Facial Skin Temperature and Discomfort When Wearing Protective Face Masks: Thermal Infrared Imaging Evaluation and Hands Moving the Mask

Abstract

Individual respiratory protective devices and face masks represent critical tools in protecting health care workers in hospitals and clinics, and play a central role in decreasing the spread of the high-risk pandemic infection of 2019, coronavirus disease (COVID-19). The aim of the present study was to compare the facial skin temperature and the heat flow when wearing medical surgical masks to the same factors when wearing N95 respirators. A total of 20 subjects were recruited and during the evaluation, each subject was invited to wear a surgical mask or respirator for 1 h. The next day in the morning at the same hour, the same subject wore a N95 mask for 1 h with the same protocol. Infrared thermal evaluation was performed to measure the facial temperature of the perioral region and the perception ratings related to the humidity, heat, breathing difficulty, and discomfort were recorded. A significant difference in heat flow and perioral region temperature was recorded between the surgical mask and the N95 respirator (p < 0.05). A statistically significant difference in humidity, heat, breathing difficulty, and discomfort was present between the groups. The study results suggest that N95 respirators are able to induce an increased facial skin temperature, greater discomfort and lower wearing adherence when compared to the medical surgical masks.

Keywords: COVID-19; Infection control; Infrared Imaging; N95 respirators; protective face masks; surgical mask.

Figure 1

N95 mask group: The infrared images of facial skin temperature distributions associated with the use of a ventilation mask in male subject prior to applying the mask, with the mask applied, and after removal of the mask. The values specified on the thermal images are the local temperatures at the sites of interest (bridge of the nose, two cheeks, and chin), averaged in the respective marked regions (bounded by ellipses). All temperature values are in Celsius.

Figure 2

Surgical mask group: The infrared images of facial skin temperature distributions associated with the use of a ventilation mask in male subject prior to applying the mask, with the mask applied, and after removal of the mask. The values specified on the thermal images are the local temperatures at the sites of interest (bridge of the nose, two cheeks, and chin), averaged in the respective marked regions (bounded by ellipses). All temperature values are in Celsius.