Chemical Composition and Emissions Factors for Cookstove Startup (Ignition) Materials

Abstract

Exposure to household air pollution from residential cookstoves is a leading risk factor for disease globally. Previous work suggests that a disproportionate fraction of emissions can occur during cookstove startup; however, these data are limited to a few materials and pollutants. This study is the first to isolate emissions from cookstove startup across a range of startup materials and pollutants.Laboratory tests were conducted to measure emissions from commonly used cookstove startup materials: kerosene, plastic bags, newspaper, fabric, food packaging, rubber tire tubes, footwear, kindling, and wood shims. Tests were designed to isolate emissions from the startup material, using a generic cookstove to simulate a real-world cookstove startup process. We measured pollutants relevant to health and climate, including: carbon monoxide, carbon dioxide, methane, fine particulate matter mass (PM2.5), PM2.5 elemental and organic carbon, volatile organic compounds (e.g., benzene, toluene), and carbonyls (e.g., formaldehyde, acetaldehyde).Emissions varied substantially across materials on a per-startup event basis. For example, PM2.5 emissions were lowest for food packaging (8 mg/startup) and plastic bags (2 mg/startup) and highest for kerosene (496 mg/startup) and kindling (355 mg/startup). Carbon monoxide emissions ranged from 30 mg/startup (plastic bags) to 999 mg/startup (kerosene). Emissions of carcinogens and other hazardous pollutants similarly varied by one to two orders of magnitude between materials. Our results demonstrate that startup materials can contribute substantially to the overall emissions from a cooking event. Startup material choice is particularly important for cleaner stove/fuel combinations, where emissions from the main cooking event are lower and the contribution from startup material is proportionally larger. The incremental increase in emissions from startup materials is expected to have a larger marginal health impact with cleaner stoves.