Nudging for cleaner air: experimental evidence from an RCT on wood stove usage

Air pollution from wood burning is a serious problem in the developing world. In the cities of south-central Chile, households experience extremely high ambient air pollution levels due to massive combustion of wood as fuel for residential heating. To address this problem, in recent years new residential wood stoves—equipped with improved combustion technologies that are designed to be less-polluting—have replaced high-polluting ones. However, users’ behaviour in operating these improved stoves is a key factor that drives actual emissions. When users ‘choke the damper’ to extend the burning time of their wood fuel, it constrains the air flow in the wood stoves and creates a highly polluting combustion process. To address this issue, a behavioural intervention was designed to provide users with real-time feedback on their wood stoves’ air pollution emissions with the goal of ‘nudging’ them to use their stoves in a less polluting way. The intervention consists of an information sign that aligns with the wood stove’s damper lever and informs users about pollution emission levels according to the chosen setting of the wood stove’s damper. The information sign is complemented by the visit of a field assistant that explains the sign and provides an informational flyer (fridge magnet). To assess the effectiveness of this behavioural intervention a randomized controlled trial was conducted with selected households in the city of Valdivia, Chile. Results from this intervention show that households that were provided with the information sign reduced the frequency with which they used the most polluting settings of their stoves, inducing a behavioural change that results in a 10.8% reduction in residential pollution emissions.