What kind of masks should students wear when the school starts?
At present, China's "civil hygiene mask" group standard has been officially released. Jin Xiangyu, one of the drafters of the standard and a professor at the Textile College of Donghua University, said: Wearing a mask is to set up a "filter barrier" for your respiratory system. This barrier should not only block particles and droplets, but also ensure smooth breathing.
However, children's lungs are relatively weak. Children's masks worn for a long time first require "ventilation comfort".
In the mask group standard, it is clearly stipulated that the ventilation resistance of the adult mask must be less than or equal to 49 Pa, and the ventilation resistance of the child mask must be less than or equal to 30 Pa. Jin Xiangyu particularly reminded parents not to be blindly keen to choose N95 masks and medical surgical masks. "The ventilation resistance of these masks is around 300 Pa. Although the protection performance is high, it is not conducive to ventilation. It is not the best choice for children's daily protection.