Abstract: “Exposure to ambient air pollution has been shown to be detrimental to human health and productivity and has motivated many policies to reduce such pollution. However, given that humans spend 90% of their time indoors, it is important to understand the degree of exposure to Indoor Air Pollution (IAP), and, if high, ways to reduce it. He designs and implements a field experiment in London that monitors households’ IAP and then randomly reveals their IAP in real-time. At baseline, he finds that IAP is worse than ambient air pollution when residents are at home and that for 38% of the time, IAP is above World Health Organization standards. Additionally, he observes a large household income-IAP gradient, larger than the income-ambient pollution gradient, highlighting large income disparities in IAP exposure. During his field experiment, he finds that the randomized revelation reduces IAP by 17% (1.9 µg/m3) overall and 34% (5 µg/m3) during occupancy time. He shows that the mechanism is households using more natural ventilation as a result of the feedback (i.e., opening up doors and windows). Finally, in terms of welfare, he finds that: (i) households have a willingness to pay of £4.8 ($6) for every 1 µg/m3 reduction in indoor PM2.5; (ii) households have a higher willingness to pay for mitigation than for full information; (iii) households have a price elasticity of IAP monitor demand around -0.75; and (iv) a £1 subsidy for an IAP monitor or an air purifier has an infinite marginal value of public funds, i.e., a Pareto improvement.”
Bio: Sefi Roth is an associate professor of environmental economics in the Department of Geography and Environment at the London School of Economics. He is the founder and co-leader of the Economics of Air Pollution (EAP) research group at the Grantham Research Institute on Climate Change and the Environment and a Research Affiliate at IZA. His research focuses on the economics of air pollution, examining the effects of both ambient and indoor air pollution on health, human capital, crime, the housing market, and the broader economy. Roth holds a Ph.D. in Economics from Royal Holloway, University of London.