You are correct to note that our preliminary estimates of health impacts of the new AQOs are worse than figures for 2007. This is because of the risk that SO2 may now be legally increased frm its present annual mean of about 22 ug/m3 up to 125!. Our prelim estimates are based on a ceiling of only 50ug/m3,not 125ug/m3. The reason is possibly that the Arup-EPD nexus does not understand ,or rejects the WHO reasoning behind the SO2 guideline. An unconfirmed report includes the observation that a senior EPD official said informally that “the WHO guideline is wrong”. It would be helpful to see minutes of meetings to see if any discussions were on this topic.
The preliminary estimates of health gains and losses from the new QO include a huge “benefit” from achieving the NO2 GL;this is unlikely to be achieved without radical and immediate changes to infrastructure,new projects ,transport vehicle standards and the use of dirty cross boundary fuels.
We shall be doing more detailed analyses on the health impact assessment.
A J Hedley;
School of Public Health
HKU ( egghead” division of Martin’s audience?)