Bakeries cooking on biomass in Ethiopia: a matter of climate and indoor air pollution

Abstract

This study set out to assess the impact of preparation of the number one staple food of Ethiopia, the Injera. As many of the Injera stoves (also called mitads) are fired using solid biomass fuel, low efficiency and indoor air pollution are common. Previous literature has focused on household stoves and indoor air pollution only, whereas this paper investigates the issue in commercial bakeries in the city of Addis Abeba. To assess indoor air pollution, Particulate matter smaller than 2.5µm (PM2.5) has been measured using personal exposure measurements and ambient indoor air pollution in bakeries. Climate impact is assessed using a Material Flow analysis of the stoves, coupled with fuel or energy use of different stove types. Data was collected from bakeries in different sub-cities of the city of Addis Abeba between December 2015 and May 2016, where 15 bakeries were using biomass and 15 were using electricity as heating source. In this research the benefits of a transition to electric cooking are quantified, and barriers for implementation were identified. The energy use of stoves can potentially be reduced by up to 95% when switching to efficient electric stoves, reducing lifetime climate impact per stove by up to 98%. The reduction in indoor air pollution that is accompanied by a switch to electric cooking leads to an almost threefold reduction in PM2.5 concentrations in bakeries (geometric mean level biomass: 394 µg/m³, electric: 134 µg/m³), and an almost twofold reduction in personal PM2.5 exposure among bakery employees (geometric mean level biomass: 415 µg/m³, electric: 216 µg/m³). This research shows the importance of a transition to electric cooking in Ethiopia and could be used in the future to assess economic and occupational health impact of a transition as well.