About two million children die each year from influenza, pneumonia and other diseases caused by acute respiratory infections, according to the World Health Organization (WHO). Researchers have identified indoor air pollution as a key culprit, with several epidemiological studies reporting a strong association between pollution exposure and acute respiratory infections.

A primary contributor of indoor air pollution is the burning of organic fuels, such as dung, brush and wood - the main sources of energy for cooking and heating for more than three billion people, according to the WHO.

In parts of Africa and Asia, women - the primary homemakers - often spend three to five hours a day in close proximity to the cookstove, typically with their infants and children close by. Despite the availability of simple technologies that would eliminate potential health risks, 75 percent of the population of South Asia - including India, Bangladesh, Pakistan and Nepal - continue to use traditional cooking methods, according to the WHO.

In 2006, a team of researchers from Stanford University set off for Bangladesh to find practical, low-cost incentives that would encourage people to use cleaner, safer cookstoves. Their ongoing research effort is supported by an interdisciplinary Environmental Venture Projects (EVP) grant from Stanford's Woods Institute for the Environment.

"We wanted to not only understand why people continue to use the traditional technology, but more importantly, why is it so hard to get them to switch to a seemingly superior technology," said Grant Miller, an assistant professor of medicine at Stanford and principal investigator of the EVP study. Other project members include Paul Wise, a professor of pediatrics, and Lynn Hildemann, an associate professor of civil and environmental engineering at Stanford.

Testing incentives

Miller, Wise and Hildemann have focused their research on rural villages in Bangladesh. On their initial visits, they met with government officials, physicians, environmental scientists, economists and non-governmental organizations, including the Bangladesh Rural Advancement Committee (BRAC), which has been involved in promoting and distributing new cookstoves with better ventilation.  The Stanford team formed a strong partnership with BRAC and with Ahmed Mushfiq Mobarak, a development economist at Yale University, who has ongoing research projects in Bangladesh.

Although improved cookstoves lead to healthier households, many Bangladeshis do not regard them as superior to traditional stoves, Miller said. As a result, he and his colleagues designed a study in which various incentives to switch to the new stoves would be tested.

On the first visit to Bangladesh, the Stanford team organized focus groups with women villagers. The goal was to learn more about the women's attitudes and preferences in relation to cooking and fuel sources, as well as to provide them information about the serious health risks of indoor air pollution. Upon returning to Stanford, the researchers analyzed the results of the focus groups and found surprisingly low demand for improving indoor air quality, suggesting that a lack of information about the problem is not the key barrier to adopting cleaner stoves.

In July 2008, the research team headed back to Bangladesh and assembled a team of BRAC field staff to help investigate why the demand was so low. The researchers went directly to households and distributed two types of cookstoves with two very different attributes - a portable stove that would improve fuel efficiency, and a chimney stove that would greatly reduce indoor air pollution by filtering smoke up and out of the house.

The stoves were offered to 3,000 households in 60 villages under a variety of randomly assigned price incentives. For example, some residents were given the option of buying one type of stove at half price, while others were offered a choice of either the portable or chimney stove. Because village leaders have an influential role in whether people adopt new technologies, some households were offered the stoves along with information about the preference of local opinion leaders. The researchers also evaluated the role of gender by offering stoves to men and women separately in certain households.

The importance of price

The results of the study revealed that that an individual's choice of cookstove is extremely dependent upon price. There were also overwhelming differences in "stated" versus "actual" adoption - that is, the respondent's initial statements of wanting the improved stove versus buying it upon delivery.  "It's a very different thing to present people with real choices and observe what they choose, and then to actually have to put their money where their mouth is," Miller said.

According to Miler, the overall results of the study suggest that people are more willing to spend extra on a stove that protects a woman's health versus one that saves them time. However, even among the groups that were offered a free cookstove with no additional cost for travel or set-up, acceptance rates were below 70 percent, suggesting that factors other than price played an important role in their decision-making.    

The researchers focused on the role of opinion leaders and gender as important factors that influence the adoption of new technologies.

"People may make decisions based upon the decision of an opinion leader," Miller said. "The idea is that there is someone that you trust and is good at understanding a technology that you may have never encountered." The study results showed that people tended to reject a technology that an opinion leader also rejected but were less likely to adopt one that an opinion leader chose. These findings are consistent with the hypothesis that villagers consider new, expensive technologies as being more appropriate for leaders who are richer or more educated.

Although women are the primary cooks in Bangladeshi households and bear disproportionate indoor air pollution effects, the researchers found surprisingly few differences in the adoption rates of men and women. However, these findings may not accurately reflect the role of gender, as women are typically not in control of household resources and do not have authority to make financial decisions, Miller explained.

To quantify the effects of indoor air pollution, the researchers also installed instruments that monitored smoke levels in 120 kitchens. The monitors were placed on women cooks and at various spots in the kitchen during cooking. The researchers are now analyzing those data.

Next steps

In fall 2009, the research team returns to Bangladesh to further investigate ways to promote cleaner cookstoves and eliminate indoor air pollution. They plan to look at social networks beyond opinion leaders - including family, friends and neighbors - and to learn more about the roles of time constraints, difficulty-of-use and taste preferences when choosing a stove.

"We weren't quite clear how to design an experimental condition to isolate the effect of taste, but certainly we're trying to ask people how important this is to them and to what extent they've observed differences in taste from the different technologies," said Miller, adding that taste might be related to gender. For example, women may be weary of using a new cookstove, because it might change their husband's opinion of their cooking.

The researchers also plan to look more closely at price issues - for example, whether charging a fee will give suppliers a strong incentive to sell improved stoves, or if making stoves available at no cost will maximize adoption.  "Individuals are the best decision-makers for themselves, and we've discovered in this case that often their sole objective is not health," Miller said. "The EVP grant has allowed us to move forward in understanding how to more effectively promote cleaner cookstoves in ways that appeal to those unconcerned with the effects indoor air pollution."

Allison McCann is a writer-intern at the Woods Institute for the Environment at Stanford University.