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

Tianwei Tang; Yongcheng Zhu; Xiaoqing Zhou; Zhisheng Guo; Yudong Mao; Huilin Jiang; Zhaosong Fang; Zhimin Zheng; Xiaohui Chen

doi:10.1016/j.buildenv.2022.108932

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

Build Environ. 2022 Apr 15:214:108932. doi: 10.1016/j.buildenv.2022.108932. Epub 2022 Feb 23.

Authors

Tianwei Tang¹, Yongcheng Zhu², Xiaoqing Zhou^{1

3

4}, Zhisheng Guo¹, Yudong Mao¹, Huilin Jiang², Zhaosong Fang^{1

3

4}, Zhimin Zheng^{1

3

4}, Xiaohui Chen²

Affiliations

¹ School of Civil Engineering, Guangzhou University, Guangzhou, 510006, China.
² The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
³ Academy of Building Energy Efficiency of Guangzhou University, Guangzhou University, Guangzhou, 510006, China.
⁴ Guangdong Provincial Key Laboratory of Building Energy Efficiency and Application Technologies, Guangzhou University, Guangzhou, 510006, China.

Abstract

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.

Keywords: ASV, Air movement sensation vote; Human body; MASV, Mean air movement sensation vote; MTSV, Mean thermal sensation vote; Masks; Operative temperature; PD, Unacceptable percentage; PMV, Predicted Mean Vote; PPD, Predicted Percentage Dissatisfied; RH, Relative humidity; SET*, Standard Effective Temperature; TSV, Thermal sensation vote; Ta, Air temperature; Thermal sensation; Tmrt, Mean radiant temperature; Top, Operation temperature; University library; Va, Air velocity.