Viruses must have a vector to survive, and individual viruses cannot survive in air for long periods of time. According to current studies, coronaviruses can survive in air for only 2 hours, but may survive slightly longer when the temperature is relatively low and may survive on the skin surface for more than 3 hours, but the virus cannot enter the body through the skin. The survival time of the virus after leaving the body depends on the condition of the surface of the object on which it depends, as well as environmental conditions such as temperature and humidity. Generally, the survival time of the virus is longer on non-permeable surfaces such as stainless steel or plastic surfaces; it is shorter on permeable surfaces such as fiber fabrics or paper towels. The survival time of different kinds of viruses also varies. Some viruses can survive on the surface of indoor objects for more than 7 days, but their pathogenicity decreases significantly within 24 hours. Therefore, hard objects such as elevators, keys and doorknobs are virus carriers and require more care.