The main parameters of meltblown cloth include filtration efficiency and flow resistance (including inspiratory and expiratory resistance in mask use).
High quality meltblown cloth has higher filter efficiency and lower resistance.
Conventional meltblown cloth is mainly mechanical barrier, because of the aperture structure and distribution problems, the filtration efficiency of fine particles including air dust, aerosol, bacteria, viruses is not high.
In order to improve the filtration efficiency, the aperture must be reduced. By increasing the gram weight, the fiber diameter of the meltblown cloth is hardly lower than 1um, which will lead to the decrease of porosity and thus increase the air flow resistance.