# Dynamic Infrared Thermographic Evaluation of Facial Thermal Response During Face Mask Wearing

## TL;DR

This study uses infrared thermography to track facial temperature changes during mask use, finding that the inner canthus is a reliable reference point.

## Contribution

A novel infrared thermography protocol is proposed to assess dynamic facial thermal responses during mask wearing.

## Key findings

- Facial temperature changes during mask use follow a reproducible pattern across participants and mask types.
- The inner canthus shows high sensitivity to thermal variations, making it a suitable reference region.
- Infrared thermography enables non-contact assessment of dynamic facial thermal behavior during mask use.

## Abstract

What are the main findings?
Dynamic facial temperature changes during mask use were captured using a four-stage infrared thermographic protocol.The inner canthus exhibited high sensitivity to temporal facial temperature variations.

Dynamic facial temperature changes during mask use were captured using a four-stage infrared thermographic protocol.

The inner canthus exhibited high sensitivity to temporal facial temperature variations.

What are the implications of the main findings?
Infrared thermography enables non-contact, protocol-based assessment of dynamic facial thermal behaviour.The inner canthus is a suitable reference region for thermographic facial measurements.

Infrared thermography enables non-contact, protocol-based assessment of dynamic facial thermal behaviour.

The inner canthus is a suitable reference region for thermographic facial measurements.

The study proposes a sensor-based experimental protocol for quantifying dynamic facial temperature changes during face mask use by means of infrared thermography (IRT). Eight face masks, including filtering respirators, surgical masks, and one textile mask, were evaluated on three participants under controlled indoor conditions. Thermographic data were acquired at four defined measurement stages: prior to mask application, immediately after donning, after 15 min of continuous wear, and immediately after removal. The measurements reveal a reproducible temporal temperature pattern across participants and mask types, consisting of an initial cooling phase, subsequent heat accumulation during wear, and a pronounced temperature increase following removal. Thermal variations were observed both in mask-covered and uncovered facial regions. The inner canthus exhibited high sensitivity to these changes, supporting its use as a stable reference area. The study demonstrates the suitability of IRT for protocol-driven, non-contact assessment of dynamic facial thermal response during mask use.