Researchers develop practical solution to reduce emissions and improve air quality from brick manufacturing in Bangladesh
A new study found that brick kiln owners were willing to implement energy-efficient operational changes after receiving training and support. The social benefits of reduced carbon emissions from these changes outweighed costs by a factor of 65 to 1
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Pictured is an overhead view of brick kilns in Bangladesh.
view moreCredit: Sushanta Kumar Paul
Brick manufacturing is a central component of the economy in South Asia, but also a major source of greenhouse gas emissions and air pollution, as the practice releases carbon dioxide (CO₂), fine particulate matter (PM2.5), and other contaminants into the environment. This coal-powered industry poses a serious threat to human health, agriculture, and the environment in low- and middle-income countries that lack the capacity to monitor and regulate these largely informal operations.
As scientists continue to sound the alarm on the increasing dangers of fossil fuels, a new study by researchers at Boston University School of Public Health (BUSPH), Stanford University, icddr,b, Greentech Knowledge Solutions, and the Bangladesh University of Engineering and Technology has introduced an evidence-based strategy proven to increase energy efficiency and reduce emissions in the brick manufacturing industry by encouraging operational changes that prioritize practicality and profit.
Published in the journal Science, the study analyzes the results of a randomized controlled trial (RCT) that showed that brick kiln owners in Bangladesh are willing and able to implement cleaner and more efficient business practices within their operations—without legal enforcement—if they receive the proper training and support, and if those changes are aligned with their profit motives. The study is the first to rigorously demonstrate successful strategies to improve efficiency within the traditional brick kiln industry.
The RCT evaluated an intervention that provided educational resources, training, and technical support to kiln owners in Bangladesh during the 2022-2023 brick kiln season with 276 brick kilns. The intervention aimed to motivate the owners to make energy-efficient adjustments to their manufacturing process, such as streamlining brick stacking and using powered biomass fuel, both of which improve complete fuel combustion and reduce heat loss in the kilns.
The study found that 65 percent of the brick kiln owners adopted these changes, which led to a 23-percent reduction in energy use. The changes substantially improved air quality, contributing to 20-percent reductions in CO₂ and PM2.5 emissions. This intervention also brought substantial savings in coal expenditures and higher-quality bricks. Notably, the researchers estimated that the social benefits due CO2 reductions from the intervention outweighed costs by a factor of 65 to 1 and that the CO2 reductions were achieved at the low cost of $2.85/ton. When the team returned to participating brick kilns the next year, they found adoption of the improved practices had not only sustained but increased.
“Brick manufacturing is central to development, urbanization, and construction in Bangladesh and across South Asia, but the industry has not experienced much innovation, leaving open the possibility for win-win solutions that target low efficiency,” says study lead and corresponding author Dr. Nina Brooks, assistant professor of global health at BUSPH. “Our findings demonstrate that brick kiln owners are willing to embrace simple changes that protect human and environmental health when they have the knowledge and training, and those changes deliver tangible economic gain.”
These findings are promising, as previous efforts to regulate the brick kiln industry have been unsuccessful in Bangladesh, where workers produce 27 billion bricks annually in harsh working conditions. This industry accounts for 17 percent of CO₂ emissions and 11 percent of PM2.5 emissions each year. Existing regulations, such as fuel mandates that ban the use of firewood, or laws that require brick kilns to be distanced from schools, health facilities, and other establishments, are only minimally enforced; for example, the majority of brick kilns in Bangladesh are located illegally near schools.
In a 2024 pilot study for this intervention, the researchers learned that zigzag brick kiln owners were unaware of proper zizgag kiln operation—which are already designed to be less polluting—or that these approaches could increase their profit. The owners were also skeptical to implement the intervention, for fear that the changes were too technologically advanced for their workers. Although the study included an experimental arm that explained the business case for incentivizing workers to adopt the new practices, these were not widely taken up. An important area for future research is identifying strategies to improve work conditions that are aligned with kiln owners’ profit motives and may be implemented within a weak regulatory state.
“From what I’ve seen in brick kilns, the people working there really make all the difference," says study coauthor Mr. Debashish Biswas, assistant scientist at icddr,b in Dhaka, Bangladesh. "It’s not just about the technology or the strategies—if the workers aren’t taken care of, things just don’t run smoothly. I think there is a real opportunity to find ways where looking after workers actually helps the business, too, even if the rules aren’t always enforced. Owners and workers both stand to gain if we can figure that out.”
When assessing the economic burden of the intervention, the researchers found that the social benefits outweighed the costs 65 to 1 by using the social cost of carbon of $185 per metric ton to value the CO2 reductions. If all zigzag kiln owners in Bangladesh adopted these changes, the team estimated that CO₂ levels could plummet by 2.4 metric tons in just one brick firing season, which would result in a two-percent reduction of the country’s annual CO₂ emissions.
“Brick kilns and other informal industries need not always look outside for finding solutions to improve their environmental performance," says study coauthor Dr. Sameer Maithel, an advisor at Greentech Knowledge Solutions in New Delhi, India. "The energy-efficient operating practices introduced in this study were identified working in close partnership with progressive brickmakers in South Asia. There are several such innovations being practiced in the field.”
There is an urgent need to put in place a system to identify these innovations and scale them, Dr. Maithel says. The researchers’ energy-efficient intervention may be scalable across South Asia, such as in India and Nepal, where brick manufacturing practices are similar—and possibly across other industries. Future research will consider how to best scale the intervention, as well as develop the next generation of efficiency improvements for the brick industry.
"The remarkable success of the intervention demonstrates the benefit of deep engagement with local stakeholders," says co-senior author Dr. Stephen Luby, Lucy Becker Professor of Medicine and senior fellow at the Stanford Woods Institute for the Environment.
Hear more from Dr. Brooks and Dr. Luby in this Q&A, in which they further discuss what these findings reveal about how to make environmental progress in settings with little regulation or weak governance.
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About Boston University School of Public Health
Founded in 1976, Boston University School of Public Health is one of the top ten ranked schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations—especially the disadvantaged, underserved, and vulnerable—locally and globally.
Journal
Science
Method of Research
Randomized controlled/clinical trial
Subject of Research
People
Article Title
Reducing Emissions and Air Pollution from Informal Brick Kilns: Evidence from Bangladesh
Article Publication Date
8-May-2025
