Some researchers have studied the protective efficiency and wearing time of KN95 medical masks. The results show that the filtration efficiency remains above 95% KN95 wearing the masks for 2+ days, and the respiratory resistance changes little, and the filtration efficiency decreases to 94.7% for 3 days.
- The N95 is the USA standard,
- The KN95 is the China standard,
- The KF94 is the Korean standard and
- FFP2 is the EU standard. This includes the UK.
N indicates that the mask is Not resistant to oil, can be used to protect non-oil suspended particles; 95 defines that the filtration efficiency is greater than or equal to 95%, indicating that after careful testing, this respirator can block at least 95% of very small (0.3-micron level) test particles.
When worn correctly, the KN95`s filtering ability is better than the ordinary mask and medical mask. However, even if worn in full compliance, 100 per cent of the risk of infection cannot be eliminated.