Steve, I think you're mistaken about mask-wearing in Asian countries if you believe it "exudes mistrust of other people".

A medical mask is worn to protect other people from YOU. That's why the operating room crew wear masks: so they don't contaminate either their sterile instruments or the patient's open wound with whatever germs might be lurking in their respiratory tracts.

In China and Japan, people are revolted by the signs of contagious respiratory disease, such as a snotty nose. (Note to file: When in China, blow your nose privately.) People wear masks as a sign to their neighbours that they're doing their best to keep their germs to themselves.

This cultural practice may be a holdover from the epidemic of pneumonic plague that hit China in the early years of the 20th century. If so, it is a neat parallel to the disappearance of spittoons, and spitting, from public spaces in Europe and North America after the Spanish Flu pandemic, and as measures to conquer tuberculosis took hold in the 1920s and '30s.

The other important reason Asian folks wear masks is, indeed, defensive: it's to avoid inhaling industrial pollution.

Neither of these reasons implies mistrust of other people.