Biomass fuel use and indoor air pollution in homes in Malawi.

BACKGROUND: Air pollution from biomass fuels in Africa is a significant cause of mortality and morbidity both in adults and children. The work describes the nature and quantity of smoke exposure from biomass fuel in Malawian homes. METHODS: Markers of indoor air quality were measured in 62 homes (31 rural and 31 urban) over a typical 24 h period. Four different devices were used (one gravimetric device, two photometric devices and a carbon monoxide (HOBO) monitor. Gravimetric samples were analysed for transition metal content. Data on cooking and lighting fuel type together with information on indicators of socioeconomic status were collected by questionnaire. RESULTS: Respirable dust levels in both the urban and rural environment were high with the mean (SD) 24 h average levels being 226 microg/m(3) (206 microg/m(3)). Data from real-time instruments indicated respirable dust concentrations were >250 microg/m(3) for >1 h per day in 52% of rural homes and 17% of urban homes. Average carbon monoxide levels were significantly higher in urban compared with rural homes (6.14 ppm vs 1.87 ppm; p<0.001). The transition metal content of the smoke was low, with no significant difference found between urban and rural homes. CONCLUSIONS: Indoor air pollution levels in Malawian homes are high. Further investigation is justified because the levels that we have demonstrated are hazardous and are likely to be damaging to health. Interventions should be sought to reduce exposure to concentrations less harmful to health.

Wood smoke exposure, poverty and impaired lung function in Malawian adults.

BACKGROUND: Household air pollution from burning biomass fuel is increasingly recognised as a major global health concern. Biomass smoke is associated with chronic obstructive pulmonary disease (COPD) in Asian and Central American countries, but there are few data from Africa. METHODS: We hypothesised that reported wood smoke as compared to charcoal smoke exposure would be associated with a reduction in forced expiratory volume in 1 second in Malawian adults. Volunteers from urban and rural locations performed spirometry and completed a questionnaire assessing lifestyle, including smoke exposure and symptoms. RESULTS: In total, 374 adults were recruited; 61% were female; 160 cooked using charcoal and 174 used wood. Individuals who used wood as their main domestic fuel had significantly worse lung function than those who used charcoal. Significant factors associated with impaired lung function in the multivariate model were age, sex, height, wood smoke exposure, poverty, smoking and previous tuberculosis. CONCLUSION: Our data suggest that wood smoke and poverty contribute to reduced lung function in rural Africans and that COPD is common in this population. The use of charcoal in rural populations may be relatively protective, and this idea merits further study. The risk factors for impaired lung function in Malawi are multiple and require more detailed characterisation to plan appropriate health interventions.