Up in smoke

by Esther Duflo, Michael Greenstone & Rema Hanna

Abstract:

It is conventional wisdom that it is possible to reduce exposure to indoor air pollution, improve health outcomes, and decrease greenhouse gas emissions in rural areas of developing countries through the adoption of improved cooking stoves. This is largely supported by observational field studies and engineering or laboratory experiments. However, we provide new evidence, from a randomized control trial conducted in rural Orissa, India (one of the poorest places in India) on the benefits of a commonly used improved stove that laboratory tests showed to reduce indoor air pollution and require less fuel. We track households for up to four years after they received the stove. While we find a meaningful reduction in smoke inhalation in the first year, there is no effect over longer time horizons. We find no evidence of improvements in lung functioning or health and there is no change in fuel consumption (and presumably greenhouse gas emissions). The difference between the laboratory and field findings appears to result from households’ revealed low valuation of the stoves. Households failed to use the stoves regularly or appropriately, did not make the necessary investments to maintain them properly, and usage rates ultimately declined further over time. More broadly, this study underscores the need to test environmental and health technologies in real-world settings where behavior may temper impacts, and to test them over a long enough horizon to understand how this behavioral effect evolves over time.

*Though many households accepted the stoves when offered, they did not use them regularly or maintain them properly, and use declined over time. Households initially cooked about 3.4 more meals per week using a good condition, low-pollution stove than those in the comparison group, out of an average of about 14 meals per week. By year three, this difference had fallen to 1.8 meals per week.

*Though many households accepted the stoves when offered, they did not use them regularly or maintain them properly, and use declined over time. Households initially cooked about 3.4 more meals per week using a good condition, low-pollution stove than those in the comparison group, out of an average of about 14 meals per week. By year three, this difference had fallen to 1.8 meals per week.


*Low usage limited the impact of the stoves on smoke exposure. In the first year of the program, when use was at its highest, there was a 7.5 percent reduction in carbon monoxide (CO) in the breath of the primary cooks in the households, but no meaningful change for other household members. By the second year, as use fell further and the stoves experienced normal wear and tear, there was no longer a significant effect.

*Low usage limited the impact of the stoves on smoke exposure. In the first year of the program, when use was at its highest, there was a 7.5 percent reduction in carbon monoxide (CO) in the breath of the primary cooks in the households, but no meaningful change for other household members. By the second year, as use fell further and the stoves experienced normal wear and tear, there was no longer a significant effect.

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