What are the biggest problems facing the world today? If you are a reader of this blog, then you probably think (like I do) that they include poverty, disease, and climate change. There is one thing that causes all three of these, but it is likely one of the most under-reported stories of daily life in the developing world: the simple daily act of cooking is killing millions of poor people each year.
More than 3 billion people in the world use solid biomass fuels (wood, dung, crop residues, etc.) to cook their daily meals. The smoke from solid biomass fuels is responsible for more than 4 million deaths per year associated with respiratory diseases according to the Global Burden of Disease Study. The smoke kills more people each year than other and more talked about diseases like malaria (660,000 deaths per year), tuberculosis (1.3 million), child and maternal malnutrition (1.4 million), and HIV/AIDS (1.7 million). Furthermore, incomplete combustion of biomass fuels releases black carbon (soot) that contributes to global warming, while cutting down trees for firewood or to make charcoal is responsible for localized areas of deforestation. Additionally, there are significant social equity concerns because the time spent collecting firewood and health burdens from cookstove smoke are largely borne by women and children.
Therefore, since the daily act of cooking is a problem with so many important implications for the world’s poor, it is worth measuring it well. In the rest of this post I describe fieldwork completed in southwestern Uganda, and analysis recently published in Biomass and Bioenergy that highlights important measurement innovations for measuring the usage of traditional three-stone fires and manufactured fuel-efficient cookstoves. This work is co-authored with Theresa Beltramo, Garrick Blalock, and David I. Levine and we extend special thanks to Joseph Arineitew Ndemere, Juliet Kyayesimira, Stephen Harrell, and the Center for Integrated Research and Community Development (CIRCODU) for managing and overseeing Uganda based field operations.
We build on the pioneering technique suggested by Ruiz-Mercado et al. and use temperature data loggers as stove use monitors. In our experiment, the stove use monitors, about the size of a watch battery, were affixed to stoves in the field and programmed to take temperature readings every 30 minutes. A technician downloaded the temperature data and reset the device once every six weeks. We followed 168 households in rural Uganda over a 6-month period by measuring stove usage on up to four stoves per household (two three-stone fires and two fuel-efficient Envirofit stoves). The manufacturer reports that the Envirofit reduces smoke and harmful gases by up to 80% and reduces biomass fuel use by up to 60%.
In total we collected about 1.7 million temperature readings. Field staff also recorded visual observations of whether a stove was in use (on/off) when they visited homes (once every 4-6 weeks). We collected about 2,400 visual observations of stove use throughout the six months and were able to match the temperature data to the exact stove and timestamp of the visual observations of use. Then we used a machine-learning algorithm to examine the temperature data immediately before and after the 2,400 visual observations of use. The algorithm analyzed the data to understand how temperature patterns change at times of observed stove use and then predicted cooking behaviors to the wider dataset of 1.7 million temperature readings. This technique allowed us to unobtrusively and inexpensively track stove usage on a larger sample and for a longer continuous time than almost all studies in the past.
We are still working on the analysis of stove usage behaviors. For now, we extend the frontier of cookstove measurement techniques by creating an algorithm to convert temperature data into stove use data. Our algorithm is the first published for traditional stove types such as the three-stone fire and it performs better than published algorithms for manufactured heat-efficient stoves. We believe this technique can be easily replicated by future researchers and will provide higher quality and more detailed information about daily cooking behaviors in the developing world. By creating better information, we hope to assist the development community to design better policies to deal with the development challenges associated with daily cooking in the developing world.
The paper’s authors thank the United States Agency for International Development, the Atkinson Center for a Sustainable Future at Cornell University, the Institute for the Social Sciences at Cornell University, and the Cornell Population Center for funding the study.
