Probability of particulate matter infection by wearing a ffp2 mask| KENJOY

Wearing ffp2 masks and keeping social distance can effectively reduce the spread of germs and harmful particles. However, due to the complexity of airborne diseases, it is difficult to quantify their effectiveness, especially in the case of one-to-one contact. Here, we introduce the concept of upper limit of one-to-one contact with infectious human respiratory particles.

Benefits of ffp2

To calculate the risk of exposure and infection, we used a comprehensive respiratory particle size distribution data; expiratory flow physics; leakage of various types and fitness masks measured for human subjects; taking into account the shrinkage of environmental particles caused by evaporation; rehydration, inhalability and deposition in the susceptible airway.

We found that for typical harmful particulate load and infection dose, only the social distance, even at 3.0 m between two speakers, reached the upper limit of 90% of bacterial infection risk after a few minutes. If only susceptible people wear masks with infectious speech within 1.5m, the upper limit is significantly lower; that is, using surgical masks, the upper limit reaches 90 per cent after 30 minutes, while using FFP2 masks remains around 20 per cent even after an hour. When both people wear surgical masks, the very conservative upper limit remains below 30 per cent after an hour, but when both men wear appropriate FFP2 masks, the upper limit is 0.4 per cent. We concluded that wearing the right ffp2 mask in the community can provide excellent protection for others and yourself, and make social distance less important.

Air propagation velocity

Infectious airborne diseases are transmitted directly and indirectly from the infected to the susceptible. One indirect route of transmission is airborne particles released from the infectious respiratory tract, namely nose / mouth, pharynx, throat, trachea and lungs-here we use the term "particles" to refer to particles suspended in the air at < 1-mm, regardless of their composition.

The composition and size of human respiratory particles vary greatly and span decades on a length scale. It has been found that the concentration and size of exhaled particles depend to a large extent on the type of respiratory activity, for example, speaking or singing compared to breathing. Respiratory activities related to sound production, namely sound pressure, peak airflow frequency and pronounced consonants, strongly affect particle emission.

Infectious respiratory particles may contain single or multiple copies of the pathogen when exhaled by an infected person, and there is a risk of infection at the absorbed dose when inhaled by a susceptible person. In addition, relative humidity and temperature affect the drying and settling of wet particles due to gravity when they are exhaled into the environment.

There is also a long-standing debate about the actual meaning of aerosols or droplets. At the heart of these arguments is our lack of understanding of how airborne diseases spread, or simply how particles produced in the infectious respiratory tract are transmitted through the air, how they change in the environment, and where and how they spread. The number of them deposited in the respiratory tract of the susceptible. Simple as it may seem, the detailed mechanisms involved in each part of these processes are extremely complex.

The above is the introduction of the probability of particulate matter infection by wearing ffp2 masks. If you want to know more about ffp2 masks, please feel free to contact us.