Indoor air pollution from solid fuel use leads to 3.9 million premature deaths a year globally, and is one of the most important environmental risk factors contributing to the global burden of pulmonary, cardiovascular, and cerebrovascular disease. In low and middle income countries like Uganda, over 95% of the population relies on biomass fuel for heating, cooking, and lighting, with women and children disproportionately affected due to the time spent indoors during high exposure activities. Particulate matter, a component of indoor air pollution, is thought to be associated with adverse acute and long term respiratory effects including an increased risk of acute respiratory infections, chronic obstructive pulmonary disease, and lung cancer.
The literature on the contribution of kerosene lighting to indoor air particulate concentrations is sparse. In rural Uganda, kitchens are almost universally located outside the main home, and kerosene is often used for lighting. The primary aim of this epidemiologic study was to determine whether reported primary lighting source was associated with indoor PM2.5 levels in the main home. In this study, we obtained longitudinal measures of particulate matter 2.5 microns or smaller in size (PM2.5) from living rooms and kitchens of 88 households in rural Uganda and compare these to the type of lighting used in the household.
Households reported using the following sources of lighting: open wick kerosene (29.5%), hurricane kerosene (35.2%), battery powered (18.2%), and solar (9.1%) lamps. Average ambient, living room, and kitchen PM2.5 levels were respectively 20.2, 35.2, and 270.0 μg/m3. Living rooms using open wick kerosene lamps had the highest PM2.5 levels (55.3 μg/m3) and black carbon levels, when compared to those using solar lighting (19.4 μg/m3). Only 27.6% of homes using open wick kerosene lamps met World Health Organization indoor air quality standards compared to 75.0% in homes using solar lighting. It was also found that indoor PM2.5 levels were higher in cooking environments as compared to non-cooking environments.
WHAT CAN BE DONE
One-fifth of the global population lacks access to electricity, and most rely on kerosene for lighting. Our findings highlight the important contribution of kerosene lighting to indoor air pollution. This has been a neglected area of research, as most epidemiologic surveys of indoor air pollution have focused on solid fuels used in cooking. Our findings suggest that in population-based health surveys conducted in rural resource-limited settings without access to a steady supply of electricity, it would be prudent to add questions targeted to lighting source, with a distinction made between open wick and hurricane lamps.
Furthermore, our findings suggest that solar lighting has the potential to reduce household air pollution. Studies performed in other resource limited settings have demonstrated that the introduction of solar lamps dramatically reduced reliance on kerosene lighting. Solar lighting is already being used in some rural communities in Uganda, and community uptake may be higher than the use of improved cookstoves due to convenience and cost savings on fuel, although solar uptake will likely be limited by the high initial cost. A solar lighting intervention has the potential to reduce exposure to indoor air particulate exposure in resource limited settings, and should be further studied.