Air pollution in Mpemba, Malawi: a multidisciplinary exploration of the burden and possible solutions

Introduction Air pollution is recognised as a leading environmental risk factor, linked to 6.67 million deaths in 2019, especially through effects on the respiratory and cardiovascular systems. In low-income countries, such as Malawi, household air pollution – caused by the burning of solid fuels for cooking, lighting, and heating – continues to constitute a significant proportion of individuals’ air pollution exposures. This thesis explores the issue of household air pollution in a village in Malawi, where existing evidence suggests high levels of household air pollution, but details of source apportionment are not clear. More generally, qualitative data have been limited to investigations of air pollution reduction interventions (mainly improved stoves), leaving significant knowledge gaps in understanding individuals’ lived experiences around ‘smoke’ itself. The aim was to perform an ethnographic study of air pollution, or ‘smoke’, in the Malawian village context, incorporating both quantitative and qualitative methodologies, using these insights to co-develop and trial a whole-village cleaner air intervention. Methods I performed a systematic review of randomised controlled trials assessing the efficacy of air pollution reduction interventions in low- and middle-income countries. A subsequent ethnography in a rural village in Malawi included participant observations, individual interviews, and participatory workshops. Exposure to airborne particulates and carbon monoxide was assessed in parallel by personal monitoring of researchers and then village residents. We supported the introduction of locally made clay cookstoves across the village, and we repeated both monitoring and participant observation to explore residents’ perceptions of the stoves and exposure impacts. Results Studies identified through systematic review were dominated by stove interventions, with little evidence of improvement in clinical respiratory diagnoses resulting from these intervention types. In Malawi, we found high levels of personal exposure to airborne particulate matter and carbon monoxide in village residents, with cooking constituting the predominant exposure source. Detailed matched activity records confirmed cooking using biomass on a three-stone fire to be the cause of highest exposure concentrations. A counterintuitive finding of higher exposures during cooking in better ventilated spaces showed the value of first-person participant observation in understanding individuals’ daily exposures. Qualitative approaches revealed the complex ways in which scarcity, through limitation, daily hardship, and insecurity, influenced exposures in this setting. The mixed-method intervention evaluation affirmed that, whilst the cookstoves were not able to significantly reduce cooking-related exposures, they were associated with reduced exposures at baseline (during non-cooking periods). Cookstoves were well-received and almost exclusively used across the village as they met residents’ immediate needs (relating to fuel savings and shortened cooking times). Conclusions Scarcity was a core component of residents’ daily lives in rural Malawi, framing and driving individual air pollution exposures. We recommend development of a national strategy for universal domestic clean energy, provided as a utility rather than a marketed product. International support, with an awareness of historical and geographical origins of international inequity, would support this aspiration. Interim steps may include trialling of liquefied petroleum gas distribution or electricity mini-grids. Research methods that seek to provide insights into individuals’ lived experiences of using these provisions constitute an important part of evaluation processes