Ключевые слова: background, bacteria, best, better, blue, breath, breathing, care, choice, choices, color, compare, concept, disease, dust, effective, epidemic, equipment, face, filter, flu, health, health care, illness, industrial, infection, influenza, mask, masks, medical, medicine, outbreak, pandemic, pneumonia, pollution, prevention, protect, protection, protective, respirator, respiratory, risk, safety, spread, virus, white,