1996 — Page 133

Page 133 of 498

of 498

Page 133 of 498

130

HONG KONG URBAN COUNCIL

than on the 10th floor and above. The proportion was roughly above 2:1. In statistics, the discrepancy between them is glaring. The phase II study revealed that children living on the 20th to 29th floor had a remarkably lower occurrence of cough, running nose, allergic rhinitis or any other related symptoms. Again, this is a glaring discrepancy in statistics. The phase II study report stated that the hazard factor of living on lower floors could be easily comprehended. The main source of pollution was the exhaust from vehicles. And residents living on the 30th floor or above were more susceptible to smoke emitted from factory chimneys. The report further stated that the number of hazard factors seemed to be at the fewest on the 10th to 19th floor. As an Urban Councillor, I am not in a position to tell the citizens how to select an apartment among the middle floors, higher floors and lower floors. I just wish to emphasise that pollution is caused by many different factors.

The above findings do not necessarily form a standard formula applicable to all districts. However, the housing estate having been studied is not exceptionally pollution-prone; rather, it passed the general requirements of the EPD. Therefore, it can be said that the findings indicate a general situation. In fact, all households within every building are affected by the following climatic and microclimatic factors. They include, first, the dust level outdoor, on-street and around the neighbouring buildings; second, wind direction and wind speed—including the ones of continental wind because, according to the EPD, sustained continental wind, be it regional wind or microclimatic wind, will bring forth plenty of dust; third, types of vehicles in the traffic flow; fourth, the distance between a building and chimneys or construction sites; fifth, orientation of a building and windows; sixth, pollution within the building; seventh, floor level and other factors.

Since there are a number of climatic factors and variables, it is virtually impossible to carry out microclimatic assessments at all locations and streets in urban areas. For instance, the quantity of dust particles may vary depending on the orientation of windows. Therefore, it is neither feasible to carry out such assessments nor to work out the frequency of street-washing for every street. However, you may refer to the study conducted by the EPD in Shatin. The findings are also attached in the handouts.

The study concluded that the Shatin testing site was in a busy but not relatively pollution-stricken area, where if the wind force remained weak in several consecutive days, e.g., 3 to 4 metres per second, dust would be accumulated to an unacceptable level, i.e., exceeding the U.S. standard of 150 micrograms per square metre. The Hong Kong standard of 180 micrograms per square metre is higher. Yet, the EPD has admitted that their standard is not flawless. Therefore, I shall put forward the following concrete proposals for your consideration. More importantly, every Councillor and district figures should take the initiative to express opinions matching the needs of their respective district, so that the frequency of street-washing for every street can be worked out.