The proper use of masks in the COVID-19 pandemic era: an experimental pilot study

초록

Community mask wearing and personal hand hygiene behaviors are emphasized as among the primary ways to impede the transmission of the coronavirus disease 2019 (COVID-19). However, there is a lack of studies on the efficacy of masks in ensuring safety. This pilot study was designed to investigate the proper use of masks by estimating the changes in temperature and humidity inside masks and examining the bacterial culture of used masks. Two points were set 100 m apart. Two masked participants were made to stand side by side then walk from the first to the second point. When the subjects arrived at the designated destination, we measured the temperature and humidity of each mask and recorded the subjective degree of discomfort on a scale of 10 points. This experiment use the same mask (cotton mask, KF94, anti-droplet mask, dental mask) was repeated ten times. Our results showed that irrespective of the mask used, the inside temperature of a mask was at an average of 2 to 3 degrees higher than the atmospheric temperature, and the humidity inside the mask was twice that on the outside. In all four types of masks investigated, bacterial culture experiments detected similar bacteria found mainly on the skin and mouth for that of the participant. For the walking test, the subjective discomfort was the highest 7.8 +/- 1.2 with the anti-droplet mask (p = 0.005). Power walking test, the subjective discomfort was the highest 9.4 +/- 0.5 with the KF94 (p = 0.063). Proper mask ventilation is advised, especially in case of subjective discomfort, but only when there is no other person within social distance or while outdoors. For hygienic reasons, discarding a used mask is recommended.

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