Face Mask are not only ineffective it may cause harm

Hospitals are kept sterile and areas are cleaned regularly, even the air is filtered.

You can wear medical face mask in hospitals for long periods as the location is kept sterile, clean and dust free.

Wearing medical Face masks in public which is a non sterile location is useless.

if not changed every hour, it becomes just a dirty rag stuck to the face and just becomes a receptacle for bacterial growth and viruses making you prone to lung diseases and worst.

Dust, pollution, brake dust, bacteria, viruses all deposited into your face mask at high concentration.

so if you wear face masks in public, make sure you dispose of it and change every hour.