5.
air quality IMPACT
Introduction
5.1
This section presents the potential
air quality impacts associated with the construction and operation of the
Project. Air sensitive receivers (ASRs)
in the vicinity of the site were identified for this study. Dust impact from the construction activities
of the proposed works and emissions (e.g. nitrogen dioxide) from helicopter
were identified as the potential environmental impact to the surrounding ASRs
during construction phase and operation of the Project. Mitigation measures required to protect the
ASRs were recommended, where necessary.
Environmental
Legislation and Standards
5.2
The criteria for evaluating air
quality impacts and the guidelines for air quality assessment are laid out in
Annex 4 and Annex 12 of the EIAO-TM, respectively.
Air Quality Objective & EIAO-TM
5.3
The Air Pollution Control Ordinance
(APCO) provides the statutory authority for controlling air pollutants from a
variety of sources. The Hong Kong Air Quality Objectives (AQOs), which stipulate
the maximum allowable concentrations over specific periods for typical
pollutants, should be met. The relevant AQOs are listed in Table 5.1.
Table
5.1 Hong Kong Air Quality
Objectives
|
Pollutant
|
Maximum Average Concentration (µg m-3) (1)
|
|
|
1-Hour (2)
|
8-Hour (3)
|
24-Hour (3)
|
Annual (4)
|
|
Total
Suspended Particulates
|
-
|
-
|
260
|
80
|
|
Respirable
Suspended Particulates (5)
|
-
|
-
|
180
|
55
|
|
Sulphur
Dioxide
|
800
|
-
|
350
|
80
|
|
Nitrogen
Dioxide
|
300
|
-
|
150
|
80
|
|
Carbon
Monoxide
|
30,000
|
10,000
|
-
|
-
|
(1) Measured at 298 K and 101.325 kPa.
(2) Not to be exceeded more
than three times per year.
(3) Not to be exceeded more
than once per year.
(4) Arithmetic mean.
(5) Suspended particulates in
air with a nominal aerodynamic diameter of 10 mm or smaller.
5.4
The EIAO-TM also stipulates that the
hourly total suspended particulates (TSP) level at sensitive receivers should
not exceed 500 µg m-3 (measured at 25°C and one atmosphere) for construction dust impact assessment.
Air Pollution Control (Construction Dust) Regulation
5.5
Notifiable and regulatory works are
under the control of Air Pollution Control (Construction Dust) Regulation. Notifiable works are site formation, reclamation,
demolition, foundation and superstructure construction for buildings and road
construction. Regulatory works are
building renovation, road opening and resurfacing, slope stabilisation, and
other activities including stockpiling, dusty material handling, excavation,
concrete production, etc. This Project
is expected to include notifiable works.
Contractors and site agents are required to inform EPD and adopt dust reduction
measures to minimize dust emission, while carrying out construction works, to
the acceptable level.
Description of
the Environment
5.6
The MFT building is located at the
seafront of Sheung Wan which is an urban area with high density of commercial
buildings. Emissions from marine
vessels (e.g. nitrogen oxides) is potential air quality pollutant sources in
the study area. The dominant pollutant
sources identified within the study area including:
·
Ferry emission: travelling between MFT
and Macau;
·
Ferry emission: travelling between MFT
and Mainland China.
5.7
There are currently two fixed air
quality monitoring stations, namely Central/Western (situated at the Upper
Level Police Station, High Street, Sai Ying Pun) and Central (situated at the
Junction of Des Voeux Road Central and Chater Road), which are located near the
Study area operated by Environmental Protection Department (EPD). The annual averages of pollutants in mg m-3 monitored at these two stations for the year 2002 & 2003 are
summarized in Table 5.2.
Table
5.2 Annual Average of Pollutants
in mg/m3
|
Pollutants
|
Central / Western
|
Central
|
|
2002
|
2003
|
2002
|
2003
|
|
Total
Suspended Particulates
|
61*
|
75
|
-
|
-
|
|
Respirable
Suspended Particulates
|
41*
|
53
|
68
|
77
|
|
Sulphur
Dioxide
|
20*
|
18
|
19
|
13
|
|
Nitrogen
Dioxide
|
46*
|
52
|
90
|
96
|
|
Carbon
Monoxide
|
-
|
NA
|
1404
|
1129
|
Note: * Asterisked values are below their respective
minimum data requirement of 66% for number of data within the period.
NA
– Insufficient data for calculation of annual average values.
Air Sensitive
Receivers
5.8
Representative air sensitive receivers
(ASRs), which are in the vicinity of the site, were identified, in accordance
with the criteria stipulated in the EIAO-TM.
The selected ASRs are the worst affected sensitive receivers and were
identified based on the latest Outline Zoning Plan and Layout Plan. Representative ASRs are summarised in Table
5.3 and their locations are shown in Figure 5.1. The assessment height of the ASRs and the
closest distance between the ASRs and the proposed new helipad are also
presented in Table 5.3.
Table
5.3 Summary of Representative Air
Sensitive Receivers
|
ASR
|
Description
|
Closest
distance between ASR and Proposed New Helipad (m)
|
Assessment
Height Above Ground Level (m)
|
|
A1
|
Sheung
Wan ex-Gala Point
|
237
|
1.5
|
|
A2
|
Sheung Wan Fire Station
|
410
|
1.5
|
|
A3
|
Waterfront Divisional Police Station, Sheung Wan
|
267
|
1.5
|
|
A4
|
Tennis
court at Shun Tak Centre
|
60
|
44
|
|
A5
|
Queen’s
Terrace
|
483
|
1.5
|
|
A6
|
Ka
On Building
|
212
|
4.5
|
|
A7
|
The
Bauhinia
|
165
|
4.5
|
|
A8
|
Vicwood
Plaza
|
213
|
1.5
|
|
A9
|
Harbour
Building
|
279
|
1.5
|
|
A10
|
Macau Ferry Terminal (Fresh air intake location at
Deck 4, refuge area, flat roof – the nearest ASR to the Proposed New Helipad
and refuelling facilities)
|
16 (vertical distance,
below the helipad)
|
21.4 (above sea level)
|
Identification
of Potential Impact
Construction Phase
5.9
The aluminium design for the proposed
new helipad would be built on the roof-top of the existing Inner Pier at the
MFT using existing pile caps on site.
No marine piles would be required and no dredging of marine sediment
would be carried out for the Project.
There would not be any demolition of existing structures for the
expansion works. Gaseous emission from
construction plant would be limited as a few construction plants would be
operated in a small size of work site during the construction phase. Dust nuisance would unlikely be associated with
the renovation, extension and re-location of the existing heliport supporting
facilities.
Operation Phase
5.10
In the existing condition, the maximum
allowable number of helicopter movements per hour was 8 (i.e. 4 landing and
take off cycles) during 0800 – 1800 hrs.
The total number of helicopter movements at existing helipad during 1801
– 2259 hours was 28 and the maximum allowable number of helicopter movements
per hour during 1801 – 2259 hours would be 6 (i.e. 3 landing and take off
cycles).
5.11
With the addition of proposed new
helipad at the MFT, the maximum allowable number of helicopter movements per
hour would be increased from 8 to 16 (i.e. 4 landing and take off cycles on
each helipad per hour) during 0800 – 1800 hrs.
The maximum allowable number of helicopter flights at existing helipad
or proposed new helipad during 1801 – 1900 would still be remained as 6 (i.e. 3
landing and take off cycles per hour).
According to the recommendations from Section 3, the maximum total
number of evening (1901 – 2259 hours) flight movements for existing and
proposed new helipad would be 34.
Referring to different possible scenarios (Table 3.18), the
maximum allowable number of helicopter movements would be 22 at existing
helipad or proposed new helipad during 1901 – 2259 hours. With this projection, the maximum number of
helicopter movements at existing or proposed new helipad would be 6 movements
(3 landing and take off cycles) per hour.
The current and future maximum flight frequency at existing helipad and
proposed new helipad are summarised in Table 5.4. The provision of additional helipad would
increase the helicopter emission during 0800 – 2259 hours. As identified, ASR A10 would be the nearest
ASRs located to the proposed new helipad.
The maximum allowable number of helicopter movements per hour at each
helipad was considered in the assessment as a worst case scenario.
Table 5.4 Current and Future Maximum Frequency
at the Existing MFT Helipad and Proposed New Helipad
|
Item
|
Current
Operation Mode
(Allowable
Condition)
|
Future
Operation Mode
|
|
Flight frequency
|
Time: 0800-1800
Existing Helipad –
Max 8 movements per hour (i.e. 4 LTO per hour )
|
Time: 0800-18:00
Existing
Helipad – Max. 8 movements per hour
Proposed New Helipad – Max. 8
movements per hour
|
|
Time 18:01 – 22:59
Existing
Helipad – Max. 6 movements (in average) per hour (i.e. 3 LTO per hour)
|
Time: 18:01 – 22:59
Existing Helipad – Max. 6 movements (in average) per hour
(i.e. 3 LTO per hour)
Proposed New Helipad – Max. 6 movements (in average) per
hour (i.e. 3 LTO per hour)
|
5.12
As identified in Section 5.6, ferry
emissions are potential air pollutant sources in the study area. As the Outlying Pier No.2 and No.3 are
located over 400m from the proposed subject site, no significant impact would be
expected at the nearest ASR A4 & A10 due to emissions from these
ferries. However, the emission from
ferries between MFT and Macau or between MFT and Mainland China during idling
and travelling, would contribute a cumulative air quality impact to these ASRs.
5.13
Regarding the traffic emissions, the
road traffic emissions of the nearest roads to affecting the study area include
Connaught Road Central, Connaught Road Flyover, Des Voeux Road Central and
Queen’s Road. The horizontal separation
distance between the MFT and the nearest major road, Connaught Road Central, is
approximate 150m. The locations of the
ASR A4 and A10 which are the worst affected by helicopter emissions are sited
at the roof of the Shun Tak Carpark and Deck 4 of the MFT, respectively. In view of large separation horizontal and
vertical separation distance between the ASRs and the roads, the air quality
impact due to traffic emissions on these ASRs would be insignificant. Further, as and some ASRs, including ASR A4,
are located between the ferry/helicopter and the vehicular emission sources,
the cumulative air quality impact from road traffic emissions on these ASRs
would also be insignificant.
Assessment
Methodology
Construction Phase
5.14
Due to limited construction work for the
Project and less dusty construction activities, significant dust impact and gas
emission from operated plants would not be expected. Quantitative assessment is
therefore considered unnecessary.
Operation Phase
5.15
The Industrial Source Complex Short-Term
(ISCST3) dispersion model was used for determination of the hourly NO2
concentrations arising from the operation of both existing MFT helipad and
proposed new helipad at the closest ASRs, Tennis Court at Shun Tak Centre (ASR
A4) and the fresh air intake at MFT Building Deck 4 (ASR A10). As a conservative approach, 4 landing and
take off cycles (LTO) per hour per helipad during 0800 - 1800 (the maximum
capacity of each helipad), and 3 landing and take off cycles (LTO) per hour per
helipad during 1801-2259 (the maximum capacity of each helipad), was assumed in
the assessment. For the calculation of
the NO2 concentrations, the emission factor for NOx was used and the
conversion factor from NOx to NO2 was assumed to be 20%.
5.16
The engine of Sikorsky S76C+ which is
currently used at existing MFT helipad is Turbomeca Arriel 2S1. As there was no information of emission
factor provided by the helicopter operator and manufacturer, the emission
factors
of a similar engine – T58-GE-8F were adopted in the assessment and summarised
in Table 5.5.
Table 5.5 NOx
Emission Factor of Engine T58-GE-8F
|
Helicopter Mode
|
NOx (lb/min)
|
|
Approach
(Approach + Hovering to Landing)
|
0.098
|
|
Idling
|
0.006
|
|
Takeoff
(Hovering to Take Off + Take Off)
|
0.143
|
5.17
The duration of each helicopter mode
was make reference to the average values of the findings from the surveys at
existing MFT Helipad conducted on 13 & 27 January, 23 March and 4 April
2005. Detail calculation of helicopter
emission factor is presented in Appendix 5.1.
5.18
In view of cumulative air quality
impact at the ASRs, the dominant air pollutant sources, emissions from the
Ferries during idling at the MFT and travelling within the study area, were
considered in the assessment. The
existing sailing schedule of Ferries at MFT piers is summarised in Appendix
5.1. According to the fact sheet in
the website of Shun Tak – China Travel Ship Management Limited, the concerned
ferries are installed with diesel gas turbine engines. In the absence of the emission
characteristics of their gas turbine engines, it may be more appropriate to use
the emission factors given in Table 3.1-1, USEPA AP 42 (5th
edition) and Analysis of Commercial Marine Vessels Emissions and Fuel
Consumption Data. The possible
types of ferry used at MFT including TriCat, Flying Cat, FoilCat, Jetfoil and
PS – 30 Jetfoil. As a worst-case
scenario, TriCat (Caterpillat Solar Taurus gas turbine), which has the greatest
engine power of 2 ´ 5220 kW, was assumed in the assessment. ISCST3 Model was used for determination of the hourly NO2
concentrations arising from the ferry travelling and idling. Based on the Analysis of Commercial
Marine Vessels Emissions and Fuel Consumption Data from USEPA, the load
factor of passenger vessel in idling mode was 10%. While the load factor for ferry during travelling was assumed
full load. The conversion factor from
NOx to NO2 was assumed to be 20%.
5.19
Based on the site survey, the engine
power would be turn off after landing and turn on before abroad. The idling period was observed as 20 minutes
per ferry.
5.20
According to the sailing schedule,
number of ferry movements during daytime and nighttime are summarized in Table
5.6. As a worst case scenario, for
each hour during daytime, it is estimated that 4 ferries and 1 ferry would be stayed at Inner Pier and Outer Pier
respectively; for each hour during night-time, 3 ferries would be stayed at
Inner Pier per hour and 2 ferries would be stayed at Outer Pier.
Table 5.6 Number
of Ferry Movements at MFT
|
Ferry Route
|
No. of Ferry Movements (daytime)
|
No. of Ferry Movements (night time)
|
|
MFT
to Macau
|
82 (07:00-19:00)
|
40 (19:01-02:30)
|
|
MFT
to China
|
22
(07:00-19:00)
|
10
(19:01-21:30)
|
5.21
The ferry exhaust emitted during
travelling would be modelled as elongated area sources, Regarding to the high temperature at the engine exhaust,
a relatively plume rise would be considered in the model. Detail emission calculation is presented in Appendix
5.1.
5.22
The meteorological data measured at
the Central (Star Ferry Pier) station of Hong Kong Observatory in Year 2003
were assumed in the ISCST3 model.
5.23
The background pollutant values adopted
for assessment were based on the EPD “Guideline on Assessing the ‘TOTAL’ Air
Quality Impacts”. The latest five
years (1999 – 2003) average monitoring data from EPD air quality monitoring
station at Central/Western, background
of NO2 (), was adopted as NO2 background
concentration. The background air
pollutant concentrations used in the assessment was 54 mg/m3.
Evaluation of
Potential Impacts
Construction Phase
5.24
Due to limited construction work for
the Project and less dusty construction activities, significant dust impact and
gas emission from operated plants would not be expected.
Operation Phase
5.25
Having considered the helicopter
emission from both existing and proposed new helipad, vessel idling and cruise emission
of Ferries at MFT, the predicted maximum 1-hour averaged NO2
concentrations for the representative closest ASRs (A4 & A10) are evaluated
and the results are summarized in Table 5.7. Results indicated that the closest ASRs would comply with the AQO,
therefore, the other identified ASRs, which are located further away from the
proposed new helipad, would also be in compliance with the AQO.
Table 5.7 Predicted
1-hour Average NO2 Concentrations at the Representative ASRs
|
ASRs
|
Cumulative 1-Hour Average NO2 Concentrations (mg/m3)
|
|
A4
|
94
|
|
A10
|
123
|
Note:
Background NO2 concentration of 54 mg/m3
is included.
Mitigation
Measures
Construction Phase
5.26
To ensure compliance with the guideline
level and AQO at the ASRs, dust mitigation measures stipulated in the Air
Pollution Control (Construction Dust) Regulation should be incorporated in the
contract document to control potential dust emission from the site. The control measures relevant to this
Project are listed below:
·
skip hoist for material transport
should be totally enclosed by impervious sheeting;
·
Any furnace, boiler or other plant or
equipment or use any fuel that might in any circumstance produce smoker should
not be installed; and
·
the contractor shall not burn debris
or other materials on the work areas.
5.27
In view of limited scale of the
Project, dust nuisance during construction phase would be expected to be insignificant
with the implementation of dust suppression measures stipulated in the Air
Pollution Control (Construction Dust) Regulation.
Operation Phase
5.28
No adverse air quality impact would be
expected during the operational phase.
Construction Phase
5.29
With the incorporation of the Air
Pollution Control (Construction Dust) Regulation, adverse residual impact would
not be expected.
Operation Phase
5.30
No adverse residual impact would be
expected during the operation phase.
Environmental Monitoring and Audit
Construction Phase
5.31
With the implementation of appropriate
mitigation measures stipulated in the Air Pollution Control (Construction Dust)
Regulation, dust levels at all ASRs would be expected to comply with the
criteria. Dust monitoring during the
construction stage is considered not necessary, however, site audit is
recommended to be conducted to check that the dust control measures are properly
implemented. The environmental audit
requirement is described in the standalone EM&A Manual.
Operation Phase
5.32
The helicopter emission from proposed
new helipad would be expected to be insignificant to the surrounding
environment. EM&A programme during
the operation phase is considered unnecessary.
Conclusion
5.33
No adverse construction dust impact
would be expected at the ASRs in vicinity of the project site due to less dusty
construction activities and with the implementation of effective dust
suppression measures during construction. Insignificant emissions from the
helicopters operation at proposed new helipad at MFT Building to the
surrounding environment would be expected.
The predicted hourly NO2 concentration at the nearest ASRs in
vicinity of the proposed new helipad would comply with the AQO in view of
cumulative emission from nearest existing pollutant sources.