Biomass cookstove emissions—a systematic review on aerosol and particle properties of relevance for health, climate, and the environment

Abstract Around one-fourth of the global population lacks access to clean fuels and technologies for cooking, most of them living in low- and middle-income countries. Reliance on rudimentary and inefficient biomass cookstoves results in high pollutant concentrations that adversely affect the health of those exposed to indoor air pollution, the environment, and the climate. In this study, we systematically reviewed the literature on aerosol and particle properties from biomass cookstoves of relevance to health, climate and the environment. We identified 187 articles reporting aerosol characterization (i.e. particulate mass or number concentrations, or particle size distributions). Of these, 82 presented detailed particle characterization (e.g. chemical composition), thus selected for further analysis. Articles were classified based on the reported particle properties and the study type and location, which allowed mapping research efforts to date and identifying major knowledge gaps. Most reviewed studies (39 articles) on particle properties reported particulate organic and elemental carbon composition. Despite considerable variability, the EC/TC ratio generally varied in the range of 0.1–0.4 for all cookstove technologies, indicating that organic carbon is the dominating PM fraction in biomass cookstove emissions. Findings from this systematic review highlight the need for further studies on particle properties from biomass cookstoves that use a multidimensional approach simultaneously combining several properties and different cookstove-fuel combinations. We also assessed the policy landscape, including the three main global policies concerning biomass cookstove emissions, and evaluated whether those policies included the state of the knowledge on particle properties and their adverse effects on human health, climate, and the environment. We finally identify key aspects that future policies should integrate, and critical knowledge gaps that must be filled to advance the overall development of the field. Notable was that field studies consistently report particle emission factors (PM 2.5 ) higher than the ones determined under laboratory conditions, for example, an average of 8.9 g/kg fuel (field) compared to 5.2 g/kg fuel (lab) for traditional cookstoves and 4.0 g/kg fuel (field) compared to 1.3 g/kg fuel (lab) for advanced cookstoves. Cookstove manufacturers, practitioners, policymakers, and society in general will benefit from a solid knowledge base regarding particle properties from biomass cookstoves and their related adverse effects on human health, climate, and the environment.