In-mask temperature and humidity can validate respirator wear-time and indicate lung health status

Abstract

The effectiveness of respiratory protection is dependent on many factors, including the duration and times during the day when it is worn. To date, these factors could only be assessed by direct observation of the respirator user. We describe the novel use of a data-logging temperature and humidity sensor (iButton Hygrochron) located inside a facemask to quantify respirator wear-time through supervised experiments (Phase 1) and an unsupervised wearing trial (Phase 2). Additionally, in Phase 1 the in-mask temperature was compared with measurements of exhaled breath temperature. We found humidity responds more rapidly than temperature to donning a mask, so it was considered a more sensitive measure of wear-time, particularly for short durations. Supervised tests showed that this method can provide accurate and precise estimates of weartime, although the approach may be unsuitable for use in situations where there is high ambient humidity. In-mask temperature is closely associated with exhaled breath temperature, which is linked to lung inflammation. This technique could provide a useful way of evaluating the effectiveness of respirators in protecting health in real-life situations.

Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives

“…Recently, the excellent photothermal properties of graphene in NIR regions have been utilized to increase the surface temperature and thus inactivate microorganisms [267,268]. Other 2D materials, such as MoS 2 [269][270][271][272] and graphitic carbon nitride (g-C 3 N 4 ) [273][274][275], also show attractive antimicrobial performance, while their potential antimicrobial application in air filtration needs to be further explored.…”

“…The Laboratory for Embedded and Programmable Systems (UC Davis) has also embedded oxygen, carbon dioxide, and flow sensor into an elevation training mask (Training Mask 2.0®) [331]. Abnormal breath patterns can indicate poor health or even lung disease [273,331].…”

Dermatological manifestation due to preventive measures used during COVID-19 pandemic

“…[ 7 ] High temperature and humidity are present inside the regular surgical masks. [ 8 ] Friction at mask area and at margins of mask, protruded wire of nose-bridge in reused masks, and stretch by elastic cords in retroauricular area contribute to irritation or erythema. Irritation/erythema over face was seen in 22.3% cases which is second most common condition seen in sample population.…”

“Therapeutic” facemasks

“…Thereafter, the "warming" of nasal cavity, oral cavity, pharyngeal cavity and upper airways may create SARS-CoV-2 containment environments under facemasks and cloth face coverings. Moreover, if Department of Homeland Security Science and Technology report can be extrapolated [5], personal "therapeutic" environments may get created under facemasks and cloth face coverings due to rebreathing of~95°F "hot" and~80% "humid" exhalations [7], which may constantly mitigate SARS-CoV-2 inside nasal cavity, oral cavity, pharyngeal cavity and upper airways. Interestingly, the physiological reason for intolerance to facemasks and cloth face coverings may be due to active and "warm" brain inefficiently dissipating heat across nolonger-cool nasal cavity and paranasal sinuses [6].…”