"Before (I came to) China, I used to do ice hockey and jogging, but since I came to Beijing, I don't do them anymore."

Camille Chanlair, 26, who arrived from France in 2008.

"I think Beijing is really a cool city. There is music and art and there are interesting people doing very creative things. There are a lot of things I've found in Beijing that can't be found anywhere else.

But you know, it's not worth it. My family sends me news reports about the pollution in Beijing and friends send me messages. They worry about me living here."

David Clough, 30, from Florida, United States

"In the short term, the pollution isn't going to make me pack up and leave Beijing, but it's certainly one of the few reasons why I won't be settling down here for the long term."

Sarah Morrison, Canadian national, Consultant at Hill+Knowlton Strategies Beijing