Microclimatic Variability and Thermal Comfort of Spectators in an Outdoor Stadium Venue

This study examines heat exposure and its impact on the thermal comfort and health of spectators within a semi-outdoor American college football stadium in the southeastern United States. Over 50 sensors were deployed during the 2016 season from late August to late November to measure temperature and humidity across various stadium locations. Significant variations in temperature, heat index, and a modified version of the physiological equivalent temperature (mPET) were found within the stadium, with some areas exceeding National Weather Service heat alert thresholds during certain games. Moreover, mean temperatures in the stadium were higher than those measured at a nearby weather station, while the mean heat index was higher in the seating areas than in other stadium locations and at the nearby weather station. Reductions in modeled wind speed resulted in significant decreases in thermal comfort and greater physical stress among spectators, particularly when the wind was calm. Heat-related illness comprised up to two-thirds of all cases treated by first aid and emergency medical services during particularly hot games. Most of these occurred in the most thermally oppressive parts of the stadium. These results highlight the need for greater monitoring of heat exposure inside stadiums, earlier implementation of heat action plans to raise awareness and educate spectators on heat mitigation strategies, and incorporation of stadium design modifications that improve circulation, increase shade, and reduce crowding.