Thermal comfort of personal protective equipment (PPE) wearers in different temperatures and activity conditions

Abstract

To avoid virus infections, healthcare workers have to wear personal protective equipment (PPE) during work. However, the high temperature and humidity in PPE threaten their physical and mental health. In this study, thermal physiological and psychosocial responses of PPE wearers at different temperatures (26 °C, 30 °C) and different combinations of alternating activity intensities (transcribing/sitting, walking/standing) were observed by experiments. The results show the increase in ambient temperature has a greater influence than the activity intensity on the increase in average skin temperature, whereas the opposite is true for heart rate and tympanic temperature. The thermal physiological state of the participants is mostly affected under ThAh condition. The average weight change can reach 586.8 g, and the participants' heart rate, average skin temperature, and tympanic temperature can reach 133bpm, 36 °C, 37.8 °C, respectively. Due to significant heat accumulation, the average heart rate during 100–120 min (standing), exceeding 120 bpm, was even higher than that during 40–60 min (walking) and the tolerance time for thermal discomfort for PPE wearers may not exceed 100 min under ThAh condition. And the discomfort caused by wearing masks and high humidity are the two most frequently reported occurrences. Furthermore, forehead, chest, and back are suggested to be primarily considered for maximum effectiveness if designing improvement measures to optimize thermal comfort for PPE wearers. This study adopted an experimental condition design that alternated between different activity intensities to reflect the working states of healthcare workers, providing a better understanding of the thermal physiological state of healthcare workers wearing PPE and could serve as a reference for future research in developing PPE cooling strategies.