Magnitude of indoor NO2 from biomass fuels in rural settings of Ethiopia.

UNLABELLED: Half of the world's population and about 80% of households in Sub-Saharan Africa depend on biomass fuels. Indoor air pollution due to biomass fuel combustion may constitute a major public health threat affecting children and women. The purpose of this study was to measure levels of indoor NO(2) concentration in homes with under-five children in rural Ethiopia. The study was undertaken in the Butajira area in Ethiopia from March 2000 to April 2002. 24-h samples were taken regularly at about three month intervals in approximately 3300 homes. Indoor air sampling was done using a modified Willems badge. For each sample taken, an interview with the mother of the child was performed. A Saltzman colorimetric method using a spectrometer calibrated at 540 nm was employed to analyze the mass of NO(2) in field samples. Wood, crop residues and animal dung were the main household fuels. The mean (s.d.) 24-h concentration of NO(2) was 97 microg/m(3) (91.4). This is more than double the currently proposed annual mean of WHO air quality guideline. Highland households had significantly higher indoor NO(2) concentration. This study demonstrates high levels of indoor NO(2) in rural homes of Ethiopia. PRACTICAL IMPLICATIONS: Respiratory infection is a major cause of morbidity and mortality, globally. Acute respiratory symptoms are also related to high levels of air pollution. Interventions aimed at reducing exposure to indoor air pollution should focus on cooking and heating practices in developing countries. This study is not undermining the role of other biomass smoke constituents in determining respiratory infections.