Masks are a kind of sanitary products. Generally, they are worn on the mouth and nose to filter the air entering the mouth and nose to block harmful gases, odors, droplets, viruses, and other substances. They are made of gauze or paper. Masks have a certain filtering effect on the air entering the lungs. When respiratory infectious diseases are prevalent, working in dust and other polluted environments, wearing masks has a very good effect. Masks can be divided into respiratory masks and medical masks.

The testing items of face masks include: particle filtration efficiency (PFE), bacterial filtration efficiency (BFE), longitudinal breaking strength, transverse breaking strength, longitudinal breaking elongation, transverse breaking elongation, air resistance, air permeability, unit area deviation, appearance, width, microbial index, etc.

1. Bacterial Filtration Efficiency Test (BEF)

Filtration efficiency is the key index of mask quality evaluation. For better protection the bacterial filtration efficiency of the mask should not be less than 95%.

2.Synthetic Blood Test

After 2ml of synthetic blood was sprayed onto the outer side of the mask at a pressure of 16. 0 kPa (120 mmHg-the diastolic pressure of the heart), the inner side of the mask should not be penetrated.It reflects whether the mask can minimize the amount of liquid that penetrates the inner layer of the droplet from the outer layer of the mask.

3. Pressure Difference Test(ΔP <49Pa)

The pressure difference ΔP for gas exchange between the two sides of the mask should not be greater than 49 Pa.

4. Air resistance Test

This means that the air will have a certain degree of impact, making people unable to breathe while wearing a mask. Therefore, test the air resistance can improve the comfort of wearing a mask. The recommended indexes are air resistance ≤350Pa and exhalation resistance ≤250Pa.

5.Particle filtration efficiency（PFE）

It is to test the filtering efficiency of particulate protective masks and medical masks and to determine the resistance of ordinary fabrics and medical protective masks to the constant flow of airflow. so referring to relevant standards, the filtering efficiency of the surgical mask for non-oily particles should not be less than 30%.

Masks should be used as part of a comprehensive strategy of measures to suppress transmission and save lives; the use of a mask alone is not sufficient to provide an adequate level of protection against COVID-19.

Here are the basics of how to wear a mask:

1.Clean your hands before you put your mask on, as well as before and after you take it off.

Make sure it covers both your nose, mouth and chin.

2.Here are some specifics on what type of mask to wear and when, depending on how much virus is circulating where you live, where you go and who you are.

3.Wear a fabric mask unless you’re in a particular risk group. This is especially important when you can’t stay physically distanced, particularly in crowded and poorly ventilated indoor settings.

4.Wear a medical/surgical mask if you:

*Are over 60,

*Have underlying medical conditions

*Are feeling unwell, and/or

*Are looking after an ill family member.

5.For health workers, medical masks are essential personal protective equipment when engaging with patients with suspected, probable or confirmed COVID-19. Respirator masks (such as FFP2, FFP3, N95, N99) should be used in settings where procedures generating aerosols are performed and must be fitted to ensure the right size is worn.