1. Determined; the outermost layer is generally PP spunbond. The liquid particle protection filter is divided into two levels: P2 and P3.20 μm. 5L/min. BFE is a test method of Nelson laboratory in the United States. Generally speaking, different types of chemical filter boxes can prevent different types of chemical substances, such as organic, acidic, comprehensive anti-virus, ammonia, etc. P-level products are European standards.　　 3. Chinese national standard GB6223-86 UDC 614.　　

2. The particles filtered by N95 masks can be as small as 0. R series: R stands for Resistant to oil, and can be used to protect non-oily suspended particles and sweaty oily suspended particles, with a time limit of eight hours.3 microns in diameter. The inspection requirements are at least equal to the European respiratory protection FFP2 standard and the respiratory protection N95 standard. The purpose of all these is to test under such harsh conditions, if the filter material can pass the test Reaching the corresponding efficiency level, then in practical applications, it will be able to protect the health of workers more effectively. The difference with the American standard is that its detection flow rate is 95L/min, and it is dusted with DOP oil.　　 my country's standard GB19083-2003 adopts American standards in principle.

These micropores can inhale toxic vapors and toxic gas molecules with different molecular sizes into them without escaping. The activated carbon in a good chemical filter box should be densely packed, with a small particle size and a large specific surface area, so that the anti-virus time will be long, and at the same time, it must be considered that the respiratory resistance is small and comfortable to wear.1 to 0. The American NIOSH (National Institute of Occupational Safety and Health) organization divides the mask filter materials into KN95 PARTICULATE RESPIRATOR Suppliers the following three according to the lipophilicity of the material: 　　

1. The diameter of the DOP oil particles is the aggregated average particle diameter of 0.0 micron particles to detect the filter material at a flow rate of 32LPM ≥95%. When the carrier of some particulates is oily, and these substances are attached to the electrostatic non-woven fabric, the electrical properties will be reduced, and the fine dust will penetrate. 2. Taiwan’s CNS standard; 　　 3. Coronavirus pneumonia (atypical pneumonia) virus has a diameter of about 0