Indoor air pollution (IAP) is a serious health threat. Across India,72.3 per cent of households use the traditional fuels of firewood,crop residue,or cow-dung cake (2001 Census). In rural areas,the reliance on traditional fuels is much higher,with 90 per cent of households using traditional fuels. The World Health Organization claims that IAP is the second largest environmental cause of childhood mortality in lower-income countries,after unsafe water.
In response,the government and many NGOs have distributed improved or clean stoves that aim to reduce IAP concentrations. For example,the Indian National Programme on Improved Chulhas (NPIC) has distributed over 32 millions improved stoves (as of 2000). The improved stoves can take a variety of forms. They can be made from concrete or mud (concrete lasts longer,but mud is easier to obtain and cheaper,especially in rural areas). Typically,they include a chimney that directs the smoke out of the room. In addition,these stoves usually enclose the cooking flame,which leads to increased efficiency and may potentially reduce wood use.
Despite the popularity of these programs,there is still considerable debate about the benefits of these improved stoves. First do the stoves actually reduce IAP? In the laboratory,we know that the stoves reduce IAP. However,misuse filling the stoves with too much fuel,not cleaning the chimney properly,not repairing cracks in the stove may mitigate these gains.
Second and more importantly,even if the stoves reduce IAP,do they lead to real health improvements?
Third,do the stoves reduce fuel use? The stoves are designed to use less fuel. However,some women believe that the stoves use the same amount of fuel. Others believe it uses more. Therefore,it is possible that the improved stoves would not reduce wood consumption,and thus have no effect on deforestation.
Finally,in many improved stove programs,the stove usage is low. Stoves often break and are not repaired. Why do so few people currently use them? Why do families fail to repair the improved stoves when they break?
Few reliable studies exist to give us answers to these questions,and we are working with Gram Vikas,an NGO that works in rural Orissa,to answer these questions.
For about 2500 households,the order according to which households will receive the stove was determined randomly. Households that obtained the stove at the beginning of the program will be compared with those that obtained it at the end of the program to measure the impacts of the stoves. Currently,midline data is being collected to understand the impacts of the improved stoves on cooking practices,fuel usage,smoke inhalation,health status and health expenditures,days worked,and school attendance of children.
Overall,the results are encouraging. About 80 per cent of households that were offered the stove decided to take it up. Further,the preliminary evidence show that the improved stoves reduced smoke inhalation or IAP exposure. The midline results will let us know whether these results translate to gains in health.
On the less positive side,the stoves experience high rates of breakages,and households frequently fail to repair them. Gram Vikas is currently working on improving institutions to allow for easier stove repairs and trainings. This will help us understand what types of institutions are needed to accompany improved stove programs.
Indoor air pollution is a serious problem. The improved cooking stove is one possible solution. However,greater evidence is needed to understand the effectiveness of the improved cooking stoves in practice before these programs are scaled up further.
This article was co-written with Esther Duflo and Michael Greenstone. The writers are at the Abdul Latif Jameel Poverty Action Lab,MIT.