When people in HK get sick, they would always use facial mask to prevent bacteria from spreading. This is not that popular before we are hit by SARS 10 years ago.
Because we have this previous history in our region, we take extra care of how we may affect others and eventually our region as a whole. Although SARS may not be a happy history for us, but we all learnt a really good lesson to care about our love and our region. We place our respect to the doctors and nurses more because of their scarify. We feel thankful that we fight it through and our city is still lovely.
But tell you what, I'm not wearing the mask because I'm sick, it's because I need to clear up my messy room.. Haha.. This is used to prevent the dirt from going into my face and noise. Just that when I picked up the facial mask, I recalled our meaningful history and would love to share them with you! Hope that you understand hk a bit more now. Cheers!