An Epidemiological Investigation on Correct Wearing of Mask by Hood Test

Inclusion Criteria:

1. Healthy people with autonomous behavior ability and language expression ability who are older than or equal to 7 years old, Persons under the age of 18 need to obtain the consent of their legal guardians；
2. The subjects and / or their legal guardians have the ability to understand the contents of the study and to participate in all the research processes with the subjects；
3. People who volunteered to take part in the study；
4. There was no respiratory infection in nearly one month.

Exclusion Criteria:

1. People with a history of allergies, including those who are allergic to pollen, dust mites, etc；
2. People with any history of drug allergy；
3. People who have participated in the experiment are not allowed to participate in this study for the second time;
4. Pregnant women；
5. The healer after COVID-19 's infection；
6. After questioning, it was found that the subjects were the factors that affected the study, such as dysosmia, or those who had decreased olfactory ability due to disease, or facial paralysis, which affected the judgment of the test；
7. Those who are participating in clinical trials of other drugs / devices；
8. Subjects with poor compliance or unwilling to cooperate with the operation as required；
9. The researchers believe that any other situation that may affect the evaluation of the study.