Abstract
An ecologically nationwide and all-year-round domestic biofuel consumption study was conducted in Zimbabwe from January 1996 to March 1997. The study aimed at (a) establishing the determinants and magnitudes of spatial and temporal variations in biofuel consumption rates, (b) estimating the overall mean national rural and urban consumption rates, and (c) estimating the contribution of domestic biomass burning in Zimbabwe to the emission of atmospheric trace gases. The main source of spatial variation in biofuel consumption rates was found to be settlement type (rural or urban). Within a settlement type, per capita consumption rates varied in time and space with household size, ambient temperature, and physical availability. In rural areas wood and agricultural residues were consumed at national average rates of 1.3±0.2 and 0.07±0.01 tonnes capita
−1 year
−1, respectively. In urban centres wood was consumed at an average rate of 0.4±0.26 tonnes capita
−1 year
−1. These consumption rates translate into emission outputs from Zimbabwe of 4.6 Tg CO
2–C year
−1, 0.4 Tg CO–C year
−1, 5.3 Gg NO–N year
−1, 14.5 Gg CH
4–C year
−1, 24.2 Gg NMHC–C year
−1, 2.9 Gg organic acid–C year
−1 (formic and acetic acids) and 48.4 Gg aerosol–C year
−1. For CO
2, CO, and NO, these domestic biofuel emissions represent 41±6%, 67±6%, and 8±1%, respectively, of the total output of all sources evaluated and documented in Zimbabwe to date. This means that of the studied sources, domestic biomass burning is the major source of CO
2 and CO emission in Zimbabwe.