3.3              Baseline Conditions and Sensitive Receivers

3.3.1        The Project Area is predominantly of rural in nature with a few of existing major sources of air emission.  NLH is the main highway arterial route in northshore of Lantau Island which serves as the main road link between the Hong Kong International Airport and the rest of the HKSAR.  Vehicular emissions from NLH is the major local source of air pollutant which influences the air quality along the northshore of the Project Area.  A toll plaza of NLH is situated at the Tsing Chau Wan area.

3.3.2        The Penny's Bay GTP commissioned in 1992 has a generating capacity of 300 MW.  The GTP currently only serves as a peak load and emergency back-up facility for the airport, Tung Chung and the future developments along NLH and the Project Area.  Emissions from the GTP may affect air quality in Penny’s Bay.  The GTP operator, CLP Limited, has operated an air quality monitoring station in Penny’s Bay for a number of years.  The annual average sulphur dioxide (SO2) and nitrogen dioxide (NO2) concentrations were recorded as 6 and 33 mgm-3, respectively, based on information provided by CLP.

3.3.3        The existing Siu Ho Wan STW and the NLTS at Sham Shui Kok are potential sources of odour emission.  Odour control installation have been equipped at the two facilities.

3.3.4        There is currently no fixed air quality monitoring station operated by EPD within the Project Area.  The nearest EPD’s monitoring stations are located in Tsuen Wan, Central/Western and the Tung Chung station.  The latter is located along the north Lantau coast and resembles the newly developed areas to the west of the metro areas.  Data collected from the Tung Chung monitoring station may therefore be used to provide information on background pollution levels.  The air quality monitoring station has been in operation since July 1999 and the average pollution levels are summarised in Table 3.3a below.

Table3.3a - Average Pollution Concentrations Recorded in Tung Chung (µgm-3)

 

Pollutants

Average Pollution Concentration

Sulphur dioxide (SO2)

14

Nitrogen dioxide (NO2)

36

Carbon monoxide (CO)

64

Ozone (O3)

42

Respirable Suspended Particulates (RSP)

39

Total Suspended Particulates (TSP)

67

Note : Levels are based on data recorded from Tung Chung Air Monitoring Station from July to October 1999

 

3.3.5        As detailed in Section 2, new roads and railway have been proposed to serve the proposed NLDFS developments shown on the Draft RODP.  Vehicular emissions from the operation of the new roads including Route 10-NLYLH, CKWLR, distributor Roads P1 and P2 and the Theme Park Resort Road will contribute to the air pollutant levels in the Project Area.  It is understood that electric trains will be used for the PBRL hence no air pollutant emissions is envisaged from its operation.

Ozone

3.3.6        O3 is the tri-atomic form of molecular oxygen and is one of the strongest oxidising agents, which makes it highly reactive.  Most of the O3 in the troposphere (lower atmosphere) is formed indirectly by a series of complex photochemical reaction of oxygen, nitrogen oxides and reactive hydrocarbons in the presence of sunlight and warm temperature. However, it should be noted that O3 is also transported from the stratosphere (upper atmosphere),where it is formed by the action of UV radiation on O2, to the ground level under certain meteorological conditions.

3.3.7        Data collected from EPD’s monitoring stations in 1997 identified O3 episodes in Hong Kong with a maximum concentration of 270 and 243 mgm-3 monitored in Sha Tin and Central/Western respectively exceeding the one-hour Air Quality Objective (AQO).  Maximum O3 concentration of  239 mgm-3, marginally below the one hour criterion of 240 mgm-3, was recorded at Tap Mun in 1998.

3.3.8        High O3 concentrations were recorded in Tung Chung exceeding the one-hour AQO level twice over the reported period in 1999.  The first episode of high O3 concentrations was recorded on 20 August 1999 when a tropical cyclone Sam swept across the Philippines and entered the South China Sea.  The weather in Hong Kong was fine and the temperature reached a maximum of 33.2 0C.  The weather was influenced by a high pressure with a mean wind speed of 3.5 ms-1 blowing from the south west.  High O3 concentrations developed in the early afternoon in Tung Chung, Shatin and Tap Mun monitoring stations exceeding the AQO.  O3 concentration reached 335 mgm-3 at 3:00pm in Tung Chung possibly due to recirculation of air pollutants and the associated photochemistry within the Tung Chung valley causing the O3 concentration to rise and maintain at a high levels throughout the afternoon.  The high O3 concentrations recorded in Shatin (295 mgm-3) and Tap Mun (294 mgm-3) are probably due to the photochemical reaction downwind of the urban plume.  Around 200 mgm-3  of O3 concentrations were recorded for the other stations suggesting this is a territory-wide O3 episode.

3.3.9        On 12 September 1999, typhoon York developed as a tropical depression about 430 km northeast of Manila tracking westwards for 4 days before hitting Hong Kong with a Number 10 tropical cyclone warning signal hoisted on 16 September 1999.  The weather on 12 September  1999 was fine with a maximum temperature of 32.5 0C though trace amount of rainfall was recorded.  The wind was relatively calm (around 2 ms-1) blowing from west, north-west direction.  High O3 concentrations were observed on that day in Tung Chung (278 mgm-3) and Tap Mun (284 mgm-3) exceeding the AQO.  O3 concentrations recorded from Shatin and Tai Po were above 150 mgm-3  whereas the stations at Tsuen Wan and Yuen Long recorded a much lower concentration.  This was probably due to the lower pollutant emissions, in particular NOx emission from vehicles, in Tung Chung and Tap Mun than in the more urbanised areas where the high NOx emission would reduce the formation of O3 under a series of photochemical reactions.

3.3.10     The formation of O3 is a complex and regional phenomena.  The high concentrations recorded in Tung Chung may not fully represent Penny’s Bay due to potential recirculation within the steep Tung Chung valley and the photochemical reactions in a regional context.  The topography of the Penny’s Bay is surrounded by hills of less than 300 m to the east and west and a much lower ridge to the north.  A wide opening to the south of the bay provides good ventilation and reduces the potential for recirculation to occur within the bay area.  It is expected that the future O3 concentrations will follow the general pattern established within the HKSAR though the projected increase in NO emission from vehicles in the Northshore Lantau could reduce the O3 formation in the Penny’s Bay area through photochemical reactions.

3.3.11     Representative air sensitive receivers (ASRs) have been identified in accordance with the criteria set out in the EIAO TM, through site inspections and review of the Draft RODP.  As stipulated in the EIAO TM, domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public worship, library, court of law, sports stadium or performing arts centre, home for the aged and active recreational activity areas are classified as ASRs.  Representative ASRs/Assessment Points identified within the Project Area are summarised in Table 3.3b with respect to 3 broad reclamation areas to represent the worst case scenario for this fugitive dust assessment.  Reference has been made to Discovery Bay Layout Plan 6.0E1 and Peng Chau Layout Plan L/1-PCN/4 for the ASR identification.  Locations of ASRs identified are shown in Figure 3.3a.

Table 3.3b - Air Sensitive Receivers/Assessment Points

ASR

Location

Construction Phase

Operational

 

 

 

 

Stage 1

Stage 2

Stage 3

Phase

 

A1

Penny’s Bay GTP

3

3

3

3

 

A2

Possible Country Park Extension Area

3

3

3

3

 

A3

Possible Country Park Extension Area

3

3

3

3

 

A4

Possible Country Park Extension Area

3

3

3

3

 

A5

Luk Keng Tsuen

3

3

3

3

 

A6

Tso Wan Village (including the proposed Village Expansion Area)

3

3

3

3

 

A7

Discovery Bay

3

3

3

3

 

A8

Peng Chau

3

3

3

3

 

A9

Siu Ho Wan Water Treatment Works

3

3

3

3

 

A10

MTRC Siu Ho Wan Depot

3

3

3

3

 

A11

Theme Park Phases I and II

7

3

3

3

 

A12

Hotels in the Theme Park (Phase I and II)

7

3

3

3

 

A13

Divisional Fire Station (West of the Penny's Bay Rail Station)

7

3

3

3

 

A14

Divisional Police Station

7

3

3

3

 

A15

Divisional Fire Station (East of the Penny's Bay Rail Station)

7

3

3

3

 

A16

Theme Park (Phase III) Extension

7

7

7

3

 

A17

Water Recreation Centre

7

3

3

3

 

A18

Eco Park

7

7

3

3

 

A19

Siu Ho Wan Residential (R2) Development

7

7

3

3

 

A20

Housing and Commercial Developments above Siu Ho Wan Depot

7

7

3

3

 

A21

Theme Park Gateway

7

7

3

3

 

A22

Tourist and Convention Village

7

7

3

3

 

A23

Technodrome

7

7

3

3

 

A24

Recreational Development at Tsing Chau Tsai East

7

7

7

3

 

 

3.4              NLDFS Development

Construction Phase

 

Identification of Environmental Impacts

3.4.1        Impacts arising from the construction of NLDFS developments primarily relate to dust nuisance and gaseous emissions from the construction plant and vehicles, with dust generation being the major concern.  Major dust generating construction activities include reclamation, site formation, construction of residential and recreational developments, road construction, and PBRL including tunnelling works, track construction and Yam O and Penny's Bay Rail Stations works.

3.4.2        Construction of the proposed NLDFS developments will last for 31 years tentatively from Q2 2000 to 2031.  The construction activities have been broadly divided into three major stages of construction periods for the cumulative dust impact assessment.  Details of the construction and development arrangements are given in Section 2 and the construction programme is presented in Annex A.

·                      Stage 1 Construction from 2000 to 2008 including :

·                     Reclamation and construction of the Theme Park Phases I and II and its associated developments and the Water Recreation Centre;

·                     Yam O Reclamation (10 ha);

·                     SDU and SBDIV Marine Base Reclamation;

·                     construction of road networks including the CKWLR section between Yam O Interchange to the R10 toll plaza, distributor Road P2 from Yam O to Penny's Bay, and the Theme Park Resort Roads (D1 and D2); and

·                     construction of PBRL.

 

·                      Stage 2 Construction from 2012 to 2022 including :

·                     Northshore reclamation (Yam O to To Kau Wan);

·                     construction of distributor Road P1; and

·                     Siu Ho Wan reclamation and its proposed developments.

 

·                      Stage 3 Construction from 2022 to 2031 including :

 

·                      Tsing Chau Tsai East reclamation and development construction;

·                      construction of Fa Peng Fresh and Salt Water Service Reservoirs;

·                      construction of CKWLR section between R10 toll plaza to the proposed long term R10-HKLL (including the Pa Tau Kwu Interchange); and

·                      Theme Park Extension reclamation and development construction.

 

3.4.3        Fugitive dust emission from all the construction activities within the three broad construction periods have been considered in the quantitative assessment to evaluate the worst case cumulative dust impacts.

3.4.4        Dredging, placement of seawall and filling are the major construction works during reclamation. All the dredged marine sediment and marine sand fill will be transported by barges.  For this fugitive dust assessment, it has been conservatively assumed that 50% of public fill materials will be transported by barges and the remaining 50% by trucks.  All surcharge material (public fill except Penny's Bay Phase I) for the site formation will be transported by trucks.  Materials handling, wind erosion, truck haulage on unpaved roads are the major dust generating activities.  Materials handled by barged will contain high moisture content and dust emission from those materials is expected to be negligible.

3.4.5        For the CKWLR section between Yam O Interchange and Penny’s Bay roundabout, drill and blast method is required for road excavation of 340 m length with total 0.14 Mm3 of soft and 0.34 Mm3 of rock generated.  Drill and blast is also required for road excavation of a section of CKWLR at Tsing Chau Tsai headland (between Penny's Bay roundabout and Pa Tau Kwu).  The excavation work will last for 21 months with total 0.8 Mm3 of soft and 1.8 Mm3 of rock generated.  One blast will be performed per day.  It is assumed that blasting will not be conducted in parallel with other construction activities in its vicinity.

3.4.6        The PBRL comprises a new 3.6 km link from the existing Tung Chung Line at Yam O to the Theme Park and associated developments.  Tunnel works, construction of Yam O and Penny's Bay Rail Stations and track construction are the major construction activities of the PBRL.  The 850 m PBRL tunnel at Yam O will be excavated by drill and blast method for total 250 tunnel blasts and 10 surface blasts with 27,000 m3 of spoil generated.  It is expected that blasting will not be conducted in parallel with other construction activities in its vicinity.  Up to two blasts will be performed per day.  A 100 m cut and cover section has been proposed for the rail works between Yam O Station and the north portal of Yam O rail tunnel.

3.4.7        The materials handling quantities and rates are summarised in Table 3.4a below.

Table 3.4a -  Material Handling Quantities and Rates for Stage 1 Construction Works

 

Construction Activities

Duration of Construction Works (months)

Quantity of materials in m3/No. of Trucks

Material Handling Rate (m3/day) (a)

Theme Park Phase I

Dredging

9

40M

185,185 (b)

 

Public Filling + Surcharge

15

2M

5,556 (b)

 

Truck Movement

-

10 trucks/hr (c)

-

Theme Park Phase II

Dredging

45

4.9M

4,556

 

Public Filling + Surcharge

33

6.75M

8,523

 

Truck Movement

-

5 trucks/hr (c)

-

Water Recreation

Excavation

21

1M

1,984

Centre

Truck Movement

-

10 trucks/hr (c)

-

Yam O

Dredging

12

0.24M

833

Reclamation

Public Filling + Surcharge

9

0.9M

4,167

 

Truck Movement

-

3 trucks/hr (c)

-

CKWLR between

Excavation

 

 

 

Yam O Interchange and Penny’s Bay

Sand

24

0.14M

242

Roundabout

Rock

24

0.34M

590

 

Truck Movement

-

10 trucks/hr (c)

-

CKWLR between

Excavation

 

 

 

Penny’s Bay

Sand

21

0.8M

1,587

Roundabout to

Rock

21

1.8M

3,571

Pa Tau Kwu

Truck Movement

-

30 trucks/hr (c)

-

CKWLR between

Dredging

21

0.4M

789

Pa Tau Kwu

Public Filling + Surcharge

24

1.9M

4,100

to R10 Toll Plaza

Truck Movement

-

8 trucks/hr c)

-

Penny’s Bay Rail Link

Excavation (Cut and Cover Tunnel)

18

16,500

38

 

Excavation (Yam O Tunnel)

18

27,000

63

 

Other Excavation (a)

18

25,000

58

 

Truck Movement

-

20 trucks/day

-

Yam O Tuk

Excavation soft and

 

 

 

Services

rock

21

0.12M

246

Reservoir

Truck Movement

-

15 trucks/hr (c)

-

SDU and SBDIV Marine Base

Dredging

36

48,000

56

 

Public Filling + Surcharge

36

51,100

59

 

Truck Movement

-

2 trucks/hr (c)

-

Note:

(a)   Working periods are assumed as 24 days a month and 16 hours a day

(b)   Working periods for Theme Park Phase I works are assumed as 24 days a month and 24 hours a day

(c)   The materials are mainly transported by barge with limited portion of materials handled by trucks

 

3.4.8        A concrete batching plant has been proposed to the north-west of the Water Recreation Centre.  A Specified Process Licence for Cement Works under the APCO should be required for the approval of the works.

3.4.9        The construction of Road P1 comprises construction of Yam Tsai Tunnel and general road construction works.  For tunnelling works, drill and blast method will be used and the construction period will last for about 21 months.  One blast will be performed per day.  It is assumed that blasting will not be conducted in parallel with other construction activities in its vicinity.

3.4.10     The quantity of materials handled and materials handling rates for Stages 2 and 3 of the construction works are summarised in Table 3.4b and Table 3.4c, respectively.

Table 3.4b - Materials Handling Quantities and Rates for Stage 2 Construction Works

 

Construction Activities

Duration of Construction Works (months)

Quantity of materials in m3/No. of Trucks

Material Handling Rate (m3/day) (a)

Northshore

Dredging

66

0.67M

424

Reclamation

Public Filling + Surcharge

66

4M

2,525

 

Truck Movement

-

10 trucks/hr (b)

-

Road P1

Dredging

12

0.4M

1,389

 

Public Filling + Surcharge

12

0.39M

1,360

 

Truck Movement

-

4 trucks/hr (b)

-

Siu Ho Wan

Dredging

12

0.54M

1,875

Residential and School

Public Filling + Surcharge

12

2.2M

7,526

Development

Truck Movement

-

3 trucks/hr (b)

-

Note:

(a)   Working periods are assumed as 24 days a month and 16 hours a day

(b)   The materials are mainly transported by barge with limited portion of materials handled by trucks

 

Table 3.4c - Materials Handling Quantities and Rates for Stage 3 Construction Works

 

Construction Activities

Duration of Construction Works (months)

Quantity of materials in m3/No. of Trucks

Material Handling Rate (m3/day) (a)

Fa Peng Reclamation

Dredging

42

0.8M

789

 

Filling

42

3.8M

3,770

 

Truck Movement

-

10 trucks/hr (b)

-

Service Reservoir

Excavation

 

 

 

at Fa Peng

Sand

21

0.46M

913

 

Truck Movement

-

15 trucks/hr (c)

-

CKWLR from

Dredging

18

3.8M

8,854

R10 toll plaza to the long term

Filling

18

3M

6,921

R10-HKLL

Truck Movement

-

3 trucks/hr (b)

-

Theme Park

Dredging

18

1.6M

3,671

Extension

Filling

18

10M

23,148

 

Truck Movement

-

4 trucks/hr (b)

-

Note:

(a)   Working periods are assumed as 24 days a month and 16 hours a day

(b)   The materials are mainly transported by barge with limited portion of materials handled by trucks

 

3.4.11     Gaseous emissions from the construction plant comprise another sources of air pollution.  SO2, NO2 and RSP will be the major pollutants emitted from the diesel-powered equipment.  Equipment such as concrete trucks, dump trucks, excavators and backhoes are expected to contribute most of the emissions.  According to the plant list provided by the Engineer and the construction programme, a large number of the above mentioned equipment will be involved in the Theme Park Phase I works.  The total number of plant operated during the site formation of Theme Park Phase I will be approximately 74.  The emission factors for tracked loader, recommended in USEPA AP-42, are used to estimate the gaseous emissions from the construction plants.  The emission factors and the total emission rates are summarised in Table 3.4d below. 


Table 3.4d - Emission Factors and Emission Rates For Construction Plants

 

Parameter

Total Worksite Area (m2)

3.8x106

Total No. of Plant

74

Emission Factors of NOx from AP-42 (g/hr)

375.22

Total Emission Rate of NOx (g/s)

7.71

Total Emission Rate of NOx per Area (g/m2/s)

2.03x10-6

Total Emission Rate of NO2 per Area (g/m2/s) (a)

6.9x10-7

Emission Factors of SO2 from AP-42 (g/hr)

34.4

Total Emission Rate of SO2 (g/s)

0.71

Total Emission Rate of SO2 per Area (g/m2/s)

1.86x10-7

Emission Factors of RSP from AP-42 (g/hr)

26.4

Total Emission Rate of RSP (g/s)

0.54

Total Emission Rate of RSP per Area (g/m2/s)

1.43x10-7

Note:

(a)   30% of NOx is assumed to be converted to NO2 due to the distance from the construction plant to the ASRs are far away and provide more time for the conversion of NOx.

 

3.4.12     However, due to the large construction area involved, the emission rates per unit area will be very small.  Pollutant emitted will be dispersed very rapidly over this large construction area.  It is therefore, expected that air pollution impact due to construction plant operation is unlikely.

3.4.13     The North Lantau section of R10-NLYLH will be constructed tentatively from Q2 2002 to Q4 2006.  Reclamation including dredging of mud, seawall construction and filling, site formation and road constructions are the major construction works.  It is expected that less than 0.5 Mm3 of mud will be dredged.  Materials handling, wind erosion and road construction are the dust generating activities during construction.

Assessment Methodology

3.4.14     Dust emissions from the construction activities are the main pollutants during construction phase.  Total Suspended Particulates (TSP) concentration levels were predicted by the Fugitive Dust Model (FDM).  Meteorological data for 1997 from Cheung Chau weather station, operated by the Hong Kong Observatory, was employed for the construction dust modelling.  Dust emission rates and associated particle size distributions for the assessment were determined based on the Compilation of Air Pollutant Emission Factors, 5th Edition, USEPA (AP-42).  The adoption of mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation has been assumed in the assessment.  The construction works, except dredging at Penny's Bay Stage I which will be undertaken 24 hours a day, are expected to be conducted 24 days a month and 16 hours a day.  The mitigated emission rates are summarised in Table 3.4d below.  The emission rate calculations are presented in Annex B1.

Table 3.4d - Mitigated Emission Factors for Construction Activities

Construction Activities

Mitigated Emission Factors (a) (b)

Remarks

Stage 1 Construction Works

Penny’s Bay Reclamation Stage 1 and 2

Materials Handling

0.52 g/Mg

·       14,079 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Concrete Batching Plant

0.0164 kg/Mg

·       capacity: 1,500 m3/day

·       90% reduction by mitigation measures

·       density: 2.4 Mg/m3

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 15 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Water Recreation Centre

Materials Handling

0.52 g/Mg

·       1,984 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: wind speed

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 10 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Yam O Reclamation for the Temporary PTI

Materials Handling

0.52 g/Mg

·       4,167 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 3 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

CKWLR from Yam O to Penny’s Bay Roundabout

Materials Handling

0.52 g/Mg

·       242 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 10 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Road Construction

9.73x10-6 g/m2/s

·       assume 30% of the site is active

Blasting

0.00022A1.5 kg/blast

·       A = horizontal area

·       1 blast per day

CKWLR from Penny’s Bay Roundabout to Pa Tau Kwu

Materials Handling

0.52 g/Mg

·       1,587 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 30 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Road Construction

9.73x10-6 g/m2/s

·       assume 30% of the site is active

Blasting

0.00022A1.5 kg/blast

·       A = horizontal area

·       1 blast per day

CKWLR from East of Tsing Chau Tsai to R10 Toll Plaza

Materials Handling

0.52 g/Mg

·       3,299 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 8 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Road Construction

9.73x10-6 g/m2/s

·       assume 30% of the site is active

Penny’s Bay Rail Link

Materials Handling

0.52 g/Mg

·       159 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 20 trucks per day

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Blasting

0.00022A1.5 kg/blast

·       A = horizontal area

·       2 blasts per day

Yam O Tuk Service Reservoir

Materials Handling

0.52 g/Mg

·       246 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 10 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Special Duties Unit (SDU) and Small Boat Division Base

Materials Handling

0.52 g/Mg

·       59 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 2 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Stage 2 Construction Works

Northshore Reclamation

Materials Handling

0.52 g/Mg

·       2,525 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 10 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Road P1

Materials Handling

0.52 g/Mg

·       1,360 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Road Construction

9.73x10-6 g/m2/s

·       assume 30% of the site is active

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 4 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Blasting

0.00022A1.5 kg/blast

·       A = horizontal area

·       1 blasts per day

Siu Ho Wan Housing Development

Materials Handling

0.52 g/Mg

·       9,201 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 3 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Stage 3 Construction Works

Fa Peng Reclamation

Materials Handling

0.52 g/Mg

·       3,770 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 10 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Service Reservoir at Fa Peng

Materials Handling

0.52 g/Mg

·       913 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 15 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

CKWLR from R10 Toll Plaza to the Long Term R10-HKLL

Materials Handling

0.52 g/Mg

·       6,921 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Road Construction

9.73x10-6 g/m2/s

·       assume 30% of the site is active

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 3 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

 

Theme Park (Phase III) Extension

Materials Handling

0.52 g/Mg

·       23,148 m3 per day

·       moisture content: 4.8%

·       particle size multiplier: 0.74

·       u: 5.1 m/s (average wind speed from Cheung Chau Weather Station 1997

·       density of spoil: 1.94 Mg/m3

·       50% reduction by water suppression

Wind Erosion

2.69x10-6 g/m2/s

-

Truck Movements on Unpaved Haul Road

0.25 kg/VKT

·       no. of truck: 4 trucks per hour

·       silt content: 10%

·       speed: 10 kph

·       weight: 12.5 Mg

·       85% reduction by paved road

Note:

(a)   Reference to Compilation of Air Pollutant Emission Factors, USEPA (AP-42), 5th Edition

(b)   Mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation has been adopted

 

Evaluation of Impacts

3.4.15     The dust impacts of the blasting and construction of NLDFS developments for Stage 1, 2 and 3 construction works have been modelled.  Mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation have been adopted in the prediction.  The predicted mitigated hourly and daily dust impacts on the ASRs at the ground level and 10 m above ground for Stage 1, 2 and 3 are summarised in Table 3.4e, 3.4f and 3.4g, respectively below.

Table 3.4e - Predicted Cumulative Hourly and Daily Dust Level for Stage 1 Construction Works (mgm-3) (a) (b)

ASRs (c)

Location

Predicted Concentrations

 

 

Ground Level

10 m above Ground

 

 

Hourly TSP

Daily TSP

Hourly TSP

Daily TSP

A1

Penny’s Bay GTP

242

109

225

105

A2

Possible Country Park Extension

153

95

153

95

A3

Possible Country Park Extension

190

100

190

100

A4

Possible Country Park Extension

226

88

225

88

A5

Luk Keng Tsuen

214

91

200

88

A6

Tso Wan Village (including the proposed Village Expansion Area)

100

70

139

81

A7

Discovery Bay

140

82

137

82

A8

Peng Chau

158

82

155

81

A9

Siu Ho Wan Water Treatment Works

116

76

114

75

A10

MTR Siu Ho Wan Depot

107

73

105

73

Dust Criteria

500

260

500

260

Note:

(a)   Background TSP concentration of 67 mgm-3 has been included in the results

(b)   Mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation has been adopted

(c)   ASRs A11 - A24 are planned receivers during Stage 1 works and no construction impacts are expected

 

3.4.16     The above results indicate that the predicted hourly and daily TSP levels at 1.5 m above ground level are in the range of 100 - 242 mgm-3 and 70 - 109 mgm-3, respectively, while hourly and daily dust impact at 10 m above ground were predicted in a range of 105 - 225 mgm-3 and 73 - 105 mgm-3, respectively.  Highest both hourly and daily TSP level at both levels were predicted at A1 (Penny’s Bay GTP).  The predicted TSP levels at all ASRs were within both hourly and daily dust criteria with the adoption of the recommended mitigation measures in the Air Pollution Control (Construction Dust) Regulation.

Table 3.4f - Predicted Cumulative Hourly and Daily Dust Level for Stage 2 Construction Works (mgm-3) (a) (b)

ASRs (c)

Location

Predicted Concentrations

 

 

Ground Level

10m above Ground

 

 

Hourly TSP

Daily TSP

Hourly TSP

Daily TSP

A1

Penny’s Bay GTP

417

162

415

162

A2

Possible Country Park Extension Area

414

173

414

173

A3

Possible Country Park Extension Area

356

169

356

169

A4

Possible Country Park Extension Area

470

189

470

189

A5

Luk Keng Tsuen

448

235

437

231

A6

Tso Wan Village (including the proposed Village Expansion Area)

382

147

382

147

A7

Discovery Bay

377

163

377

163

A8

Peng Chau

451

185

450

185

A9

Siu Ho Wan Water Treatment Works

407

160

407

160

A10

MTRC Siu Ho Wan Depot

401

133

398

133

A11

Theme Park Phase I and II

382

156

382

156

A12

Hotels in the Theme Park (Phase I and II)

373

157

373

157

A13

Divisional Fire Station (West of the Penny's Bay Rail Station)

408

174

407

174

A14

Divisional Police Station

368

157

368

156

A15

Divisional Fire Station (East of the Penny's Bay Rail Station)

348

148

348

148

A17

Water Recreation Centre

418

154

416

154

Dust Criteria

500

260

500

260

Note:

(a)   Background TSP concentration of 67 mgm-3 has been included in the results

(b)   Mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation has been adopted

(c)   ASRs A16, A18 - A24 are planned receivers during Stage 2 works and no construction impacts are expected

 

3.4.17     The above results indicate that the predicted hourly and daily TSP levels at ground level are in the range of 348 - 470 mgm-3 and 133 - 235 mgm-3, respectively, while hourly and daily dust impact at 10 m above ground were predicted in a range of 348 - 470 mgm-3 and 133 - 231 mgm-3, respectively.  Highest hourly TSP level at both levels were predicted at A4 (Possible Country Park Extension) while highest daily TSP level at both levels were predicted at A5 (Luk Keng Tsuen).  With the adoption of the mitigation measures recommended, the predicted TSP levels at all ASRs are within both hourly and daily dust criteria.

Table 3.4g - Predicted Cumulative Hourly and Daily Dust Level for Stage 3 Construction Works (mgm-3) (a) (b)

ASRs

Location

Predicted Concentrations

 

 

Ground Level

10m above Ground

 

 

Hourly TSP

Daily TSP

Hourly TSP

Daily TSP

A1

Penny’s Bay GTP

206

111

206

111

A2

Possible Country Park Extension Area

194

109

194

109

A3

Possible Country Park Extension Area

177

96

177

96

A4

Possible Country Park Extension Area

175

90

175

90

A5

Luk Keng Tsuen

162

87

162

87

A6

Tso Wan Village (including the proposed Village Expansion Area)

271

105

260

104

A7

Discovery Bay

180

100

180

100

A8

Peng Chau

214

107

212

107

A9

Siu Ho Wan Water Treatment Works

146

84

146

84

A10

MTRC Siu Ho Wan Depot

136

79

136

79

A11

Theme Park

219

109

219

108

A12

Hotels in the Theme Park

208

106

208

106

A13

Divisional Fire Station (West of the Penny's Bay Rail Station)

197

111

197

111

A14

Divisional Police Station

210

105

210

105

A15

Divisional Fire Station (East of the Penny's Bay Rail Station)

222

120

222

119

A16 (C)

Theme Park (Phase 3) Extension

-

-

-

-

A17

Water Recreation Centre

212

104

212

104

A18

Eco Park

149

85

149

85

A19

Siu Ho Wan Residential (R2) Development

136

79

136

79

A20

Comprehensive Development Area above MTRC Siu Ho Wan Depot

139

80

139

79

A21

Theme Park Gateway

172

88

172

88

A22

Tourist and Convention Village

189

89

189

89

A23

Technodrome

205

92

205

92

A24 (C)

Recreational Development at Tsing Chau Tsai East

-

-

-

-

Dust Criteria

500

260

500

260

Note:

(a)   Background TSP concentration of 67 mgm-3 has been included in the results

(b)   Mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation has been adopted

(c)   ASRs A16 and A24 are planned receivers during Stage 3 works and no construction impacts are expected

 

3.4.18     The above results indicate that the predicted hourly and daily TSP levels at ground level are in the range of 136 - 271 mgm-3 and 79 - 120 mgm-3, respectively, while hourly and daily dust impact at 10 m above ground were predicted in a range of 136 - 260 mgm-3 and 79 - 119 mgm-3, respectively.  Highest hourly TSP level at both levels were predicted at A6 (Tso Wan Village).  The predicted TSP levels at all ASRs are within both hourly and daily dust criteria with the adoption of the recommended mitigation measures.

3.4.19     Since only Penny’s Bay GTP is located very close to the Penny’s Bay Reclamation and the dust impact on the Penny’s Bay GTP has been modelled and the results has been shown in Table 3.4e, no isopleth was therefore produced for the Stage 1 construction works.  Isopleths of hourly dust impacts on Penny’s Bay due to the stage 2 and 3 construction works and Luk Keng due to the stage 2 construction works were plotted and shown in Figures 3.4a-c respectively.  The isopleths show that there is no exceedance of dust criteria found in the Theme Park Phase I and II and Luk Keng Tsuen where is the nearest ASR identified near the northshore reclamation.

3.4.20     It is understood that the northshore reclamation will be carried out in various stages starting from the Theme Park Gateway area and end at Technodrome area.  Dust impact would only affect the adjacent development.  However, with the incorporation of the control measures stipulated in the Air Pollution Control (Construction Dust) Regulation, it is expected that the dust impact will be minimized and meet the established dust criteria.  In addition, air monitoring station at the adjacent development has been recommended in the Project EM&A Manual to ensure the dust impact from the adjacent work area is low and would not affect the adjacent development.

3.4.21     The sample output files for the dust model run are presented in Annex B2.

Cumulative Impacts

3.4.22     Cumulative dust impacts of R10-NLYLH has been assessed with Stage 1 works.  The findings from Route 10 EIA Report ([1]), indicated that the predicted hourly and daily TSP levels at ground level of the most affected area, Tso Wan, were 204 and 101 mgm-3 respectively with background of 67 mgm-3.  Therefore, the cumulative hourly and daily TSP level at ground level of A6 (Tso Wan Village) will be 237 and 104 mgm-3 respectively.  Thus, established dust criteria at all identified ASRs would be complied.

Mitigation Measures

3.4.23     The following control measures are stipulated in the Air Pollution Control (Construction Dust) Regulation and shall be implemented to limit the dust emissions from the construction sites:

·                      the stockpile shall be properly treated and sealed with latex, vinyl, bitumen or other suitable surface stabiliser if a stockpile of dusty materials is more than 1.2 m high and lies within 50 m from any site boundary that adjoins a road, street, or other area accessible to the public;

 

·                      effective dust screens, sheeting or netting shall be provided to enclose the scaffolding from the ground floor level of the building or if a canopy is provided at the first floor level, from the first floor level, up to the highest level of the scaffolding where a scaffolding is erected around the perimeter of a building under construction;

 

·                      skip hoist for material transport shall be totally enclosed by impervious sheeting;

 

·                      any excavated dusty materials or stockpile of dusty materials shall be covered entirely by impervious sheeting or sprayed with water so as to maintain the entire surface wet, and recovered or backfilled or reinstated within 24 hours of the excavation or unloading;

 

·                      stockpile of dusty materials shall not extend beyond the pedestrian barriers, fencing or traffic cones;

 

·                      dusty materials remaining after a stockpile is removed shall be wetted with water and cleared from the surface of roads;

 

·                      vehicle washing facilities shall be provided at every vehicle exit point;

 

·                      the area where vehicle washing takes place and the section of the road between the washing facilities and the exit point shall be paved with concrete, bituminous materials or hardcores;

 

·                      where a site boundary adjoins a road, streets or other area accessible to the public, hoarding of not less than 2.4 m high from ground level shall be provided along the entire length except for a site entrance or exit;

 

·                      every main haul road shall be scaled with concrete and kept clear of dusty materials or sprayed with water so as to maintain the entire road surface wet;

 

·                      the portion of road leading only to a construction site that is within 30m of a designated vehicle entrance or exit shall be kept clear of dusty materials;

 

·                      every stock of more than 20 bags of cement shall be covered entirely by impervious sheeting or placed in an area sheltered on the top and the 3 sides;

 

·                      cement delivered in bulk shall be stored in a closed silo fitted with an audible high level alarm which is interlocked with the material filling line such that, in the event of the silo approaching an overfilling condition, an audible alarm is triggered and the material filling stops within one minutes;

 

·                      silos used for the storage of cement shall not be overfilled;

 

·                      loading, unloading, transfer, handling or storage of bulk cement or any cement during or after the de-bagging process shall be carried out in a totally enclosed system or facility, and any vent or exhaust shall be fitted with an effective fabric filter or equivalent air pollution control system or equipment;

 

·                      Cement, or any other dusty materials collected by fabric filters or other air pollution control system or equipment shall be disposed of in totally enclosed containers;

 

·                      stockpile of dusty materials shall be either covered entirely by impervious sheeting, placed in an area sheltered on the top and the 3 sides; or sprayed with water so as to maintain the entire surface wet;

 

·                      all dusty materials shall be sprayed with water prior to any loading, unloading or transfer operation so as to maintain the dusty material wet;

 

·                      vehicle speed shall be limited to 10 kph except on completed access roads;

 

·                      every vehicle shall be washed to remove any dusty materials from its body and wheels before leaving the construction sites;

 

·                      the load of dusty materials carried by vehicle leaving a construction site shall be covered entirely by clean impervious sheeting to ensure that the dusty materials do not leak from the vehicle;

 

·                      the working area of excavation shall be sprayed with water immediately before, during and immediately after the operation so as to maintain the entire surface wet;

 

·                      the area within 30 m from the blasting area shall be wetted with water prior to blasting; and

 

·                      blasting shall not be carried out when the strong wind signal or tropical cyclone warning signal No.3 or higher is hoisted unless prior permission of the Commissioner of Mines is obtained.

 

3.4.24     In addition, according to the EPD’s Best Practicable Means Requirements for Cement Works (Concrete Batching Plant), the following mitigation measures should be adopted to prevent fugitive dust emissions:

·                      loading, unloading, handling, transfer or storage of any dusty materials shall be carried out in totally enclosed system;

 

·                      all dust-laden air or waste gas generated by the process operations shall be properly extracted and vented to fabric filtering system to meet the emission limits for TSP;

 

·                      vents for all silos and cement/pulverized fuel ash (PFA) weighing scale shall be fitted with fabric filtering system;

 

·                      the materials which may generate airborne dusty emissions shall be wetted by water spray system;

 

·                      all receiving hoppers shall be enclosed on three sides up to 3 m above unloading point;

 

·                      all conveyor transfer points shall be totally enclosed;

 

·                      all access and route roads within the premises shall be paved and wetted; and

 

·                      vehicle cleaning facilities shall be provided and used by all concrete trucks before leaving the premises to wash off any dust on the wheels and/or body.

 

Operational Phase

 

Emissions from Fireworks Displays at the Theme Park

3.4.25     According to the Theme Park EIA([2]) , dioxins, volatile organic compounds (VOCs), RSP and the associated heavy metals, and odour have been identified as potential pollutants emitted during the fireworks displays.  The potential air quality impacts have been addressed in the Theme Park EIA.

 

3.4.26     The Theme Park EIA([3]) concluded that the impacts from the fireworks displays are not expected.  No cumulative impacts with other emissions has been identified during the fireworks displays.

Odour Emissions from Sewage Pumping Station, Siu Ho Wan Sewage Treatment Works and North Lantau Refuse Transfer Station

3.4.27     Potential odour impacts arising from the sewage pumping stations proposed in the Theme Park Phase I and II, recreational development at Tsing Chau Tsai East, Theme Park Gateway and near Ta Pang Po, as well as the existing sewage treatment works (STW) at Siu Ho Wan and the North Lantau Transfer Station (NLTS).

3.4.28     Four sewage pumping stations are proposed above ground at the following locations:

·                      north-west of the International Theme Park and to the south of the Water Recreation Centre with a capacity of 112,000 m3/day;

 

·                      south of the proposed Recreational Development on the Tsing Chau Tsai East reclaimed area with a capacity of about 45,000 m3/day;

 

·                      Theme Park Gateway at Yam O on the Northshore reclaimed area with a capacity of about 130,000 m3/day; and

 

·                      at Tong Yip Hang near Ta Pang Po with the capacity of about 130,000 m3/day.

 

3.4.29     Odour, originating mainly from hydrogen sulphide in the sewage, could be released from the pumping station and is a potential source of nuisance to the vicinity.  As the flows of sewage are small and it is anticipated that odour suppression measures such as enclosing the odour sources and providing odour scrubbing system would be incorporated in the design of the facilities, odour nuisance from sewage would be sufficiently mitigated to meet odour criteria.

3.4.30     In addition, sewage pumping chambers with maximum capacity of about 17,000 m3/day are proposed underground along the Resort Road (D1 and D2).  As the chambers will be constructed underground, odour will not be emitted to the air and it would not cause any adverse odour impacts.

3.4.31     The Siu Ho Wan STW and NLTS are potential odour sources to the proposed residential development at Siu Ho Wan, and the SDU Base and SBDIV Base.

3.4.32     The air quality impact due to the odour emissions from the Siu Ho Wan STW has been assessed in the Siu Ho Wan STW Report([4]) .  The findings in the report indicated that with the adoption of the effective odour reduction (up to 92%) due to the chemical treatment together with other odour reduction measures such as aeration, the maximum 5-second average odour levels would comply with the guideline level of 5 OU at distances equal or greater than 300 m from the STW site boundary in the areas.

3.4.33     The nearest planned ASRs identified in our assessment, i.e., A17 (Siu Ho Wan Residential Development) and A18 (CDA Development above MTRC Siu Ho Wan Depot), are located at approximately 480 m and 350 m, respectively.  It can therefore be concluded that the odour levels at A17 and A18 would comply with the guidelines.

3.4.34     The air quality impact due to the operation of NLTS has been qualitatively discussed in the NLTS Report([5]).  Odour will be produced during the tipping of the refuse into the push-pits, however, the report stated that the tipping process will be carried in an enclosed tipping hall with odour scrubbing system.  In addition, a design odour criteria for NLTS of 2 OU would be met at site boundary agreed by the NLTS operator.  Thus the odour impacts on the adjacent ASRs particularly the SDU and SBDIV Base would not be expected.

Open Road Networks

3.4.35     The USEPA approved air dispersion model, CALINE4 was used to predict the pollutant levels of NO2, RSP and CO from the open section of the road networks.  The hourly and daily average of pollutants at two representative heights, the ground level and 10 m above ground, have been modelled in the assessment.

3.4.36     Fleet emission factors based on the EURO III criteria have been used for this assessment.  As emission factors beyond 2011 are not available, the 2011 vehicle emission factors were therefore assumed for traffic beyond 2011.  Based on the current trend, it is however believed that emission rates beyond 2011 are likely to be lower than 2011 as more stringent controls will be put in place and more vehicles will be fitted with advanced emission control systems.  The predicted results will therefore be conservative.

3.4.37     The design traffic conditions of the road networks provided by the Project Traffic Consultant has been employed for the analysis of vehicle emissions from the road networks.  It was assumed that peak hour traffic conditions will occur during daytime and worst case scenario of neutral meteorological conditions have been used in the model run.  Typical input parameters for the model are listed below:

·                      wind speed                                    1ms-1;

·                      wind direction                              worst case for each receivers;

·                      stability class                              D;

·                      mixing height                              500 m;

·                      standard deviation of wind direction            12 degree;

·                      surface roughness                              80 cm; and

·                      temperature                              250C.

 

3.4.38     The NOx gas is assumed to be inert and levels of NO2 were taken as 20% of total NOx emissions.

3.4.39     Vehicular emissions from open sections of the road are one of the major sources of pollutants and will mainly affect air quality at lower levels.

3.4.40     In addition, noise barriers and semi-enclosure have been proposed near Siu Ho Wan Residential (R2) Development in Section 4.  Barrier effect of the air pollutant dispersion would be expected.

3.4.41     Pollutant levels at the two worst affected heights, ground level and 10m above ground, have been modelled taking the noise barrier and semi-enclosure into account and the results are presented in Table 3.4h.  Both the existing and planned road networks have been included in the model.  For the daily NO2 and RSP prediction, a factor of 0.4 was used in for the conversion of hourly NO2 and RSP concentrations to daily concentrations.  For Tso Wan village, air quality impacts from vehicle emissions assessed in the R10-NLYLH (Southern Section) EIA Final Report([6]) are referenced.  Contribution from CKWLR were assessed in Section 3.5.28 and will be included as cumulative impact to this ASR.

Table 3.4h - Predicted Pollutant Concentrations from Open Road Traffic (mgm-3)

ASRs

Predicted Concentration (a)

 

Ground Level

10m Above Ground

 

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

 

A1

135

74

984

58

131

72

984

58

 

A2

48

39

179

42

48

39

179

42

 

A3

44

38

179

41

44

38

179

41

 

A4

63

45

294

45

63

45

294

45

 

A5

135

74

984

58

135

74

984

58

 

A6 (b)

77

-

960

61

-

-

-

-

 

A7

56

42

294

44

56

42

294

44

 

A8

56

42

294

43

56

42

294

43

 

A9

151

83

1,214

65

150

80

1,099

84

 

A10

93

57

639

52

93

57

639

52

 

A11

93

57

639

50

93

57

639

50

 

A12

82

53

524

48

78

51

409

47

 

A13

116

66

869

54

112

65

754

54

 

A14

119

68

869

55

116

66

869

54

 

A15

97

59

639

51

97

59

639

51

 

A16

135

74

984

59

131

72

869

58

 

A17

104

62

754

52

101

60

639

51

 

A18

138

75

984

60

138

75

984

60

 

A19

93

57

639

52

93

57

639

52

 

A20

- (c)

- (c)

-(c)

-(c)

127

71

869

58

 

A21

157

83

1,214

63

153

81

1,214

62

 

A22

142

77

1,099

59

135

74

984

58

 

A23

146

78

1,444

61

142

77

1,099

61

 

A24

146

78

1,329

61

142

77

984

61

 

AQO Criteria

300

150

30,000

180

300

150

30,000

180

 

Note:

(a)   Background pollutant concentrations have been included in the results

(b)   Pollutant concentrations at Tso Wan village were extracted from the R10-NLYLH (Southern Section) Final EIA. No assessment was made at 10 m above ground in the R10 EIA as  all the ASRs are low-rise in nature.

(c)   The housing development will be built on the decked over Siu Ho Wan Depot, therefore, air quality impact is only predicted on 10m above ground.

 

3.4.42     Full compliance of AQO criteria was predicted at all ASRs.  The above results indicate that NO2 is the critical pollutant.  Maximum NO2 concentration of 157 mgm-3 was predicted at ground level of the Theme Park Gateway (A21).

3.4.43     Interpretation of the model results indicates that there will be no adverse air quality impacts associated with the open road networks.  However, pollution loads will be emitted from the Yam Tsai tunnel portals and toll plazas at NLH and R10-NLYLH and the cumulative air quality impacts have been assessed in the following section.

3.4.44     Sample CALINE4 output files are shown in Annex B3.

Portal Emissions from Yam Tsai Tunnel

3.4.45     Air pollutants from vehicular emissions accumulated inside the proposed Yam Tsai Tunnel will be emitted and dispersed from the two portals (western portal at Ta Pang Po and the eastern portal at Yam O Tuk).  It is expected that the tunnel air will be emitted horizontally under the action of jet fans.

3.4.46     The ISCST3 air dispersion model was used to predict the portal emission from the Yam Tsai Tunnel of Road P1.  Portal emissions were assessed based on the procedures stated in Section III of Permanent International Association of Road Congresses (PIARC), 1991 and portal emission plumes of 100 m have been assumed along the axis of roads and only the well diluted parts would gradually become sheared off.  Meteorological data for 1997 from Cheung Chau weather station, operated by Hong Kong Observatory, were employed for the model run.  The emission rates for NO2, CO and RSP have been calculated based on the capacity traffic flow and is given in Table 3.4i below:

Table 3.4I - Portal Emission Rates for the Yam Tsai Tunnel

Tunnel Emissions

Road P1 EB

Road P1 WB

Length of Tunnel (m)

750

750

Traffic Flow (veh/hr)

3,087

3,030

Fleet Emission of NOx (g/km/veh) (a)

1.43

1.53

Fleet Emission of CO (g/km/veh) (a)

2.70

2.80

Fleet Emission of RSP (g/km/veh) (a)

0.13

0.14

NOx Emission Rate (g/s)

0.90

0.97

NO2 Emission Rate (g/s) (b)

0.18

0.19

CO Emission Rate (g/s)

1.70

1.77

RSP Emission Rate (g/s)

0.08

0.09

Notes:

(a)   The emission rate is calculated from fleet emission factors based on year 2011 of EURO III.

(b)   NO2 emission rate is assumed to be 20% of the total NOx emission.

 

Emissions from NLH & R10 Toll Plaza

3.4.47     Greater volumes of pollutants may be emitted due to acceleration/deceleration and idling operations of vehicles at the toll plazas of the NLH and Route 10.  The ISCST3 air dispersion model was used to predict the emission from the toll plaza.  It was assumed that about 50 vehicles would be idling in front of the booths for each direction (only EB carriageway for NLH).  Area sources of 50 m wide (1/2 of the width of the toll plaza) x 30 m long (about 5-6 vehicles) for each direction were input into the model.  Meteorological data for 1997 from Cheung Chau weather station, operated by Hong Kong Observatory, were employed for the model run.  Vehicle idling emission factors provided by EPD were used as average emission factors for the vehicle operations and are shown in Table 3.4j below. The levels of NO2 were taken as 20% of total NOx emissions.  RSP emission is considered negligible as reference to MOBILE6 Emission Factor Model for heavy-duty diesel engines (RSP emission rate = 0.043 g/min-veh) developed by the USEPA and was therefore not included in the assessment.

Table 3.4j - Vehicle Idling Emission Factors (g/min-veh)

Pollutants

PLB, LGV

Bus, MGV, HGV

Taxi

Private Car

NOx

0.5

2.0

0.5

0.2

CO

0.3

2.0

0.3

4.0

Note:

(a)   PLB, LGV, MGV and HGV represent public light bus, light goods vehicle, medium goods vehicle and heavy goods vehicle respectively

Emissions from Tunnel Portal and NLH and Route 10 Toll Plaza

3.4.48     The impacts due to the emissions from the Yam Tsai tunnel portals and toll plazas of NLH and R10 at two worst affected heights have been modelled and presented in Table 3.4k.

Table 3.4k - Predicted Pollutant Concentrations from Tunnel Portal and Toll Plazas (mgm-3)

ASRs

Predicted Concentration (a)

 

Ground Level

10m above ground

 

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

 

A1

56

4.1

518

1.1

53

3.8

488

1

 

A2

45

3.9

206

0.6

42

3.6

203

0.6

 

A3

113

10

487

1.4

98

8.6

474

1.3

 

A4

749

35

694

2

615

29

667

1.9

 

A5

209

18

1,320

3

153

14

964

2.5

 

A6 (b)

60

-

786

-

-

-

-

-

 

A7

69

5.2

343

0.5

62

4.8

307

0.9

 

A8

44

3.4

225

0.4

42

3.3

219

0.5

 

A9

83

5.1

761

0.9

79

4.8

721

0.8

 

A10

30

1.3

395

0.4

29

1.2

377

0.4

 

A11

80

3.8

255

0.9

75

3.6

240

0.8

 

A12

65

3.3

209

0.5

61

3.1

196

0.5

 

A13

82

3.9

689

0.6

78

3.7

651

0.5

 

A14

58

3.1

757

1

55

3

717

0.9

 

A15

48

2.8

155

0.5

44

2.6

144

0.5

 

A16

772

76

6,180

15

348

39

3,294

11

 

A17

109

8.1

515

1.2

102

8

485

1.1

 

A18

53

4.1

272

0.6

50

3.9

259

0.5

 

A19

77

6.6

613

1.7

66

6

554

1.6

 

A20

- (c)

- (c)

-(c)

-(c)

125

7

584

1.3

 

A21

51

2.8

212

0.4

48

3

225

0.4

 

A22

128

6.1

1,003

0.3

122

6

1,246

0.3

 

A23

69

5

655

1.4

65

5

611

1

 

A24

38

2.6

351

0.9

37

3

338

0.8

 

AQO Criteria

300

150

30,000

180

300

150

30,000

180

 

Note:

(a)   Background pollutant concentrations are not included in the results

(b)   Pollutant concentrations at Tso Wan village were extracted from the R10-NLYLH (Southern Section) Final EIA. No assessment was made at 10 m above ground in the R10 EIA as  all the ASRs are low-rise in nature.

(c)   The housing development will be built on the decked over Siu Ho Wan Depot, therefore, air quality impact is predicted at 10m above ground.

(d)   BOLD figures indicate exceedance of AQO

 

Emissions from Combustion Equipment

3.4.49     Boilers for mainly heating uses are the major sources of industrial emissions at the Theme Park and its hotel development.  There are totally 254 small size boilers with capacity in a range of 240 and 330 kW proposed associated with the Theme Park operation  The total fuel consumption rates are 105.72x106 kWh per year.  NO2  is the major pollutant source and the total emission rate is calculated 0.17 g/s.  The heights of all stacks has been assumed 6 m above ground for the worst case assessment, therefore, the air quality impact of the boiler emissions on low level receivers would be assessed.  This will be controlled under Air Pollution Control (Furnaces, Ovens and Chimneys) (Installation and Alteration) Regulations.  The emission rate from boilers using gaseous fuel is shown in Table 3.4l below.  Since the distance from the ASRs to the emission sources are greater than 1km and it provides more time for the conversion of the NOx to NO2 , thus the conversion of NOx to NO2 was assumed to be 30% as more conservative.

Table 3.4l - Emission Rate of Boiler

 

Boiler

Total Fuel Consumption Rate (kWh/hr)

105.72x106

Emission Factors of NOx(a)

1,600 kg/106 m3

Hourly Fuel Consumption Rate

1256 m3

Emission Rate of NOx (g/s) (b)

0. 56

Emission Rate of NO2 (g/s)

0.17

Note:

(a)   Reference to AP-42

(b)   Assumes 30% of NOx converts to NO2

 

3.4.50     NO2 emission comprises the critical pollutant attributed to the Theme Park combustion equipment, and the NO2 impacts on receivers located at different heights were assessed.  Impacts of the combustion equipment were modelled with the air dispersion model, ISCST3.  Meteorological data of Cheung Chau Weather Station for the year 1997 were used for the model run.  Combustion data of the boilers are provided by HKITP and are shown in Annex B4.  Types of the fuel, fuel consumption rates, physical dimension for stacks, exit gas temperature are included.  Emission rates of pollutants are calculated based on Compilation of Air Pollutant Emission Factors, 5th Edition (AP-42).

3.4.51     Gaseous fuel is assumed to be used as fuel for other tourism and recreation developments in the Draft RODP including the Theme Park Extension, Tourism and Recreation Development at Tsing Chau Tsai East, the Tourist and Convention Centre, and the Technodrome.  Whilst information pertaining to the number and capacity of the boilers is not available at this stage, it may be assumed that the localised potential air quality impact due to boiler emissions to be similar to that of the Theme Park, which has been quantitatively assessed in this EIA.

3.4.52     The impacts on the low level receivers due to the emissions from combustion equipment has been modelled and the results are shown in Table 3.4m.

Table 3.4m - Predicted Pollutant Concentrations from Combustion Equipment at Low Level (mgm-3)

ASRs

Predicted Concentration (a)

 

Ground Level

10m above ground

 

Hourly NO2

Daily NO2

Hourly NO2

Daily NO2

A1

2.06

0.43

2.05

0.42

A2

3.81

0.74

3.36

0.67

A3

2.51

0.33

2.23

0.31

A4

2.29

0.26

2.09

0.24

A5

2.74

0.32

2.7

0.31

A6

1.54

0.27

1.58

0.27

A7

2.23

0.26

2.34

0.26

A8

1.46

0.34

1.57

0.36

A9

2.37

0.17

2.36

0.17

A10

1.89

0.13

1.86

0.13

A11

1.56

0.9

3.18

1.03

A12

3.08

1.04

3.54

1.19

A13

2.17

0.45

2.18

0.43

A14

1.91

0.72

2.09

0.69

A15

1.66

0.51

1.68

0.5

A16

1.94

0.45

1.94

0.43

A17

2.08

0.42

2.07

0.44

A18

3.62

0.35

3.56

0.34

A19

1.18

0.11

1.16

0.11

A20

1.87

0.15

1.85

0.15

A21

1.32

0.17

1.33

0.16

A22

1.17

0.15

1.19

0.15

A23

1.77

0.23

1.79

0.23

A24

1.24

0.25

1.35

0.24

AQO Criteria

300

150

300

150

Note:

(a)   Background pollutant concentrations are not included in the results

(b)   Since NO2 is the critical pollutant for the boiler emissions, only NO2 prediction does consider the cumulative impact with boiler emission.

 

3.4.53     The higher level of ASRs are affected mainly by the emissions from combustion equipment at the Theme Park.  The predicted hourly NO2 concentration at 20 m, 30 m and 40 m above ground are listed in Table 3.4n below.

Table 3.4n - Predicted Hourly NO2 Concentration at High Level Receiver (mgm-3)

ASRs

Predicted Hourly NO2 Concentration (a)

 

20m Above Ground

30m Above Ground

40m Above Ground

A1

36

37

35

A2

35

35

34

A3

35

35

34

A4

35

34

34

A5

36

35

34

A6

35

35

34

A7

36

36

36

A8

35

35

35

A9

35

35

35

A10

35

35

34

A11

37

38

35

A12

38

42

37

A13

36

37

35

A14

36

38

35

A15

36

37

35

A16

36

36

35

A17

36

36

35

A18

36

36

35

A19

34

34

34

A20

35

35

34

A21

34

34

34

A22

34

34

34

A23

35

35

34

A24

35

35

34

AQO Criteria

300

300

300

Note:

(a)   Background of NO2 (33 mgm-3) from CLP’s Monitoring Station at Penny’s Bay has been included in the prediction.

 

3.4.54     The above results indicated that the NO2 criteria will be satisfied at all elevations.  It also indicated that the worst affected level is 30 m above ground.  The highest hourly NO2 is predicted at A10 (Hotels in the Theme Park Phase I and II) which is 42mgm-3.

3.4.55     Since the prediction of the impacts of boiler emissions is low (9 mgm-3 contribution at 30 m above ground), the similar impacts at Theme Park (Phase III) Extension, Tourism and Recreation Development at Tsing Chau Tsai East, the Tourist and Convention Centre, and the Technodrome to the surrounding ASRs are not expected.

Cumulative Impacts from Open Road Emissions, Portal Emissions, Toll Plaza Emissions and Emissions from Combustion Equipment

3.4.56     NO2, CO and RSP are the major pollutants in vehicle exhaust emissions.  ASRs at lower levels, i.e., at ground level and 10m above ground, are expected to receive the highest impacts.  The cumulative air pollutant levels at low level receivers, taking into account contributions from vehicle emissions from road networks, Yam Tsai tunnel portal, NLH and R10 Toll Plazas, Penny’s Bay GTP and combustion equipment in Theme Park (Phase I and II), are shown in Table 3.4o below.

Table 3.4o - Cumulative Pollutants Concentration at Low Level Receivers (mgm-3)

ASRs

Predicted Cumulative Concentration

 

Ground Level

10m above ground

 

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

A1

193

78

1,502

60

186

76

1,472

59

A2

157 (c)

104  (c)

385

42

153 (c)

103 (c)

382

42

A3

220 (c)

108 (c)

666

42

205 (c)

106 (c)

653

42

A4

815

80

988

47

680

74

961

47

A5

346

92

2,304

61

290

88

1,948

61

A6 (d)

163

-

1942

64

-

-

-

-

A7

127

48

637

44

119

47

601

45

A8

101

46

519

44

99

46

513

44

A9

243

88

1,975

66

231

85

1,820

85

A10

125

58

1,034

52

124

58

1,016

52

A11

235 (c)

122 (c)

894

51

232 (c)

122 (c)

879

51

A12

209 (c)

117 (c)

733

48

202 (c)

115 (c)

605

47

A13

260 (c)

130 (c)

1,558

55

252 (c)

129 (c)

1,405

54

A14

239 (c)

131 (c)

1,626

56

233 (c)

130 (c)

1,586

55

A15

207 (c)

122 (c)

794

52

203 (c)

122 (c)

783

51

A16

968 (c)

210 (c)

7,164

73

541 (c)

171 (c)

4,163

69

A17

275 (c)

130 (c)

1,269

53

265 (c)

128 (c)

1,124

53

A18

195

80

1,256

60

192

79

1,243

60

A19

171

64

1,252

53

161

63

1,193

53

A20

- (e)

- (e)

- (e)

- (e)

254

78

1,453

59

A21

209

86

1,426

63

203

84

1,439

62

A22

272

83

2,102

59

258

80

2,230

58

A23

217

83

2,099

62

208

82

1,710

62

A24

185

81

1,680

62

180

79

1,322

61

AQO Criteria

300

150

30,000

180

300

150

30,000

180

Note:

(a)   Background pollutant concentrations have been included in the results

(b)   BOLD figures indicate exceedance of AQO

(c)   NO2 of 60mgm-3 predicted from EIA of Gas Turbine Plant at Penny’s Bay has been included

(d)   Pollutant concentrations at Tso Wan village were extracted from the R10-NLYLH (Southern Section) Final EIA. No assessment was made at 10 m above ground in the R10 EIA as all the ASRs are low-rise in nature.  Contributions from CKWLR were also included.

(e)   The housing development will be proposed on the Siu Ho Wan Depot, therefore, only air quality impact is predicted at 10m above ground.

 

3.4.57     The predicted cumulative maximum hourly pollutant concentrations from vehicle emissions from open roads, portal and toll plaza emissions, emissions from combustion equipment in International Theme Park show exceedance of AQO criteria of NO2 at A4 (Possible Country Park Extension Area), A5 (Luk Keng Tsuen) and A18 (Eco Park).  Highest hourly NO2 concentration at ground level was predicted at A18 (Eco Park) near the Yam Tsai tunnel portal (eastbound).

3.4.58     It is stated in the EIA of Gas Turbine Plant at Penny’s Bay([7]) that about 60 mg m-3 of NO2 should be added to predicted level under high wind speed conditions, and the predicted NO2 levels at ASRs located at Penny’s Bay (A2, A3, and A11 - A17) are still within the AQO criteria.

3.4.59     The exceedances are primarily due to portal emission from Yam Tsai Tunnel.  It is recommended that proper ventilation arrangements such as axial fans or a ventilation building should be provided at the tunnel to facilitate vertical dispersion of vehicle exhaust.  Prediction of effect on emitting portal exhaust via ventilation building presence at each portal has been performed by assuming typical ventilation building with height at 10m above ground and at an exit flow of 240 m3s-1.  TAQG will be met at this flow rate as shown in Table 3.4p.  However, the design of the ventilation system is still to be refined during the detailed design stage of the tunnel.  Contribution from ventilation building and toll plazas and cumulative results are shown in Table 3.4q and 3.4r respectively:

Table 3.4p - Tunnel Ventilation Calculation

Tunnel Emission

Road P1 EB

Road P1 WB

Length of Tunnel (m)

750

750

Cross-sectional Area (m2)

60

60

Tunnel Volume (m3)

45,000

45,000

Peak Hourly Traffic Flow (veh hr-1)

3,087

3,030

Total NOx Emission Rate (g km-1 hr-1)

4,414

4,636

Total NOx Emission Rate (g hr-1) within Tunnel

3,311

3,477

Total NO2 Emission Rate (g hr-1) within Tunnel

331.1

347.7

Ventilation Rate (m3 s-1)

240

240

Ventilation Rate (m3 hr-1)

864,000

864,000

NO2 Concentration attributed to the fleet (mgm-3)

383

402

Total NO2 Concentration with Background (mgm-3)

416

435

TAQG Criteria

1,800

Note:

(a)   Fleet emission calculation shown in Table 3.4i.

(b)   The percentage conversion of NOx to NO2 is 10% inside tunnel and 20% outside tunnel.

 

Table 3.4q - Predicted Pollutant Concentrations from Ventilation Building and Toll Plazas (mgm-3)

ASRs

Predicted Concentration (a)

 

Ground Level

10m above ground

 

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

 

A1

35

1.49

458

0.17

33

1.41

433

0.17

 

A2

15

0.68

190

0.22

14

0.6

183

0.21

 

A3

19

0.85

243

0.41

18

0.81

232

0.37

 

A4

7

0.88

201

1.03

7

0.5

175

0.93

 

A5

18

1.09

230

0.84

17

1.05

220

0.8

 

A6 (b)

60

-

786

-

-

-

-

-

 

A7

2

0.22

30

0.11

2

0.19

30

0.11

 

A8

8

0.39

100

0.08

7

0.38

97

0.08

 

A9

58

2.43

761

0.17

55

2.3

721

0.17

 

A10

30

1.26

395

0.08

29

1.2

377

0.08

 

A11

7

0.41

86

0.18

7

0.29

85

0.18

 

A12

14

0.67

187

0.19

14

0.64

177

0.2

 

A13

53

2.30

689

0.1

50

2.17

651

0.1

 

A14

58

2.54

757

0.19

55

2.41

717

0.19

 

A15

11

0.48

137

0.21

10

0.47

130

0.21

 

A16

9

3.33

103

2.05

9

2.85

99

1.88

 

A17

5

0.40

44

0.19

3

0.15

49

0.2

 

A18

7

0.37

93

0.09

7

0.36

91

0.09

 

A19

7

0.48

94

0.28

7

0.46

93

0.29

 

A20

- (e)

- (e)

- (e)

- (e)

9

0.41

182

0.25

 

A21

14

1.27

212

0.15

13

1.32

225

0.15

 

A22

77

4.34

1,003

0.25

96

4.15

1,246

0.26

 

A23

11

0.6

147

0.19

11

0.58

142

0.2

 

A24

5

0.33

68

0.11

5

0.33

65

0.11

 

AQO Criteria

300

150

30,000

180

300

150

30,000

180

 

Note:

(a)   Background pollutant concentrations are not included in the results

(b)   Pollutant concentrations at Tso Wan were assessed and obtained from Route 10 (Southern Section) Final EIA. No assessment was made at 10 m above ground in the R10 EIA as all the ASRs are low-rise in nature.

(c)   The housing development will be proposed on the Siu Ho Wan Depot, therefore, only air quality impact is predicted at 10m above ground.

 

Table 3.4r - Cumulative Pollutant Concentration at Low Level Receivers with Ventilation Building (mgm-3) (a)(b)

ASRs

Predicted Cumulative Concentration (a)

 

Ground Level

10m above ground

 

Hourly NO2

Daily NO2

Hourly CO

Daily RSP

HourlyNO2

Daily NO2

Hourly CO

Daily RSP

A1

172

76

1,442

59

166

74

1,417

58

A2

126 (c)

100 (c)

369

42

125 (c)

100 (c)

361

42

A3

125 (c)

99 (c)

422

41

124 (c)

99 (c)

411

41

A4

73

46

495

46

72

46

469

46

A5

155

75

1,214

59

154

75

1,204

59

A6 (d)

163

-

1,942

64

-

-

-

-

A7

60

42

324

44

60

42

324

44

A8

65

43

394

43

65

43

391

43

A9

218

85

1,975

65

207

82

1,820

84

A10

125

58

1,034

52

124

58

1,016

52

A11

161 (c)

118 (c)

725

50

163 (c)

118 (c)

724

50

A12

159 (c)

114 (c)

711

48

155 (c)

113 (c)

586

47

A13

231 (c)

129 (c)

1,558

54

224 (c)

127 (c)

1,405

54

A14

239 (c)

131 (c)

1,626

55

233 (c)

129 (c)

1,586

54

A15

169 (c)

120 (c)

776

51

169 (c)

120 (c)

769

51

A16

205 (c)

137 (c)

1,087

61

201 (c)

135 (c)

968

60

A17

171 (c)

122 (c)

798

52

166 (c)

121 (c)

688

52

A18

149

76

1,077

60

149

76

1,075

60

A19

102

58

733

52

101

58

732

52

A20

-  (e)

-  (e)

- (e)

- (e)

138

71

1,051

58

A21

172

84

1,426

63

168

83

1,439

62

A22

220

81

2,102

59

231

78

2,230

58

A23

159

79

1,591

61

155

77

1,241

61

A24

152

79

1,397

62

148

77

1,049

61

AQO Criteria

300

150

30,000

180

300

150

30,000

180

Note:

(a)   Background pollutant concentrations have been included in the results

(b)   Since NO2 is the critical pollutant for the boiler emissions, only NO2 prediction does consider the cumulative impact with boiler emission.

(c)   NO2 of 60 mgm-3 predicted from EIA of Gas Turbine Plant at Penny’s Bay has been included

(d)   Pollutant concentrations at Tso Wan were assessed and obtained from Route 10 (Southern Section) Final EIA. No assessment was made at 10 m above ground in the R10 EIA as all the ASRs are low-rise in nature.  Contributions from CKWLR are also included.

(e)   The housing development will be proposed on the Siu Ho Wan Depot, therefore, only air quality impact is predicted at 10m above ground

 

3.4.60     Full compliance of the AQO criteria were predicted at all ASRs.  Conservative approaches have been used to calculate the cumulative impacts.  Compliance with the AQO’s has been demonstrated at all ASR’s, where maximum NO2 concentration of 239 mgm-3 predicted at the Divisional Police Station (A14) at ground level, comprises 80% of AQO for the worst case scenario.

3.4.61     Isopleths of hourly NO2 concentration at ground levels and 10 m above ground are plotted and are shown in Figures 3.4 d -m.  Isopleths near Tso Wan village area were provided in R10 EIA Report([8]).  Results of the assessments show that there are no exceedance at the ground level and 10 m above ground for all existing and planned ASRs.  In general, a buffer distance of 40 m shall be allowed from centreline of NLH to ASRs to ensure full compliance of the AQOs.  In addition, any air sensitive development between Yam Tsai Tunnel and NLH near Yam Tsai area shall be avoided.  For developments along R10-NLYLH section within the NLDFS Project Area, a buffer distance of 40 m from the centreline of the road is recommended.

Emissions from Penny’s Bay GTP

3.4.62     The Penny's Bay GTP comprises of 3 x 100 MW open cycle units with three separate 50 m stacks.  The plant is fired by distillate fuel oil (diesel) with scope for possible future expansion to 600 MW.  Air quality impact from this GTP has been evaluated based on results of the EIA report conducted in 1990 supplemented by computer modelling.

3.4.63     A review of the air quality impact from the Penny’s Bay GTP has been carried out to identify the potential air quality constraints to the Theme Park and associated developments based on the findings from EIA of Gas Turbine Plant at Penny’s Bay([9]).  The report identified potential constraints on high-rise developments within the Penny’s Bay Area.

3.4.64     The proposed development layout will be reviewed to confirm the proposed height restriction in the vicinity of the GTP is adequate to avoid any potential air quality impact.  Any proposed development exceeding the specified limit will need to be addressed in terms of potential impact and or obstruction to the dispersion of the GTP plume.

3.4.65     In line with the wind tunnel modelling, ISCST3 model was also be used for the supplementary information.  Meteorological data of Cheung Chau Weather Station for the year 1997 have been used.  Locations of sources, types of the fuel, their maximum fuel consumption rates, emissions rates of pollutants, physical dimension of stacks, exit gas temperature based on the Specified Process Licence under APCO, Licence No.: L-7-008(3), November 1996, have been included in the model run.

3.4.66     The EIA of Penny's Bay GTP concluded that even the worst case emission will not cause any unacceptable air quality impact to ground level receptors.  The predicted SO2 concentration was in excess of the AQO under a high wind speed (15 m/s) situation at elevated receptor, 100 m above ground and 500 m away from the GTP, causing constraints on the proposed high-rise developments to the west of the GTP under the worst case operating scenario with 6 units running at 50% load.

3.4.67     Further mathematical modelling was carried out to assess the air quality impact to the proposed high-rise development within the Penny’s Bay area.  The predicted SO2 concentration 500 m away from the GTP reaches 400 mg/m3 at about 60 m above ground and the 400 mg/m3 contour remains relatively flat until it approaches the elevated ground.  This forms the basis for the recommended height restriction of 60 m above ground to the high-rise development under a conservative assumption of 6 units operating at 50% load.

3.4.68     Review of the wind tunnel modelling results suggests height restriction up to 50 m within the first 500 m distance should be applied to protect elevated receptors in the immediate vicinity and reduce obstruction to the dispersion of the GTP plume.  Building within 0.5 to 1 km from the GTP should not be taller than 100 m to avoid any physical obstruction to plume dispersion.

3.4.69     In addition, ISCST3 dispersion model has also been carried out for the supplementary information of the Penny’s Bay GTP emissions in line with wind tunnel modelling.  Hourly SO2 and NO2 levels have been modelled at ground level, 50 m above ground and 100 m above ground.  Isopleths of SO2 and NO2 at different elevations were plotted and shown in Figures 3.4n - 3.4s.  Isopleths indicated that an exceedance of hourly SO2 and NO2 were predicted at some elevated receivers.  However, no developments has been proposed at such elevations and hence will not be subjected to AQO exceedance in these affected areas.  Moreover, height restrictions have also been recommended in the immediate vicinity of the GTP to avoid air quality impact, the air quality due to the emissions from GTP is therefore acceptable.

3.4.70     Buildings within the Water Recreation Centre will be low-density and low-rise in character and will not exceed 6 m in height and the buildings within the Theme Park (Phase I and II) will be limited to 100 m in height.  It is understood from HKITP that there may be some building structures taller than 50 m but these would be tall and slim structures located outside from the 500 m zone and will not affect the wind flow pattern or plume dispersion at the GTP.  Hotel development along the south side of the development will be limited to a maximum building height of 40 m to provide further safeguard to any potential obstruction to the approach flow.

3.4.71     It is therefore predicted that the dispersion of the chimney emissions from the GTP will not be affected by the proposed low-rise development in the immediate vicinity and the land use planning of the area will avoid constraints imposed by the Penny’s Bay GTP.

Mitigation Measures

3.4.72     Although the predicted results show no exceedance of the established criteria, some recommendations are required for ensuring good air quality at the developments.

3.4.73     Ventilation building, with exit flow of 240 m3s-1, was recommended at Yam Tsai Headland for reducing the impacts from the tunnel portal emissions from Yam Tsai tunnel.

3.4.74     Building height restrictions of 50 m within 500 m from the GTP and 100 m within 0.5 to 1 km from GTP are recommended to avoid impact to elevated receptors in the immediate vicinity and reduce obstruction to plume dispersion.  For example, the theme park building structures taller than 50 m would be tall and slim structures located outside the 500 m zone and buildings within the Water Recreation Centre should be low-density and low-rise in character and should not exceed 6 m in height.  Hotel development along the south side of the development should be limited to a maximum building height of 40 m provide further safeguard to any potential obstruction to the approach flow.

3.4.75     Since the detail design of the sewage pumping stations is not available at this stage, detailed mitigation measures cannot be prescribed.  However, odour suppression measures such as enclosing the odour sources and providing odour scrubbing system should be incorporated in the design of the facilities so as to minimise the odour nuisance to the adjacent ASRs.