Response to “Comment on ‘COVID-19, the Built Environment, and Health’”

Abstract

I thank Drs. Erren and Lewis for highlighting the role of daylight and of the circadian timing system in human health and well-being. Their observations about the potential of COVID-19 restrictions to disrupt circadian rhythms are well placed. Providing more daylight in the built environment nicely exemplifies the complexities in seemingly simple solutions. On the positive side, generous windows can provide not only daylight but also a substantial cobenefit: views of vegetation and other natural features. Evidence from homes, schools, offices, and health care settings suggests the value of such views (Elsadek et al. 2020; Ko et al. 2020; Li and Sullivan 2016; Ulrich 1984). On the negative side, generous windows create challenges with respect to thermal loading and energy demand, especially in hot and cold environments (Alwetaishi and Benjeddou 2021). Excessively hot or cold indoor environments undermine comfort and performance and may threaten health, and increased energy use, if sourced from fossil fuel combustion, also threatens health. These challenges must be addressed through careful window design and placement, choice of glass, and shading (Gasparella et al. 2011; Kiran Kumar et al. 2017). Drs. Erren and Lewis’s excellent points remind us that optimizing light exposure, like so many environmental health interventions, requires systems thinking, multidisciplinary collaboration, and thoughtful trade-offs.