Ключевые слова: air, air pollution, allergic, background, bacteria, blue, city, concept, coronavirus, covid19, disaster, ecology, epidemic, face, face mask, filter, future, guy, health, health care, help, industry, infect, infection, infectious, isolated, man, mask, medical, medical mask, medicine, outside, people, person, portrait, protection, protective, quarantine, respirator, respiratory, sick, street, student, surgical mask, symptom, urban, virus, young,