Karunch,
I am very familiar with the SARS outbreak (as longtime readers here may recall). The "escalation" of respiratory problems that you refer to is a myth caused by the hysteria surrounding the whole episode. The number of deaths from pneumonias (of all kinds) during the SARS period was not significantly different from that during other years. Moreover, senior medical people have been quoted as saying that many of the relatively few SARS deaths were caused by the "treatment" rather than by the virus, and for some unfortunates who survived the treatment the complications continue.
I haven't the time at the moment to do the comparison on other respiratory problems, but as Shortly says, the incidence of asthma in many western countries is increasing at an alarming rate. Personally, my feeling is that this is far more linked to the "vaccinate against everything and do everything possible to avoid exposure to things that might help children develop a healthy immune system" mentality that seems prevalent in many western countries than it is linked to increases in pollution.
I am unable to consult my GP (or Ame, whatever that is) on the simple grounds that I don't have one, having had no need to consult a doctor for over 15 years, excluding a couple of sporting injuries. I like to think that this is not unrelated to the fact that I have an immune system developed by exposure to chickenpox, mumps, measles, scarlet fever and other stuff which kids these days aren't allowed to catch.
But we are way off topic here, so I guess we will just have to agree to disagree. Like Shortly, for me the upside of living in HK far outweighs the downside so I am planning to stay here for the foreseeable future.