Ключевые слова: adult, air, asian, backpack, bad, care, city, coronavirus, covid19, disease, downtown, environment, epidemic, face, female, flu, girl, health, ill, infection, influenza, mask, medical, outbreak, people, pm 25, pollution, prevention, problem, protect, protection, protective, safety, sick, smog, street, surgical, thailand, train, traveller, urban, virus, walking, weather, woman,