Smoke and malaria: are interventions to reduce exposure to indoor air pollution likely to increase exposure to mosquitoes?

Indoor air pollution from the domestic use of biomass fuels by poor households in developing countries is known to be harmful to health, and efforts are being made to address this problem by changes in fuel type, stove technology, house design and fuel-use practices. However, anecdotal evidence suggests that smoke may play an important role by providing protection from biting insects and that efforts to reduce smoke may increase exposure, particularly to mosquitoes and malaria. This paper reviews the literature relating to the repellent effect of smoke on mosquitoes and finds that there is currently no evidence that smoke from domestic fuel use provides effective protection from mosquitoes and malaria. Given the limited number and quality of studies, this finding cannot be interpreted as conclusive. The literature relating to house ventilation and mosquito entry was also reviewed, and an association between eaves spaces and increased indoor mosquito density was noted. Additionally, literature on the effect of soot on the efficacy of insecticide-treated bed nets was considered, but no direct impact was shown. Efforts to reduce indoor air pollution remain desirable even in areas of malaria transmission.