Reducing emissions and air pollution from informal brick kilns: Evidence from Bangladesh
INTRODUCTION
In many low- and middle-income countries, it is commonly believed that weak state and regulatory capacities limit the ability to reduce pollution and mitigate climate impact. In Bangladesh and across South Asia, most brick manufacturing takes place in informal, traditional coal-fired kilns. These kilns are among the largest sources of greenhouse gas emissions and air pollution, leading to an enormous public health burden.
RATIONALE
In Bangladesh, efforts to improve the brick kiln industry over the past 30 years have had limited success. Our past work suggests that a correctly operated zigzag kiln (a traditional kiln type that accounts for 81% of the sector) can not only improve efficiency but also increase kiln profits. However, most zigzag kilns in Bangladesh are incorrectly operated, leaving these social and private benefits unrealized. Improving energy efficiency presents an alternative strategy to reduce emissions and pollution while also delivering productivity gains.
RESULTS
We developed a low-cost intervention to improve the energy efficiency of zigzag kilns and conducted a randomized controlled trial (RCT) of the intervention among 276 kilns in Bangladesh. Our study included a control arm and two intervention arms (a “technical” arm and a “technical+incentive information” arm). All kilns assigned to both intervention arms received information, training, and technical support to adopt operational improvements that improve fuel combustion and reduce heat loss in the kilns. These improvements specifically targeted how coal is fed during the firing process and how bricks are stacked inside the kiln, along with several other aspects of operation. Kilns assigned to the “technical+incentive information” arm also received explicit information regarding the business rationale for incentivizing workers to adhere to the new practices.
There was high demand for the intervention, with 65% of intervention kilns adopting the intervention’s recommended firing and stacking practices. Notably, 20% of control kilns also adopted these practices, bolstering the interpretation that demand was high. There were no differences in adoption between the two intervention arms and no use of incentives or benefits in the “technical+incentive information” arm.
We studied the intention-to-treat (ITT) effect of random assignment to the intervention, as well as the impact of the intervention after adjusting for compliance using an instrumental variables (IV) framework. Among compliers, the intervention led to substantial reductions in the amount of energy used to fire bricks (23%) and corresponding reductions in carbon dioxide (20%) and particulate matter with a diameter of <2.5 µm (20%). These gains were achieved without any evidence of a rebound in energy demand. Kiln owners also benefited financially from the intervention; production of the highest quality category of bricks increased in intervention kilns and spending on fuel per brick declined.
The primary costs of the RCT were the training costs and technical support costs throughout the season. Using a social cost of carbon of 185 USD per metric ton to value the reductions in CO2 emissions, we find the benefits of the intervention outweighed the costs by a factor of 65 to 1, and that these reductions were achieved at an average cost of 2.85 USD per ton.
CONCLUSIONS
Our study demonstrates that meaningful reductions in emissions by traditional kilns are achievable, even in the absence of stronger regulations, if they can be made financially attractive to private kiln owners.
Authors
Brooks, Nina; Biswas, Debashish; Maithel, Sameer; Miller, Grant; Mahajan, Aprajit; Uddin, M. Rofi; Ahmed, Shoeb; Mahzab, Moogdho; Rahman, Mahbubur; Luby, Stephen P.
Citation
Brooks, Nina; Biswas, Debashish; Maithel, Sameer; Miller, Grant; Mahajan, Aprajit; Uddin, M. Rofi; et al. 2025. Reducing emissions and air pollution from informal brick kilns: Evidence from Bangladesh. Science 388(6747): eadr7394. https://www.science.org/doi/10.1126/science.adr7394
Country/Region
Bangladesh
Keywords
Asia; Southern Asia; Air Pollution; Drying Kilns; Greenhouse Gas Emissions
Access/Licence
Open Access
Record type
Journal Article