Primitive cooking stoves are used throughout half the world and kill more people per year -- about two million -- than malaria, said a study published in the United States on Thursday.
Three billion people worldwide cook indoors by burning solid fuels such as wood, charcoal or dung, yet little public awareness surrounds what the World Health Organization describes as the globe's top environmental killer.
The smoke that pours from these unvented fires fills indoor spaces and causes pneumonia and chronic lung disease that particularly affects women and children who tend to spend more time in the home while men are outside working.
More research and programs to sell more efficient cookstoves to residents in remote or impoverished areas could help improve health and allow girls to get educated rather than spend time gathering fuel, said the research in the journal Science.
"Many people in developed countries don't realize that smoke from indoor cooking fires is a terrible scourge upon the health of a large number of people," said co-author Francis Collins, director of the US National Institutes of Health.
"International efforts to combat this scourge are now beginning. The NIH's role is to support the research that will determine the most efficient, cost-effective means to do so while safe guarding human health."
One program in the Andean highlands of Peru has had some success. In that area, where about 30 percent of the Peruvian population lives (10 million people), 40 percent of women have heart and chronic obstructive lung diseases.
In addition, up to 60 percent of children are malnourished and suffer "relentless respiratory diseases," said an accompanying editorial by Peru's former first lady Pilar Nores Bodereau.
She founded a program called Sembrando, a private initiative that helps local members of the community build better cookstoves, latrines and grow family orchards, all at a cost of about 200 US dollars per family.
In the past five years, the project has served 92,000 families, or about 500,000 people in the Andes, and early studies show a "substantial decrease in bronchopulmonary diseases and a clear increase in the height/weight ratio of children under five years old," she wrote.
The project has "inspired the Peruvian government to start a campaign to build 500,000 clean cookstoves nationwide," she added.
The United Nations Foundation has launched its own public-private partnership to establish a market for clean and efficient cookstoves and fuels in the developing world, called the Global Alliance for Clean Cookstoves.
Its goal is to have 100 million homes using cleaner cookstoves and fuels by 2020. More than 175 countries, foundations, corporations, and other nongovernmental organizations (NGOs) are involved.
The study in Science said the US government "has committed more than $50 million, including about $25 million of the NIH's ongoing research funds" toward studying the impact of indoor air pollution from cooking fires.
Between $150 and $200 million is needed for a comprehensive research program on how much pollution reduction is needed to see a health improvement, as well as the benefits of current efforts to use better cookstoves, said the study.
In addition, the UN program does not aim to give stoves away for free, even though the people who need them are already quite poor.
"A stove purchased by the consumer is inherently more valued than one that is received without charge, especially if the free stove was designed without consumer input," said the study.