How long a disposable mask can be worn depends on the user and the actual situation. Disposable masks should not exceed 4 hours.
The specific time should be determined according to the environment in which you wear the mask.
If someone who comes into contact with the flu or the virus carrier needs to be replaced immediately to reduce the infection, during the prevention of the disease

What grade of mask should the dental hygienist wear?
1 Different types of masks should be selected according to different operating requirements.
2 For general diagnosis and treatment activities, you can wear gauze masks or surgical masks; you should wear surgical masks when working in the operating room or nursing patients with low immune function

N95 masks and medical surgical masks are currently very good at preventing the spread of respiratory droplets and isolating viruses and bacteria.
The difference between them should be that the sealing of N95 masks will be better.
If it is in an open environment, it is recommended to wear a medical surgical mask.

Medical surgical masks are generally made of three layers of non-woven fabrics. The material of the three-layer non-woven fabric is spun-bonded non-woven fabric + melt-blown non-woven fabric + spun-bonded non-woven fabric.
You can also use a layer of staple fiber to improve skin feel, that is, ES hot-rolled nonwoven fabric + meltblown nonwoven fabric + spunbond nonwoven fabric.
The outer layer of the mask has anti-spray design, the middle layer filters, and the memory absorbs moisture.