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edit this page How many of these improvements are in your stoves programme?
Autres interventions que sur les foyers afin d'améliorer la qualité de l'air
Dans cet article, l'auteur identifie différentes solutions visant à réduire les émissions de fumée résultant de la cuisson avec les bio-combustibles, Hormis les foyers améliorés, d'autres options existent et pourraient même être plus efficaces que l'adoption de foyers améliorés. Cinq types d'interventions sont listées avec leurs avantages et inconvénients: autres équipements de cuisson, autres formes d'énergie, amélioration de la ventilation, action sur les besoins, comportement des usagers. |
Poverty deprives people of choice. They lack the power to make their lives better and are confined to repeating behaviour that they frequently know to be detrimental to their well-being. I remember visiting an elderly grandmother living in a poverty stricken part of South Africa. I watched her prepare the midday meal over an open fire built in the middle of the floor in one room of her house. After a few minutes of exposure to the smoke my eyes started to water and I rushed to the door to breathe some fresh air. 'See how we suffer!' the grandmother declared to me. I could not understand, so I asked: 'But why do you cook indoors?'. She replied: The sun's bright and it's too hot outside'. This response helped me realise that human behaviour is far more complicated than we often suppose. The reply is difficult for me to understand - why not build an outside shelter from the sun, open to the air, with a small wind-break so the fire burns steadily?
I have gradually come to realise that, for one reason or another, there are legitimate barriers to actions that seem obvious to me (conceptual, social, practical, and economic obstacles for instance). Identifying options and helping people to overcome the barriers, I believe, is one of the main tasks of a development organisation. Development in my opinion is all about empowering people.  Figure 1: An area near Johannesburg in South Africa: steam rises from the power station while non-electrified houses are trapped in a sea of smoke from coal stoves. The power station towers penetrate the temperature inversion and therefore the steam rises whereas the smoke from the houses is trapped |
With this in mind, a number of alternatives available to development organisations for reducing exposure to emissions from cooking are listed. It is easy to see emission reductions as merely a matter of disseminating improved stoves when, in reality, there are many options; some of which may be more cost effective than stoves. Interventions can be divided into five groups: - alternative cooking devices
- alternative fuels
- improved ventilation
- reduced need for the fire
- alternative behaviour
Some of these suggestions may seem radical, but they may spark off other ideas and thus serve their purpose. How many of these are elements of your stove programme?
[top] [end]Alternative cooking devices | Improved cooker with lower emissions | Some improved cookers have lower emissions than traditional cooking fires (but many 'improved' stoves do not). A simple improved cooking device can be made by lifting the traditional 'three-stone' fire on a grate. This simple intervention reduced emissions and improves efficiency. Improved stove designs should always be tested to check whether they do indeed have lower emissions than the traditional methods of cooking. | | 'Wonder' box | This is an insulated box into which a hot pot of food is placed. The insulation keeps the food cooking slowly for hours without any additional fuel. Great idea but it has not found favour in many areas, probably because it requires a complete change in cooking culture. | | Stove with chimney | Chimneys remove emissions from the room and are therefore a great addition to an improved stove. But in some areas smoke gets trapped in villages that are built in valleys and then comes straight in through the door or windows. | | Waist high cooker | Lifting the cooking surface from ground level means that a cook does not need to lean over a fire while tending it and attending to the food, and so she breathes in less smoke. |
| Charcoal | Charcoal has substantially lower emissions than 'raw' wood. However a lot of fuel can be wasted (leading to deforestation and fuel shortages) if the charcoal is produced inefficiently. It is possible, though, to make charcoal efficiently without losing all the energy released during production. | | Kerosene | Paraffin has lower carbon monoxide and smoke emissions than wood when burned in a well adjusted cooker or lamp. Drawbacks include the risk of poisoning from children drinking it. | | Bottled gas | The expense of appliances and fuel is the main barrier to this option to the use of bottled gas. But the fuel is very clean and efficient. Government subsidies could enhance acceptance especially in urban areas. | | Biogas | This is gas produced by the anaerobic digestion of dung. Requires a reasonable number of cattle (or a steady supply of dung), a source of water, and some fairly expensive equipment. But a reasonably clean fuel. | | Solar-thermal | Solar cooking seems the ideal solution - clean and free. But appliances are frequently costly, complex and inconvenient (often requiring the user to cook under the midday sun while looking into a shiny glare - especially a problem where culture/tastes require food to be stirred continuously). | | Low smoke fuel | Low smoke coal or wax/wood/waste paper substitute fuels could be an improvement to wood or coal but careful testing of these fuels to see whether they do indeed have lower emissions is necessary. The paper/wax idea is being seriously explored in South Africa, particularly for use in non-electrified urban communities. Cost and social acceptance could also be limitations. | | Gas from wood | Gas can be made from wood by burning it with too little oxygen - it could feasibly be piped from a central location to a number of houses. The fuel is largely made up of carbon monoxide which is poisonous, so the appliances need to be designed carefully, and the users need to be well trained in its use. |
[top] [end]Improved ventilation | Build separate cooking hut or shelter | A separate cooking hut takes the smoke away from living areas. Fires should be sheltered from the wind for maximum fuel conservation but the emissions should be able to disperse easily. This is already part of many cultures. | | Build hoods or fireplaces | The fireplace is a fairly common feature of Western homes. They can be constructed in such a way that a fire can provide warmth, light and a place for cooking (preferably with a fire built on a grate, see above). | | Open windows; holes in the roof | This option seems obvious. But in areas where it gets cold (less then 19°C) and people use a fire to keep warm, it is tempting to restrict outside air as much as possible; this is dangerous as high levels of toxic gases can build up. | | Avoid temperature inversions | New settlements should be sited where temperature inversions will be minimised. Temperature inversions trap emissions of toxic fumes around the house. |
[top] [end]Reduced need for the fire | Thermally efficient houses and passive solar design | Thermally efficient housing can reduce or eliminate the need for heating. This can lower a family's exposure to fire emissions substantially. Improving a house's thermal efficiency need not be costly - some measures, such as correct solar orientation cost nothing at the time of construction. If a house has reduced ventilation as a result of improved thermal insulation it is essential that the household understands the implications, and that a hood or fireplace is provided if the family intends to cook indoors. | | Solar water heaters | Solar water heaters are easier to build and use than solar cookers and may reduce the need for heating water over a fire. | | District heating or supply of hot water | This option is expensive but possibly feasible in some areas. A charcoal-making system that produces hot water as a by-product (hot water and charcoal could be fetched from the site perhaps) has the potential for a feasible cottage industry in some places. |
[top] [end]Alternative cooking methods (Inform, educate, encourage) | Use dry fuel | Air dry fuel emits less smoke than moist or green fuel. | | Use larger pieces of wood | Large pieces of wood have lower emissions than small pieces - this is largely because they burn slower. | | Use pot lids during simmering actions | The use of a pot lid reduces total emissions from a fire. Lids have been found to reduce the fuel consumed during simmering by a factor of three. | | Try not to carry baby on back while cooking | Children are especially susceptible to combustion emissions and when the baby is carried on the back while the mother is tending the fire, the child is exposed to high levels of smoke. This should be avoided. | | Keep children out of the smoke | Children should be encouraged to play away from the smoke of fires. This may be problematic if the mother is the only child-minder. | | Adjust paraffin lamps and cookers carefully | Paraffin lamps and cookers are very susceptible to maladjustment and will emit noxious fumes. Wicks should be carefully trimmed. | | Repair cooking devices | People should be encouraged to repair cooking devices as soon as they become damaged. The performance of a stove - especially one with a chimney - is very susceptible to cracks and poor joints and could thus emit extra smoke into the living space. | | Clear the ash away before building a new fire | Residual ash may restrict the access of oxygen to the combustion zone and therefore increase noxious emissions because gases are less completely burned. Stoves and chimneys should always be kept clear of ash. | | Do not overfill stoves with fuel | There is an optimum size and quantity of fuel that will lead to the best performance for a stove. Operators should be aware that overfilling a stove may increase emissions substantially. |
[top] [end]Contents: Boiling Point 40: Household energy and health  . |
Household energy, smoke and health - Smoke from biomass and its effects on infants - Health risk caused by domestic smoke - Emissions from high altitude stoves - a case study in Nepal - Biomass smoke and ill-health in India - preliminary results from a national survey - Global network for the health effects of environmental air pollution - Fuels, stoves and indoor air pollution in Jaracuaro, Mexico - Redesign of liquified petroleum gas stove for the blind - How many of these improvements are in your stoves programme - Participatory Technology Development in stove manufacture - a case study - Renewable energy sources in Nigeria- Efficient household energy use in Uttara Kannada District, Karnataka - Research into cooking and heating applications of down-draught stoves - Comparing forestry wood species for the charcoal supply of Antananarivo city, Madagascar
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