Christoph Reinhart, Jay Dhariwal

MIT North Court Study (journal article)

For this project we teamed up with SOOFA, an MIT Media Lab spinoff and Internet of Things (IOT) company, to develop and test a novel approach to validate the capability of biometeorological indices to predict the likelihood of urban dwellers to be outside during midday. Over a period of ten months three Wi-Fi scanners were used in a public courtyard in Cambridge, MA, to record outside dwelling patterns. Based on encrypted MacIDs courtyard attendees could be divided into 16,000 regulars and 676,000 visitors. Universal Thermal Climate Index (UTCI) predictions based on a combination of measured microclimatic conditions and mean radiant temperature simulations using ENVI-met were shown to strongly correlate with the number of regulars present during lunchtime with coefficients of determination (R2) of 92% during spring and 70% during summer/fall, respectively. Lunchtime attendance peaked for UTCI values in the thermal comfort and moderate heat stress ranges. In parallel, the probability for regulars to have lunch outside more than doubled during those UTCI conditions and the median lunchbreak length increased from 8min to 12min. These findings suggest that UTCI can be used as a reliable environmental performance metric to support the design and preservation of comfortable outdoor spaces. The reported use of public Wi-Fi data can help city governments to better understand – and potentially improve – the use of outdoor spaces while maintaining the privacy of their constituents.

Many knowledge workers are spending increasing amounts of time away from their desk

We wanted to know under what environmental conditions people decide to be outside in the MIT North Court

We positioned 3 Wi-Fi scanners for 11 months in the courtyard to correlate lunch-time presence again UTCI calculations

UTCI calculations were based on measurements, Envi-MET simulations and custom scripts

We identified 16,000 regular courtyard attendees and 676,000 visitors

UTCI calculations correlated strongly with the number of regulars present