Mask manufacturers believe that regular mask replacement is common sense, but the replacement cycle is not the same, so how long is the replacement cycle of the mask? What? There are professional PM2.5 masks and masks with replaceable filters, medical masks, cotton masks. Different types of masks have different names. Professional PM2.5 protective masks (such as N99 masks and N95 masks) will be replaced after two days of use, otherwise they will not have a good protective effect. In addition, these masks are not suitable for long-term use, because they have good air tightness, which can easily lead to breathing difficulties and hypoxia. Mask manufacturers believe that they can choose according to environmental quality. If the air quality is good, they can choose ordinary dust masks. For masks embedded in an environment with poor air quality, the replacement cycle is also relatively short, otherwise the goal will not be achieved. Mask summary, the replacement cycle of the mask is not fixed, and even depends on the specific environmental quality.