Using smarter stoves to combat household air pollution

(Originally published here)

When it comes to cooking indoors over open fires, the harmful health effects can be equal to smoking two packs of cigarettes a day. This indoor air pollution plagues nearly nine out of every 10 Bangladeshi households, which use wood and other biofuels to cook inside.

Over time, exposure to smoke from indoor cooking leads to deadly diseases such as lung cancer, stroke, and heart disease. This is why it’s the most deadly environmental problem in the world. In Bangladesh, such indoor air pollution is responsible for 10-15 percent of all deaths.

It may seem obvious to say that we need to focus on cutting household air pollution. But such policies compete with many other potentially beneficial proposals for how to use scarce resources from the national budget or international stakeholders. 

So what are the very best policies? This is what the Bangladesh Priorities – a cooperation with BRAC and dozens of the world’s top economists – promises to help answer.

Our research suggests two principal ways to help decrease deadly air pollution inside the home: People could either burn the same biofuels that most Bangladeshi households currently use, but with smarter cook stoves that emit much less pollution, or they could change to liquefied petroleum gas (LPG), which burns much more cleanly.

The cheapest way to quality indoor air is to get widespread investment in an improved biomass cook stove. This is simply an enclosed stove, often with a chimney, that reduces heat loss, protects against the wind, and transfers heat to a cooking pot more efficiently than traditional stoves or open fires. It burns the fuel – often biomass – more effectively and hence with less pollution. In Bangladesh, the cost of such a stove with two burners and a chimney that will last three years is about Tk. 1,000 per year. This is both to cover the aggregate that needs replacement every third year, as well as some maintenance. And almost a third of the cost goes to promoting awareness of the opportunity in the first place.

But the benefits are many. If all 30 million households switched to improved cook stoves, it would save more than 33,000 lives each year. Each life will live on average another 28 years, which is worth about Tk. 79 billion or Tk. 2,600 per household each year. Moreover, each family will get slightly fewer sick days, worth another Tk. 260.

But the families would also save 15 minutes per day in cooking time, because the improved cook stoves are faster, and because less fuel is needed, it will reduce fuel collection time by half each day. In total, that benefit is worth another Tk. 2,000. For each Tk. 1,000 spent on a better cook stove, a family will get almost Tk. 5,000 in health and time savings benefits: every taka spent will do Tk. 5 of good.

This is an important step to improve household air quality. But it still leaves most of the problem in place – we will “only” save 33,000 of 150,000 deaths each year.

That is why we could consider a more thorough option. LPG burns very clean – almost like an electric stove. Adoption of these stoves would produce much higher benefits: it would save 91,000 lives, a total value of Tk. 218 billion, or Tk. 7,300 per household. It would also avoid some Tk. 700 of disease per household, speed up cooking by 40 minutes, and save all fuel collection time, at a net worth of Tk. 5,200. 

But, the cost of LPG is also significantly higher. It would cost about Tk. 10,000 each year, plus Tk. 2,000 in cooking fuel costs. In total, you would pay about Tk. 12,000 for about Tk.13,200 in benefits. So spending on LPG stoves would not be a loss. 

This shows that the most expensive option is not necessarily the best option. Cheaper options, despite helping less, can be a much better way to help everyone. In the long term, however, the more expensive options can be solutions. Many countries at similar income levels as Bangladesh have adopted modern cooking fuels such as LPG at substantially higher rates.

But there are challenges to implementing smarter stoves. With some prior efforts, it has proven difficult to get households to adopt new stoves. And widespread adoption is crucial given the community-based nature of fighting air pollution. If not everyone in a community adopt improved cook stoves, there would be more local air pollution leading to fewer benefits.

Well-targeted information campaigns about the benefits of cleaner cook stoves could help spread the message about their benefits, and projects should also tailor stoves to customers’ preferences. And, ideally, households would be allowed to pay for stoves over the course of multiple installments, making them more affordable.

Last week you saw how poverty policies can help do Tk. 2 of good for each taka spent. Making cook stoves cleaner can help fight household air pollution with about Tk. 5 of good for every taka spent. Are these some of the best investments for Bangladesh? Let your voice be heard on Let’s start the conversation about where Bangladesh can do the most good.


Written by: Dr. Bjorn Lomborg, President, Copenhagen Consensus Center