If it is a new medical mask can be worn directly, if the non-medical fabric mask, it is recommended to wash and then wear. If it is a newly purchased disposable mask, or sterilized medical masks, generally can be worn directly, medical masks in the packaging will be sterilized, generally new medical masks will have a smell, is the residual flavor of ethylene oxide sterilization, can be worn directly. If it is an ordinary fabric mask, generally will not be sterilized, it is not recommended to buy and wear directly. This type of masks in the process of processing, transportation, sales and other processes usually go through a number of transit and contact, so it is relatively unclean, there may be a certain amount of dust or bacteria, it is best to wash it before wearing it. Mask is a hygiene product, the main role is to help filter the air inhaled into the mouth and nose, non-medical fabric masks can not be very good isolation of viruses, it is recommended to try to choose the regular medical masks, when buying.