Ethanol Cookstoves and Their Impact on Pregnant Women: Lessons from Nigeria

In Nigeria and much of the developing world, kerosene and biomass fuels are used to provide energy for cooking, heating, and lighting. Reliance on these fuels leads to high levels of household air pollution (HAP), which causes 4.3 million premature deaths worldwide, according to a 2012 World Health Organization (WHO) estimate. Women and children account for 60 percent of HAP-related deaths. Globally, 12 percent of ambient particulate matter pollution, which is associated with several acute and chronic illnesses, comes from cooking with solid fuels, according to the same WHO study.

Links between exposure to HAP and various health outcomes are well established; however, there is slim scientific evidence for health benefits associated with interventions designed to reduce it. A pair of studies in Nigeria provide some evidence in this direction: The first study evaluated the impact of transitioning to cleaner bioethanol-burning stoves on inflammatory biomarkers, which are proteins or enzymes indicating the presence of inflammation in pregnant women. The study hypothesized that switching to bioethanol stoves would decrease the inflammatory biomarkers among pregnant women in the treatment group, which might in turn reduce the risk of cardiovascular diseases (CVDs). A total of 324 women in their first trimester of pregnancy were recruited and were randomly assigned to control and treatment groups. The treatment group was given improved bioethanol cook stoves as well as free bioethanol fuel.

*For high income countries with no information, the estimate is assumed to be >95%.

Produced by: Christine Chung

Source: World Health Organization, “Population with primary reliance on clean fuels”


Cardiovascular diseases are chronic diseases and take years to develop—too long for a study of this nature. However, doctors can predict the development of CVDs by the presence of tumor necrosis factor-alpha (TNF-α) and other proteins. Pregnant women using bioethanol-burning stoves showed significantly lower levels of TNF-α than women in the control group; the control group had 68 percent higher level of TNF-α than the treatment group. Additionally, the researchers found a significant difference in blood pressure levels between the two groups. Overall, the study concluded that the switch from kerosene to bioethanol lowers the exposure to HAP and, hence, may lead to lower levels of CVDs.

While switching to a higher-performing cookstove reduces HAP exposure, it may not be sufficient to observe the desired health impact. Past studies that introduced improved cooking technologies to reduce HAP faced the problem of “stove stacking.” Stove stacking occurs when people continue to use their traditional stove along with the new cooking technology.

To address this issue, a related group of researchers conducted a second study in urban Nigeria that focused on cooking patterns of households when given bioethanol stoves valued at $60. Researchers selected women who were pregnant for less than 18 weeks and who primarily cooked with kerosene. From a total of 50 women, 25 received the improved bioethanol cookstoves and were given free bioethanol fuel until the delivery of the baby. Researchers monitored cooking patterns and the usage of the cookstoves using a combination of stove use monitors and interview-administered survey data.

Ethanol stoves served as near full-time replacements for kerosene stoves. For the 25 women who received a new stove, kerosene stove usage fell from 85 percent of cooking days to five percent by the second month of the study. Additionally, the stove use monitor data indicated that changing stove types did not alter cooking patterns. The sustained use of bioethanol stoves may be attributed to their similarity with the traditional kerosene cookstoves. Both kerosene and ethanol stoves use liquid fuel, only need to be filled once before using, have smaller size burners, are portable, and do not need electricity to operate. Additionally, the study participants received free ethanol for use during the study. The researchers monitored post-study usage by supplying subsidies so that ethanol prices matched kerosene prices; 76 percent of the women continued to use ethanol.

The combined results of these two studies show bioethanol provides a sustainable cooking alternative to more harmful fuels, particularly for countries like Nigeria, where high-quality ethanol is already being produced locally for cooking. WHO recently released health-based air quality guidelines discouraging the use of kerosene for household fuel combustion. In this context, ethanol-based cookstoves are one way forward in addressing the issue of household air pollution.

Article source: Alexander D., Anna G., Ibigbami T., Notthcross A., Ojengbede O., Olamijulo J., Olopade C.O., and Shupler M. “Sustained Usage of Bioethanol Cookstoves Shown in an Urban Nigerian City via New SUMs Algorithm.” Energy for Sustainable Development 35 (2016): 35-40.

Olopade, C.O., et al. “Effect of a Clean Stove Intervention on Inflammatory Biomarkers in Pregnant Women in Ibadan, Nigeria: A Randomized Controlled Study.” Environment International 98 (2017): 181-190.

Featured photo: cc/(Tevarak, photo ID: 623822732, from iStock by Getty Images)

riddhimamishra@uchicago.edu'
Riddhima Mishra

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