Exposure to ambient air pollution has been shown to be detrimental to human health and has motivated many policies to reduce such pollution. However, given that humans spend 90% of their time indoors, it is vital to understand the degree of exposure to indoor air pollution (IAP) in the general population and ways to reduce such pollution. We design and implement a field experiment in London that monitors households’ IAP and then randomly allocates some households to real-time feedback on their air pollution exposure at home. We find that access to real-time monitor readings yields a significant reduction in indoor IAP levels during the evening time (4 pm-11 pm) in which residents are more likely to be home. Furthermore, the treatment increases the likelihood of being in a healthy IAP range and reduced the likelihood of being in a hazardous range. We also find initial evidence that the provision of real-time pollution information might lead to improved health and well-being outcomes and estimate the WTP for pollution monitors and air purifiers.