True dat. When I was in the Philippines in 1994 people were wearing masks in the cities. The pollution was nasty in the dense cities, but in the rural areas the air was nice with some of the clearest night skies I've ever seen.It’s not just Hong Kong. I lived in Seoul, Korea and it was very common for people to wear masks while out and about. I imagine other eastern Asian cultures do this as well. When you’re living in a city the size of Seoul that is so densely populated and you’re in close proximity at all times, it makes sense. Plus, the yellow dust periodically coming from China clouds the sky and no one wants to breath that.