An expert survey on the material types used to start cookstoves

Household air pollution generated using solid-fuel cookstoves is a leading risk factor for morbidity and mortality worldwide. Many studies have quantified cookstove emissions with respect to the main fuels used (e.g., wood, charcoal and other biomass fuels). Anecdotal evidence suggests a variety of fuels are used to ignite cookstoves, however quantitative information on startup fuel types is lacking. Emissions from startup materials contribute to household air pollution. As such, understanding startup practices and the choices of startup materials is integral to understanding the full burden of household air pollution from cookstoves on health and the environment. We conducted an expert elicitation style survey to gather information about startup practices worldwide. Twenty-three respondents from academic and private sectors responded to a survey instrument on cookstove startup, providing information that covered 48 geographic locations across 22 countries. Responses to the open-ended questions were analyzed to quantify how startup materials vary according to factors such as location, seasonality, and the main cooking fuel/stove type. A wide variety of materials were reportedly used to ignite cookstoves, including many non-biomass materials that may have toxic combustion byproducts. Paper, plastic, agricultural wastes, waxes and other petroleum fuels (e.g., kerosene), and rubber-like materials (e.g., tires, footwear) were the most commonly indicated startup materials. Additional materials mentioned included fabrics, plastic packaging, soda bottles, snack food wrappers, and trash. Results from this survey can be used to direct future research on the impacts of startup materials on health and the environment, such as justifying the choice of materials to test in the laboratory.