On my recent trip to NY, I began to understand the invisible villain that was pollution. Cities in South East Asia have their levels of pollution as well, I find you notice it a lot sooner because the air also feels and looks dirty. When I was NY, the air was a lot dryer and although it looked a lot clearer than countries, like China or Vietnam, there was a certain weight to it. Maybe I'm just used to the crisp air of Sydney. It was through this trip, that I noticed the difference between my skin and the skin of local New Yorkers. (P.S. I know this is a sort of generalisation but there are also numerous cases that support this fact).