Emission quantification associated with firewood usage: A case study of Mangondi village in Limpopo Province, South Africa

Abstract

For a long time, firewood has been used as an affordable source of energy, available for cooking, lighting, and heating. Firewood combusted using informal stoves which are not properly designed are characterized by not having regulatory control facilities to achieve complete combustion, hence, resulting in increased smoke and gaseous emissions since the firewood is not fully combusted. A large quantity of criteria pollutants and greenhouse gas (GHG) are released to the atmosphere from such combustion which potentially contributes to global warming and climate change. The aim of this study was to quantify the emissions resulting from the use of firewood in Mangondi village, a rural village in the Limpopo Province, South Africa. This study employed structured questionnaires and face-to-face interview to gather required information, to identify preferred tree species used as firewood in Mangondi village. The questionnaires were administered to forty households that were selected randomly in the village. Additionally, a crane scale was used to quantify the firewood mass burnt daily by the 40 households during the winter and summer seasons of 2021. The study used the data generated as a baseline for estimating the GHG, and criteria pollutants’ emissions released from burning firewood in winter and summer by the participating households in Mangondi village. The results obtained from the questionnaires and interviews, revealed that the preferred tree species used as firewood in the households were Dichrostachys cinerei, Euclea divinorum Hiern and Combretum imberbe. Firewood was the main source of energy used by the households of Mangondi village for preparing meals and space heating. The results from this study illustrate that several factors, such as, socio-economic conditions, accessibility and availability were reasons for the utilization of firewood as a preferred choice of energy for households in Mangondi village. The average wood mass burnt in 2021, in the morning sessions (2-5 hours) was 4.04 kg/day and 2.94 kg/day in the evening (1-1h30) and amounted to an average of 2545.30kg per household, per year. More firewood was used in winter than summer mostly due to space-heating needs. The emission rate per household for GHG, CO2 (1771.12 g/day) was higher in winter than in summer (1014.86 g/day). Results for the criteria pollutants estimated, show that PM2.5, PM10, CO, SO2 and NOx was 169.24 g/day; 60.23 g/day; 68.09 g/day; 0.79 g/day; 5.12 g/day in winter and 1014.86 g/day; 96.98 g/day; 3.38 g/day; 34.51 g/day; 39.02 g/day;0.45 g/day; 2.93 g/day in summer. This study shows that households in rural areas still choose to use firewood to meet their daily energy needs because it is easily accessible and cheap. This study illustrated that burning firewood leads to GHG and criteria pollutants being emitted, therefore, intensive awareness and pollution control programs are suggested to improve indoor air quality and health condition of the rural population.