboratory nor field testing are sufficient, however, for quantifying cookstove impact. Field-testing provides invaluable data on cookstove use but is limited by the large variability typically seen in the results. Drawing conclusions from field tests is challenging due to this variability. Many groups attempt to address testing variability by increasing the number of test replicates conducted. A numeric model was developed to determine the number of test replicates required to quantify cookstove performance in field settings. Because of the large number of test replicates required to have statistical confidence in field-based data, an improved method of quantifying biomass cookstove performance is needed. Therefore, to address this need a probabilistic Monte Carlo prediction model was developed to quantify cookstove performance. The intention of the model is to serve as a tool for predicting the impact of various cookstove designs. The model integrates various facets of existing cookstove performance knowledge in more a cohesive fashion. Model simulations were compared to experimental studies to validate this approach. Numeric tools are only valuable if they result in useful information; for example, information that allows informed decisions to be made. The potential of numeric models to provide valuable information for cookstove programs has been demonstrated by simulating the performance of multiple cookstove designs. Three improved cookstoves designs have been compared to a traditional three-stone fire. Each design was evaluated for multiple scenarios, use patterns, and locations. The impact of each design (in regard to climate and health) was then quantified and monetized. This exercise yielded two important findings. First, consideration of location and context is critical when comparing the performance of cookstoves. Second, numeric models can be used as highly informative tools to support decision-making in the cookstove sector. Empirical testing is necessary for most technical programs; this is especially true for cookstoves projects. There are aspects of cookstove designs that can only be evaluated experimentally. Examples include whether an individual likes the cookstove, or if the design is appropriate for the specific cooking requirements of a particular community. Physical testing is needed to answer some basic questions such as: Do users find the cookstove intuitive to use? Do they like the color? However, empirical testing is not well-suited to answer every question related to cookstove performance. For example, comparing the climate impact of different cookstove designs is difficult in the field. The work presented demonstrates the potential of numerical models to provide invaluable information to the cookstove sector. The development and validation of these models has been documented. These models can help quantify the impact of current designs and help guide the development of future cookstove programs

Uncertainties in global aerosols and climate effects due to biofuel emissions

Aerosol emissions from biofuel combustion impact both health and climate; however, while reducing emissions through improvements to combustion technologies will improve health, the net effect on climate is largely unconstrained. In this study, we examine sensitivities in global aerosol concentration, direct radiative climate effect, and cloud-albedo aerosol indirect climate effect to uncertainties in biofuel emission factors, optical mixing state, and model nucleation and background secondary organic aerosol (SOA). We use the Goddard Earth Observing System global chemical-transport model (GEOS-Chem) with TwO Moment Aerosol Sectional (TOMAS) microphysics. The emission factors include amount, composition, size, and hygroscopicity, as well as optical mixing-state properties. We also evaluate emissions from domestic coal use, which is not biofuel but is also frequently emitted from homes. We estimate the direct radiative effect assuming different mixing states (homogeneous, core-shell, and external) with and without absorptive organic aerosol (brown carbon). We find the global-mean direct radiative effect of biofuel emissions ranges from −0.02 to +0.06 W m−2 across all simulation/mixing-state combinations with regional effects in source regions ranging from −0.2 to +0.8 W m−2. The global-mean cloud-albedo aerosol indirect effect (AIE) ranges from +0.01 to −0.02 W m−2 with regional effects in source regions ranging from −1.0 to −0.05 W m−2. The direct radiative effect is strongly dependent on uncertainties in emissions mass, composition, emissions aerosol size distributions, and assumed optical mixing state, while the indirect effect is dependent on the emissions mass, emissions aerosol size distribution, and the choice of model nucleation and secondary organic aerosol schemes. The sign and magnitude of these effects have a strong regional dependence. We conclude that the climate effects of biofuel aerosols are largely unconstrained, and the overall sign of the aerosol effects is unclear due to uncertainties in model inputs. This uncertainty limits our ability to introduce mitigation strategies aimed at reducing biofuel black carbon emissions in order to counter warming effects from greenhouse gases. To better understand the climate impact of particle emissions from biofuel combustion, we recommend field/laboratory measurements to narrow constraints on (1) emissions mass, (2) emission size distribution, (3) mixing state, and (4) ratio of black carbon to organic aerosol

A conceptual framework for evaluating cooking systems

PUBLISHED 7 March 2022Tami C Bond, Christian L, Orange, Paul R Medwell, George Sizoomu, Samer Abdelnour, Verena Brinkmann, Philip Lloyd and Crispin Pemberton-Pigot

Interventionen in Reallaboren : ein Handbuch für die Praxis

Für eine nachhaltige Entwicklung unserer Gesellschaft haben lokale Initiativen und deren innovativen Aktivitäten eine grosse Bedeutung. Eine systematische Beobachtung und Begleitung durch die Forschung kann dabei helfen, aus den Initiativen zu lernen, andernorts Ähnliches anzustossen und somit eine breitere Wirkung zu entfalten. Orte, wo eine solche Zusammenarbeit von lokalen Initiativen, anderen Praxisakteuren und Forschenden für eine nachhaltige Entwicklung stattfindet, sind sogenannte „Reallabore“. Das Anstossen, Durchführen und systematische Beobachten und Analysieren von konkreten Interventionen und deren praktische Umsetzung bilden den Schwerpunkt dieses Handbuchs. Es ist als ein Hauptprodukt des Reallabors im Hunziker Areal in Zusammenarbeit mit vielen anderen Reallabor-Forschenden aus Deutschland und der Schweiz entstanden

A novel root-to-shoot stomatal response to very high CO2 levels in the soil: electrical, hydraulic and biochemical signalling

Investigations were undertaken in the context of the potential environmental impact of Carbon Capture and Storage (CCS) transportation in the form of a hypothetical leak of extreme levels of CO2 into the soil environment and subsequent effects on plant physiology. Laboratory studies using purpose built soil chambers, separating and isolating the soil and aerial environments, were used to introduce high levels of CO2 gas exclusively into the rhizosphere. CO2 concentrations greater than 32% in the isolated soil environment revealed a previously unknown whole plant stomatal response. Time course measurements of stomatal conductance, leaf temperature and leaf abscisic acid show strong coupling between all three variables over a specific period (3 hrs following CO2 gassing) occurring as a result of CO2-specific detection by roots. The coupling of gs and ABA subsequently breaks down resulting in a rapid and complete loss of turgor in the shoot. Root access to water is severely restricted as evidenced by the inability to counter turgor loss, however the plant regains some turgor over time. Recovery of full turgor is not achieved over the longer term. Results suggest an immediate perception and whole plant response as changes in measured parameters (leaf temperature, gs and ABA) occur in the shoot, but the response is solely due to detection of very high CO2 concentration at the root/soil interface which results in loss of stomatal regulation and disruption to control over water uptake

An evaluation of a biomass stove safety protocol used for testing household cookstoves, in low-middle income countries

To mitigate the impact of: excess pollution, deforestation and injuries attributable to cookstoves in low-middle income countries, humanitarian and private sector organisations have made a commitment to distribute 100 million improved cookstoves (ICS) by 2020. In order to evaluate the safety of these ICS for the end users, a ten test ‘Biomass Stove Safety Protocol’ (BSSP) has been developed by the Global Alliance for Clean Cookstoves (GACC). However, there is no published evidence that this protocol has been independently assessed or benchmarked. This study aimed to determine whether the BSSP is fit for purpose such that, it will produce repeatable safety ratings for a range of cookstoves when performed by different testers. Results indicated that the scores for each stove varied considerably between each of the six testers with only one of five ICS receiving the same overall safety rating. While individually some tests produced relatively coherent scores, others led to large discrepancies. We conclude that although BSSP is an important starting point in highlighting the need for stove safety assessment, there are some aspects of the protocol that require further development to ensure that it can be reliably replicated by different testers