When I was in Japan for business, I wondered the same thing. There were people wearing masks on trains, subways, etc. There was no emergency or disease (that I knew about) on the loose. We’re talking the late 90’s, a period of relative calm compared to the last several years.
I didn’t want to be impolite and ask “Hey! You! What’s up with the mask?!” but I found out that there’s a bunch of people in Japan who are, for lack of a better or more graceful word, hypochondriacs. They’re concerned about germs, air pollution, “bad mists” and so on - all the time.
Some older women wearing masks on trains were truly terrified to see me and my fellow engineer (from Canada) step onto their trains. We towered over the average females at 6’1”+, both of us wearing boots and our appearance simply terrified a great number of women, especially those 60+ years old. With our beards and red or blonde hair, they openly stared at us, clutched their purses tighter and moved well back into their seats.
At first, it was funny. Then tedious. And after awhile, it was annoying and tedious.
But they are what they are. They’re hyper-concerned about germs, dirt, foreign substances, you name it.
You should see the produce in their markets. Really. You’ve probably never seen such perfect fruit in your life, and I’m sure you’ve probably never seen it wrapped and packaged in a more wasteful manner to comply with the Japanese obsession for purity in their food.
If you were in a large city , many people may have been wearing masks due to the air pollution levels .
I have lived in Japan since 1985 . I for one am glad kids at my school wear masks in class when they have colds . : )