I think everyone is angry at pachinko parlors which continue to operate despite requests to refraining from sales and customers visiting from outside the prefecture. I do not take sides with a pachinko parlor, but from the scientific facts I tried to address this issue.
I saw the following information on the net. However, it is “undecided” and may change in the future.
Imagine that the diameter of coronavirus is 0.5㎛, and corona is not suspended in the air by itself, but is normally excreted in the air in the form of aerosol. Regarding the size of the aerosol, there is no precise rule and it is around 5 or 10 mm.
With nasal breathing, particles larger than 5-6 µm are almost completely eliminated due to the complex structure inside the nose and the resulting turbulence. Furthermore, deposition of particles with a size of 5 µm or less increases as the particles become larger due to humidification. Generally, in nasal respiration, about 50% of particles of 1 to 5 µm are deposited in the tracheobronchial region, but large particles of 10 µm or more rarely reach the tracheobronchial region. In other words, the particles that come in through nasal breath stay in the nose for a long time and do not go to the bronchi much.
On the other hand, in oral breathing, more than 95% of large particles of 10 to 20 µm are deposited in the tracheobronchi. Approximately 60-80% of the smaller 1-10 µm particles deposit at the bronchiolar level, especially 40-60% of the 1-5 µm particles at the alveolar level. In other words, corona aerosole reaches the bronchi and even the peripheral alveoli by mouth. How important is nasal breathing.
Because of this, people don’t talk much at pachinko parlors and just keep on chasing the ball, so even if it’s 3 dense, it may be hard to get infected. On the other hand, opportunities for corona infection will increase at izakaya and clubs that accompany drinking and chatting, and venues where people sing and dance.
From this, it seems reasonable to prioritize the types of industries that should be self-restraint.