Insights into human behavior to inform exposure assessment using a low-cost, time-resolved location and activity monitoring system: a case study from a Ghanaian household energy study

Abstract

Background: Human behaviors play a key role in determining patterns of exposure to environmental pollution. A better understanding of where and how people are spending their time can generate insights into ways to reduce overall exposure and associated health burdens. We develop a low-cost location and activity monitoring system designed for use in a household energy study, but with widespread applicability across the exposure sciences. Methods: The study sample includes 41 rural and 45 urban households in Northern Ghana enrolled in the Prices, Peers, and Perceptions (P3) cookstove study. To measure minute-to-minute variation in participants’ proximity to pollution sources at home and beyond the household, primary cooks were outfitted with wireless Bluetooth proximity monitors, GPS logging devices, and accelerometers (to measure instrument compliance) for multiple 2-day deployments. Minute-level location data were categorized into distinct classifications of ‘at home’ or ‘away’ and discrete zones of proximity to stoves. We examine compliance patterns, and then focus on days with high compliance (>30% of 24hr period) to explore and model the variability of participant location among stove groups, hour of day, and urban vs. rural location. Results: Compliance is variable and low overall; we observe strong diurnal trends peaking at late morning and decreasing to lows around midnight. Focusing on a subset of 36 high-compliance deployment days, we find that location patterns can vary substantially within and between unique 24hr periods and across repeat visits. Participants are seldom compliant and away from home (<5%). While at home, participants are closest to their stoves during dinner hours (14:00-19:00) and half of that time is spent within 5 meters of stoves. Conclusions: A low-cost sensor system can provide valuable behavioral information to inform exposure assessments. Understanding how to increase compliance with these systems could unlock the potential to provide actionable information for researchers and practitioners.