In Malawi, a country in sub-Saharan Africa, pneumonia is one of the main causes of death in children under 5 years of age. Pneumonia is a lung infection, which makes it hard for you to get enough oxygen into your bloodstream (i.e. you have low oxygen saturation).
Pneumonia in kids has been linked to exposure to smoke from open fires as their mothers cook family meals on them.
We predicted that replacing open fires with cleaner-burning cookstoves would reduce the number of cases of pneumonia in young children. To find out if this was true, we ran a two-year trial in Malawi, comparing the effects of using a cleaner-burning cookstove with continuation of open-fire cooking on childhood pneumonia rates.
After two years, we found no evidence that using cleaner-burning cookstoves reduced the risk of pneumonia in young children. But the improved cookstoves were beneficial for other important reasons (e.g. avoiding cooking-related injuries such as burns).