LAUSR

Key Points Question What proportion of people in public places are wearing face masks without proper airtight seals, what factors are associated with face mask protection efficacy, and can they be improved? Findings This cross-sectional study, including 6003 participants wearing face masks in public places, found that face mask airtightness was commonly suboptimal, mostly secondary to gaps at the upper face mask edge. Using simple and tolerable approach of sealing the upper face mask edge with an adhesive tape was associated with significant improvement of face mask airtightness. Meaning These findings suggest that compromised protection due to suboptimal face mask airtightness was common, and use of adhesive tape to seal the upper edge was associated with easily and quickly improving the airtightness of existing masks.