Wearing a mask can limit the spread of the new crown. Can it still send science?

Wearing a mask can reduce the spread of the new crown virus, which is justified in the minds of many people

Let's take a look at what this paper says

However, researchers pointed out that whether masks are really effective in daily life is still a controversial topic

Are general surgical masks really useful? Some previously published studies indicate that the effect may be limited or even no effect

In this study, the scientists established a virus transmission model that can not only explain these conclusions, but also quantitatively analyze the actual utility of masks

Specifically, they assume that the probability of each virus particle infecting a person is equal, and based on how many virus particles are in the air, they can calculate the corresponding probability of infection

▲The virus concentration in the environment has a significant impact on the effectiveness of masks (picture source: reference [1])

In other words, when the virus concentration reaches a certain value, the difference between wearing a mask or not may not be very big

In order to better understand the relationship between masks and the total number of viruses, researchers have done more research

Some people may ask, does a large number of aerosol particles and droplets mean that there are more viruses? Researchers also thought of this

As mentioned earlier, a person can exhale 3 million particles and droplets in half an hour, but there may only be 53 coronaviruses (common coronaviruses found in the past that only cause mild symptoms), 38 influenza viruses, And 96 rhinoviruses

Generally speaking, in the environment where ordinary people live, the level of the new coronavirus is actually not high

Of course, this is still a relatively large range, and the corresponding infection rate is also low and high

▲The protective effect of not wearing a mask, wearing a general surgical mask, and wearing an N95 mask when sneezing (A), coughing (B), talking (C), and breathing (D), it can be seen that general surgical masks and N95 masks have similar effects (Image source: Reference [1])

Let's just say the conclusion

Researchers also subdivided the question of "who wears a mask".

Of course, the paper also pointed out that in order to achieve the best protective effect, it is also necessary to wear a mask on both sides

▲People who are infected with the new crown and those who are susceptible wear masks.

Taken together, the important point of this study is to find that the protective effectiveness of masks is not a pure linear relationship as previously assumed
.
According to previous assumptions, no matter how high the risk of virus infection is, as long as you wear a mask, you can achieve the same protective effect
.

However, this study points out that when the number of viruses is limited, masks can better filter residual viruses; and in environments with high numbers of viruses (such as hospitals for treating patients with new crown infection), ordinary surgical masks may not be enough.

.
In order to obtain protection, people also need more advanced masks, supplemented by other protective equipment, and other measures such as social isolation
.

The researchers summarized the significance of their research at the end of the paper: When ordinary people are watching epidemic-related videos, they will see that a single cough can cough up millions of small particles, so they worry about whether the filtering effect of masks will be insufficient.

.
This study pointed out that even though the number of these particles seems to be huge, only a few particles carry the virus, so the level of the virus in the environment in which ordinary people live is actually low
.
Wearing a mask at this time can further reduce the spread of the virus, which has practical significance
.

Reference materials:

[1] Yafang Cheng et al.
, (2021), Face masks effectively limit the probability of SARS-CoV-2 transmission, Science, DOI: 10.
1126/science.
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