Water Engineering and Development Centre
Series: WELL Studies in Water, Sanitation and Environmental Health Task 512
Indoor air pollution is a serious environmental health problem in developing countries that has received relatively little attention in comparison to other issues. The most significant source of indoor air pollution is cooking smoke from low-grade fuels burnt using inefficient stoves. Indoor air pollution is strongly poverty-related, as it is the poor who predominantly rely on lower-grade fuels and have least access to clean technologies for cooking and heating. Furthermore, poor women and children are generally most exposed to indoor smoke, as women cook and simultaneously care for young children, and thus are also likely to be most at risk from the associated health effects.
There is now strong evidence to support a link between indoor air pollution and health, particularly respiratory disease, including acute respiratory infections, chronic obstructive lung disease and lung cancer. Increasing evidence also suggests links with cataracts, tuberculosis, asthma and possibly low birth weight, perinatal mortality and heart disease. There is some consensus that respirable particulates, especially those measuring less than 2.5µg in diameter (PM2.5) have the greatest health impact, as they penetrate furthest into the lungs. However, few studies have explored the health impacts of other pollutants.
Interventions to alleviate indoor air pollution in developing countries have tended to overtly focus on improved cooking stoves, despite the potential of other interventions such as smoke hoods, cleaner fuels or modified kitchen our house design to increase ventilation. There is a general lack of information on the effectiveness of these types of intervention in reducing indoor smoke, and studies published to date are both difficult to compare and have produced conflicting findings. There is much discussion around the most effective intervention(s) t reduce pollution levels, and the debate at present is inconclusive.
The promotional experience of improved technologies to reduce indoor air pollution in developing countries has been mixed, and has focused on the design and dissemination of improved stoves. Both large national-scale programmes and smaller independent initiatives have been implemented, each with instances of success and failure. Many initiatives have been designed according to the priorities of the implementers, or assumed priorities of intended beneficiaries, with little participation from users. As with other development projects, many initiatives have failed through failing to meet users' needs, which include both practical and socio-cultural factors. Many sources believe that a commercial focus is the optimal way to promote stoves, with government and international agencies playing a supporting role.
Very little work has been done to establish the necessary reductions in pollution levels for the health impacts to be significantly reduced. Although this is priority for future research, the evidence supporting the health links suggests that they way forward is to work towards any attainable reduction, on the assumption that this will pose a reduced health risk.