Christep, may I suggest you talk to your Ame or Gp (as I did) regarding this issue. They are the ones dealing with respiratory problems on a regular basis and will no doubt enlighten you. Life expectancy is too simple for this (and does not consider cause of death), you need to compare the incidence of respiratory problems in Hkg to the countries you list and then see how respiratory problems feature as cause of death. Anecdotal evidence suggests the respiratory problem of Sars would not have escalated as it did had Hkg (and other polluted cities)residents not been particularly prone to respiratory illness.
Finally, take a look out the window and try telling me you are happy your kids are breathing that air. Cheers.