Kathleen Cagney, Professor of Sociology and Director of the Population Research Center at the University of Chicago, discusses the Chicago Health and Activity Space in Real Time (CHART) study on a webinar on June 8th at 12pm EST. The CHART study uses new technology to address fundamental questions in urban sociology and in life course studies of older adult health. CHART employs innovative smartphone-based methods for the identification of older adults’ activity spaces (i.e., locations of routine activities in daily life). Analyses of 450 adults from ten Chicago neighborhoods who carried smartphones for GPS tracking and ecological momentary assessments (i.e., short phone-based surveys) assess how the span, characteristics, and experiences of activity spaces vary across socioeconomic status and racial/ethnic groups. These data are then linked to Chicago-based sensor data, Array of Things, that characterize factors such as air quality. A central goal of this research program is to describe the social and spatial environments in which older adults spend their time and how activity space influences social connectedness and health, and may be an unexplored source of inequalities in health. Application of this approach to assessing COVID-19 vulnerability will be described.