But the durability of some coronavirus on a surface does not mean that it remains just as infectious as the hours go by. Most virus particles degrade in a matter of minutes or hours outside a living host, and the quantity of infectious particles goes down exponentially over time. Outside, on an inanimate surface, the virus will gradually lose the ability to be an infectious agent. A person sneezing on a surface may deposit many thousands of virus particles, and some may remain viable for days. Simultaneously, people in the United States have been urged by the CDC to clean and disinfect surfaces in their homes.

Source: Washington Post March 13, 2020 12:02 UTC