Field investigation of the heat stress in outdoor of healthcare workers wearing personal protective equipment in South China.

Since the advent of coronavirus disease 2019 (COVID-19), healthcare workers (HCWs) wearing personal protective equipment (PPE) has become a common phenomenon. COVID-19 outbreaks overlap with heat waves, and healthcare workers must unfortunately wear PPE during hot weather and experience excessive heat stress. Healthcare workers are at risk of developing heat-related health problems during hot periods in South China. The investigation of thermal response to heat stress among HCWs when they do not wear PPE and when they finish work wearing PPE, and the impact of PPE use on HCWs' physical health were conducted. The field survey were conducted in Guangzhou, including 11 districts. In this survey, HCWs were invited to answer a questionnaire about their heat perception in the thermal environment around them. Most HCWs experienced discomfort in their back, head, face, etc., and nearly 80% of HCWs experienced "profuse sweating." Up to 96.81% of HCWs felt "hot" or "very hot." The air temperature had a significant impact on thermal comfort. Healthcare workers' whole thermal sensation and local thermal sensation were increased significantly by wearing PPE and their thermal sensation vote (TSV) tended towards "very hot." The adaptive ability of the healthcare workers would decreased while wearing PPE. In addition, the accept range of the air temperature (T a) were determined in this investigation. Graphical Abstract.

Human thermal physiological response of wearing personal protective equipment: An educational building semi-open space experimental investigation.

With the outbreak and spread of the COVID-19 epidemic, HCWs are frequently required to wear personal protective equipment (PPE) for nucleic acid sample collection in semi-open transition spaces. Wearing PPE causes significant psychological and physical stress in HCWs. In this study, operative temperature (Top) and wet-bulb globe temperature (WBGT) were used to assess thermal conditions through field experiments, while multiple physiological parameters were measured in the subjects. The results indicated that the subjects showed statistically significant differences in thermal perception and physiological parameters with and without PPE. Using observed increases in heart rate (HR), auditory canal temperature (Tac), mean skin temperature (MST), and end-tidal CO2 pressure, subjects were shown to have an increased metabolic rate and heat storage while wearing PPE. Additionally, a decrease in oxygen concentration was also observed, and this decrease may be linked to fatigue and cognitive impairment. Moreover, HR, MST, and Tac showed a significant linear relationship, which increased with temperature and operative temperature, and the HR response was stronger with PPE than without PPE. The neutral, preferred, and acceptable temperatures were significantly lower with PPE than without PPE, and the deviations for neutral Top/WBGT were 9.5/7.1 °C and preferred Top/WBGT was 2.2/4.0 °C, respectively. Moreover, the upper limits of acceptable WBGT, 29.4 °C with PPE and 20.4 °C without PPE, differed significantly between the two phases. Furthermore, the recorded physiological parameter responses and thermal perception responses of the subjects while wearing PPE indicated that they were at risk of thermal stress. Overall, these results suggest that people who wear PPE should focus on their health and thermal stress. This study provides a reference for the development of strategies to counteract heat stress and improve thermal comfort.

Experimental investigation of the effects of personal protective equipment on thermal comfort in hot environments.

Since the outbreak of COVID-19, wearing personal protective equipment (PPE) has become increasingly common, especially for healthcare workers performing nucleic acid sample collection. A field experiment and questionnaire survey were conducted in a semi-open transition space of a university building in Guangzhou, southern China. Thirty-two subjects wore PPE to simulate nucleic acid sample collection, during which thermal parameters were recorded and subjective questionnaires were completed. The relationship between thermal sensation and thermal index was analyzed to determine the neutral temperature and comfort temperature zones. Subjects had higher requirements for thermal environment parameters when wearing PPE than when not wearing PPE, and were found to have statistically significant differences in thermal perception when wearing and not wearing PPE. Wearing PPE significantly raised the subjects' thermal and humidity sensations and restricted their airflow. Wearing PPE resulted in thermal discomfort for the subjects and a high unacceptability rate for environmental thermal parameters. The subjects wore PPE for an acceptable duration of approximately 1.5 h. The neutral operative temperatures were significantly lower when wearing PPE than when not wearing PPE, and the deviation from the neutral temperature was 9.7 °C. The neutral operative temperature was 19.5 °C and the comfort temperature zone was 17.4-21.5 °C when subjects wore PPE, demonstrating that subjects who wore PPE preferred lower temperatures. These results suggest that people who wear PPE for work, especially outdoors, should receive more attention to ensure thermal comfort and safety.

Thermal discomfort caused by personal protective equipment in healthcare workers during the delta COVID-19 pandemic in Guangzhou, China: A case study

Background In contrast to the previous COVID-19 pandemic, most frontline healthcare workers (HCWs) worked on residents’ nucleic acid tests in outdoor environments, instead of taking care of COVID-19 patients in hospitals during the hot summer of 2021. Therefore, it is necessary to investigate the prevalence and characteristics of thermal discomfort caused by personal protective equipment (PPE). Methods A cross-sectional survey was conducted online at hospitals from 11 administrative regions of Guangzhou for the assessment of thermal discomfort among HCWs from June 12–16, 2021. Univariate and logistic regression analyses were used to explore the risk factors associated with thermal discomfort. Results A total of 3658 valid responses were collected. The thermal discomfort and humid discomfort levels increased from 2.91 ± 1.19 to 3.61 ± 0.72 and from 0.98 ± 1.36 to 3.06 ± 1.1 after wearing PPE, respectively (p < 0.01). Feelings of being “very hot” and “uncomfortably humid” were the most influenced by wearing PPE, increasing from 31% to 69.1% and from 9.1% to 45.7%, respectively. There were significant increases in the thermal discomfort level (3.75 ± 0.57 vs. 3.33 ± 0.89, p < 0.01) and the humid discomfort level (3.33 ± 0.95 vs. 2.54 ± 1.19, p < 0.01) between the comfortable group and uncomfortable group, accompanied by similar patterns in the feelings of being “very hot” and “uncomfortably humid.” For general thermal-related symptoms, the most common new-onset symptom was profuse sweating (80%) followed by labored breathing (55.2%) and excessive dehydration (46.8%), while facial swelling (74%) was associated with local thermal-related symptoms, followed by hand maceration erosion (56.7%) and visual impairment (49.3%). In the multivariate analysis, the apparent temperature of the environment (≥35 °C), working in negative-pressure ambulances and outdoors, continuing to wear PPE for 1–3 days during this period, being aged >40 years, and previous experiences fighting the pandemic were independently associated with thermal discomfort (p < 0.01). Immediately after PPE removal, 32.3% of respondents considered drinking ice water/another drink, followed by 25% shortening the duration of wearing PPE and 19.1% going to the toilet. A large proportion of the participants looked forward to modifications to the material of the suit (72.9%) and mask (53.4%) for heat dissipation and dehumidification, as well as anti-fogging goggles (60.2%), adding hydration equipment to PPE (53.4%), and using soft materials to reduce pressure (40%). Conclusions Thermal discomfort is common and degrades health physiology related to PPE in summer environments. This suggests that modifications to the current working practices are urgently required to improve the resilience of HCWs and enhance their services during pandemics.

Investigation of the effects of face masks on thermal comfort in Guangzhou, China.

Wearing masks to study and work places has become a daily protective measure during the COVID-19 pandemic. In the summer of 2021, environmental parameters were monitored, and students in a university library in Guangzhou, China, were surveyed to analyze the possible symptoms of wearing masks for a long time, and to assess the sensitivity of various body parts to the environmental parameters. Concurrently, the preference of subjects wearing masks for various environmental parameters was also analyzed. Additionally, the relationship between thermal sensation and thermal index was analyzed to identify acceptable and comfortable temperature ranges. The expected duration of wearing masks was counted. Subjects wearing masks had greater requirements for environmental comfort, and reported increased thermal discomfort of the face and head, compared to those without masks. More than 70% of the subjects wearing masks reported that they experienced discomfort on their faces. Among the subjects who experienced discomfort, 62.7% reported that facial fever was the main symptom; while some reported symptoms of dyspnea (25.4%) and rapid heartbeat (9.1%). More than 75% of the subjects were expected to wear masks for 2.0 h or less. Evaluation of environmental thermal sensation, including overall, facial, and head thermal sensation, differed among subjects who wore and did not wear masks. The indexes of neutral Operative temperature/Standard Effective Temperature (T op /SET*) and preferred T op /SET* were lower among subjects with masks than among those without masks. The neutral T op /SET* deviation was 0.3 °C, and the preferred T op /SET* deviation was 0.5 °C. Additionally, the acceptable and comfortable temperature zones differed between the two cases. The subjects who wore masks preferred colder temperatures. These findings indicated that the environmental parameters should be adjusted to improve the thermal comfort of the human body while wearing masks in work or study places.