Indoor air pollution in developing countries: a major environmental and public health challenge

Around 50% of people, almost all in developing countries, rely on coal and biomass in the form of wood, dung and crop residues for domestic energy. Th ese materials are typically burnt in simple stoves with very incomplete com bustion. Consequently, women and young children are exposed to high levels of indoor air pollution every clay. There is consistent evidence that indoor air pollution increases the risk o f chronic obstructive pulmonary disease and of acute respiratory infections in childhood, the most important cause of death among children under 5 yea rs of age in developing countries. Evidence also exists of associations wit h low birth weight, increased infant and perinatal mortality, pulmonary tub erculosis, nasopharyngeal and laryngeal cancer, cataract, and, specifically in respect of the use of coal, with lung cancer. Conflicting evidence exis ts with regard to asthma. All studies are observational and very few have m easured exposure directly, while a substantial proportion have not dealt wi th confounding, As a result, risk estimates are poorly quantified and may b e biased. Exposure to indoor air pollution may be responsible for nearly 2 million excess deaths in developing countries and for some 4% of the global burden of disease. Indoor air pollution is a major global public health threat requiring great ly increased efforts in the areas of research and policy-making. Research o n its health effects should be strengthened, particularly in relation to tu berculosis and acute lower respiratory infections. A more systematic approa ch to the development and evaluation of interventions is desirable, with cl earer recognition of the interrelationships between poverty and dependence on polluting fuels.