Nudging for Cleaner Air: Experimental Evidence from an RCT on Wood Stove Usage

Abstract

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.

A systematic review to assess the evidence-based effectiveness, content, and success factors of behavior change interventions for enhancing pro-environmental behavior in individuals

“…All publications were published in English, dating from 2010 to 2021. As depicted in Figure 2 , four of the described studies in these publications were conducted in Australia, one in New Zealand, three in Africa (one each in Nigeria, Ethiopia, and South Africa), and six in Asia (one each in China, India, Singapore, and Taiwan, and two in Japan), 35 in North America (USA n = 32, Canada n = 3), and two in South America (Chile n = 2) (Carrico and Riemer, 2011 ; Dowd et al, 2012 ; Hall et al, 2013 ; Jacobsen et al, 2013 ; Largo-Wight and Wight, 2013 ; Cornelius et al, 2014 ; Hoicka et al, 2014 ; Matsui et al, 2014 ; Asensio and Delmas, 2015 ; Keall et al, 2015 ; Schultz et al, 2015 ; Morris et al, 2016 ; Nishida et al, 2016 ; Sintov et al, 2016 ; Staddon et al, 2016 ; Ro et al, 2017 ; Benka-Coker et al, 2018 ; Hammed et al, 2018 ; Wynes et al, 2018 ; Boso et al, 2019 ; Chiu et al, 2020 ; Malan et al, 2020 ; Jorgensen et al, 2021 ; Ruiz-Tagle and Schueftan, 2021 ).…”

“…Therefore, in Chilean households, the damper is mostly set to higher emitting settings with decreased air inflow. After field assistants provided information about the connection between damper settings and air quality including periodic check-in phone calls or visits, the individuals' behavior shifted to less polluting damper settings (Ruiz-Tagle and Schueftan, 2021 ).…”

“…For example, if regulations specify that only the sustainable option, e.g., renewable energy, is to be used as a default, every individual, business, and sector will automatically consume more sustainable energy—in a few cases even without the need for active behavior change of individuals. Governments can also take a leading role, prioritize interventions, and provide funding, which is a frequently mentioned barrier regarding interventions, their resources (e.g., staff, and technology), and their scalability (Ruiz-Tagle and Schueftan, 2021 ).…”

“…However, this policy shifted indoor air pollution to outdoor air pollution because of the stove users' behavior, thereby calling for subsequent behavior change interventions (Ruiz-Tagle and Schueftan, 2021 ).…”

“…For example, self-reported outcomes in questionnaires are vulnerable to biases such as “social desirability,” “recall,” and “reporting” (Meloni et al, 2011 ; Dowd et al, 2012 ; Revell, 2014 ; Sintov et al, 2016 ; Staddon et al, 2016 ; Ro et al, 2017 ; Iweka et al, 2019 ). Additionally, an individual's behavior might change simply by taking part in an intervention study (Hawthorne effect) (Iweka et al, 2019 ; Ruiz-Tagle and Schueftan, 2021 ). Furthermore, RCTs are not common in research regarding PEB-promoting interventions but would yield the most robust evidence.…”