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

John W Cherrie,Shuohui Wang,Charlotte Wendelboe-Nelson,William Mueller,Miranda Loh

doi:10.1038/s41370-018-0089-y

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 wear-time, 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.

Highlights

Respirators have been an integral part of protecting workers who may need to be in situations where the air around them contains high concentrations of hazardous pollutants
We have shown that in practice many subjects were not motivated to keep a diary record of when they wore a facemask during their daily activities, so iButton data can overcome this obstacle
From the results of our pilot study, we believe that this type of measurement device is an essential part of any attempt to quantify the actual effectiveness of respirators in protecting individuals who have pre-existing cardiovascular or respiratory disease from particulate air pollution

Summary

Introduction

Respirators have been an integral part of protecting workers who may need to be in situations where the air around them contains high concentrations of hazardous pollutants. Respirator may not provide consistent and effective protection and so the attribution of any physiological changes to reduced exposure is uncertain [4]. A simple method for effectively monitoring respirator wear is needed. This study investigates the potential for a simple temperature and humidity logger to both assess wearer compliance and a potential health impact

Methods

Results

Conclusion