This is not correct. Before covid only people who felt like thay might have a cold or similar wore face masks, to reduce risk of infecting others.
(This is my understanding after living there for one year and then travelling for a month every other year for ~20 years. I’m not native though so there may be some nuance to mask wearing I’m missing)
IIRC, I've also read that they consider it helpful for allergy season. Japan supposedly has one of the worst allergy seasons in the world due to misguided industrial policy around timber.
TL,DR; After WWII Japan heavily incentivized reforestation to provide cheap domestic timber for industrial and defense purposes, but only with two types of trees, Japanese cedar and Japanese cypress. It turns out that even with this explicit industrial policy, it's cheaper to import timber, so trees weren't being cut down as fast as expected and the forestry industry had a declining workforce that couldn't maintain the forests. The resulting bi-cultural conifer forests grew so thickly that no sunlight reached the forest floor and these forests became devoid of biodiversity. And now all of these trees release a lot of pollen.
In Japan this isn’t really a problem, since the forests are clearly able to breed if they are growing denser, and the streets are mostly not wide enough to have trees except maybe on major roads.
That’s just false. In many places in Asia it’s considered a must to wear a mask when you’re sick, but nobody in Japan is wearing it 24/7. Not sure where you got this information from.
