Semi-continuous coal stove indoor air quality intervention in a South African low-income settlement

The persistent use of solid fuel for domestic energy in South Africa's low-income settlements remains a critical air quality concern, posing severe health risks to vulnerable populations. Previous interventions have focused on a top-down approach of total fuel replacement, which frequently fails as households revert to coal and wood due to economic volatility and high electricity costs. The Semi-Continuous Coal Stove (SCCS), co-developed by North-West University and New Dawn Engineering (Pty) Ltd., offers a pragmatic alternative. However, while the SCCS performs exceptionally well in laboratory settings, its success in reducing real-world exposure depends on overcoming intricate social and behavioural barriers that lab tests cannot simulate. This study evaluates the impact of the SCCS through a socio-technical framework, utilising an unsupervised field trial in the Metsimaholo township in the Northern Free State. The novelty of this research lies in its integrated socio-technical evaluation of the Semi-Continuous Coal Stove (SCCS) as a realistic transition pathway. A dual-methodology approach was employed: qualitative assessments of socioeconomic profiles and user perceptions, and quantitative monitoring of indoor air quality PM 2.5 and CO during stove operation. The social findings reveal that households are experiencing significant economic challenges, including 38% unemployment and 41% relying on government pensions and grants. Although all houses are connected to the electricity grid, fuel stacking is practised for cooking and heating due to cost factors. Wood (63%), gas (40%), and coal (17%) are the most used energy sources. The SCCS significantly reduces indoor PM 2.5 and CO exposures by more than 50% during operational and burnout phases compared to traditional stoves. The SCCS ignition phase resulted in increased concentrations between 15% and 40%. About 50% of the participants found the stove easy to use, while the other 50% faced difficulties, particularly with ignition. Overall, the SCCS operational characteristics were viewed favourably by more than 90% of the households. The SCCS serves as a pragmatic transition pathway for coal-supplied communities, offering a realistic means to reduce indoor pollutant exposure. The study establishes a compelling case for a broader rollout on the South African Highveld to meet national clean air targets. • Solid fuel stacking is practised due to affordability. • Stove use proficiency is essential for successful improved cookstove interventions. • The SCCS demonstrated improvements in indoor air quality. • Households perceive the SCCS as a preferred alternative to conventional cookstoves. • The SCCS is a viable technology for solid fuel-burning low-income households