While the increment in temperature and humidity can alleviate or exacerbate occupational heat strain, the correlations between temperature, humidity, and heat stress exposure level are not well defined across a wide range of hot environments in the construction sector. To this end, this study seeks to quantify the impact of varying levels of humidity and temperature on heat stress exposure levels at construction sites. For this purpose, 10 able-bodied workers were prompted to perform common construction tasks (roofing and material handling) while exposed to varying levels of temperature and humidity. During each task, three biosignals, namely photoplethysmography (PPG), electrodermal activity (EDA), and skin temperature (ST), were collected from the workers through wearable biosensors. To assess the workers' heat stress level, various metrics were extracted from PPG, EDA, and ST signals. Correlation analysis shows that air temperature and humidity are highly correlated with the workers' extracted physiological metrics. Analysis revealed compelling evidence for the temperature and humidity ranges that would harm construction workers. This study can inform new plans and policies for occupational health agencies, potentially maintaining health and productivity in a construction site.
