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However, you shouldn't just wear a mask, you should use it properly with a proper product. These days, it's hot, so many thin masks called dental masks are used, especially depending on how you use this mask.

Let's see and refer to the experiment results of two reporters Choi Jae-young and Son Hyeong-an.

<Reporter Choi Jae-young> This

is the street in Myeong-dong, Seoul last week.

Some people wear a mask over their chin because it is hot, and some people only cover their mouths without nose.

Even couples have different judgments.

[Reporter: Do you often get off from outside?]

[Citizen: Yes, it’s too stuffy. I'm sweating a lot.] The

coverage team observed about 800 people over 4 hours, but about 8 out of 10 people were wearing masks properly on the street.

But when I went into an indoor coffee shop, the situation was different.

People sitting alone usually wear masks properly, but rather, most people with a group have problems wearing masks.

Of the 120 or so people observed over the course of 4 hours, more than half of them did not wear a mask or wore it incorrectly.

You should wear a mask better indoors, but as you can see, it wasn't.

The type of mask can also have an effect, especially in enclosed rooms.

Of course, it is popular that most masks are effective in preventing my saliva from splashing on the other side.

However, there are some differences depending on the mask to protect me.

We checked the difference by measuring the'leakage rate', which indicates how well it blocks ultrafine particles in the air, including health masks with KF80 or higher, non-woven fabric masks called dental masks, and various fashion masks.

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<Reporter Son Hyung-an>

Sprinkle fine salt powder in a closed laboratory.

Air particles smaller than saliva, the size of an aerosol.

Assuming that they are particles containing viruses, we tested how much they penetrate inside the mask.

First, KF80, a health mask.

The amount of particles entering the mask is about 1-4%.

This time, a fashion mask that has good ventilation.

Outside air can easily enter, so the leak rate cannot be measured at all.

[Kim Jae-myeong / Leak Rate Experiment Researcher: The situation where the pressure value continues to rise as minus 258, you can see that the (leak rate) is not being measured.] I

also experimented with a nonwoven fabric mask, also known as a dental mask, and the leak rate was 50. % Exceeded.

As you move your head, the contact surface between the face and the mask widens, allowing 75% of the particles to leak in, and you are finally judged unmeasurable.

[Kim Jae-myeong / Leak Rate Experiment Researcher: In the speaking motion, the leak rate (measurement) did not come out, and in the fifth motion (walking for 2 minutes without moving), the mask collapsed at this time and the leak rate did not come out.]

But this time, the non-woven fabric mask I tightened the strings of the earrings on each side to make it as close to each face as possible.

[Mask subject: (You have tightened the dental mask, how is the sensitivity of your breathing?) Certainly, air or wind does not enter the nose much more than the one that is worn loosely, and it feels tight.] The

result was a KF80 mask and It has improved to a similar degree.

The type of mask is also considered, but it is important to wear it closely above all else.

[Chun Eun-mi/Professor of Department of Respiratory Medicine, Ewha Womans University Mokdong Hospital: (mask) adheres well to the nose, so there is a support on the nose. The mask is all. You need to press it tightly to make a tight fit on your nose.

Chindo .] In the end, if you stay in a dense or confined space for a long time, wearing a health mask such as KF80 or using a non-woven mask to reduce the gap is the most effective in preventing corona.

(Video coverage: Choi Woong Choi, video editor: Jiyoung Hwang, CG: Sungyong Hong, Jaeyoung Choi, Jaeeun Sung, VJ: Youngsam Jung, Hanwook Jung, Choa Kim)

▶ "I didn't know" walking on the street… The first day of mandatory masking in Seoul