One film was a tank truck and a big one, with the owner wearing a special mask
Among the indicators of the mask, the greatest concern is the filtration efficiency of particulate matter. So before you buy masks, you can learn more about the efficiency of various standards of particulate filter. NIOSH in the "N95" of particles as small as 0.3 micron filtration efficiency up to 95%. In fact, the highest level of particle filtration efficiency required in the ASTM and FFP standards is higher than that of NIOSH N95. For example, ASTM Level 3 to 0.1 micron particles as small as the filtration efficiency of the 98%
To say that the standard, we are most familiar with should be 3X brand N90, N95 series masks, they are named after the NIOSH standard. In addition to the NIOSH standards, there are also common American Materials Laboratory Association ASTM standards, China's KN standards and European FFP standards, can be used to measure important indicators of masks.
When buying anti fog masks, one can see the standard, two can see the filter efficiency.
