Sounds like you've made a very tough decision so well done for biting the bullet. I moved out here from London a few months ago (after almost 20 years in London) and like some people have already said, I don't find the pollution in HK any worse than London. In fact, compared to where I lived in London (Shoreditch), I find HK less polluted, especially for roadside pollution. Personally, I would never consider raising children in London (although clearly there are millions of people who disagree with me lol) because of not just the pollution but a whole variety of socio-economic reasons. As a relative newbie to HK who doesn't have strong feelings about the place either way, it surprises even me that I would just choose HK over London for children.