Kaitlyn Kelly

Project title: Informing the use of N95 respirators by the general public to reduce wildfire smoke exposure

Degree: MPH | Program: Environmental and Occupational Health (EOH) | Project type: Thesis/Dissertation
Completed in: 2020 | Faculty advisor: Tania M Busch Isaksen


Climate change is increasing the frequency, intensity, and duration of wildfires. To reduce personal exposure to wildfire smoke and resulting adverse health effects, N95 respirators are increasingly used by the general public to filter out fine particles (PM2.5) present in smoke. When mandated in an occupational setting, the use of N95 masks requires medical clearance, proper training, and fit testing. This rigorous attention to training and proper respirator fit is generally, neither required or practiced by, the lay public. A literature resource summary was conducted to understand the current state-of-knowledge around the use of N95 respirators and training in occupational and other settings to inform novel use for the general public during wildfire smoke events. The goal of this study pilot was to assess the efficacy of training materials by quantifying the transference of knowledge from selected interventions into N95 respirator fit in a convenience sample of untrained, lay public. This is the first study to assess efficacy of N95 respirator training materials for the general public during wildfire smoke events. To this end, we administered a Knowledge, Attitude and Practices (KAP) survey to identify baseline knowledge and training retention; conducted a quantitative respirator fit test prior to, and after, each participant received their randomly assigned training material; and observed and analyzed the actions taken by participants during the donning process that affect fit. This study found that without prior knowledge, the selected trainings significantly improved fit, but fit factors equivalent with occupational use were not observed. Pre-training fit testing found that most individuals achieved a fit factor of 2, a 50% decrease in particulate exposure. Post-training fit testing found most individuals reached a fit factor of at least 10, an expected 90% reduction in exposure. In comparing participants pre-intervention KAP survey results with initial fit factors, participants tended to overestimate their knowledge on proper fit. We found that the selected factsheet and manufacturer training significantly improved the fit factor of participants, though the improvement did not achieve the passing fit factor of 100 for required use in an occupational setting. In the absence of fit testing, effective training and risk communication is necessary for the use of N95 respirators by the general public. With training, N95 respirators can provide protection for the general public during wildfire smoke events, but without proper use, N95 respirators may not reduce PM2.5 exposure to levels considered safe for public health. The results of this study will provide evidence on the efficacy of N95 respirators and training for proper fit as a personal intervention to reduce exposure to wildfire smoke. URI