WHO recommends mask-wearing in indoor spaces with inadequate ventilati… stocking 0 67 2020.12.03 09:34 https://youtu.be/zDxVs1Z4enQ + 16 WHO "환기 충분치 않으면 실내서도 마스크 착용해야" The World Health Organization updated its mask-wearing guidelines in a bid to lower the risk of COVID-19 ...