http://www.epd.gov.hk/epd/english/environmentinhk/air/pub_consult/files/book_en.pdf
Need for Review
3.5 In October 2006, the WHO released a new set of AQGs. A number of overseas countries / economies such as the US, the European
Union (EU) and Australia have also updated their AQOs or air quality standards in the light of new scientific evidence and data
on health effects of air pollution. Annex C gives a comparison between Hong Kong’s existing AQOs, the air quality standards
being adopted by other countries / economies and the latest AQGs issued by the WHO. The current AQOs are lagging behind
those being pursued by other developed countries / economies in at least two aspects –
(a) they allow for much higher concentration levels of key
pollutants; and
(b) they do not provide for the assessment of fine suspended
particulates (FSP or PM2.5), which has been scientifically
proven to have greater adverse impact on human
health than PM10.3
3 PM10 and PM2.5 refer to particulate matters (PM) with particle sizes of less than 10 microns and 2.5 microns respectively. Recent health studies show that PM2.5 has greater association with adverse health effects and would pose a greater health risk to the public.
4.7 The current concentration levels of air pollutants in Hong Kong
are much higher than the WHO AQGs, partly due to local emissions
and partly due to regional air pollution. The regional impact
on the air quality in Hong Kong could best be illustrated by Table
4.1 below showing the compliance status at Tap Mun air quality
monitoring station, which is far away from local air pollution
sources.
Table 4.1 : Compliance Status of Tap Mun Air Quality Monitoring Station with WHO
AQGs from 2006 to 2008
Pollutant Averaging
Time
of WHO AQGs
2006 2007 2008 2006 2007 2008
4.8 The monitoring data show that even for such remote area as Tap Mun, which does not have any local emission sources, the WHO
AQGs were breached to various extents for up to half of the time in a year. It underscores the transboundary nature of the air pollution
problem facing Hong Kong. It is therefore proposed to adopt a staged approach in updating the AQOs to take account
of the local situations and prevailing international practices. The WHO AQGs will be taken as a long-term goal, the pursuit of which will be considered with reference to international practices, the latest technological developments and local circumstances.
(2) Early Retirement of Aged / Heavy Polluting Vehicles (Pre-Euro, Euro I and Euro II Commercial Diesel
Vehicles and Franchised Buses)
6.8 Euro V vehicles emit only about 30% of NOx comparing to Euro II models. Early retirement of aged vehicles (including pre-Euro,
Euro I and Euro II commercial diesel vehicles and franchised buses) and replace them with models meeting the latest Euro standards
(i.e. Euro V standards which will be in force in the EU by phases starting this year) will help reduce significantly vehicular
emissions. It is estimated that about 3,102, 300 and 184 tonnes of NOx, RSP (or PM10) and VOC emissions could be reduced respectively
following implementation of this initiative. Due to the close proximity of vehicular emissions to receptors, the consultant’s assessment shows that this initiative would generate significant health benefits.
(3) Earlier Replacement of Euro III Commercial Diesel Vehicles with Models Meeting Latest Euro Standards
6.10 Compared to Euro III models, Euro V vehicles emit only about 36% (for light duty diesel vehicles) to 40% (for heavy duty diesel
vehicles) of NOx. Assuming that 50% of the Euro III commercial diesel vehicles are replaced with new models meeting Euro
V standards, it would cut the emissions of NOx, RSP (or PM10) and VOCs by about 743, 75 and 24 tonnes respectively. This
proposed measure would generate major health benefits due to the close proximity of vehicular emissions to receptors. However,
the Euro III vehicles currently in use are relatively new (eight years old at most).Depending on the types of vehicle, their vehicle owners are likely to be more reluctant to replace them early with new ones.
Transport Management
(10) Low Emission Zones
6.17 This proposed measure seeks to ban commercial vehicles of Euro III or below standards from entering busy areas such as Central,
Mong Kok and Causeway Bay. It could help reduce the exposure of air pollutants at street levels within the low emission zones
(LEZs), although net emission reduction in the whole territory is not expected as traffic might be diverted to other areas. The assessment
conducted by the consultant shows that LEZs could bring about considerable health benefits to the population within
the zones. The cost-effectiveness of the scheme would be highly dependent upon how the proposed LEZs are to be designed and
implemented, and whether the affected vehicle owners would agree to upgrade or replace their vehicles to meet the emission standards required for entering the LEZs, including those who operate businesses or live within the zones. The potential diversion of the more polluting vehicles to other areas will need to be considered carefully in designing LEZs.
Infrastructure Development and Planning
(13) Expand Rail Network
6.20 Railway-based transportation generates substantially less air pollution than vehicles, even after taking into account emissions from
power plants which produce the necessary electricity to power the trains. Following development of the committed rail projects
including the Express Rail Line, the Sha Tin to Central Link (the Tai Wai to Hung Hom section), the West Island Line, the South Island
Line (East), the Kowloon Southern Link and the Kwun Tong Line Extension, it is estimated that the transport sector’s emissions of
SO2, NOx, RSP (or PM10) and VOCs could be reduced by about 17, 501, 46 and 207 tonnes respectively, bringing about considerable
health benefits to the community. Whilst the costs for developing the rail network are principally incurred and justified on
transport grounds, the health benefits so generated would lend additional support to the case for expanding the rail network.
(CTA Comment : but only a road , not rail link to Zhuhai / Macau on the proposed bridge is considered ! The report fails to address the 2nd highest sulphur emitter Ocean Going vessels burning 3% sulphur bunker fuel)