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The smoke rising from a cookstove fills the air with thetantalizing aroma of dinner - and a cloud of pollutants andparticles that threaten both health and the environment. Howfamilies in developing countries use their cookstoves has a bigeffect on emissions from those stoves, and laboratory emissiontests don't accurately reflect real-world operations, according toa study by University of Illinois researchers. Biomass-burning cookstoves are used throughout the developingworld, using wood, agricultural waste and other organic matter asfuel. They are also a major cause of poor air quality in theregions where use is prevalent. Policymakers and nonprofitorganizations are working to develop and distribute "improved"cookstoves, for example, adding insulation or chimneys to reduceemissions. They are especially concerned with fine particles thatare emitted, which cause health problems and also affect climate. Much like automobiles undergo emission testing before hitting themarket, cookstoves are tested in the lab before distribution togauge how effective improvements are at reducing emissions. But ifthe conditions aren't the same as how people use them at home, thenthe changes that designers make to the stove may not actuallyreduce emissions in the field. "The understanding of how people really use combustion devices isimportant if we're going to optimize that device," said studyleader Tami Bond, a professor of civil and environmentalengineering at U. of I. "In the laboratory, where tests areconducted by trained people, there's a lot more attention tooperating the stove carefully. At home, people are not as concernedwith its operation; they're more concerned with making a meal. Sothey operate in ways that are non-optimal." However, these variations in use are masked by the current methodsof testing, which use only average values to determine emissions -sort of like a snapshot of the stove in operation, not accountingfor variation in use. Bond's team developed a real-time analysistechnique called Patterns of Real-Time Emissions Data (PaRTED) thatallows researchers to compare emissions under different operatingconditions and to measure how often a stove operates under certainconditions in the field. "Wood burning is like a dance," Bond said. "A movie gives you abetter understanding than a photograph. This is a way to makemovies of how users change as they make fires, and that can helppeople understand emission rates and make better stoves." Using PaRTED, Bond's team tested cookstoves in use in a village inHonduras and compared the field results to lab results. Theresearchers found that operation under less-than-ideal conditionsproduces the highest emissions. They also found that in the field,stoves are rarely used under optimal conditions, a scenario notreproduced in laboratory tests. The team compared emission profiles, or the chemical makeup of thesmoke, from traditional cookstoves and two types of improvedstoves: insulated stoves and stoves with chimneys. They found thatalthough stoves with an insulated combustion chamber could increaseoverall efficiency, they did not significantly reduce emissions permass of fuel burned. Chimneys did reduce certain types of particleemissions - but chimneys did not cut down on black particles, thetype most harmful to climate. "Our measurements confirm that changes in stove design cause achange in the way they operate," Bond said. "I think people weren'taware that changes in design actually change the profile of theemissions rather than just reducing emissions." Next, the researchers will use PaRTED analysis to study variationsin cookstove use in different regions of the world. Bond hopes thatPaRTED and this study will inform future testing protocols forcookstoves in the lab, enabling researchers to more accurately testunder realistic conditions and providing insight into a whole rangeof possible use scenarios. "Insulated and chimneyed stoves are a step in the right direction,but not as far as we need to go to get really clean stoves," Bondsaid. "The next step is to identify both the patterns of stoveoperation and the factors that lead to the characteristic profileof operation so that those can be brought into the lab andoptimized. The cookstove world is moving toward having emissionstandards. It would be best if those standards were relevant toreal operations." The researchers published their study in the journal EnvironmentalScience and Technology. The National Science Foundation and theEnvironmental Protection Agency supported this work. Postdoctoralresearch associate Yanju Chen and Bond group alumnus ChristophRoden were co-authors of the paper. The e-commerce company in China offers quality products such as Atom Mini PC , Touch Screen Tablet Notebook Manufacturer, and more. For more , please visit Portable Ebook Reader today!
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