Window opening behavior and exposure in the U.S.

Abstract

< Open windows dramatically alter occupant exposure to air pollutants of indoor and outdoor origin. However few studies have quantified the extent to which windows are open in North American residences. In this research, we use readily available data and survey instruments to understand when and how much windows are open by U.S. region. We reviewed a large set of images of residences, available from Google Streetview, to determine what fraction of these residences have windows open during the daytime (when images were collected). In addition, we surveyed 3000 randomly selected individuals across the US about window opening habits. During the 9 months of spring, summer and autumn, 20% of occupants open house windows 8 or more hours per day. Residents in the US Southeast are much more likely to keep windows closed than the rest of the country (2.8 hours vs 4.7 hours on average). Windows are more likely to be opened during the morning (28%) and afternoon (28%) than in the evening (18%). Implications: given regional differences in behavior, building construction and ambient air pollution, we anticipate significant differences in inhalation dose that may be greater than the differences in outdoor air pollution concentrations. For example, daily integrated inhalation dose of ozone in St Louis is estimated to be equal or greater than that in Atlanta, where ambient ozone concentrations trend higher. The tendency towards morning and afternoon window opening will increase relative exposure to ozone and some other photochemical oxidants. Lower window-opening frequency at night enhances exposure to indoor sourced pollutants while sleeping.