Personal Monitoring of Occupational Heat Exposure among Grounds Management Workers: Preliminary Results from Three University Campuses

Ambient heat exposure is a major threat to occupational health, particularly for workers who engage in activities requiring much physical exertion and who spend the majority of their workday in hot and sometimes humid environments. To date, most strategies aimed at reducing occupational heat exposure are based on data obtained from fixed locations across broad geographic areas and are not work place specific. However, this particular approach can miss important spatial and temporal variability in the meteorological conditions experienced by workers, as well as details in the physiological, behavioral, and social factors that drive susceptibility to heat-related health outcomes. In this presentation, we will discuss preliminary results from a study of personal heat exposure among grounds management (e.g. landscape) workers during a 4-week period from July to August 2016 at three university campuses: Appalachian State University in Boone, NC (moderate heat environment), North Carolina State University in Raleigh, NC (extreme heat environment), and Mississippi State University in Starkville, MS (extreme heat and humid environment). Personal heat exposure was measured using Thermochron iButtons that measure ambient air temperature and Hygrochron iButtons that measure ambient air temperature and relative humidity surrounding the workers as they went about their workday. Specifically, we will examine how personal heat exposure varied among outdoor workers at each campus and how the temperature and humidity experienced by these workers compared to official weather observations at fixed locations (i.e. automated weather stations at nearby airports). To better understand the factors that drive differences in personal heat exposure, we linked the iButton measurements to various environmental, physiological, and behavioral characteristics of the workers (e.g. their location on campus, activity level, heart rate, reported symptoms of heat stress) using daily activity logs and GARMIN GPS Smartwatches. By doing so, we can better understand where and why exposure is the greatest, and determine which individuals are most at risk for heat-related health outcomes. The results of this work may be used to inform more targeted occupational health interventions and heat warning systems.