The first one is green, which means that I have not been exposed to the polluted environment in COVID-19 before the data update date. I suggest you wear a mask when you go out and go home to change clothes and wash your hands.
The second color is yellow, which means that I may have been exposed to the polluted environment in COVID-19 in the past 14 days. The CDC reminds you to contact the local community health service center or the Center for Disease Control and Prevention, and try not to go out in the near future.
The third color is red, indicating that you have had close contact with patients in COVID-19 in the past 14 days. You should contact the local community health service center or disease prevention and control center as soon as possible to accept centralized isolation medical observation.