3                          air quality impact

3.1                    Introduction

3.1.1              This section presents an assessment of potential air quality impacts associated with the construction and operation phases of the Project.  These potential air quality impacts are expected to be dust nuisance during the construction phase and vehicular emissions during the operation phase.  Appropriate mitigation measures are proposed to alleviate the potential air quality impacts if necessary.

3.2                    Environmental Legislation, Standards and Criteria

3.2.1              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 as well as the requirements set out under Clause 3.4.1 of the EIA Study Brief.

Air Quality Objective & EIAO-TM

3.2.2              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 3.1.

Table 3.1      Hong Kong Air Quality Objectives

Pollutant

Maximum Concentration (µg m-3) (1)

Averaging Time

1 hour (2)

8 hour (3)

24 hour (3)

3 month (4)

Annual (4)

Total Suspended Particulates (TSP)

-

-

260

-

80

Respirable Suspended Particulates (RSP) (5)

-

-

180

-

55

Sulphur Dioxide (SO2)

800

-

350

-

80

Nitrogen Dioxide (NO2)

300

-

150

-

80

Carbon Monoxide (CO)

30,000

10,000

-

-

-

Photochemical Oxidants

(as Ozone, O3) (6)

240

-

-

-

-

Lead

-

-

-

1.5

-

Note:

(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.

(6)            Photochemical oxidants are determined by measurement of ozone only.

 

3.2.3              The EIAO-TM stipulates that the hourly TSP level should not exceed 500 mgm-3 (measured at 25oC and one atmosphere) for construction dust impact assessment.  Mitigation measures for construction sites have been specified in the Air Pollution Control (Construction Dust) Regulation.

Air Pollution Control (Construction Dust) Regulation

3.2.4              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 involve both notifiable works (road construction) and regulatory works (dusty material handling, excavation).  Contractors and site agents are required to inform EPD and adopt dust control measures to minimize dust emission, while carrying out construction works, to the acceptable level.

Practice Note on Control of Air Pollution in Vehicle Tunnels

3.2.5              The Practice Note on Control of Air Pollution in Vehicle Tunnels, prepared by the EPD provides guidelines on control of air pollution in vehicle tunnels.  Guideline values on tunnel air quality are presented in Table 3.2 below.

Table 3.2      Tunnel Air Quality Guidelines (TAQG)

        Air Pollutant

Averaging Time

Maximum Concentration

(mg/m3) (1)

ppm

Carbon Monoxide (CO)

5 minutes

115,000

100

Nitrogen Dioxide (NO2)

5 minutes

1,800

1

Sulphur Dioxide (SO2)

5 minutes

1,000

0.4

Note:

(1) Expressed at reference conditions of 298K and 101.325kPa.

3.3                    Description of Environment

3.3.1              The Project is to provide a highway connecting TKO at Po Yap Road in the east and Trunk Road T2 in the west with associated interchange.  The study areas include both Lam Tin area and Tiu Keng Leng and Town Centre South area (TKO side).

3.3.2              The locality of study area at Lam Tin area is a developed urban area with middle density of residential developments and educational institutes.  The dominant existing emission source at this study area is the existing traffic from the Kwun Tong Bypass and Eastern Harbour Crossing (EHC) as well as emissions from EHC ventilation building. 

3.3.3              The study area at TKO side is a newly developed area with residential buildings and educational institutes.  Existing air quality in the study area is affected by emissions from local road traffic and construction activities in and around the study area. 

3.3.4              For Lam Tin area, the nearest Environmental Protection Department (EPD) fixed air quality monitoring station is located at Kwun Tong.  For TKO side, EPD’s air quality monitoring station at TKO ceased operation in 1993 and there is no recent air quality monitoring data available for this area.  The annual average monitoring data recorded at EPD’s Kwun Tong air quality monitoring station has shown the pollutants’ concentrations tend to be steady in the past five years.  The recent five years (2007 –2011) annual average concentrations are summarized in Table 3.3.  

Table 3.3      Annual Average Concentrations of Pollutants in the Latest Five Years (Year 2007 - 2011) at Kwun Tong EPD Air Quality Monitoring Station

 

Pollutant

Annual Average Concentration (μg/m3)

NO2

60

RSP

49

TSP

73

 

3.4                    Air Sensitive Receivers

3.4.1              In accordance with Annex 12 of the EIAO-TM, any 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 are considered as air sensitive receivers (ASRs).  Any other premises or place with which, in terms of duration or number of people affected, has a similar sensitivity to the air pollutants as the aforelisted premises and places is also considered to be a sensitive receiver.

3.4.2              As stated in the EIA Study Brief, the boundary of the assessment area for air quality assessment should be 500m from the boundary of the Project site.  After review of the latest Outline Zoning Plans (OZP) including Kai Tak OZP (Plan No. S/K22/4) dated September 2012, Cha Kwo Ling, Yau Tong, Lei Yue Mun OZP (Plan No. S/K15/19) dated June 2011 and Tseung Kwan O OZP (Plan No. S/TKO/20) dated April 2012, 21 representative ASRs in the proximity of the Project site which are most likely to be affected by the construction of the Project and 44 representative existing and planned ASRs which would be affected by the operation of the Project are identified for assessment and the details are listed in Table 3.4 and 3.5, respectively.  The ASRs for the assessment are selected according to Clause 3.4.1.4(ii)(a) of the EIA Study Brief as representing the worst impact point of the identified ASRs within 500m from the Project boundary.  Their locations are illustrated in Figures 3.1a to 3.4b.

 

Table 3.4      Representative Air Sensitive Receivers During Construction Phase

ASR

Description

Land Use

Distance from the nearest Open Works Area (m)

No. of storey

Assessment Height (mPD)

Respective Assessment Height (metres above ground)

Lam Tin side

CL1

Tin Hau Temple

Place of public worship

42

1/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL2

Cha Kwo Ling Village

Residential

80

3/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL3

Sitting out area

Recreation

75

-

7

1.5

CL4

Cha Kwo Ling Village

Residential

120

3/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL5

Planned ASR

GIC

260

-

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL6

Sai Tso Wan Recreation Ground

Recreational

135

-

15.5

1.5

CL7

Sin Fat Road Tennis Court

Recreational

24

-

15.5

1.5

CL8

Lam Tin Ambulance Depot

GIC

90

4/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL9

Yau Lai Estate Bik Lai House

Residential

63

42/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL10

Yau Lai Estate Cheuk Lai House

Residential

90

40/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL11

Yau Tong Road Playground

Recreational

96

-

7

1.5

CL12

C.C.C. Kei Fat Primary School (Yau Tong)

Institutional

183

8/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL13

Eastern Harbour Crossing Admini-
stration Building (1)

GIC

12

5/F

15.5, 20.5, 25.5

10, 15, 20

CL14

Wing Shan Industrial Building

Industrial

120

13/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL15

Cha Kwo Ling Village

Residential

30

3/F

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

CL16

Sitting-out Area at Cha Kwo Ling Village

Recreational

16

-

7, 10.5, 15.5, 20.5, 25.5

1.5, 5, 10, 15, 20

TKO side

CT1

Village House at Chiu Keng Wan

Residential

270

1/F

5.5, 9, 14, 19, 24

1.5, 5, 10, 15, 20

CT2

Ocean Shore Tower 1 (2)

Residential

18

48/F

14, 19, 24

10, 15, 20

CT3

Ocean Shore Tower 6 (2)

Residential

90

48/F

14, 19, 24

10, 15, 20

CT4

HK Design Institute Campus Block C

Institutional

235

11/F

5.5, 9, 14, 19, 24

1.5, 5, 10, 15, 20

CT5

Park Central Tower 6

Residential

175

48/F

5.5, 9, 14, 19, 24

1.5, 5, 10, 15, 20

Note:

(1)     It is identified that the administration building of Eastern Harbour Crossing has been provisioned with central air conditioning located at the rooftop of the building without openable windows.  Hence, the first assessment height is at 10 metres above ground.

(2)      The residential tower of Ocean Shore is situated on top of the 3-storey podium without air sensitive uses facing to the construction works area of Road P2.  Hence, the first assessment height is at 10 metres above ground.

 

Table 3.5      Representative Air Sensitive Receivers During Operation Phase

ASR

Description

Land Use

No. of storey

Assessment Height (metres above ground)

Lam Tin Side

LT-A1

Yau Lai Estate Bik Lai House

Residential

42/F

1.5, 5,10,15

LT-A2

Yau Lai Estate Nga Lai House

Residential

42/F

1.5, 5,10,15

LT-A3

Yau Lai Estate Fung Lai House

Residential

42/F

1.5, 5,10,15

LT-A4

St. Antonius Primary School

Educational

8/F

1.5, 5,10,15

LT-A6

Sai Tso Wan Recreation Ground

Recreational

-

1.5, 5,10,15

LT-A7

Sceneway Garden Block 9

Residential

28/F

1.5, 5,10,15

LT-A8

Ping Tin Estate Ping Wong House

Residential

38/F

1.5, 5,10,15

LT-A9

Laguna City Block 23

Residential

25/F

1.5, 5,10,15

LT-A10

Yau Lai Estate Yung Lai House

Residential

40/F

1.5, 5,10,15

LT-A11

Yau Lai Estate Cheuk Lai House

Residential

40/F

1.5, 5,10,15

LT-PA1(1)

Planned ASR at Yau Tong Bay Redevelopment

Residential

-

1.5, 5,10,15

LT-PA2(1)

Planned ASR at Yau Tong Bay Redevelopment

Residential

-

1.5, 5,10,15

LT-PA3(1)

Planned ASR at Yau Tong Bay Redevelopment

Residential

-

1.5, 5,10,15

LT-PA4(1)

Planned ASR at Yau Tong Bay Redevelopment

Residential

-

1.5, 5,10,15

LT-PA7(2)

Planned Refuse Transfer Station at Cha Kwo Ling

GIC

-

1.5, 5,10,15

LT-PA10(1)

Planned ASR at Kaolin Site

Residential

-

1.5, 5,10,15

LT-PA11(1)

Planned ASR at Kaolin Site

Residential

-

1.5, 5,10,15

TKO Side

TKO-A1

Village House

Residential

1/F

1.5, 5,10,15

TKO-A2

Ocean Shore Tower 1

Residential

48/F

1.5, 5,10,15

TKO-A3

Ocean Shore Tower 8

Residential

48/F

1.5, 5,10,15

TKO-A4

Ocean Shore Tower 17

Residential

48/F

1.5, 5,10,15

TKO-A5

Shing Ming Estate

Residential

38/F

1.5, 5,10,15

TKO-A6

Caritas Bianchi College of Careers

Educational Institute

10/F

1.5, 5,10,15

TKO-A7

Metro Town I Tower 1

Residential

55/F

1.5, 5,10,15

TKO-A8

Metro Town I Tower 5

Residential

50/F

1.5, 5,10,15

TKO-A9

Metro Town II – Le Point Tower 7

Residential

53/F

1.5, 5,10,15

TKO-A10

HK Design Institute Campus Block D

Educational Institute

10/F

1.5, 5,10,15

TKO-A11

HK Design Institute Campus Block C

Educational Institute

10/F

1.5, 5,10,15

TKO-A12

HK Design Institute Campus Block A

Educational Institute

8/F

1.5, 5,10,15

TKO-A13

Choi Ming Court Choi Kwai House

Residential

40/F

1.5, 5,10,15

TKO-A14

Park Central Tower 6

Residential

48/F

1.5, 5,10,15

TKO-A15

Park Central Tower 7

Residential

46/F

1.5, 5,10,15

TKO-A16

Choi Ming Court Choi To House

Residential

40/F

1.5, 5,10,15

TKO-A17

Tong Ming Court Tong Fai House

Residential

40/F

1.5, 5,10,15

TKO-PA1(2)

Planned ASR at Area 66

Residential

-

1.5, 5,10,15

TKO-PA2(2)

Planned ASR at Area 67

GIC

-

1.5, 5,10,15

TKO-PA3(2)

Planned ASR at Area 67

GIC

-

1.5, 5,10,15

TKO-PA4(2)

Planned ASR at Area 67

GIC

-

1.5, 5,10,15

TKO-PA5(2)

Planned ASR at Area 67

GIC

-

1.5, 5,10,15

TKO-PA6(2)

Planned ASR at Area 68

Residential

-

1.5, 5,10,15

TKO-PA7(2)

Planned ASR at Area 68

Residential

-

1.5, 5,10,15

TKO-PA8(2)

Planned ASR at Area 68

Residential

-

1.5, 5,10,15

TKO-PA9(2)

Planned ASR at Area 68

Residential

-

1.5, 5,10,15

TKO-PA10(2)

Planned ASR at Area 68

Residential

-

1.5, 5,10,15

Note:

(1) The locations of the planned ASRs located at planned residential site at ex-Cha Kwo Ling Kaolin Mine Site and CDA at Yau Tong Bay (YTB) are based on the building layout plans provided by the Planning Department (PlanD) and the YTB project proponent.

(2) The exact layouts for planned development are not available at the time of assessment.  In these cases, the locations of the representative planned ASRs would be in accordance with any site condition/restriction as stipulated in the OZP/Layout Plan.  If not, these planned ASRs are assumed to be located at the respective zone boundary, which would be the nearest to the roads, as indicative assessment points for assessment.

 

3.5                    Identification of Pollutant Sources

Construction Phase

3.5.1              The construction activities for the Project would be commenced in February 2016 and completed in November 2020.  The major construction activities with construction dust concern are summarized as below:

– Tunnel and Lam Tin Interchange

·               Surface blasting

·               Slope works/site formation

·               Construction of highway structures

 

– TKO interchange & Depressed Road P2

·               Reclamation

·               Construction of highway structures

 

– Roads P2/D4 Junction Works and P2/D4 Cycle Track Cum Footbridge

·               At-grade Road works

3.5.2              For this Project, there is one on-site rock crusher to be located within the works area at the south-western side of the Lam Tin Interchange.  There are also two on-site barging points to be provided for this Project, one would be located at Cha Kwo Ling Pier and the other one would be proposed at Chiu Keng Wan.

3.5.3              The rock crusher is an enclosed plant which would handle the excavated rock materials from the TKO-LT Tunnel main tunnel, as well as those excavated materials from the Lam Tin Interchange.  Rocks would be transported from the excavation areas to the rock crusher by trucks.  The trucks would unload the rocks to the feed hopper of the crusher inside the enclosed structure.  Dust collector would be provided at the exhaust of the enclosure to suppress the dust emission to the atmosphere.  The crushed rocks would be transferred through the enclosed conveyor belt system to the barging point at Cha Kwo Ling Pier.

3.5.4              Both the rock crusher and the barging points would operate for 11 hours a day (7:00 to 12:00 and 13:00 to 19:00), while works areas would operate for 12 hours a day (7:00 – 19:00) except the hoisting of Typhoon No.3 or above, Sundays and public holidays.  There would therefore be 21 – 27 working days per month, depending on the number of Sundays and public holidays in the month.

3.5.5              Apart from the enclosed conveyor belt system for transportation of the rocks to the barging point at Cha Kwo Ling, the spoil materials would also be transported to the tipping halls of the barging points at both Cha Kwo Ling and Chiu Keng Wan by trucks and then unloaded to the barges.  The haul roads within the barging site would be all paved and provided with water spraying.  Vehicles would be required to pass through designated wheel washing facilities before leaving the barging facility.  Moreover, the dusty materials on the trucks would be well covered and flexible dust curtain together with water spraying system would be provided at the loading points (from barging point to the barges).

3.5.6              Referring to the construction programme received at the time of the assessment, the construction period for Trunk Road T2 tunnel portal, associated slope works and road works may be overlapped with this Project.  The dusty activities of these construction works of Trunk Road T2 in the vicinity of Lam Tin side of TKO-LT Tunnel are therefore considered in the cumulative dust impact assessment.  For TKO side, the construction works for some piers of CBL would be undertaken within 500m of Study Area of this Project.  However, it is expected that the dust nuisance from the pier construction would be limited and no cumulative dust impacts are expected.     

Operation Phase

3.5.7              As mentioned in Section 2.9 and Table 2.11, potential cumulative air quality impact on the surrounding ASRs during the operation phase of the Project considered in the assessment includes:

·               Background pollution levels predicted by PATH Model provided by EPD;

·               Vehicle emissions from open road sections of the existing and planned new roads (including T2 and CBL) within 500m Study Area with the incorporation of the proposed vertical barriers, semi-enclosures and full enclosures;

·               Portal emissions from the proposed TKO-LT Tunnel, T2 and EHC;

·               Portal emissions from the proposed landscape decks/full enclosures on Lam Tin Interchange and landscape deck on Road P2; and

·               Emissions from TKO-LT Tunnel, T2 and EHC ventilation buildings.

3.5.8              Within the 500m Study Area, there is no industrial chimney identified, therefore, no industrial emission is considered in the cumulative air quality impact assessment. 

3.5.9              Marine emissions from local vessels, large marine vessels and ocean going vessels within the study area have been assessed using the EPD PATH model of 2012.  There is no pier/mooring/typhoon shelter identified within the 500m Study Area except the Public Cargo Working Area (PCWA) at Cha Kwo Ling. However, it has been closed in October 2011 to make way for the development of Southeast Kowloon, according to the information presented by Marine Department and government’s press release[1] [2].  On the Lam Tin side, the Kwun Tong Ferry Pier, the future Cruise Terminal at Kai Tak and the Sam Ka Tsuen and Kwun Tong Typhoon Shelters are at least 200m to 500m away from the site boundary of the Study Area.  For marine facilities on the Tseung Kwan O side, the nearest Junk Bay Anchorage is at least 400m away from the Study Area.  Regarding navigation routes for ocean-going vessels in the vicinity, the closest navigation channel to the Project is the Tathong Channel.  Based on the “Charts for Local Vessels – Hong Kong Waters” issued by Marine Department in 2011, it is some 400m away from the closest site boundary of the Study Area.  Moreover, there are no planned marine facilities in the Study Area.  Given the above and the fact that the PATH model updated in July 2012 has included and adequately represented relevant marine emissions in the general environment as part of the future background, additional marine emission assessment for specific sources on top of those already covered in the PATH model is considered not necessary in the cumulative air quality impact assessment.

3.6                    Assessment Methodology

Construction Phase

Identification of Key/Representative Air Pollutants of Emissions from Construction Activities

3.6.1              As above-mentioned, blasting activities, slope works/site formation, sandfilling activities for reclamation, road works, operation of the rock crusher and the barging points are major construction activities which would induce particulates emission impact.  SO2, NO2 and smoke emitted from diesel-powered equipment may also the air pollutants from construction activities.  However, the number of such plant required on-site (land based and water based) will be limited and under normal operation.  Equipment with proper maintenance is unlikely to cause significant dark smoke emissions and gaseous emissions are expected to be minor.  Thus, the principal source of air pollution during the construction phase will be dust from the construction activities.  According to Annex 4: Criteria for Evaluating Air Quality Impact and Hazard to Life of EIAO-TM, Total Suspended Particulates (TSP) is the air pollutant parameter for construction dust impact assessment. Therefore, quantitative assessment of TSP emission impact is conducted for assessing construction phase air quality impact.  The potential dust emission sources considered in the assessment are shown in Appendix 3.1.

Emission Inventory

3.6.2              Predicted dust emissions are based on emission factors from USEPA Compilation of Air Pollution Emission Factors (AP-42), 5th Edition.  The major dusty construction activities for the Project to be considered in the modelling assessment include:

Lam Tin Side

 

(a)    Blasting, Slope Work/Site Formation at Lam Tin Area

·         Excavation and material handlings within the construction site modelled as heavy construction activities

·         Wind erosion of open active site

·         Rock crusher with loading, screening and crushing

 

(b)   Barging Points at Cha Kwo Ling

·         Unloading point to the barge

 

(c)    Construction for T2 Tunnel Portal, associated Slope works and Road Works at Lam Tin Area

·         excavation and material handlings within the construction site modelled as heavy construction activities

·         Wind erosion of open active site

 

TKO Side

 

(a)    Reclamation at Junk Bay

·               Sandfilling activities within the reclamation site modeled as heavy construction activities. 

·               Wind erosion of open active site

 

(b)   Road Works for TKO Interchange, Depressed Road P2, Roads P2/D4 Junction

·               excavation and material handlings within the construction site modelled as heavy construction activities

·               Wind erosion of open active site

 

(c)    Barging Points at Chiu Keng Wan

·               Unloading point to the barge

3.6.3              According to the engineering design information, dust control measures have been incorporated into the design of the rock crusher and barging facilities, as presented in Table 3.6.  These dust control measures have also been taken into account in the assessment.

Table 3.6      Rock Crusher and Barging Facilities – Dust Emission Design Control Measures

Process

Description

Dust Emission Design Control Measures

Rock Crusher

Unloading from trucks, Screening and Crushing

Unloading from trucks, Screening and Crushing

The rock crushing plant is in the enclosed structure with dust curtains would be provided at the opening of the plant.  Dust collector would be installed at the exhaust of the rock crusher to suppress the dust emission to the atmosphere.

Trucks

Vehicles leaving the rock crusher

Vehicles would be required to pass through the wheel washing facilities provided at site exit.

Barging Facilities

Unloading of materials

Unloading of spoil materials from trucks and conveyor belt (for barging point at Cha Kwo Ling only)

The unloading process would be undertaken within a 3-sided screen with top tipping hall.  Water spraying and flexible dust curtains would be provided at the discharge point for dust suppression.

Trucks

Vehicles leaving the barging facility

Vehicles would be required to pass through the wheel washing facilities provided at site exit.

 

3.6.4              Due to the tight construction programme, it will be necessary for active construction activities to be undertaken at multiple work faces spread across each site.  Therefore, it is not feasible to identify the exact location of individual dust emission source at a time.  As such, for the purpose of predicting annual TSP concentrations and in conservative approach, it is assumed that dust emissions would be distributed across the whole area of each site with all activities operating at the same time for a complete year.  The dust emission rates are estimated based on the annual average percentage active works area of each works site.  Based on the preliminary engineering design, the annual average active area is estimated to be 30% as presented in Appendix 3.1 and would be assumed for predicting the annual average concentrations.  The rock crusher and the two barging points are considered to be working at full capacity throughout the construction period, taken as a worst-case assumption.  Thus, 100% emission from the operation of the rock crusher and barging points is assumed in the model.

3.6.5              Works activities and plant would not be concentrated in certain areas of the site close to ASRs for an extended period of time during the construction period.  However, notwithstanding that such a scenario would not be expected to occur, a hypothetical Tier 1 screening test assuming 100% active area of construction site of the Project with mitigation measures in place has been undertaken for predicting hourly and daily average TSP levels.  It aims to highlight the hot spot locations where construction dust may potentially become an issue.  However, it should be emphasized that Tier 1 screening test is a hypothetical one which is very conservative and does not occurred in reality.

3.6.6              The Tier 1 results have allowed a more focused Tier 2 assessment to be undertaken at the specific hot spot locations where TSP non-compliance is predicted under the Tier 1 screening test, a focused Tier 2 assessment is undertaken whereby the percentage of daily maximum active works areas, which is assumed to be 30%, for the Project are positioned closest to the potentially worst affected ASRs. The Tier 2 assessment areas are shown in Appendix 3.1.  Same as for predicting annual average TSP levels, 100% emission from the operation of rock crusher and barging points is assumed in the model. 

3.6.7              The excavation rate, material handling rate, percentage active area, moisture content, silt content, number of trucks and truck speed are based on the preliminary engineering design.  The emission rate of identified pollutant sources are summarised in Table 3.7.  The justification for the percentage active area within the construction work sites and the detailed calculations of the emission factors are given in Appendix 3.1. 

Table 3.7      Emission Factors for Dusty Construction Activities

 

Emission Source

Activity

Emission Rate

Remarks

Lam Tin Side

 

 

 

1.      Excavation, Surface Blasting and Cut & Cover under TKO-LT Tunnel Project

2.      Excavation, Cut & Cover under T2 Project

Heavy Construction Activities

E=2.69 Mg/hectare

/month of activity

 

100% area actively operating (for hourly and daily concentration prediction)

30% area actively operating (for annual concentration prediction)

AP42, Section 13.2.3

Wind Erosion

 

E=0.85Mg/hectare

/year

 

100% area actively operating (for hourly and daily concentration prediction)

30% area actively operating (for annual concentration prediction)

AP42, Section 11.9, Table 11.9.4

Rock Crusher at Lam Tin Works Area

Loading Point

E = 0.000008kg/Mg

 

 

RSP to TSP factor = 2.1

100% area actively operating

 

RSP Emission Factor

EPA AP-42, 5th ed. 8/04 ed., Sec11.19.2, Table 11.19.2-1

 

RSP to TSP factor

EPA AP-42 5th ed. 1/95 ed., Sec 11.19.2, Table 11.19.2-1

Screening

E = 0.0015 kg/Mg

EPA AP-42, 5th ed. 8/04 ed., Sec11.19.2, Table 11.19.2-1

Crushing

E = 0.0027 kg/Mg

EPA AP-42, 5th ed. 8/04 ed., Sec11.19.2, Table 11.19.2-1

Barging Point at Cha Kwo Ling

Unloading of spoils to barge

E = k x (0.0016) x [(U/2.2)1.3 / (M/2)1.4]

AP-42, S13.2.4, particle size < 30 um, 11/06 ed

AP-42, Table 13.2.4-1, 11/06 ed

Handling capacity: 11550Mg/day

Number of berth: 1

TKO Side

Reclamation, Excavation under TKO-LT Tunnel Project

Heavy Construction Activities

E=2.69 Mg/hectare

/month of activity

 

100% area actively operating (for hourly and daily concentration prediction)

30% area actively operating (for annual concentration prediction)

AP42, Section 13.2.3

Wind Erosion

 

E=0.85Mg/hectare

/year

 

100% area actively operating (for hourly and daily concentration prediction)

30% area actively operating (for annual concentration prediction)

AP42, Section 11.9, Table 11.9.4

Barging Point at Chiu Keng Wan

Unloading of spoils to barge

E = k x (0.0016) x [(U/2.2)1.3 / (M/2)1.4]

AP-42, S13.2.4, particle size < 30 um, 11/06 ed

AP-42, Table 13.2.4-1, 11/06 ed

Handling capacity: 11550Mg/day

Number of berth: 1

 

3.6.8              For the prediction of maximum daily average TSP concentration and annual average TSP concentration, 12-hour (07:00-19:00) per day is assumed for the construction period in the assessment except the operation period of the rock crusher and the two barging points is 11 hours (07:00-12:00 and 13:00-19:00).   

Dispersion Modelling & Concentration Calculation

3.6.9              Fugitive Dust Model (FDM) (1993 version) is adopted to assess potential dust impact from the construction works.   

3.6.10          Hourly meteorological data including wind speed, wind direction, air temperature and Pasquill stability class in Year 2009 from the nearest Hong Kong Observatory weather station, Kai Tak Station is employed for the model run in the work sites at Lam Tin side.  For TKO side, it is noted that the valid data from Year 2007 to 2011 for Junk Bay Station are less than 90%.  Hence, Year 2009 Hong Kong Observatory Kai Tak Station which is another nearest meteorological station is employed for the model run in the work sites at TKO side.  Since no construction activities would occur on Sundays and public holidays, only wind erosion would be assumed for these days as well as for other non-working hours (19:00 to 07:00 of the following day) on normal working days.

3.6.11          As mentioned in Section 3.3.4, the background TSP level of 73 mg/m3 is adopted as the future TSP background concentration in the assessment. 

Operation Phase

Determination of the Assessment Year

3.6.12          According to Clause 3.4.1.4 (iv) (b) of the EIA Study Brief, the air pollution impacts of future road traffic should be calculated based on the highest emission strength from vehicles within the next 15 years upon commencement of operation of the proposed project.  The selected assessment year should therefore represent the highest emission scenario for the roads within the 500m study boundary.

3.6.13          Vehicular tailpipe emissions from open roads are calculated based on the EPD EMFAC-HK model v2.1 at the time of assessment (end 2012).  However, the latest model version EMFAC-HK v2.5 is just released by EPD in early January 2013.  As concluded in the “Outline of Changes in January 2013 Release of EMFAC-HK” in EPD website[3], the overall effects on emission estimates are insignificant.  There are only some changes in the output file formats due to items removal as comparing with v2.1.  Besides, one output file name is also changed and the format for input files is changed from VKT to VMT to ensure the consistency in units used in input files (US units).  The above format changes would not impose any change in the emission rate.  Therefore, the vehicular tailpipe emission rates generated from v2.1 are still adopted in this assessment.  As NO2 is the pollutant of primary concern for a road project, the assessment year is determined based on the highest total NOx emission from the roads in the study area using the EMFAC-HK model.  Appendix 3.2 presents the methodology and assumptions adopted in estimating the emission factors, and the calculated results.  Table 3.8 below summarise the total emission of NOx and RSP (in ton/year) for different road types among Year 2021, 2029 and 2036.

Table 3.8      Total Emission of NOx and RSP (in ton/year) for different Road Types among Year 2021, 2029 and 2036

Year

Total NOx Emission (ton/year)

Total RSP Emission (ton/year)

Local Road
(50kph)

Trunk Road
(70kph)

Express-
way
(80kph)

Local Road
(50kph)

Trunk Road
(70kph)

Express-
way
(80kph)

2021

77.1613

27.5650

56.6059

3.7967

1.6028

2.9677

2029

37.5575

12.2910

25.9166

2.3908

1.1432

1.9864

2036

27.8650

8.9417

19.0490

1.9282

0.9563

1.6170

 

3.6.14    Based on Table 3.8 as shown above, it is concluded that the highest vehicular emissions are found in Year 2021. Therefore, Year 2021 is selected as the assessment year for the operational phase air quality impact assessment.  The hourly emissions of NOx and RSP in Year 2021 are divided by the number of vehicles and the distance travelled to obtain the emission factors in gram per miles per vehicle.  The calculated 24-hour emission factors of 16 vehicle classes for the different road types in Year 2021 adopted in this air quality impact assessment are presented in Appendix 3.3.  The 24-hour projected traffic flows and vehicle compositions for Year 2021 which have been agreed by TD (The agreement from TD for the methodology and traffic data adopted in this EIA is attached in Appendix 3.2) are presented in Appendix 3.4.

Background Pollutant Concentrations – PATH Model

3.6.15    PATH model is used to quantify the background air quality during operation phase of the Project.  The emission sources including those in Pearl River Delta Economic Zone, roads, marine, airport, power plants and industries within Hong Kong are all considered in the PATH model.  The hourly concentration data of background concentration predicted by PATH model provided by EPD are Year 2020 and 2030.  As presented in Sections 3.6.14, Year 2021 is selected as the assessment year for the operation phase air quality impact assessment.  In addition, the trend for the background air quality concentration is decreasing from Year 2020 to Year 2030 due to the technology advancement on the vehicle emissions.   Therefore, as a conservative assumption, Year 2020 background concentration are adopted in the calculation of the cumulative results.  Graphical plots of the PATH background results are presented in Appendix 3.5.

Identification of Key/Representative Air Pollutants of Vehicle Emissions from Open Road

3.6.16         Vehicular emission comprises a number of pollutants, including Nitrogen Oxides (NOx), Respirable Suspended Particulates (RSP), Sulphur Dioxides (SO2), Carbon Monoxide (CO),  Lead (Pb), Toxic Air Pollutants (TAPs) etc.  Accordingly to “An Overview on Air Quality and Air Pollution Control in Hong Kong”[4] published by EPD, motor vehicles are the main causes of high concentrations of respirable suspended particulates (RSP) and nitrogen oxides (NOx) at street level in Hong Kong and are considered as key air quality pollutants for road projects.  For other pollutants, due to the low concentration in vehicular emission, they are not considered as key pollutants for the purpose of this study. 

(i)            Nitrogen Dioxide (NO2)

 

3.6.17         Nitrogen oxides (NOx) is a major pollutant from fossil fuel combustion.  According to the Emission Inventory for 2010 published on EPD’s website[5], navigation is the dominant contributor to NOx generation in Hong Kong, accounted for 32% of NOx emission in 2010.  Road transport is the second largest NOx contributor which accounted for 30% of the total in the same year.

3.6.18         In the presence of O3 and VOC, NOx would be converted to NO2.  Increasing traffic flow would inevitably increase the NOx emission and subsequently the roadside NO2 concentration.  Hence, NO2 is one of the key pollutants for the operational air quality assessment of the Project. 1-hour, 24-hour and annual averaged NO2 concentrations at each identified ASRs would be assessed and compared with the relevant AQO to determine the compliance.

(ii)          Respirable Suspended Particulates (RSP)

 

3.6.19         Respirable Suspended Particulates (RSP) refers to suspended particulates with a nominal aerodynamic diameter of 10um or less.  According to the Emission Inventory for 2010 published on EPD’s website, navigation is the dominant contributor to RSP generation in Hong Kong, accounted for 36% of RSP emission in 2010.  Road transport is the second largest RSP contributor which accounted for 21% of the total in the same year.  Increasing traffic flow would inevitably increase the roadside RSP concentration.  Hence, RSP is also one of the key pollutants for the operational air quality assessment of the Project.  The 24-hour and annual averaged RSP concentrations at each identified ASRs would be assessed and compared with the relevant AQO to determine the compliance.

(iii)        Sulphur Dioxide (SO2)

 

3.6.20         Sulphur dioxide (SO2) is formed primarily from the combustion of sulphur-containing fossil fuels.  In Hong Kong, power stations and marine vessels are the major sources of SO2, followed by fuel combustion equipment and motor vehicles.[6]  SO2 emission from vehicular exhaust is due to the sulphur content in diesel oil.  According to EPD’s “Cleaning the Air at Street Level”[7], ultra low sulphur diesel (ULSD) with a sulphur content of only 0.005% has been adopted as the statutory minimum requirement for motor vehicle diesel since April 2002, which is 3 years ahead of the European Union.  With the use of ULSD, according to the Emission Inventory for 2010 published on EPD’s website, road transport is the smallest share of SO2 emission sources in 2010 and only constitutes less than 1% of the total SO2 emission.  From 1 July 2010, EPD has tightened the statutory motor vehicle diesel and unleaded petrol specifications to Euro V level, which further tightens the cap on sulphur content from 0.005% to 0.001%.

3.6.21         In addition, the measured 1-hr average, daily average and annual average SO2 concentration at all EPD air monitoring stations are all less than 40% of the respective AQO.  In view that road transport only contributes a very small amount of SO2 emission, relatively low measured concentrations and the adoption of low-sulphur and ultra-low-sulphur fuel under the existing government policy, SO2 would not be a critical air pollutant of concern. 

(iv)         Carbon Monoxide (CO)

 

3.6.22         Carbon Monoxide (CO) is a typical pollutant emitted from fossil fuel combustion and comes mainly from vehicular emissions. With reference to the “Air Quality in Hong Kong 2011”, measured the highest 1-hour average (4030µg/m3) and the highest 8-hour average (3309 µg/m3) were both recorded at the Causeway Bay roadside station; these values were around one seventh and one third of the respective AQO limits.  In view that there is still a large margin to the AQO, CO would not be a critical air pollutant of concern.  

(v)           Ozone (O3)

 

3.6.23         Ozone (O3) is produced from photochemical reaction between NOx and VOCs in the presence of sunlight, which will not be generated by this project.  Concentration of O3 is governed by both precursors and atmospheric transport from other areas.  When precursors transport along under favorable meteorological conditions and sunlight, ozone will be produced.  This explains why higher ozone levels are generally not produced in the urban core or industrial area but rather at some distance downwind after photochemical reactions have taken place.  In the presence of large amounts of NOx in the roadside environment, O3 reacts with NO to give NO2 and thus results in O3 removal. O3 is therefore not considered as a key air pollutant for the operational air quality assessment of a road project.

(vi)         Lead (Pb)

 

3.6.24         The sale of leaded petrol has been banned in Hong Kong since April 1999.  According to the “Air Quality in Hong Kong 2011”, the measured ambient lead concentrations were ranging from 20ng/m3 to 104ng/m3.  The measured concentrations were well below the AQO limits.  Therefore, lead is not considered as a critical air pollutant of concern.

(vii)       Toxic Air Pollutants (TAPs)

 

3.6.25         Vehicular exhaust is one of the emission sources of Toxic Air Pollutants (TAPs), which are known or suspected to cause cancer or other serious health and environmental effects.  With reference to EPD’s Assessment of Toxic Air Pollutant Measurements in Hong Kong Final Report [8], monitored TAPs in Hong Kong include diesel particulate matters (DPM), toxic elemental species, dioxins, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), carbonyls, and volatile organic compounds (VOCs).  According to the results of Assessment of Toxic Air Pollutant Measurements in Hong Kong Final Report and Sources of PCB emissions[9], vehicular emission is not considered as primary source of dioxins, PCBs, carbonyls and most toxic elemental species in Hong Kong. Therefore, these pollutants are not considered as key pollutants for quantitative assessment for the operation phase of a road project.

Diesel Particulate Matters (DPM)

3.6.26         Diesel Particulate Matters (DPM), as part of the overall Respirable Suspended Particulates (RSP), is one of the most important parameter contributing to the overall health risk of the population.  Local vehicular emission is one of the major sources of DPM.

3.6.27         EPD has embarked on the following three key programmes to reduce the diesel particulate level at the roadside[10]: (a) the LPG taxi and light bus program; (b) the introduction of an advanced test to check diesel vehicle smoke emission; and (c) the retrofit of pre-Euro diesel commercial vehicles with diesel oxidation Catalysts (DOCs).  According to EPD’s website[11], franchised bus companies have also retrofitted their Euro I buses with diesel oxidation catalysts (DOCs) and Euro II and III buses with diesel particulate filters (DPFs).  A DPF can reduce particulate emissions from diesel vehicles by over 80%.  

3.6.28         As recommended by EPD’s Assessment of Toxic Air Pollutant Measurements in Hong Kong Final Report, elemental carbon (EC) is used as a surrogate for DPM, and with reference to Measurements and Validation for the 2008/2009 Particulate Matter Study in Hong Kong[12], EC showed a significant decrease in concentration from 2001 to 2009 in Hong Kong, i.e. -47.5%, -30.0% and -28.3% at Mong Kok, Tsuen Wan and Hok Tsui Monitoring Sites, respectively.  With the continual efforts by EPD to reduce particulate emission from the vehicular fleet, a discernible decreasing trend is noted in the level of particulate matter.  Therefore, DPM is not selected as representative pollutant for quantitative assessment for this Project.

Polycyclic Aromatic Hydrocarbons (PAHs)

3.6.29         Polycyclic Aromatic Hydrocarbons (PAHs) are organic compounds of two or more fused benzene rings, in liner, angular or cluster conformations. Local vehicular traffic is also an important source of PAHs.  For this group, the most important TAP is Benzo[a]pyrene, and it is often selected as a marker for the PAHs[13].  The EU Air Quality Standards for PAHs (expressed as concentration of Benzo[a]pyrene) is 1 ng/m3 for annual average[14].  With reference to “Air Quality in Hong Kong 2011”, annual average concentrations of PAHs (Benzo[a]pyrene) measured at EPD’s TAP monitoring stations (Tsuen Wan and Central/Western) were 0.22ng/m3, which is far below the EU Standards. Thus, PAHs are not considered as key pollutants for quantitative assessment for this Project.

Volatile Organic Compounds (VOCs)

3.6.30         Volatile Organic Compounds (VOCs) are of great concern due to the important role played by them in a range of health and environmental problems. The US EPA has designated many VOC, including those typically found in vehicular emission, as air toxic. According to Assessment of Toxic Air Pollutant Measurements in Hong Kong Final Report, among the VOC compounds, benzene and 1,3-butadiene are the most significant ones for Hong Kong The UK Air Quality Standards for benzene and 1,3-butadiene are 5.0µg/m3 and 2.25 µg/m3 respectively[15].  Accordingly to “Air Quality in Hong Kong 2011”, annual average concentrations of benzene and 1,3-butadiene at EPD’s TAP monitoring stations (Tsuen Wan and Central/Western) were 1.53 - 1.62 µg/m3 and 0.13 µg/m3, respectively, which is far below the UK Standards.  Thus, VOCs are not considered as key pollutants for quantitative assessment for this Project.

Identification of Key/Representative Air Pollutants of Vehicle Emissions in Tunnel, Full Enclosures and under proposed Landscape Decks

Nitrogen Dioxide (NO2)

3.6.31         As stated in Section 3.6.17 to 18, nitrogen oxides (NOx) is a major pollutant from fossil fuel combustion.  Traffic flow would inevitably increase the NOx and NO2 concentration in tunnel, full enclosures and under proposed landscape decks.  Hence, NO2 is one of the key pollutants for the in-tunnel air quality assessment and compared with the relevant TAQG to determine the compliance.

Sulphur Dioxide (SO2)

3.6.32         From 1 July 2010, EPD has tightened the statutory motor vehicle diesel and unleaded petrol specifications to Euro V level, which further tightens the cap on sulphur content from 0.005% to 0.001%.  Referring to “Practice Note on Control of Air Pollution in Vehicle Tunnels” issued by EPD, continuous monitoring of SO2 is normally not required considering the traffic mix in Hong Kong.  Therefore, SO2 vehicle emission impact in tunnel is expected to be insignificant. Thus, SO2 is not considered as key pollutant for quantitative in-tunnel air quality assessment in this Project.

Carbon Monoxide (CO)

3.6.33         Carbon Monoxide (CO) is a typical pollutant emitted from fossil fuel combustion and comes mainly from vehicular emissions.  In view of the ratio of guideline standard of CO (5-minute) concentration to NO2 (5-minute) concentration is 64, however, the emission rate of CO is only 2.8 times of emission rate of NOx according to the EMFAC v.2.1 emission factors. Therefore, CO would comply with the AQO if NO2 concentration complies with the standard. Thus, CO is not considered as key pollutant for quantitative in-tunnel air quality assessment in this Project.  In addition, continuous measurement of CO would be conducted inside the tunnel according to the monitoring requirements of “Practice Note on Control of Air Pollution in Vehicle Tunnels” issued by EPD to ensure the compliance of the TAQG.

Model Assumptions for Open Road Vehicle Emission

3.6.34    The USEPA approved line source air dispersion model, CALINE4 developed by the California Department of Transport is used to assess vehicular emissions impact from existing and planned road network.  Since all the vehicular emissions associated with this Project are from ground level only, the first ASR level as tabulated in Table 3.5 would therefore represent the worst-case scenario.

3.6.35    The dispersion modelling is conducted based on the meteorological data extracted from the PATH model. The grid cells used for extraction of meteorological data and background pollutant concentration are summarized in Table 3.9.  Surface roughness coefficients as shown in Table 3.9 are taken in the CALINE4 model.

Table 3.9      PATH Model Grid Cells for Extraction of Meteorological Data and Background Pollutant Concentrations

Study Area

Grid Cells

Surface Roughness (cm)

Lam Tin Area

32_27

370

33_27

370

TKO Area

34_26

100

34_27

100

35_27

100

3.6.36    Ozone Limiting Method (OLM) is adopted for conversion of NOx to NO2 based on the predicted O3 level from PATH.  A tailpipe emission NO2/NOx ratio of 7.5% based on the EPD’s “Guidelines on Choice of Models and Model Parameters” has been assumed.  The NO2/NOx conversion is calculated as follows:

 

[NO2]pred = 0.075x[NOX]pred + MIN {0.925x[NOX]pred, or (46/48)x [O3]bkgd}

where

[NO2]pred    is the predicted NO2 concentration

[NOX]pred   is the predicted NOX concentration

MIN             means the minimum of the two values within the brackets

[O3]bkgd      is the representative O3 background concentration

(46/48) is the molecular weight of NO2 divided by the molecular weight of O3

 

3.6.37    Secondary air quality impacts arising from the implementation of roadside noise mitigation measures including vertical noise barriers, cantilevered noise barriers and semi-enclosures, and landscape decks for TKO-LT Tunnel Interchange are incorporated into the air quality model.  

3.6.38    The locations of open road emission sources, 24-hour traffic flows and composite emission factors for each road link are presented in Appendix 3.6.

 

Model Assumptions for Emissions from Portals/Full Enclosures, Road P2 Landscape Deck and Ventilation Buildings

3.6.39    The portal emissions from TKO-LT Tunnel, EHC, Trunk Road T2, proposed full enclosures and the proposed landscape decks at Lam Tin Interchange and on Road P2, emissions from ventilation buildings of TKO-LT Tunnel (Lam Tin side and TKO side), EHC and Trunk Road T2 are predicted by EPD approved dispersion model, the Industrial Source Complex Short Term (ISCST3) model. 

3.6.40    According to the design information, for the westbound carriageway of TKO-LT Tunnel, 40% vehicle emissions would be emitted from the Lam Tin side portal and remaining 60% emission would be emitted from the ventilation building located at the western portal of TKO-LT Tunnel.  For the eastbound carriageway of TKO-LT Tunnel, 40% vehicles emissions would be emitted from TKO side portal and the remaining 60%emissions would be extracted and discharged at the ventilation building located at the eastern portal of TKO-LT Tunnel.  The emission inventory and the design of the vent shaft adopted in the assessment are based on the design assumptions at the time of the assessment.  The preliminary design of the ventilation buildings (including exit height, exhaust directions, exit velocity, design airflow rate and the exhaust area of the ventilation building) is summarized in Table 3.10.

Table 3.10     Design of TKO-LT Tunnel Ventilation Buildings

 

 

Design Airflow Rate (m3/s)

Exit Velocity (m/s)

Exit Height (m above ground)

Exhaust Area (m2)

Exhaust Direction

Ventilation Building at eastern portal

390

6

8

65

Upward with inclined angle at 45˚

Ventilation Building at western portal

390

6

8

65

Upward with inclined angle at 45˚

 

3.6.41    There is no partition wall between the opposite traffic directions of Road P2 under the landscape deck.  50% of the emissions from the decked section of Road P2 are assumed to be emitted from the southbound portal while another 50% of the emission would be emitted from northbound portal.

3.6.42    The data of portal emissions from tunnel section of Trunk Road T2 and the design information for its ventilation building are provided by Trunk Road T2 Consultant.  About 10% of the emissions from the eastbound carriageway of T2 Tunnel would be emitted from the portal at Lam Tin Area while the remaining 90% emission would be discharged at the ventilation building which is located at the top of the T2 Tunnel portal at Lam Tin Area.  The emission information and locations for T2 ventilation building are presented in Appendix 3.7.

3.6.43    The emissions from EHC ventilation building at Kowloon side and its portal emissions from Kowloon bound are also considered in the cumulative operational air quality impact assessment.  The data for EHC ventilation building are based on the Kai Tak Development Schedule 3 EIA Report.  The emission data are presented in Appendix 3.7.

3.6.44    The portal emissions from tunnels/full enclosures are modelled in accordance with the recommendations of the Permanent International Association of Road Congress Report (PIARC, 1991).  The pollutants are assumed to eject from the portal as a portal jet such that 2/3 of the total emissions is dispersed within the first 50m of the portal and the other 1/3 of the total emissions within the second 50m.  The locations of the portal emissions considered in the assessment and emission calculations for the portals are presented in Appendix 3.7.

3.6.45    A summary for the mentioned portals and ventilation building emissions within 500m study area for Lam Tin area and Tseung Kwan O area are presented in Table 3.11 and 3.12 respectively.  A summary summarizing the total emissions from ventilation buildings is presented in Table 3.13.

Table 3.11     Summary of Portals and Ventilation Building Emissions within 500m Study Area (Lam Tin side)

 

Location

Daily Emission Rates in gram/second

Portal

Ventilation Building

NOx

RSP

NOx

RSP

Deck of Sceneway Garden at Lei Yue Mun Road Southbound

(Portal Name: A)

2.2080

0.1064

N/A

N/A

Slip Road from Eastbound of Trunk Road T2 at Lam Tin Interchange

(Portal Name: B;

Ventilation Buildings: V1 & V2)

0.4335

0.0232

3.9010

0.2088

10% Emission from Portal

90% Emission from Ventilation Building

Slip Road S02 at Lam Tin Interchange

(Portal Name: C)

0.2973

0.0153

N/A

N/A

Slip Road EHC4 at Lam Tin Interchange

(Portal Name: D)

0.2168

0.0106

N/A

N/A

Slip Road S02 at Lam Tin Interchange

(Portal Name: E)

0.2392

0.0123

N/A

N/A

Trunk Road T2 Eastbound Main Line (Portal Name: F;

Ventilation Buildings: V1 & V2)

0.6200

0.0326

5.5800

0.2931

10% Emission from Portal

90% Emission from Ventilation Building

TKO-LT Tunnel Westbound Main Line

(Portal Name: G;

Ventilation Building: V3)

2.719

0.1422

4.0790

0.2133

40% Emission from Portal

60% Emission from Ventilation Building

Slip Road EHC1 at Lam Tin Interchange

(Portal Name: H)

0.4088

0.0203

N/A

N/A

Slip Road from Westbound of TKO-LT Tunnel

(Portal Name: J;

Ventilation Building: V3)

1.0670

0.0576

1.6010

0.0864

40% Emission from Portal

60% Emission from Ventilation Building

Eastern Harbour Crossing Kowloon Bound

(Portal Name: K;

Ventilation Building: V4)

2.8560

0.1481

6.6630

0.3455

30% Emission from Portal

70% Emission from Ventilation Building

  Note: Refer to the Appendix 3.6 for the detailed locations of the portals and ventilations buildings.

Table 3.12     Summary of Portals and Ventilation Building Emissions within 500m Study Area (Tseung Kwan O side)

 

Location

Daily Emission Rates in gram/second

Portal

Ventilation Building

NOx

RSP

NOx

RSP

Landscape Deck at Road P2

(Portal Name: A)

0.2280

0.0107

N/A

N/A

Landscape Deck at Road P2

(Portal Name: B)

0.2280

0.0107

N/A

N/A

TKO-LT Tunnel Eastbound Main Line

(Portal Name: B;

Ventilation Building: V1)

3.6960

0.1930

5.5430

0.2895

40% Emission from Portal

60% Emission from Ventilation Building

  Note: Refer to the Appendix 3.6 for the detailed locations of the portals and ventilations buildings.

Table 3.13     Summary of Total Emissions from Ventilation Building Emissions within 500m Study Area

 

Location

Daily Emission Rates in gram/second

 

NOx

RSP

Lam Tin side

Eastern T2 Ventilation Building Stack 1

(Source ID: V1) (1)

9.2610

0.4884

Eastern T2 Ventilation Building Stack 2

(Source ID: V2) (1)

9.2610

0.4884

TKO-LT Western Ventilation Building

(Source ID: V3) (2)

5.6790

0.2998

Eastern Harbour Crossing Kowloon Bound

(Source ID: V4)

6.6630

0.3455

Tseung Kwan O side

TKO-LT Eastern Ventilation Building

(Source ID: V1)

5.5430

0.2895

Note: Refer to the Appendix 3.6 for the detailed locations of the ventilations buildings.

(1) The emission from Eastern T2 Ventilation Building includes emissions from eastbound slip road, eastbound main line and westbound main line of the Trunk Road T2, and distributing to Stack 1 and Stack 2 at the Eastern T2 Ventilation Building.  (Emissions from westbound main line of Trunk Road T2: NOx = 9.0420g/s; RSP = 0.4748g/s.)

(2) The emission from TKO-LT Western Ventilation Building includes emissions from westbound slip road and westbound main line of TKO-LT Tunnel.

3.6.46    Meteorological data extracted from the PATH model from different grid cells as listed in Table 3.9 is employed for the model run.  NOx concentrations from the open roads, the portals/full enclosures and ventilation buildings are firstly added together and OLM as mentioned in Section 3.6.33 is also applied subsequently.  The rural dispersion mode in ISCST3 model is selected depending on the land uses where the ASRs locate.

 

Cumulative Impact of Criteria Air Pollutants

3.6.47    The PATH model outputs based on Year 2020 emission inventories are added to the sum of the CALINE4 (for open road emissions from existing and proposed road networks) and ISCST3 (for all portal emissions, emissions from Road P2 landscape deck and emissions from ventilation building) model results sequentially on an hour-by-hour basis to derive the short-term and long-term cumulative impacts at each receptor.  The highest pollutant concentration predicted at a receptor amongst the 8760 hours is taken as the worst predicted hourly pollutant concentration for that receptor.  The maximum 24-hour average pollutant concentration at a receptor amongst the 365 days is the highest predicted daily average concentration. The annual average pollutant concentration at a receptor is the average of 8760 hourly concentrations. 

 

3.7                    Prediction and Evaluation of Environmental Impacts

Construction Phase

3.7.1              With considerations of dust emissions during construction phase of both TKO-LT Tunnel and Trunk Road T2, the predicted unmitigated cumulative maximum hourly, daily and annual average TSP concentrations at the representative ASRs are summarized in Table 3.14.

3.7.2              Based on the results shown in Table 3.14, the predicted cumulative maximum hourly, daily and annual average TSP concentrations at some representative ASRs at Lam Tin side and TKO side would exceed the criteria stipulated in EIAO-TM and AQO under unmitigated scenario.  Hence, proper dust mitigation measures should be implemented.  The contour plots of cumulative maximum hourly, daily and annual average unmitigated TSP concentrations at 7mPD and 15.5mPD (the worst-hit levels) at Lam Tin side are presented in Figures 3.5a to 3.10b.  The contour plots of cumulative maximum hourly, daily and annual average unmitigated TSP concentrations at 5.5mPD and 14mPD (the worst-hit levels) at Tseung Kwan O side are presented in Figures 3.11a to 3.16b.

Table 3.14     Predicted Cumulative Maximum Hourly, Daily and Annual Average TSP Concentrations at Representative Air Sensitive Receivers (Unmitigated)

 

ASRs

Assessment

Height (mAG)

Assessment

Height (mPD)

Cumulative Maximum TSP Concentrations in ug/m3

Hourly Average

24-hour Average

Annual Average

Lam Tin Side

CL1

1.5

7.0

5082

1026

99.8

CL1

5.0

10.5

3952

842

94.8

CL1

10.0

15.5

2129

532

85.8

CL1

15.0

20.5

1204

343

80.5

CL1

20.0

25.5

859

239

77.6

CL2

1.5

7.0

4813

837

103.9

CL2

5.0

10.5

3833

720

101.6

CL2

10.0

15.5

2088

468

93.6

CL2

15.0

20.5

1506

299

86.8

CL2

20.0

25.5

1099

202

82.1

CL3

1.5

7.0

2215

405

101.7

CL4

1.5

7.0

2201

396

103.1

CL4

5.0

10.5

1971

390

102.8

CL4

10.0

15.5

1357

332

98.0

CL4

15.0

20.5

1157

268

93.0

CL4

20.0

25.5

947

216

88.5

CL5

1.5

7.0

1783

433

88.4

CL5

5.0

10.5

1686

420

88.7

CL5

10.0

15.5

1204

333

86.7

CL5

15.0

20.5

829

254

84.5

CL5

20.0

25.5

714

221

82.4

CL6

1.5

15.5

1614

331

87.8

CL7

1.5

15.5

2170

481

87.0

CL8

1.5

7.0

4424

670

81.7

CL8

5.0

10.5

3745

583

81.2

CL8

10.0

15.5

2250

386

79.4

CL8

15.0

20.5

1424

285

77.9

CL8

20.0

25.5

1115

222

76.8

CL9

1.5

7.0

3542

440

84.3

CL9

5.0

10.5

3104

373

83.1

CL9

10.0

15.5

2015

300

80.3

CL9

15.0

20.5

1332

251

78.2

CL9

20.0

25.5

1034

212

76.9

CL10

1.5

7.0

3159

601

84.9

CL10

5.0

10.5

2680

550

84.1

CL10

10.0

15.5

1576

402

81.3

CL10

15.0

20.5

1191

281

78.8

CL10

20.0

25.5

910

201

77.2

CL11

1.5

7.0

2707

617

85.8

CL12

1.5

7.0

2092

421

81.1

CL12

5.0

10.5

1866

403

80.8

CL12

10.0

15.5

1188

326

79.3

CL12

15.0

20.5

913

258

77.8

CL12

20.0

25.5

737

209

76.5

CL13

10.0

15.5

1423

381

88.5

CL13

15.0

20.5

994

238

81.8

CL13

20.0

25.5

798

184

78.3

CL14

1.5

7.0

2139

500

81.3

CL14

5.0

10.5

1806

469

80.9

CL14

10.0

15.5

1138

352

79.1

CL14

15.0

20.5

921

247

77.3

CL14

20.0

25.5

741

175

76.1

CL15

1.5

7.0

2791

453

99.2

CL15

5.0

10.5

1794

347

95.7

CL15

10.0

15.5

1295

283

90.6

CL15

15.0

20.5

997

242

86.8

CL15

20.0

25.5

754

202

83.8

CL16

1.5

7.0

2929

507

102.1

CL16

5.0

10.5

1716

328

97.3

CL16

10.0

15.5

1263

275

91.5

CL16

15.0

20.5

957

240

87.7

CL16

20.0

25.5

818

208

84.7

TKO Side

CT1

1.5

5.5

1377

287

76.1

CT1

5.0

9.0

1317

284

76.1

CT1

10.0

14.0

1010

245

75.6

CT1

15.0

19.0

702

204

75.1

CT1

20.0

24.0

466

168

74.7

CT2

10.0

14.0

1108

228

90.0

CT2

15.0

19.0

728

177

81.3

CT2

20.0

24.0

483

149

77.7

CT3

10.0

14.0

891

232

91.1

CT3

15.0

19.0

561

176

84.7

CT3

20.0

24.0

449

150

80.5

CT4

1.5

5.5

966

185

78.6

CT4

5.0

9.0

963

183

78.6

CT4

10.0

14.0

798

159

77.9

CT4

15.0

19.0

607

134

77.0

CT4

20.0

24.0

431

115

76.3

CT5

1.5

5.5

1597

182

75.1

CT5

5.0

9.0

1474

174

75.1

CT5

10.0

14.0

1075

144

74.7

CT5

15.0

19.0

772

131

74.4

CT5

20.0

24.0

537

121

74.2

Note:

(1) The background TSP level of 73 ug/m3 is included in the above results.

(2) The hourly, daily and annual average TSP EIAO-TM/AQO criteria are 500 ug/m3, 260 ug/m3 and 80 ug/m3 respectively.

(3) Boldfaced values represent the predicted TSP concentration exceeds the respective criteria.

Operation Phase

Traffic Emission Impact from Open Roads, Portals and Ventilation Buildings

Lam Tin Side

3.7.3              Taking into account vehicle emissions from open road networks, portal emissions from the tunnels (including TKO-LT Tunnel (Lam Tin side), EHC, Trunk Road T2 Tunnel) and proposed landscape decks/full enclosures at Lam Tin Interchange, emissions from Trunk Road T2, EHC and TKO-LT Tunnel (Lam Tin side) ventilation buildings, and background pollutant concentrations based on the PATH model outputs for Year 2020, the cumulative maximum 1-hour average NO2, daily average NO2 and RSP concentrations, and annual average NO2 and RSP are predicted and presented in Table 3.15.

Table 3.15     Predicted Cumulative Maximum Hourly, Daily and Annual Average Air Pollutants Concentrations at Representative Air Sensitive Receivers at Lam Tin

ASRs

Assessment Height (mPD)

Cumulative Maximum NO2 Concentrations in µg/m3

Cumulative Maximum RSP Concentrations in µg/m3

Hourly Average

24-hour Average

Annual Average

24-hour Average

Annual Average

LTA1

1.5

248

91.6

32.0

110.0

39.7

LTA1

5

248

89.8

31.2

109.8

39.7

LTA1

10

247

87.3

29.0

109.5

39.5

LTA1

15

246

85.7

26.7

109.2

39.4

LTA2

1.5

248

94.1

33.0

110.0

39.8

LTA2

5

247

92.3

31.7

109.9

39.7

LTA2

10

247

87.9

28.7

109.6

39.5

LTA2

15

246

84.3

25.7

109.3

39.3

LTA3

1.5

248

86.5

27.2

108.5

39.4

LTA3

5

249

87.0

27.6

108.5

39.4

LTA3

10

248

85.8

26.4

108.5

39.3

LTA3

15

248

84.1

24.5

108.3

39.2

LTA4

1.5

247

88.6

32.4

109.0

39.6

LTA4

5

247

87.3

30.1

108.9

39.5

LTA4

10

246

84.2

25.9

108.6

39.3

LTA4

15

246

81.5

23.3

108.5

39.2

LTA6

1.5

227

81.3

32.5

108.2

39.7

LTA6

5

227

81.3

32.3

108.2

39.7

LTA6

10

227

81.1

31.7

108.1

39.6

LTA6

15

226

80.9

30.8

108.1

39.6

LTA7

1.5

225

85.1

38.3

108.0

40.0

LTA7

5

224

84.7

37.2

108.0

39.9

LTA7

10

224

83.6

34.2

108.0

39.7

LTA7

15

224

82.3

30.6

108.0

39.5

LTA8

1.5

247

80.3

26.1

109.2

39.4

LTA8

5

247

80.0

25.9

109.1

39.3

LTA8

10

246

79.1

25.4

109.0

39.3

LTA8

15

243

78.6

24.6

108.8

39.2

LTA9

1.5

245

80.6

30.3

108.7

39.6

LTA9

5

237

80.3

28.6

108.4

39.5

LTA9

10

226

79.7

25.5

108.0

39.3

LTA9

15

222

78.5

23.8

107.8

39.2

LTA10

1.5

249

87.8

29.1

108.9

39.5

LTA10

5

249

87.2

28.7

108.9

39.5

LTA10

10

248

86.2

27.5

108.8

39.4

LTA10

15

248

84.8

26.0

108.6

39.3

LTA11

1.5

248

90.5

29.1

109.1

39.5

LTA11

5

248

88.8

28.7

109.0

39.5

LTA11

10

247

86.2

27.6

108.9

39.4

LTA11

15

247

84.7

26.2

108.7

39.3

LTPA1

1.5

247

93.0

36.7

108.6

40.1

LTPA1

5

247

89.8

35.0

108.5

39.9

LTPA1

10

247

87.4

32.0

108.4

39.7

LTPA1

15

246

86.1

29.6

108.3

39.5

LTPA2

1.5

247

93.2

33.3

108.4

39.8

LTPA2

5

246

90.6

31.5

108.3

39.6

LTPA2

10

246

87.1

28.5

108.2

39.4

LTPA2

15

240

85.5

26.6

108.1

39.3

LTPA3

1.5

248

98.9

37.1

108.7

40.0

LTPA3

5

247

89.7

32.1

108.4

39.7

LTPA3

10

245

86.0

28.0

108.2

39.4

LTPA3

15

236

84.3

25.9

108.1

39.3

LTPA4

1.5

249

92.7

33.8

108.6

39.8

LTPA4

5

247

86.7

27.9

108.3

39.4

LTPA4

10

246

84.4

25.0

108.1

39.2

LTPA4

15

243

83.3

23.7

108.1

39.2

LTPA7

1.5

222

89.2

38.2

108.1

40.0

LTPA7

5

222

87.4

35.8

108.1

39.9

LTPA7

10

222

83.9

32.2

108.0

39.6

LTPA7

15

222

81.7

30.6

108.0

39.5

LTPA10

1.5

226

81.9

34.2

107.9

39.9

LTPA10

5

225

81.9

34.1

107.9

39.9

LTPA10

10

225

81.9

33.9

107.9

39.9

LTPA10

15

224

82.1

33.5

107.9

39.9

LTPA11

1.5

225

81.1

34.8

107.9

39.9

LTPA11

5

225

81.1

34.7

107.9

39.9

LTPA11

10

224

80.9

34.4

107.9

40.0

LTPA11

15

224

80.8

34.0

107.9

40.0

Note:

(1) The maximum 1-hour and 24-hour average NO2 concentration limit under AQO:300 and 150 µg/m3.

(2) The maximum 24-hour average RSP concentration limit under AQO:180 µg/m3.

(3) The annual average NO2 and RSP concentration limit under AQO:80 and 55 µg/m3.

 

3.7.4              Referring to the predicted results, no exceedance of maximum 1-hour average NO2, daily average NO2 and RSP, and annual average NO2 and RSP AQO standards would occur at any representative ASR in the Study Area of Lam Tin side.  The predicted maximum hourly average NO2, daily average NO2 and RSP, annual average NO2 and RSP concentration contours at 1.5metres Above Ground(mAG) (The level that the highest predicted pollutants concentrations occur) are shown in Figures 3.31a to 3.35b.  The contour results show that no exceedance zone is predicted within the study area of the Project at Lam Tin side.

TKO Side

3.7.5              Taking into account vehicle emissions from open road networks, portal emissions from the TKO-LT Tunnel (TKO side) and proposed landscape deck on Road P2, emissions from the TKO-LT Tunnel ventilation building (TKO side) and the background pollutant concentrations predicted by PATH Model provided by EPD, the cumulative maximum 1-hour average NO2, daily average NO2 and RSP concentrations, and annual average NO2 and RSP are predicted and presented in Table 3.16.

Table 3.16     Predicted Cumulative Maximum Hourly, Daily and Annual Average Air Pollutants Concentrations at Representative Air Sensitive Receivers at Tseung Kwan O

ASRs

Assessment Height (mPD)

Cumulative Maximum NO2 Concentrations in µg/m3

Cumulative Maximum RSP Concentrations in µg/m3

Hourly Average

24-hour Average

Annual Average

24-hour Average

Annual Average

TKO-A1

1.5

253

75.7

19.4

103.4

38.8

TKO-A1

5

253

75.7

19.4

103.4

38.8

TKO-A1

10

253

75.6

19.3

103.4

38.8

TKO-A1

15

253

75.6

19.1

103.4

38.8

TKO-A2

1.5

209

74.6

18.0

104.4

38.3

TKO-A2

5

209

74.5

17.9

104.4

38.3

TKO-A2

10

209

73.9

17.5

104.4

38.3

TKO-A2

15

209

73.3

17.1

104.4

38.3

TKO-A3

1.5

217

75.2

20.7

105.4

38.9

TKO-A3

5

217

75.1

20.5

105.4

38.8

TKO-A3

10

216

74.8

20.2

105.4

38.8

TKO-A3

15

216

74.5

19.8

105.4

38.8

TKO-A4

1.5

222

79.2

21.8

105.6

38.9

TKO-A4

5

220

78.1

21.4

105.5

38.9

TKO-A4

10

218

76.2

20.6

105.5

38.8

TKO-A4

15

217

74.9

19.9

105.4

38.8

TKO-A5

1.5

219

73.6

20.4

105.6

38.8

TKO-A5

5

217

73.2

19.6

105.5

38.8

TKO-A5

10

216

72.5

19.0

105.4

38.8

TKO-A5

15

216

72.1

18.7

105.4

38.8

TKO-A6

1.5

218

74.3

21.5

105.6

38.9

TKO-A6

5

218

73.6

20.1

105.5

38.8

TKO-A6

10

217

73.1

19.5

105.4

38.8

TKO-A6

15

217

72.8

19.1

105.4

38.8

TKO-A7

1.5

218

79.8

25.0

105.5

39.0

TKO-A7

5

218

78.0

23.2

105.5

38.9

TKO-A7

10

218

75.8

21.2

105.5

38.9

TKO-A7

15

217

74.6

20.2

105.5

38.8

TKO-A8

1.5

218

77.2

22.1

105.5

38.9

TKO-A8

5

218

77.0

21.6

105.5

38.9

TKO-A8

10

218

76.4

20.7

105.5

38.8

TKO-A8

15

217

75.6

19.9

105.4

38.8

TKO-A9

1.5

221

77.4

21.7

105.6

38.9

TKO-A9

5

218

75.6

20.9

105.5

38.9

TKO-A9

10

217

74.3

20.2

105.5

38.8

TKO-A9

15

217

73.7

19.7

105.4

38.8

TKO-A10

1.5

222

76.8

22.7

105.6

38.9

TKO-A10

5

220

76.4

22.3

105.5

38.9

TKO-A10

10

218

75.5

21.3

105.5

38.9

TKO-A10

15

217

74.6

20.4

105.4

38.8

TKO-A11

1.5

220

76.6

22.6

105.5

38.9

TKO-A11

5

220

76.4

22.3

105.5

38.9

TKO-A11

10

219

75.7

21.6

105.5

38.9

TKO-A11

15

218

74.9

20.7

105.5

38.8

TKO-A12

1.5

226

78.5

22.9

105.6

38.9

TKO-A12

5

223

77.6

22.4

105.6

38.9

TKO-A12

10

218

75.7

21.3

105.5

38.9

TKO-A12

15

217

74.3

20.4

105.5

38.8

TKO-A13

1.5

219

78.8

29.7

105.9

39.2

TKO-A13

5

219

76.4

24.3

105.7

39.0

TKO-A13

10

218

74.8

21.6

105.6

38.9

TKO-A13

15

217

74.0

20.5

105.5

38.8

TKO-A14

1.5

215

76.5

20.5

104.6

38.4

TKO-A14

5

214

76.1

20.0

104.6

38.4

TKO-A14

10

212

75.1

18.9

104.5

38.3

TKO-A14

15

211

74.0

17.9

104.5

38.3

TKO-A15

1.5

217

78.1

20.2

104.6

38.4

TKO-A15

5

216

77.4

19.9

104.6

38.4

TKO-A15

10

214

75.9

19.0

104.5

38.3

TKO-A15

15

212

74.5

18.0

104.5

38.3

TKO-A16

1.5

211

75.9

21.9

104.6

38.5

TKO-A16

5

211

75.5

21.3

104.6

38.4

TKO-A16

10

211

74.5

19.8

104.5

38.4

TKO-A16

15

210

73.4

18.5

104.5

38.3

TKO-A17

1.5

216

77.4

21.2

104.7

38.4

TKO-A17

5

214

76.6

20.4

104.6

38.4

TKO-A17

10

212

75.2

19.0

104.6

38.3

TKO-A17

15

211

73.9

18.1

104.5

38.3

TKO-PA1

1.5

219

76.8

19.9

104.7

38.4

TKO-PA1

5

217

75.4

19.1

104.6

38.4

TKO-PA1

10

214

73.5

17.9

104.5

38.3

TKO-PA1

15

213

72.7

17.1

104.5

38.3

TKO-PA2

1.5

218

79.7

21.0

104.6

38.5

TKO-PA2

5

217

78.0

20.0

104.6

38.4

TKO-PA2

10

214

75.4

18.2

104.5

38.3

TKO-PA2

15

212

73.8

17.2

104.5

38.3

TKO-PA3

1.5

220

79.6

21.1

104.7

38.4

TKO-PA3

5

216

77.2

19.9

104.7

38.4

TKO-PA3

10

212

75.1

18.5

104.5

38.3

TKO-PA3

15

211

74.0

17.6

104.5

38.3

TKO-PA4

1.5

217

81.8

21.7

104.8

38.5

TKO-PA4

5

212

78.7

19.5

104.5

38.4

TKO-PA4

10

211

76.1

18.3

104.5

38.3

TKO-PA4

15

210

74.5

17.5

104.4

38.3

TKO-PA5

1.5

214

75.9

18.8

104.6

38.4

TKO-PA5

5

213

75.5

18.5

104.5

38.3

TKO-PA5

10

211

74.7

17.7

104.5

38.3

TKO-PA5

15

210

73.7

17.2

104.4

38.3

TKO-PA6

1.5

212

74.0

16.8

104.5

38.3

TKO-PA6

5

211

73.7

16.7

104.5

38.3

TKO-PA6

10

211

73.2

16.4

104.5

38.3

TKO-PA6

15

211

72.5

16.2

104.5

38.2

TKO-PA7

1.5

212

73.9

17.5

104.5

38.3

TKO-PA7

5

212

73.3

17.1

104.5

38.3

TKO-PA7

10

211

72.6

16.7

104.5

38.3

TKO-PA7

15

211

72.2

16.3

104.5

38.2

TKO-PA8

1.5

211

74.0

17.6

104.5

38.3

TKO-PA8

5

211

73.6

17.3

104.5

38.3

TKO-PA8

10

210

73.0

17.0

104.5

38.3

TKO-PA8

15

210

72.6

16.6

104.4

38.3

TKO-PA9

1.5

212

74.1

16.9

104.5

38.3

TKO-PA9

5

212

73.9

16.8

104.5

38.3

TKO-PA9

10

211

73.2

16.7

104.5

38.3

TKO-PA9

15

210

72.5

16.4

104.4

38.3

TKO-PA10

1.5

210

72.2

16.5

104.4

38.3

TKO-PA10

5

209

72.2

16.4

104.4

38.3

TKO-PA10

10

209

72.0

16.3

104.4

38.2

TKO-PA10

15

209

71.8

16.2

104.4

38.2

Note:

(1) The maximum 1-hour and 24-hour average NO2 concentration limit under AQO:300 and 150 µg/m3.

(2) The maximum 24-hour average RSP concentration limit under AQO:180 µg/m3.

(3) The annual average NO2 and RSP concentration limit under AQO:80 and 55 µg/m3.

 

3.7.6              Referring to the predicted results, no exceedance of maximum 1-hour average NO2, daily average NO2 and RSP, and annual average NO2 and RSP AQO standards would occur at any representative ASR in the Study Area of Tseung Kwan O side.  The predicted maximum hourly average NO2, daily average NO2 and RSP, annual average NO2 and RSP concentration contours at 1.5mAG (The level that highest predicted pollutants concentrations occur) are shown in Figures 3.36a to 3.40c.  The contour results show that no exceedance zone is predicted within the study area of the Project at Tseung Kwan O side.

Vehicular Emission Impact inside the Tunnel, Full Enclosures and under proposed Landscape Decks

3.7.7             The mechanical ventilation system for TKO-LT Tunnel is designed following “The Practice Note on Control of Air Pollution in Vehicle Tunnels” issued by EPD.  The predicted maximum NO2 concentrations at eastbound of TKO-LT Tunnel under normal peak traffic flow conditions and congested traffic flow conditions, would be 378 mg/m3 and 880 mg/m3, respectively.  The predicted maximum NO2 concentrations at westbound of TKO-LT Tunnel under normal peak traffic flow conditions and congested traffic flow conditions, would be 365 mg/m3 and 724 mg/m3, respectively.  Therefore, the air pollutants concentrations inside the vehicle tunnel should meet its Tunnel Air Quality Guideline.  The detailed calculation and results are presented in Appendix 3.8.  In-tunnel air quality assessments have been conducted for proposed two landscape decks and three full enclosures at Lam Tin Interchange, and proposed landscape deck at Road P2.  The predicted maximum NO2 concentrations at proposed three landscape decks and two full enclosures at Lam Tin Interchange under normal peak traffic flow conditions and congested traffic flow conditions, would be 270 mg/m3 and 582 mg/m3, respectively.  These would comply with the Tunnel Air Quality Guidelines (1800mg/m3).  The predicted maximum NO2 concentrations at the area under the proposed landscape deck at Road P2 would be 217 mg/m3 under normal peak traffic flow conditions and 254 mg/m3 under congested traffic flow conditions, which would also comply with the Tunnel Air Quality Guidelines.  Detailed calculations and results are presented in Appendix 3.9.

 

3.8                    Mitigation of Adverse Environmental Impacts

Construction Phase

3.8.1              In order to minimise the construction dust impact, the following dust mitigation measures shall be implemented:

·               Watering eight times a day on active works areas, exposed areas and paved haul roads to reduce dust emission by 87.5%.  Any potential dust impact and watering mitigation would be subject to the actual site condition.  For example, a construction activity that produces inherently wet conditions or in cases under rainy weather, the above water application intensity may not be unreservedly applied.  While the above watering frequency is to be followed, the extent of watering may vary depending on actual site conditions but should be sufficient to achieve the removal efficiency. The dust levels would be monitored and managed under an EM&A programme as specified in the EM&A Manual.

 

·               Enclosing the unloading process at barging point by a 3-sided screen with top tipping hall, provision of water spraying and flexible dust curtains to reduce dust emission by 90%.

3.8.2              With the implementation of the above measures, the predicted mitigated cumulative maximum hourly, daily and annual average TSP concentrations at the representative ASRs at Lam Tin side and TKO side during construction are summarized in Table 3.17.

Table 3.17     Predicted Cumulative Maximum Hourly, Daily and Annual Average TSP Concentrations at Representative Air Sensitive Receivers (Mitigated Tier 1)

 

ASRs

Assessment

Height (mAG)

Assessment

Height (mPD)

Cumulative Maximum TSP Concentrations in ug/m3

Hourly Average

24-hour Average

Annual Average

Lam Tin Side

CL1

1.5

7.0

707

199

77.1

CL1

5.0

10.5

563

174

76.2

CL1

10.0

15.5

332

133

74.8

CL1

15.0

20.5

215

108

74.1

CL1

20.0

25.5

172

96

73.6

CL2

1.5

7.0

666

173

77.8

CL2

5.0

10.5

543

158

77.4

CL2

10.0

15.5

325

125

76.0

CL2

15.0

20.5

252

103

75.0

CL2

20.0

25.5

201

90

74.3

CL3

1.5

7.0

341

118

77.4

CL4

1.5

7.0

339

118

77.6

CL4

5.0

10.5

310

117

77.5

CL4

10.0

15.5

233

108

76.7

CL4

15.0

20.5

209

99

75.9

CL4

20.0

25.5

182

92

75.2

CL5

1.5

7.0

287

120

75.4

CL5

5.0

10.5

275

118

75.4

CL5

10.0

15.5

214

107

75.1

CL5

15.0

20.5

167

98

74.7

CL5

20.0

25.5

153

93

74.3

CL6

1.5

15.5

266

109

75.2

CL7

1.5

15.5

335

128

74.9

CL8

1.5

7.0

617

148

74.3

CL8

5.0

10.5

532

137

74.2

CL8

10.0

15.5

345

112

73.9

CL8

15.0

20.5

242

101

73.7

CL8

20.0

25.5

203

92

73.5

CL9

1.5

7.0

507

123

74.7

CL9

5.0

10.5

452

114

74.5

CL9

10.0

15.5

316

104

74.1

CL9

15.0

20.5

230

97

73.7

CL9

20.0

25.5

193

91

73.5

CL10

1.5

7.0

459

143

74.8

CL10

5.0

10.5

399

136

74.7

CL10

10.0

15.5

261

117

74.2

CL10

15.0

20.5

213

100

73.8

CL10

20.0

25.5

178

90

73.6

CL11

1.5

7.0

402

145

74.9

CL12

1.5

7.0

325

119

74.2

CL12

5.0

10.5

297

117

74.2

CL12

10.0

15.5

212

107

73.9

CL12

15.0

20.5

178

98

73.7

CL12

20.0

25.5

156

92

73.5

CL13

10.0

15.5

242

113

75.2

CL13

15.0

20.5

188

95

74.2

CL13

20.0

25.5

164

87

73.7

CL14

1.5

7.0

334

129

74.3

CL14

5.0

10.5

292

125

74.2

CL14

10.0

15.5

206

109

73.9

CL14

15.0

20.5

179

95

73.6

CL14

20.0

25.5

157

86

73.4

CL15

1.5

7.0

413

125

77.0

CL15

5.0

10.5

288

109

76.4

CL15

10.0

15.5

226

101

75.6

CL15

15.0

20.5

189

96

75.0

CL15

20.0

25.5

158

90

74.6

CL16

1.5

7.0

430

133

77.4

CL16

5.0

10.5

278

106

76.6

CL16

10.0

15.5

222

101

75.7

CL16

15.0

20.5

184

95

75.2

CL16

20.0

25.5

166

91

74.7

TKO Side

CT1

1.5

5.5

236

101

73.5

CT1

5.0

9.0

229

100

73.5

CT1

10.0

14.0

190

95

73.4

CT1

15.0

19.0

152

90

73.3

CT1

20.0

24.0

122

85

73.2

CT2

10.0

14.0

202

94

75.4

CT2

15.0

19.0

155

86

74.1

CT2

20.0

24.0

124

83

73.6

CT3

10.0

14.0

175

95

75.6

CT3

15.0

19.0

134

87

74.6

CT3

20.0

24.0

120

83

74.0

CT4

1.5

5.5

185

87

73.9

CT4

5.0

9.0

184

87

73.9

CT4

10.0

14.0

164

84

73.7

CT4

15.0

19.0

140

81

73.6

CT4

20.0

24.0

118

78

73.5

CT5

1.5

5.5

264

87

73.3

CT5

5.0

9.0

248

87

73.3

CT5

10.0

14.0

198

84

73.3

CT5

15.0

19.0

160

82

73.2

CT5

20.0

24.0

131

80

73.2

Note:

(1) The background TSP level of 73 ug/m3 is included in the above results.

(2) The hourly, daily and annual average TSP EIAO-TM/AQO criteria are 500 ug/m3, 260 ug/m3 and 80 ug/m3 respectively.

(3) Boldfaced values represent the predicted TSP concentration exceeds the respective criteria.

3.8.3              Based on the results of the Tier 1 screening test, the predicted hourly TSP levels at ASRs CL1, CL2, CL8 and CL9 at Lam Tin side would still exceed the criteria stipulated in EIAO-TM while the predicted daily and annual TSP levels at all representative ASRs at Lam Tin side would comply with the criteria stipulated in AQO.  The contour plots of cumulative maximum hourly, daily and annual average mitigated TSP concentrations at 7mPD and 15.5mPD (the worst-hit levels) at Lam Tin side are presented in Figures 3.17a-b, 3.18a-b, 3.21a-b, 3.22a-b, 3.23a-b and 3.24a-b.  The contour results for cumulative maximum hourly TSP levels at 7mPD in Figures 3.17a-b indicated that apart from the Tin Hau Temple at Cha Kwo Ling (CL1), part of the Cha Kwo Ling Village (CL2), the Lam Tin Ambulance Depot (CL8) and part of the Yau Lai Court (CL9), the EHC ventilation building, EHC Administration Building (CL13) and Towngas Pigging Station at Cha Kwo Ling Road would also fall within the exceedance zone.  However, the EHC ventilation building is for tunnel exhaust for EHC, the Towngas Pigging Station is utility’s facility which is not of air sensitive use, and as mentioned in Table 3.4 that the first assessment height is at 15.5mPD (equivalent to 10mAG) for the EHC Administration Building, hence no adverse hourly TSP impact would pose to the mentioned three buildings/facilities, while ASRs CL1, CL2, CL8 and CL9 would be selected for further assessment, i.e. Tier 2 assessment.  As shown in Figure 3.21a-b and 3.23a-b, the cumulative maximum daily TSP and annual TSP levels at 7mPD have exceedance zone at Sin Fat Road, EHC Administration Building and some steep slopes enclosing the Lam Tin Interchange of TKO-LT Tunnel.  However, as there are no air sensitive use for Sin Fat Road and EHC Administration Building, the first assessment height is at 15.5mPD (equivalent to 10mAG) for the Sin Fat Road and EHC Administration Building and no air sensitive uses are anticipated for the steep slopes enclosing Lam Tin Interchange.  Hence, with the dust mitigation measures proposed, no adverse cumulative daily and annual average TSP levels at 7mPD would be expected in the Lam Tin area.  There is also no exceedance zone identified in all the contour plots (Figures 3.18a-b, 3.22a-b and 3.24a-b) of the mitigated TSP concentrations for all the time-averaged at 15.5mPD at Lam Tin area.

3.8.4              The four ASRs (CL1, CL2, CL8 and CL9) where TSP non-compliance predicted under the Tier 1 screening test are selected to undergo the Tier 2 assessment.  The assessment results of Tier 2 test are summarized in Table 3.18.  Based on the results of the Tier 2 assessment, the cumulative maximum hourly average TSP at ASRs CL1, CL2, CL8 and CL9 located within the hot spot area would comply with the criterion in EIAO-TM.  The Tier 2 contour plots of cumulative maximum hourly average TSP concentrations at 7mPD are presented in Figure 3.19a-b and 3.20a-b.  From the contour plots of Tier 2 assessment, it is found that no land lots with air sensitive uses are located within the exceedance zone at 7mPD.

  Table 3.18  Predicted Cumulative Maximum Hourly, Daily and Annual Average TSP Concentrations at Representative Air Sensitive Receivers (Mitigated Tier 2)

ASRs

Assessment

Height (mAG)

Assessment

Height (mPD)

Cumulative Maximum TSP Concentrations in ug/m3

Hourly Average

Lam Tin Side

CL1

1.5

7.0

413

CL1

5.0

10.5

335

CL1

10.0

15.5

192

CL1

15.0

20.5

157

CL1

20.0

25.5

128

CL2

1.5

7.0

379

CL2

5.0

10.5

292

CL2

10.0

15.5

198

CL2

15.0

20.5

154

CL2

20.0

25.5

123

CL8

1.5

7.0

184

CL8

5.0

10.5

159

CL8

10.0

15.5

114

CL8

15.0

20.5

102

CL8

20.0

25.5

93

CL9

1.5

7.0

174

CL9

5.0

10.5

137

CL9

10.0

15.5

110

CL9

15.0

20.5

98

CL9

20.0

25.5

90

Note:

(1) The background TSP level of 73 ug/m3 is included in the above results.

(2) The hourly, daily and annual average TSP EIAO-TM/AQO criteria are 500 ug/m3, 260 ug/m3 and 80 ug/m3 respectively.

3.8.5              Referring to the results of Tier 1 screening test shown in Table 3.17, the cumulative maximum hourly, daily and annual average TSP levels at all representative ASRs at TKO side would comply with the criteria stipulated in EIAO-TM and AQO after implementation of the proposed dust mitigation measures.  The contour plots of cumulative maximum hourly, daily and annual average TSP concentrations at 5.5mPD and 14mPD are presented in Figures 3.25a to 3.30b.  From the contour plots (Figures 3.25a-b, 3.27a-b and 3.29a-b), it is observed that exceedance zone of cumulative maximum hourly, daily and annual average TSP levels at 5.5mPD are confined within the works areas of the proposed Road P2 under the Project, part of the Ocean Shore (CT2), part of the slope at the TKO-LT Tunnel eastern tunnel portal and part of the Tseung Kwan O Cemetery.  However, as mentioned in Table 3.4, the residential tower of Ocean Shore (CT2) is situated on top of the 3-storey podium without air sensitive uses facing to the construction works area of Road P2, the first assessment height is at 14mPD (equivalent to 10mAG) instead of 5.5mPD.  Also, for the exceedance zone inside the Tseung Kwan O Cemetery, there are no normal active air sensitive use identified and the construction works areas would be closed during the peak public access to the cemetery on public holidays (Ching Ming Festival and Chung Yueng Festival) and Sundays.  It is also noted that no air sensitive uses are present at the slope area of TKO-LT Tunnel eastern portal.  Hence, no adverse air quality impact of cumulative maximum hourly, daily and annual average TSP concentrations at 5.5mPD at Tseung Kwan O area would be expected.  There is also no exceedance zone identified in all the contour plots (Figures 3.26a-b, 3.28a-b and 3.30a-b) of the mitigated TSP concentrations for all the time-averaged at 14mPD at Tseung Kwan O area.

3.8.6              From the contour plots, localised exceedances of 1-hour average, 24-hour average and annual average TSP concentration at 1.5m above ground were found.  However, no existing or planned ASR is identified within these predicted exceedance areas at the relevant heights.  The detailed discussion on localised exceedance are summarised in Table 3.19. The modeling results indicate that the predicted cumulative concentrations of TSP at all representative ASRs would comply with the respective AQO.

Table 3.19     Summary of Localised Exceedance

Exceedance Area

Remarks

1-hr TSP concentration

Figure 3.18a & 3.18b and 3.19a & 3.19b

(Exceedance area found at 7mPD)

Figure 3.25b

(Exceedance area found at 5.5mPD)

No ASR identified in the exceedance zone areas.

Figure 3.17a – ASR CL7

(Exceedance area found at 7mPD)

ASR CL7 Sin Fat Road Tennis Court is located on a hill. 7mPD is well below the ground level at CL7, and hence there is no air sensitive use at the level.

Figure 3.17b – ASR CL13

(Exceedance area found at 7mPD)

Referring to Table 3.4, the first assessment height of the ASR CL13 administration building of Eastern Harbour Crossing is at 10 m above ground (15.5 mPD). Hence, there is no air sensitive use at the level.

Figure 3.25a – ASR CT2

(Exceedance area found at 5.5mPD)

Referring to Table 3.4, the first assessment height of the ASR CT2 residential tower of Ocean Shore is at 10 m above ground (14mPD). Hence, there is no air sensitive use at the level.

24-hr TSP concentration

Figure 3.21b

(Exceedance area found at 7mPD)

Figure 3.27a & 3.27b

(Exceedance area found at 5.5mPD)

No ASR identified in the exceedance zone areas.

Figure 3.21a – ASR CL7

(Exceedance area found at 7mPD)

ASR CL7 Sin Fat Road Tennis Court is located on a hill. 7mPD is well below the ground level at CL7, and hence there is no air sensitive use at the level.

Annual TSP concentration

Figure

No ASR identified in the exceedance zone area.

Figure 3.23a – ASR CL7

(Exceedance area found at 7mPD)

ASR CL7 Sin Fat Road Tennis Court is located on a hill. 7mPD is well below the ground level at CL7, and hence there is no air sensitive use at the level.

Figure 3.23b – ASR CL13

(Exceedance area found at 7mPD)

Referring to Table 3.4, the first assessment height of the ASR CL13 administration building of Eastern Harbour Crossing is at 10 m above ground (15.5mPD). Hence, there is no air sensitive use at the level.

Figure 3.29a – ASR CT2

(Exceedance area found at 5.5mPD)

Referring to Table 3.4, the first assessment height of the ASR CT2 residential tower of Ocean Shore is at 10 m above ground (14mPD). Hence, there is no air sensitive use at the level.

Figure 3.29b

(Exceedance area found at 5.5mPD)

No ASR identified in the exceedance zone areas.

3.8.7              In addition to the dust control measures described above, dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation and good site practices listed below shall be carried out to further minimize construction dust impact:

·               Use of regular watering to reduce dust emissions from exposed site surfaces and unpaved roads, particularly during dry weather.

·               Use of frequent watering for particularly dusty construction areas and areas close to ASRs.

·               Side enclosure and covering of any aggregate or dusty material storage piles to reduce emissions.  Where this is not practicable owing to frequent usage, watering shall be applied to aggregate fines.

·               Open stockpiles shall be avoided or covered.  Where possible, prevent placing dusty material storage piles near ASRs.

·               Tarpaulin covering of all dusty vehicle loads transported to, from and between site locations.

·               Establishment and use of vehicle wheel and body washing facilities at the exit points of the site.

·               Provision of wind shield and dust extraction units or similar dust mitigation measures at the loading area of barging point, and use of water sprinklers at the loading area where dust generation is likely during the loading process of loose material, particularly in dry seasons/ periods.

·               Provision of not less than 2.4m high hoarding from ground level along site boundary where adjoins a road, streets or other accessible to the public except for a site entrance or exit.

·               Imposition of speed controls for vehicles on site haul roads.

·               Where possible, routing of vehicles and positioning of construction plant should be at the maximum possible distance from ASRs.

·               Every stock of more than 20 bags of cement or dry pulverised fuel ash (PFA) should be covered entirely by impervious sheeting or placed in an area sheltered on the top and the 3 sides.

·               Instigation of an environmental monitoring and auditing program to monitor the construction process in order to enforce controls and modify method of work if dusty conditions arise.

 

Operation Phase

3.8.8              The predicted cumulative maximum 1-hour average NO2 concentrations, maximum daily average NO2 and RSP concentrations, annual average NO2 and RSP concentrations at the representative ASRs would comply with the AQO.  There is also no exceedance zone predicted within the Study Area of the Project.  The predicted air pollutants concentrations inside the TKO-LT Tunnel, the proposed full enclosures and under the landscape decks at Lam Tin Interchange and Road P2 would comply with the EPD Tunnel Air Quality Guidelines.  No mitigation measure would be required during operation phase.

 

3.9                    Evaluation of Residual Impacts

Construction Phase

3.9.1              With the implementation of the mitigation measures as stipulated in the Air Pollution Control (Construction Dust) Regulation together with the recommended dust control measures and good site practices, no adverse residual impact would be expected on the work sites at both Lam Tin and TKO sides.

Operation Phase

3.9.2              During operation phase of the Project, the predicted maximum 1-hour and daily average NO2, annual average NO2 and maximum daily average and annual average RSP concentrations at the representative ASRs would comply with the AQO and no exceedance zone is predicted within the Study Area of the Project.  Hence evaluation of residual impacts is not required.       

3.9.3              The predicted air pollutants concentrations inside the proposed underpasses and under the landscape decks would also comply with the EPD Tunnel Air Quality Guidelines.  No adverse residual in-tunnel air quality is anticipated.

3.10                Environmental Monitoring and Audit Requirements

Construction Phase

3.10.1          With the implementation of the proposed dust suppression measures, good site practices and dust monitoring and audit programme, no adverse dust impact would be expected at the ASRs.  Details of the monitoring requirements are presented in the stand-alone EM&A Manual.

Operation Phase

3.10.2          Since the Project would not pose adverse air quality impacts to the ASRs, no environmental monitoring and audit is proposed.

 

3.11                Conclusion

Construction Phase

3.11.1          Potential air quality impacts from the construction works of the Project would mainly be related to construction dust from excavation, materials handling, spoil removal and wind erosion.  With the implementation of mitigation measures specified in the Air Pollution Control (Construction Dust) Regulation together with the recommended dust suppression measures, good site practices, and EM&A programme, the predicted dust impact at ASRs would comply with the hourly, daily and annual TSP criteria in the EIAO-TM and AQO.

Operation Phase

3.11.2          The potential impacts arising from the background pollutant levels within and adjacent to the Project site, vehicle emissions from open road networks, portal emissions from the TKO-LT Tunnel, T2 tunnel and EHC, proposed landscape decks and full enclosures, emissions from the ventilation buildings of TKO-LT Tunnel, T2 and EHC, and the implementation of roadside noise barriers/semi-enclosures/landscape decks are assessed.  Results show that the predicted maximum 1-hour and daily average NO2, annual average NO2 and maximum daily average and annual average RSP concentrations at the representative ASRs and within the Study Area would comply with the AQO.  No mitigation measures are required.  

3.11.3          The predicted air pollutants concentrations inside the TKO-LT Tunnel, proposed full enclosures and under the landscape decks would comply with the EPD Tunnel Air Quality Guidelines.  No mitigation measures are required.

Overall

3.11.4          An air quality impact assessment has been conducted in accordance to the criteria and guidelines as stated in Annexes 4 and 12 of the EIAO-TM.  The predicted results showed that the air quality impact during both construction and operation phases of the Project would comply with the criteria and guidelines as stated in the aforesaid Annexes in the EIAO-TM.


[1] http://www.mardep.gov.hk/en/publication/pdf/coer.pdf

[2] http://www.info.gov.hk/gia/general/201112/09/P201112080164.htm

[3] http://www.epd.gov.hk/epd/english/environmentinhk/air/guide_ref/files/Note_on_Emfac-HK_Changes_Jan2013.pdf

[4] http://www.epd.gov.hk/epd/english/environmentinhk/air/air_maincontent.html

[5] http://www.epd.gov.hk/epd/english/environmentinhk/air/data/emission_inve.html

[6] Air Quality in Hong Kong 2011

[7] http://www.epd.gov.hk/epd/english/environmentinhk/air/prob_solutions/cleaning_air_atroad.html

[8] http://www.epd.gov.hk/epd/english/environmentinhk/air/studyrpts/assessment_of_tap_measurements.html

[9] http://www.eea.europa.eu/publications/EMEPCORINAIR5/Sources_of_PCB_emissions.pdf/view

[10] http://www.epd.gov.hk/epd/english/news_events/legco/files/EA_Panel_110526a_eng.pdf

[11] http://www.epd.gov.hk/epd/english/environmentinhk/air/prob_solutions/cleaning_air_atroad.html

[12] http://www.epd.gov.hk/epd/english/environmentinhk/air/studyrpts/files/HKEPDFinalReportRev_11-29-10_v2.pdf

[13] Assessment of Toxic Air Pollutant Measurements in Hong Kong Final Report

[14] http://ec.europa.eu/environment/air/quality/standards.htm

[15] http://www.medway.gov.uk/environmentandplanning/environmentalhealth/airquality/airqualityfordevelopers.aspx