Section    Title                                                                                                                           Page

3.1              Introduction________________________________________________________________ 3-1

3.2              Environmental Legislations, Standards and Guidelines______________________________ 3-1

3.3              Baseline Condition and Sensitive Receivers_______________________________________ 3-3

3.4              Identification of Pollution Sources and Assessment Methodology_______________________ 3-6

3.5              Identification, Prediction and Evaluation of Environmental Impact______________________ 3-20

3.6              Mitigation of Adverse Environmental Impact_______________________________________ 3-36

3.7              Evaluation of Residual Impact_________________________________________________ 3-38

3.8              Environmental Monitoring and Audit_____________________________________________ 3-39

3.9              Conclusion_______________________________________________________________ 3-39

 

 

 

Figure

3-1.1 to 3-1.11              Location of Air Sensitive Receivers and the Assessment Area

3-2.1 to 3-2-11              Location of Potential Dust Emission Source

3-3.1 to 3-3.17              Location of 30% Active Areas of Dust Sources Assumed for Tier 2 Assessment

3-4.1a to 3-4.9a            Cumulative Result  - Contour of Tier 1 Hourly TSP Concentration (mg/m3) at 1.5m Above  Ground during Construction Phase (unmitigated)

3-4.1b to 3-4.9b            Cumulative Result  - Contour of Tier 1 Hourly TSP Concentration (mg/m3) at 1.5m Above  Ground during Construction Phase (mitigated)

3-5.1 to 3-5.17              Cumulative Result  - Contour of Tier 2 Hourly TSP Concentration (mg/m3) at 1.5m Above Ground during Construction Phase (mitigated)

3-6.1a to 3-6.9a            Cumulative Result  - Contour of Tier 1 Daily TSP Concentration (mg/m3) at 1.5m Above Ground during Construction Phase (unmitigated)

3-6.1b to 3-6.9b            Cumulative Result  - Contour of Tier 1 Daily TSP Concentration (mg/m3) at 1.5m Above Ground during Construction Phase (mitigated)

3-7.1 to 3-7.6                Cumulative Result  - Contour of Tier 2 Daily TSP Concentration (mg/m3) at 1.5m Above Ground during Construction Phase (mitigated)

3-8.1a to 3-8.9a            Cumulative Result  - Contour of Annual TSP Concentration (mg/m3) at 1.5m Above Ground during Construction Phase (unmitigated)

3-8.1b to 3-8.9b            Cumulative Result  - Contour of Annual TSP Concentration (mg/m3) at 1.5m Above Ground during Construction Phase (mitigated)

3-9.1 to 3-9.11              Classifications of Road Types

3-10.1 to 3-10.9            Cumulative Result  - Contour of Hourly NO2 Concentration (mg/m3) at 1.5m Above Ground during Operational Phase (Stability Class D)

3-11.1 to 3-11.9            Cumulative Result  - Contour of Daily NO2 Concentration (mg/m3) at 1.5m Above Ground during Operational Phase (Stability Class D)

3-12.1 to 3-12.9            Cumulative Result  - Contour of  Daily RSP Concentration (mg/m3) at 1.5m Above Ground during Operational Phase (Stability Class D)

3-13.1 to 3-13.9            Cumulative Result  - Contour of Hourly NO2 Concentration (mg/m3) at 1.5m Above Ground during Operational Phase (Stability Class F)

3-14.1 to 3-14.9            Cumulative Result  - Contour of Daily NO2 Concentration (mg/m3) at 1.5m Above Ground during Operational Phase (Stability Class F)

3-15.1 to 3-15.9            Cumulative Result  - Contour of  Daily RSP Concentration (mg/m3) at 1.5m Above Ground during Operational Phase (Stability Class F)

3-16.1 to 3-16.9            Cumulative Result  - Contour of Annual NO2 Concentration (mg/m3) at 1.5m Above Ground during Operational Phase

3-17.1 to 3-17.9            Cumulative Result  - Contour of  Annual RSP Concentration (mg/m3) at 1.5m Above Ground during Operational Phase

 

 

 

Appendix

3.1a               Details of Dust Emission Sources for 1-hour and Daily TSP Assessment (Tier 1)

3.1b               Details of Dust Emission Sources for Annual TSP Assessment

3.1c               Details of Dust Emission Sources for 1-hour and Daily TSP Assessment (Tier 2)

3.1d               Estimation of Percentage Active Area for Different Stages of Construction Activities

3.1e               Estimation of Total Percentage Active Area for Hourly, Daily and Annual TSP Assessment

3.1f                Estimation of Dust Suppression Efficiency

3.2                 Exhaust Technology Fractions

3.3                 Vehicle Population in Years 2018, 2023, 2028 and 2033.

3.4                 Diurnal Traffic Pattern, VMT and Trips in 2018, 2023, 2028 and 2033

3.4-1              Traffic Forecast for 2018, 2023, 2028 and 2033

3.4-2              Road Type and Distance

3.4-3              Trips and VMT for Petrol Vehicles in Hong Kong

3.4-4              VMT and Trips for 2018, 2023, 2028 and 2033 in the Study Area

3.5                 Relative Humidity and Temperature

3.6                 Peak Hour Speed, Volume/Capacity Ratio and Speed Fractions in 2018, 2023, 2028 and 2033.

3.7a               Comparison of Emissions with Peak and Non-peak Speeds in 2018, 2023, 2028 and 2033

3.7b               Calculation of Worst Case Emission Rates for Different Road Types

3.8                 Calculations of the Composite Emission Factors

3.9a               Calculations of the Emission Rates for Ventilation Shafts and Building

3.9b               Selection of Worst Case Hourly Emission for Calculation of Emission Rates for Ventilation Shafts and Building

3.10a             Calculations of Idling Emissions

3.10b             Determination of Idling Emission Factors as Extracted from the Feasibility Study

3.10c             Estimation of NOx Composite Idling Emission Factors

 

Tables

Table 3.1:__ Hong Kong Air Quality Objectives_ 3-1

Table 3.2:__ Tunnel Air Quality Guidelines_ 3-2

Table 3.3:__ Representative ASRs Identified for the Assessment 3-4

Table 3.4:__ Assumptions for Calculation of Dust Emission Factors_ 3-6

Table 3.5:__ Vehicle Classification in the EMFAC-HK Model 3-10

Table 3.6:__ Worst Case Emission Factors as Predicted by EMFAC-HK Model 3-13

Table 3.7:__ Forecast of Idling Vehicles in Kiosks, L&UL and PTI in Peak Hour 3-16

Table 3.8:__ Idling Emissions from Kiosks, L&UL areas and PTI 3-17

Table 3.9:__ Predicted Cumulative Hourly Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Unmitigated) 3-20

Table 3.10:_ Predicted Cumulative Hourly Average TSP Concentration in Sha Tau Kok (Tier 1– Unmitigated) 3-21

Table 3.11:_ Predicted Cumulative Hourly Average TSP Concentration in Po Kak Tsai (Tier 1– Unmitigated) 3-21

Table 3.12:_ Predicted Cumulative Hourly Average TSP Concentration in Fanling (Tier 1 – Unmitigated) 3-21

Table 3.13:_ Predicted Cumulative Hourly Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Mitigated) 3-22

Table 3.14:_ Predicted Cumulative Hourly Average TSP Concentration in Sha Tau Kok (Tier 1– Mitigated) 3-22

Table 3.15:_ Predicted Cumulative Hourly Average TSP Concentration in Po Kak Tsai (Tier 1– Mitigated) 3-23

Table 3.16:_ Predicted Cumulative Hourly Average TSP Concentration in Fanling (Tier 1 – Mitigated) 3-23

Table 3.17:_ Predicted Cumulative Hourly Average TSP Concentration at Selected ASRs (Tier 2 – Mitigated) 3-23

Table 3.18:_ Predicted Cumulative Daily Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Unmitigated) 3-24

Table 3.19:_ Predicted Cumulative Daily Average TSP Concentration in Sha Tau Kok (Tier 1 – Unmitigated) 3-25

Table 3.20:_ Predicted Cumulative Daily Average TSP Concentration in Po Kak Tsai (Tier 1 – Unmitigated) 3-25

Table 3.21:_ Predicted Cumulative Daily Average TSP Concentration in Fanling (Tier 1 – Unmitigated) 3-25

Table 3.22:_ Predicted Cumulative Daily Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Mitigated) 3-25

Table 3.23:_ Predicted Cumulative Daily Average TSP Concentration in Sha Tau Kok (Tier 1 – Mitigated) 3-26

Table 3.24:_ Predicted Cumulative Daily Average TSP Concentration in Po Kak Tsai (Tier 1 – Mitigated) 3-26

Table 3.25:_ Predicted Cumulative Daily Average TSP Concentration in Fanling (Tier 1 – Mitigated) 3-26

Table 3.26:_ Predicted Cumulative Daily Average TSP Concentration at Selected ASRs (Tier 2 – Mitigated) 3-27

Table 3.27:  Predicted Cumulative Annual Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Unmitigated) 3-27

Table 3.28: Predicted Cumulative Annual Average TSP Concentration in Sha Tau Kok (Unmitigated) 3-28

Table 3.29: Predicted Cumulative Annual Average TSP Concentration in Po Kak Tsai (Unmitigated) 3-28

Table 3.30:_ Predicted Cumulative Annual Average TSP Concentration in Fanling (Unmitigated) 3-28

Table 3.31:  Predicted Cumulative Annual Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Mitigated) 3-29

Table 3.32: Predicted Cumulative Annual Average TSP Concentration in Sha Tau Kok (Mitigated) 3-29

Table 3.33: Predicted Cumulative Annual Average TSP Concentration in Po Kak Tsai (Mitigated) 3-30

Table 3.34:_ Predicted Cumulative Annual Average TSP Concentration in Fanling (Mitigated) 3-30

Table 3.35:_ Predicted Cumulative Hourly and Daily NO2 and Daily RSP concentrations for Stability Class D_ 3-30

Table 3.36:_ Predicted Cumulative Hourly and Daily NO2 and Daily RSP concentrations for Stability Class F_ 3-32

Table 3.37:_ Predicted Cumulative Annual NO2 and RSP concentrations_ 3-34

 

 

 



3.1               Introduction

The section presents the assessment of potential air quality impacts associated with the construction and operational phase of the proposed BCP and associated facilities in accordance with section 3.4.3 of the EIA Study Brief (ESB-199/2008).  Dust generated from various construction activities is the primary concern during the construction phase. Vehicular emissions from open roads, ventilation shafts, as well as kiosks, loading and unloading areas and public transport interchange (PTI) of the BCP are the major sources of air pollution during the operational phase.  Suitable mitigation measures, where necessary, have been recommended to protect the nearby sensitive receivers and to ensure that the legislative criteria and guidelines can be satisfied.

3.2               Environmental Legislations, Standards and Guidelines

3.2.1           Technical Memorandum on Environmental Impact Assessment Ordinance

The criteria and guidelines for evaluating air quality impacts are laid out in Annex 4 and Annex 12 of the Technical Memorandum on Environmental Impact Assessment (EIAO-TM), respectively.

3.2.2           Air Pollution Control Ordinance

The principal legislation for the management of air quality is the Air Pollution Control Ordinance (APCO) (Cap 311).  The APCO specifies Air Quality Objectives (AQOs) which stipulate the statutory limits of air pollutants and the maximum allowable numbers of exceedance over specific periods.  The AQOs are summarized in Table 3.1.

Table 3.1:      Hong Kong Air Quality Objectives

 

Concentration in micrograms per cubic metre (i)

Pollutant

Averaging Time

 

1 hour

(ii)

8 hours

(iii)

24 hours

(iii)

3 Months

(iv)

1 year

(iv)

Sulphur Dioxide

800

N.A.

350

N.A.

80

Total Suspended Particulates

500(vii)

N.A.

260

N.A.

80

Respirable (v) Suspended Particulates

N.A.

N.A.

180

N.A.

55

Nitrogen Dioxide

300

N.A.

150

N.A.

80

Carbon Monoxide

30000

10000

N.A.

N.A.

N.A.

Photochemical Oxidants (as Ozone) (vi)

240

N.A.

N.A.

N.A.

N.A.

Lead

N.A.

N.A.

N.A.

1.5

N.A.

Legend:

i.              Measured at 298K (25oC) and 101.325 kPa (one atmosphere).

ii.              Not to be exceeded more than three times per year;

iii.             Not to be exceeded more than once per year;

iv.            Arithmetic means

v.             Respirable suspended particulates means suspended particles in air with a nominal aerodynamic diameter of 10    micrometres and smaller.

vi.            Photochemical oxidants are determined by measurement of ozone only.

vii             This is not an AQO but a criterion for construction dust impact assessment as stated in Annex 4 of the EIAO-TM.

3.2.3           Air Pollution Control (Construction Dust) Regulation

The Air Pollution Control (Construction Dust) Regulation enacted under the APCO defines notifiable and regulatory works activities that are subject to construction dust control, as listed below:

Notifiable Works:

(a)            Site formation

(b)            Reclamation

(c)            Demolition of a building

(d)            Work carried out in any part of a tunnel that is within 100 m of any exit to the open air

(e)            Construction of the foundation of a building

(f)              Construction of the superstructure of a building or

(g)            Road construction work

Regulatory Works:

(h)            Renovation carried out on the outer surface of the external wall or the upper surface of the roof of a building

(i)              Road opening or resurfacing work

(j)              Slope stabilisation work or

(k)            Any work involving any of the following activities:

¡           Stockpiling of dusty materials

¡           Loading, unloading or transfer of dusty materials

¡           Transfer of dusty materials using a belt conveyor system

¡           Use of vehicles

¡           Pneumatic or power-driven drilling, cutting and polishing

¡           Debris handling

¡           Excavation or earth moving

¡           Concrete production

¡           Site clearance or

¡           Blasting

Notifiable works require that advance notice of activities shall be given to EPD. The Regulation also requires the works contractor to ensure that both notifiable works and regulatory works are conducted in accordance with the Schedule of the Regulation, which provides dust control and suppression measures.

3.2.4           Practice Note on Control of Air Pollution in Vehicle Tunnels

The EPD’s “Practice Note on Control of Air Pollution in Vehicle Tunnels” controls the air pollution inside vehicle tunnels. The controlled pollutants and their allowed concentrations are summarized in Table 3.2 below.

Table 3.2:      Tunnel Air Quality Guidelines

Pollutant

Averaging Time

Maximum Concentration (µg/m³)*

Sulphur Dioxide

5 minutes

1,000

Nitrogen Dioxide

5 minutes

1,800

Carbon Monoxide

5 minutes

115,000

* Concentrations at reference conditions of 298K and 101.325kPa. 

3.3               Baseline Condition and Sensitive Receivers

The latest available 5-year average ambient concentrations of pollutants measured at EPD’s Tai Po Air Quality Monitoring Station have been taken as the background concentrations for the air quality assessments, as this Monitoring Station is closest to the Project site when compared to all other Monitoring Stations.  The background level of total suspended particulates (TSP) has been estimated as the 5-year average of the available data from 1 January 2005 to 31 December 2009, and the estimated background TSP level is 66.6µg/m³..  The background levels of nitrogen dioxide (NO2), and respirable suspended particulates (RSP) have been estimated as the 5-year averages of the data available from 1 July 2005 to 30 June 2010, and the estimated NO2 and RSP background levels are respectively 50.4µg/m³ and 49.9µg/m³.

It is noted that the emissions within the Pearl River Delta will be reduced in future years according to the Mid-term Review Study on Pearl River Delta Regional Air Quality Management Plan. This will lead to a reduction of the background concentration of the assessment area, and therefore the background pollutant levels adopted for this assessment would be on the conservative side.

In accordance with clause 3.4.3.2 of the EIA Study Brief, the existing and planned representative Air Sensitive Receivers (ASRs) that could be affected by the Project and located within 500m from the works boundary have been identified for the assessment based on the latest Outline Zoning Plans, Development Permission Area Plans, Outline Development Plans, Layout Plans and other relevant published land use plans. The ASRs of interest are mainly scattered village houses situated in the vicinity of the BCP or alongside the BCP connecting road, as well as the air intake point(s) of the buildings in the BCP which are tabulated in Table 3.3. The locations of ASRs and the boundary of the 500m assessment area are as shown in Figures 3-1.1 to 3-1.11.   

According to the planned programme (see Appendix 2.2), the Chuk Yuen Village Resite will be completed in early 2012 for population intake by early 2013, and construction of this Project will commence in around mid 2013.  Therefore the existing Chuk Yuen Village that is within the BCP site will have been relocated to the Resite (as represented by ASR CY3) before commencement of construction of this Project.  Hence, the existing Chuk Yuen Village located within the future BCP site will not be subject to any construction or operational phase impacts of this Project, and is not included in this assessment.   However, the Chuk Yuen Village Resite (ASR CY3) will be subject to both construction and operational phase impacts, and is included in the assessment.

According to the final report on the "Land Use Planning for the Closed Area” study (see Section 2.10.6), the Recommended Development Plan has proposed land use changes in the study area.  In order to assess the potential impact on the planned village areas of the Closed Area that are within the assessment area of this BCP Project, three ASRs, namely, KTW6, TF1 and FWW1, have been identified to represent such planned village development in this assessment.

Since all the ASRs except BDG1 are low-rise village houses or playground, three assessment levels have been adopted, which are 1.5m, 5m and 10m above local ground level (AGL).  For BDG1, as it represents the air intake point of the proposed BCP building, only the assessment level of 35m above local ground level, which is the roof level of the building, has been used.

Table 3.3:      Representative ASRs Identified for the Assessment

No.

ASR ID

Land Use

Description

Separation distance from Project Site Boundary (m)

Construction Phase

Operational Phase

1

TYHP

Recreational

Tsung Yuen Ha Playground

73.4

Ö

Ö

2

TYH

Residential

Tsung Yuen Ha Village House

49.1

Ö

Ö

3

V1

Residential

Village House near Lin Ma Hang Road

9.2

Ö

Ö

4

V2

Residential

Village House near Lin Ma Hang Road

19.5

Ö

Ö

5

CY3

Residential

Chuk Yuen Village Resite

56.4

Ö

Ö

6

KL1

Residential

Kau Liu Village House

46.1

Ö

Ö

7

TKL1

Residential

Ta Kwu Ling Village House 1

16.3

Ö

Ö

8

TKL2

Residential

Ta Kwu Ling Village House2

8.3

Ö

Ö

9

KTW6*

Residential

Kan Tau Wai Village House 6

95.8

Ö

Ö

10

TF1*

Residential

Tong Fong Village House 1

395.2

Ö

Ö

11

FWW1*

Residential

Fung Wong Wu Village House 1

313.6

Ö

Ö

12

KTW1

Residential

Kan Tau Wai Village House 1

62.7

Ö

Ö

13

KTW2

Residential

Kan Tau Wai Village House 2

39.7

Ö

Ö

14

KTW4

Residential

Kan Tau Wai Village House 4

13.7

Ö

Ö

15

KTW5

Residential

Kan Tau Wai Village House 5

34.3

Ö

Ö

16

KTW7

Residential

Planned Village House at Kan Tau Wai

32.1

x

Ö

17

NYH1

Residential

Nga Yiu Ha Village House 1

41.4

Ö

Ö

18

PY1

Residential

Ping Yeung Village House 1

1.2

Ö

Ö

19

PY3

Residential

Ping Yeung Village House 3

50.4

Ö

Ö

20

PY6

Residential

Ping Yeung Village House 6

54.3

Ö

Ö

21

WKS1

Residential

Wo Keng Shan Village House 1

25.1

Ö

Ö

22

WKS2

Residential

Wo Keng Shan Village House 2

88.6

Ö

Ö

23

WKS3

Residential

Wo Keng Shan Village House 3

235.6

Ö

Ö

24

WKS4

Residential

Wo Keng Shan Village House 4

33.9

Ö

Ö

25

WKS5

Residential

Wo Keng Shan Village House 5

15.6

Ö

Ö

26

WKS7

Residential

Wo Keng Shan Village House 7

31.7

Ö

Ö

27

WKS8

Residential

Planned Village House at Wo Keng Shan

64.3

x

Ö

28

ST1

Residential

Shan Tong Village House 1

55.8

Ö

Ö

29

ST2

Residential

Shan Tong Village House 2

14.4

Ö

Ö

30

ST3

Residential

Shan Tong Village House 3

56.1

Ö

Ö

31

ST4

Residential

Shan Tong Village House 4

6.2

Ö

Ö

32

TTW1

Residential

Tai Tong Wu Village House 1

13.8

Ö

Ö

33

TTW2

Residential

Tai Tong Wu Village House 2

104.3

Ö

Ö

34

TTW3

Residential

Tai Tong Wu Village House 3

5.5

Ö

Ö

35

LT1

Residential

Loi Tung Village House 1

62.2

Ö

Ö

36

LT2

Residential

Loi Tung Village House 2

72.6

Ö

Ö

37

PKT1

Residential

Po Kak Tsai Village

225.8

Ö

Ö

38

PKT2

Residential

Po Kak Tsai Village

12.3

Ö

Ö

39

PKT3

Residential

Po Kak Tsai Village

23.8

Ö

Ö

40

TH1

Residential

Tong Hang Village House 1

0.5

Ö

Ö

41

TH4

Residential

Tong Hang Village House 4

15.2

Ö

Ö

42

KT1

Residential

Kiu Tau Village House 1

56.0

Ö

Ö

43

KT2

Residential

Kiu Tau Village House 2

37.5

Ö

Ö

44

KT3

Residential

Kiu Tau Village House 3

18.3

Ö

Ö

45

NWP1

Residential

Nam Wa Po Village House 1

3.0

Ö

Ö

46

NWP2

Residential

Nam Wa Po Village House 2

13.9

Ö

Ö

47

NWP3

Residential

Nam Wa Po Village House 3

13.4

Ö

Ö

48

KLH1

Residential

Kau Lung Hang Village House 1

60.4

Ö

Ö

49

BDG1

--

Air Intake Point of BCP Building

Within site boundary

x

Ö

Legend:   Ö - subject to impact; x - not subject to impact

*Note:      These three ASRs have been identified to represent the planned village developments as per the Recommended Development Plan of the final report on the "Land Use Planning for the Closed Area” study.

 

 

3.4               Identification of Pollution Sources and Assessment Methodology

3.4.1           Construction Phase

3.4.1.1         Potential Sources of Pollution

The major construction activities of the Project that would contribute to construction dust impacts include:

·         Excavation/earth works within the work site areas except the tunnel sections;

·         Road works involving the realignment and widening of Lin Ma Hang Road in BCP section, construction of at-grade and viaduct roads in Lin Ma Hang to Frontier Closed Area section, Ping Yeung to Wo Keng Shan section, Sha Tau Kok Road section and Fanling section of the Project;

·         Slope works near the BCP, in Ping Yeung to Wo Keng Shan, near the Tunnel Portal of Sha Tau Kok, Lau Shui Heung and Tunnel Portal of Fanling section;

·         Site formation in the BCP; and

·         Construction of the superstructures such as buildings in the BCP, ventilation shafts near both ends of the two tunnels, and mid-ventilation building for one of the tunnels.

No significant fugitive dust emissions would be expected from tunnelling activities.

3.4.1.2         Air Dispersion Model

The air pollutant concentrations were assessed in accordance with the Guidelines for Choice of Models and Model Parameters in Air Quality Assessment published by EPD.  The extent of dust impacts arising from the construction of proposed Project have been predicted by using the USEPA approved model Fugitive Dust Model (FDM) in conjunction with the construction programme.

3.4.1.3         Emission Factors

Prediction of dust emissions is based on emissions factors from the USEPA Compilation of Air Pollution Emission Factors (AP-42), 5th Edition. The emission factor for a typical heavy construction activity is 2.69 megagrams (Mg)/hectare/month of activities according to Section 13.2.3.3 of AP-42.  The number of working days for a month and number of working hours per day are assumed to be 26 days and 12 hours, respectively. Based on Table 11.9-4 of AP-42, the emission factor of wind erosion is 0.85 megagrams (Mg)/hectare/year.  The locations of assumed dust sources are given in Figures 3.2.1 to 3.2.11. The key dust emission factors adopted in the FDM are summarized in Table 3.4. The emission inventory and calculation of emission factors for the construction activities are detailed in Appendices 3.1a to 3.1c.

Table 3.4:      Assumptions for Calculation of Dust Emission Factors

Activities

Emission Factors

Reference

Heavy construction activities including all above ground and open construction works, excavation and slope cutting works

 2.69 Mg/hectare/month

Section 13.2.3.3

AP-42, 5th Edition

Wind erosion from heavy construction or stockpile  areas

0.85 Mg/hectare/year

Table 11.9-4

AP-42, 5th Edition

Material handling at stockpiles areas

Emission Facror =

K x 0.0016 x (U/2.2)1.3/(M/2)1.4 kg/Mg

where

k is particle size multiplier *

U is average wind spped

M is material moisture content

Section 13.2.4

AP-42, 5th Edition

* The particle size distribution was made reference to Section 13.2.4 of the USEPA Compilation of Air Pollution Emission Factors (AP-42), 5th Edition .

3.4.1.4         Meteorological Data

The hourly meteorological data for a full year measured at the Ta Kwu Ling station of Hong Kong Observatory (HKO) in 2008 has been adopted as input to the FDM.

3.4.1.5         Cumulative Impacts

There are a number of identified major concurrent projects in the vicinity of this Project, the details of which are given in Section 2.10 and Appendix 2.2.  Of those concurrent projects, the Regulation of Shenzhen River (RSR) Stage 4 project and the North East New Territories (NENT) Landfill Extension project have been considered in the cumulative construction dust impact assessment.  For the other identified concurrent projects, no sufficient information was available for assessing the cumulative dust impacts at the time of preparing this EIA report. 

The locations of assumed dust sources of the two concurrent projects, namely, the RSR Stage 4 project and the NENT Landfill Extension project, are as shown in Figures 3-2.1, 3-2.2 and 3-2.3.  For the NENT Landfill Extension project, only the portion of the project site (i.e., the location where capping of the existing landfill will be carried out) that is within the 500m assessment area of this Project has been taken into account in the cumulative construction dust impact assessment (see Figure 3-2.3), and the associated dust emission data as extracted from the approved EIA report (No.: EIA-133/2007) has been used in the cumulative impact assessment.  For the RSR Stage 4 project, the latest dust emission data as provided by the Consultants responsible for conducting EIA of the project have been used in the cumulative impact assessment.  The emission inventory and calculation of emission factors for construction activities of the two concurrent project are detailed in Appendices 3.1a to 3.1c.

For the North East New Territories New Development Area, the Widening of Tolo Highway / Fanling Highway projects and the Drainage Improvements in Northern New Territories – Package C (Remaining Works), no sufficient information on these projects is available for assessing the construction dust impacts and hence they are not included in the assessment. 

3.4.1.6         Modelling Approach

For hourly and daily TSP, a tiered modelling approach has been adopted. A hypothetical Tier 1 screening that assumes 100% active area of construction site with or without dust mitigation measures in place was carried out in order to identify the ASRs which could be subject to significant impacts. However, it should be emphasized that this Tier 1 scenario (i.e. assuming 100% active area for the proposed Project and the two concurrent projects) is a hypothetical one for screening purposes.   For the purpose of the Tier 1 screening, the dust mitigation measures, including frequent water spraying and covering of stockpile areas, as detailed in Section 3.6.1.1 have been taken into account when estimating the dust emission rates from the construction activities.  Details of the Tier 1 dust sources including their coordinates, dimensions and estimated emission rates are  detailed in Appendix 3.1a.      

In the course of the Tier 1 screening, the ASRs identified with hourly or daily TSP non-compliance were selected for the subsequent Tier 2 assessment. For these identified ASRs, it is assumed in the Tier 2 assessment that the 30% active areas of this proposed Project and the corresponding active areas of the relevant concurrent project would be located closest to the particular ASRs. The hourly or daily TSP levels at each of these ASRs were then predicted with the dust mitigation measures in place. Under normal circumstances, construction activities for the proposed Project and the concurrent project would likely spread over the whole work sites. As such, assuming the 30% active area of this Project and the corresponding active areas of the relevant concurrent project to be located closest to a particular ASR at any one time during the Tier 2 assessment is a very conservative approach.  Details of the Tier 2 dust sources including their coordinates, dimensions and estimated emission rates are given in Appendix 3.1c.

For the assessment of annual TSP concentrations, the active work area over the entire year would be less than that for a typical working hour or a typical working day.  On this basis, it is considered that 10% active work area would be a more representative assumption for predicting the annual TSP levels for the proposed Project.   Similar to the Tier 1 assessment of hourly and daily TSP, the annual TSP levels were predicted with or without the dust mitigation measures in place.  Details of the dust sources for annual TSP assessment including their coordinates, dimensions and estimated emission rates are given in Appendix 3.1b.

The above-mentioned assumed percentages active work areas for heavy construction activities for hourly, daily and annual TSP assessment are conservative values when compared to the percentages active work that are estimated based on Project-specific information, as detailed in Appendices 3.1d and 3.1e. 

For stockpiles, 20% of the stockpiling area is adopted to represent the mitigated dust sources during the assessment as it is recommended in Section 3.6.1.1 that 80% of the stockpiling area is covered by impervious sheets and all dusty materials should be sprayed with water immediately prior to any loading or transfer operation so as to keep the dusty material wet during material handling at the stockpile areas. 

For modelling purpose, the entire Project site has been split into 4 areas, namely, (1) BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan, up to the north portal of the Cheung Shan tunnel (see Figures 3-1.1 to 3-1.4); (2) Sha Tau Kok section, starting from  the south portal of the Cheung Shan tunnel (see Figures 3-1.4 to 3-1.6); (3) Po Kak Tsai section (see Figure 3-1.8); and (4) Fanling section (see Figures 3-1.9 to 3-1.11).

With addition of the TSP background level of 66.6µg/m³, the hourly, daily and annual TSP concentrations at the identified ASRs have been predicted and compared with the TSP criteria of 500μg/m3, 260 μg/m3 and 80 μg/m3 respectively.

3.4.2           Operational Phase

3.4.2.1         Vehicular Emissions

During the operational phase, there would be potential air quality impacts upon the ASRs due to the vehicular emissions from open roads, ventilation shafts, mid-ventilation building as well as kiosks, loading and unloading areas and public transport interchange (PTI) of the BCP.  The key air pollutants of concern from vehicle emissions are NO2 and RSP and their levels have been modelled against the relevant criteria (hourly and daily AQOs for NO2; daily AQO for RSP) in 2018, 2023, 2028 and 2033 (i.e. covering 15 years from the commencement of operation of the Project).  Details of the emissions, assumptions adopted and assessment approach are presented in Sections 3.4.3 to 3.4.9.

3.4.2.2         Odour from the Proposed Sewage Treatment Works

As detailed in Section 6.6, it is recommended to construct and operate an on-site sewage treatment works at the proposed BCP to treat the sewage to be generated from operation of the BCP and the Chuk Yuen Village Resite.  The location of the sewage treatment works is as shown in Figure 3-1.1.  During the operational phase, the potential odour impact on nearby ASRs that could be caused by the sewage treatment works has been assessed in Section 3.5.2.2.

3.4.3           Emissions from Open Roads

For the open roads connecting the BCP, the EMFAC-HK model (v1.2) has been used to determine the fleet average emission factors and the assumptions and input parameters are presented in the following sections.  The traffic data used for the assessment, including the hourly traffic flows of 16 vehicle classes at various road links and the speed fractions of various vehicle classes in all the 4 model years of 2018, 2023, 2028 and 2033 are provided by the Traffic Consultant, which are presented in the following sections.  The traffic forecast data has been submitted to the Transport Department (TD) for review and TD has made no adverse comment on the traffic data.  The 24-hour traffic patterns together with the graphical plots are given in Appendix 3.4-1.

3.4.3.1         Vehicle Emission Standards

Cross-boundary vehicles must be registered in Hong Kong and all motor vehicles seeking first registration in Hong Kong must comply with the Air Pollution Control (Vehicle Design Standards) (Emission) Regulations.   As such, it is reasonable to assume that both cross-boundary and Hong Kong vehicles will perform similarly in terms of tailpipe emissions in the assessment.

The emission standards, according to the latest implementation programme (as of June 2010) and information provided by the Mobile Sources Group of EPD, have been adopted in EMFAC-HK model for diesel vehicles registered in Hong Kong for both Hong Kong and cross-boundary vehicles as follows:

¡      Diesel vehicles with gross vehicle weight (GVW) of 3.5 tonnes or less:  Euro IV by Jan 2007; Euro V not later than 2012 and

¡      Diesel vehicles with GVW of over 3.5 tonnes:  Euro IV by Oct 2006, Euro V not later than 2012.

 

As the EMFAC-HK (v1.2) is incorporated with the Euro V emission standards (or technology group indexes) for only some of the vehicle classes including diesel vehicles with GVW over 3.5 tonnes, the diesel vehicles with GVW of 3.5 tonnes or less could only be modelled as complying with Euro IV emission standards from 2013 onwards (though those vehicles should have fulfilled Euro V standards since then). Nevertheless, the emission results so obtained are on the conservative side.

3.4.3.2         Road Grouping

Emission factors for the following four road types have been calculated:

·            Road Type 1 - Expressway (Design speed limit: 100kph);

·           Road Type 2 - Trunk Road (Design speed limit: 80kph);

·           Road Type 3 - Trunk Road (Design speed limit: 50kph); and

·           Road Type 4 - Rural & Local Roads (Design speed limit: 50kph).

The four road types are characterized by continuous and interrupted flow with different design speed limits. It is assumed that there will be continuous traffic flow in Expressway and Trunk Roads (Road Types 1, 2 & 3) whereas there will be interrupted flow in Rural & Local Roads (Road Type 4). The road type classification of individual road links in the study area is as shown in Figures 3-9.1 to 3-9.11.

3.4.3.3         Vehicle Classes

Vehicles operating on open roads have been categorized into 16 vehicle classes according to the Guideline on Modelling Vehicle Emission – Appendix 1, which is presented in Table 3.5 below:

Table 3.5:      Vehicle Classification in the EMFAC-HK Model

Vehicle Class

Notation in EMFAC-HK Model

Description

Gross Vehicle Weight

MC 1

PC+LGV(1)

Petrol Private Cars & Light Goods Vehicles

ALL

MC 3

PC+LGV(3)

Diesel Private Cars & Light Goods Vehicles <=2.5 tonne

<=2.5ton

MC 4

LGV(4)

Light Goods Vehicles >2.5-3.5 tonne

>2.5-3.5ton

MC 5

PLB

Public Light Buses

ALL

MC 6

LGV(6)

Light Goods Vehicles >3.5 tonne

>3.5ton – 5.5ton

MC 7

HGV(7)

Medium Goods Vehicles with GVW <15 tonne

>5.5ton – 15ton

MC 8

HGV(8)

Medium & Heavy Goods Vehicles with GVW >=15 tonne

>15ton

MC 10

FBDD

Double Deck Franchised Buses

ALL

MC 11

MC

Motor Cycles

ALL

TAXI 3

Taxi

Taxi

ALL

TAXI 4

PrLB(4)

Private Light Buses <=3.5 tonne

<=3.5ton

TAXI 5

PrLB(5)

Private Light Buses >3.5 tonne

>3.5ton

TAXI 6

NFB(6)

Non-franchised Buses <=6.4 tonne

<=6.4ton

TAXI 7

NFB(7)

Non-franchised Buses 6.4-15 tonne

>6.4ton – 15ton

TAXI 8

NFB(8)

Non-franchised Buses >15 tonne

>15ton

TAXI 10

FBSD

Single Deck Franchised Buses

ALL

3.4.3.4         Exhaust/evaporation technology fraction

Vehicle classes are grouped with different exhaust technology indexes and technology fractions. Each technology group represent a distinct emission control technologies. Exhaust technology fractions has made reference to “Vehicle Licensed Number by Age and Technology Group Fractions” updated to year 2008 as provided by EPD. According to the updated Guideline on Modelling Vehicle Emissions Appendix II – Implementation Schedule of Vehicle Emission Standards in Hong Kong (June 2010), assumptions on future emission standards are made. The details for each vehicle class together with the graphical plots are shown in Appendix 3.2.

3.4.3.5         Vehicle Population

According to the Guideline on Modelling Vehicle Emissions, the vehicle population has made reference to the latest vehicle age distribution (in 2008) as provided by EPD. There are available data on the overall growths of broad vehicle types (e.g. overall growth rates for the total population of private vehicles in different years), however more specific growth rates and retention rates for vehicles of different age groups could not be identified. Due to the data limitation, the vehicle age distributions in 2018, 2023, 2028 and 2033 could not be projected, and therefore it is assumed that the vehicle age distributions in all these 4 model years would be the same as that in 2008, Details of the input data together with the graphical plots of the vehicle population in 2008 are provided in Appendix 3.3. While the vehicle age distributions in different model years are assumed to be unchanged, the traffic forecasts of the study area in various years (see Appendix 3.4-1) have been taken into account for estimating the Vehicle Mile-Travelled.

Taxi

With the implementation of Vehicle Emission Standards, new registration of diesel taxi was banned in Hong Kong from 2001.  100% of LPG taxi was therefore assumed in this study and all diesel taxies were regrouped into LPG fuel type.

Private Light Bus <=3.5 tonne and >3.5 tonne

The former Environment, Transport and Works Bureau (ETWB) implemented an incentive scheme to encourage the early replacement of diesel light buses with LPG or electric ones in 2002.  As a conservative approach, the incentive scheme for light buses has not been considered in this assessment.

3.4.3.6         Accrual Rate

Default values and compositions have been adopted with reference to in the EMFAC-HK Guideline.

3.4.3.7         Diurnal Variation of Daily Vehicle Mile-Travelled (VMT)

For each vehicle class, the VMT of individual hours is calculated by multiplying the hourly number of vehicles with the length of the corresponding road link (in miles). Diurnal (24-hour) traffic pattern has been provided by Traffic Consultant.  The lengths of individual road links of the connecting road are given in Appendix 3.4-2.  The 24-hour VMT values for all vehicle classes in each of the model years 2018, 2023, 2028 and 2033 together with the graphical plots are provided in Appendix 3.4-4.

3.4.3.8         Daily Trips

The daily trips were used to estimate the cold start emissions of the petrol vehicles only. Therefore, trips for vehicles other than petrol type vehicles would be assumed to be zero. Different road type has different number of trips as follows.

3.4.3.9         Expressway and Trunk Road (Road Types 1, 2 & 3)

Zero trips are assumed in Expressway and Trunk Roads since there will be no cold start under normal circumstance.

3.4.3.10     Rural and Local Road (Road Type 4)

For Rural and Local Roads, the number of trips in the study area, Trip within study area, has been estimated as:

Trip within study area = (Trip within HK/VMT within HK) x VMT within study area

Trip within HK is the default data of EMFAC-HK model.  VMT within HK is the VMT of rural and local roads in Hong Kong, which is estimated based on the default VMT data of EMFAC-HK model and the relevant data as published in the Annual Traffic Census 2009 by TD.  Details of the trip estimation are as shown in Appendix 3.4-3. According to the Mobile Source Group of EPD, the default VMT and trips in the model are based on EPD’s estimated data for Hong Kong. VMT within study area is calculated as mentioned above. The trips in year 2018, 2023, 2028 and 2033 are provided in Appendix 3.4-4.   The 24-hour variations of total VMT and trips for individual road types are presented graphically in Appendix 3.4-4.

While the number of trips is dependent on vehicle population, no project-specific vehicle population data can be identified for the study area according to the Traffic Consultants.  However, project-specific VMT has been estimated based on the traffic forecast in the study area.  Moreover, it can be argued that VMT is related to vehicle population in such a way that a higher vehicle population would generally result in a higher VMT.   As a result, it has been proposed to estimate the number of trips in the study area on the basis of the project-specific VMT and the assumption that the number of trips per VMT in the study area would be similar to the number of trips per VMT in Hong Kong.  It is considered that this proposed approach is based on best available data and reasonable assumption.  This approach for estimating the number of trips together with the results of estimation has been submitted to TD for review and TD has made no adverse comment on the results.

3.4.3.11     Hourly Temperature and Relative Humidity Profile

Annual and monthly hourly average ambient temperature and relative humidity (Appendix 3.5) obtained from HKO’s Ta Kwu Ling meteorological station in year 2008 have been adopted (with at least 90% valid data) will be adopted.  The 24-hour variations of the annual averages of temperature and relative humidity are presented graphically in Appendix 3.5.

3.4.3.12     Speed Fractions

A sensitivity test has been undertaken to determine if the worst case emissions are produced by peak-hour speed or non-peak hour speed (i.e., design speed of road).   During the peak-hour speed scenario, the traffic flow has reached the maximum capacity of the road, and therefore only a portion of vehicles could be running at the design speed of the road, with the rest running at below the design speed. During the non-peak hour speed scenario, the traffic flow has not reached the maximum capacity so that all vehicles could be running at the design speed of the road.

The peak-hour speeds, which are provided by the Traffic Consultant, are calculated based on the peak traffic flow in each model year and the volume/capacity ratio of different road types. To calculate the speed fractions for each vehicle class, the speeds of each road were calculated and weighed by VMT. For each vehicle class, the VMT of each road link was grouped into sub-groups with speed interval of 5mph (0 - 5 mph, 5 - 10 mph, 10 - 15 mph, etc.).  The speed fraction of each sub-group was derived by the summation of the total VMT of road link within this sub-group divided by the total VMT of all road links. The estimated speed fractions, together with the volume/capacity ratio and the calculation of peak hour traffic, provided by the Traffic Consultant are given in Appendix 3.6.

3.4.3.13     Worst Case Scenario amongst Peak and Non-peak Hour Speeds of Different Model Years

To determine the worst case emissions within 15 years after commencement of the Project, emission rates for both peak and non-peak hour speeds are modelled for years 2018, 2023, 2028 and 2033.  By using the VMT for respective years (Appendix 3.4-4), the total emissions of different vehicle classes in each of the 4 model years have been estimated for both peak and non-peak hour speeds (Appendix 3.7a).   The combination of speed and model year that would give rise to the highest total daily emissions for each road type is selected in the assessment as the worst case scenario.  Based on the results of comparison (Appendix 3.7a), the worst case nitrogen oxides (NOx) and RSP emission rates for the following combinations of speeds and model years are adopted in the assessment: 

 

Road Type

For NOx Emission Rates

For RSP Emission Rates

Local Road & Rural Road

Peak-hour speed in 2018

Peak-hour speed in 2018

Trunk Road (50kph)

Peak-hour speed in 2018

Peak-hour speed in 2018

Trunk Road (80kph)

Peak-hour speed in 2018

Peak-hour speed in 2018

Expressway (100kph)

Non-peak hour speed in 2018

Non-peak hour speed in 2018

3.4.3.14     Predicted Emission Factors by EMFAC-HK model

Upon determination of the combination of speeds and model years that would give rise to the worst case daily emissions as discussed above, the hour during which the hourly total emissions of all vehicle types as predicted by the EMFAC-HK model is the largest has then been selected to represent the worst case emission hour, and the emissions of this worst case hour are then divided by its corresponding VMT to obtain the worst case emission factors in grams/vehicle-km, as a conservative approach.  Table 3.6 summarizes the results of such worst case emission factors.  Details of selection of the worst case hours and calculation of the worst case emission factors are given in Appendix 3.7b.

Table 3.6:      Worst Case Emission Factors as Predicted by EMFAC-HK Model

Vehicle Class

Notation in EMFAC-HK Model

Worst Case Emission Factors (g/veh-km)

Expressway (100kph) (Type 1)

Trunk Road (80kph) (Type 2)

Trunk Road (50kph) (Type 3)

Local Road & Rural Road (Type 4)

NOx

MC 1

PC+LGV(1)

0.0812

0.0749

0.0840

0.1798

MC 3

PC+LGV(3)

0.8294

0.5058

0.8231

0.5086

MC 4

LGV(4)

0.2937

0.1771

0.1725

0.1928

MC 5

PLB

0.0000

0.0859

0.0644

0.0758

MC 6

LGV(6)

2.5908

1.6199

1.4161

1.5964

MC 7

HGV(7)

2.9029

2.8747

2.7458

3.0281

MC 8

HGV(8)

3.6699

3.6387

3.4858

3.8701

MC 10

FBDD

2.5983

2.5204

2.5768

2.6153

MC 11

MC

0.8459

0.5517

0.7414

1.3571

TAXI 3

Taxi

0.1846

0.1570

0.1255

0.2038

TAXI 4

PV(4)

0.0326

0.0268

0.0000

0.0564

TAXI 5

PV(5)

0.3055

0.1084

0.1121

0.0628

TAXI 6

NFB(6)

1.2621

1.1975

1.1864

1.3027

TAXI 7

NFB(7)

2.3861

2.3950

2.4004

2.4091

TAXI 8

NFB(8)

2.6986

2.6168

2.7613

2.6872

TAXI 10

FBSD

1.7036

0.0000

0.0000

2.7778

RSP

MC 1

PC+LGV(1)

0.00301

0.00134

0.00200

0.00749

MC 3

PC+LGV(3)

0.11848

0.05268

0.06859

0.22604

MC 4

LGV(4)

0.02447

0.02951

0.08626

0.09638

MC 5

PLB

0.00000

0.02864

0.06442

0.07582

MC 6

LGV(6)

0.06132

0.07363

0.10893

0.12280

MC 7

HGV(7)

0.12197

0.12306

0.16950

0.18926

MC 8

HGV(8)

0.10750

0.10566

0.13861

0.17680

MC 10

FBDD

0.02095

0.03819

0.04295

0.11371

MC 11

MC

0.06266

0.02299

0.00000

0.05654

TAXI 3

Taxi

0.01086

0.00872

0.01045

0.01274

TAXI 4

PV(4)

0.01086

0.00000

0.00000

0.00000

TAXI 5

PV(5)

0.10183

0.05421

0.07471

0.04184

TAXI 6

NFB(6)

0.04352

0.02495

0.03296

0.02714

TAXI 7

NFB(7)

0.04772

0.04990

0.06668

0.05019

TAXI 8

NFB(8)

0.02444

0.02181

0.03835

0.04479

TAXI 10

FBSD

0.00000

0.00000

0.00000

0.00000

Note: The emission factors for some combinations of vehicle types and road types appear as zero because their computed values are too small to be displayed by the EMFAC model due to the corresponding low VMT values.

3.4.3.15     Inputs of Caline4 Model

The composite fleet emission factors for the road links have been calculated by using the worst case emission factors in Table 3.6 and the peak hour traffic flow and vehicle composition in the year with the highest traffic forecast.  Details of the calculations of the composite emission factors for each road link are provided in Appendix 3.8.

The worst case meteorological conditions input to the Caline4 model for the assessment are as follows:

¡           Wind speed: 1 m/s

¡           Wind direction: worst case

¡           Stability Class: D (day-time) and F (night-time)

¡           Wind variability: 12° (day-time) and 6° (night-time)

¡           Surface roughness: 1m

¡           Mixing height: 500m

Since the Calline4 model can predict hourly pollutant concentrations only, the 24-hour pollutant concentrations are calculated as 0.4 x (1-hour concentration) according to the Screening Procedures for Estimating the Air Quality Impact of Stationary Source (EPA-454/R-92-019). The annual pollutant levels are calculated by averaging the concentrations predicted by running the Caline4 model on an hour-to-hour basis with the full year of hourly meteorological data at HKO’s Ta Kwu Ling station in 2008.  It is also assumed that NO2 is taken as 20% of NOx.

The pollution levels at the ASRs have included those predicted by Caline4 and the background levels. The assessment levels of 1.5m, 5m and 10m above ground are assumed for all ASRs, except using actual height for the air intake point for the BCP.

3.4.4           Emission from Ventilation Shafts and Building of Tunnels

The Project consists of two vehicle tunnels – one short tunnel (Cheung Shan tunnel section) with a length of about 0.9 km (Figures 3-1.4) and one long tunnel (Lau Shui Heung tunnel section) with a length of about 4.8 km (Figures 3-1.6 to 3-1.9). One ventilation shaft is assumed to be located at each tunnel portal. For the long tunnel, a mid-ventilation building is also proposed (Figure 3-1.8).  The emissions from ventilation shafts and mid-ventilation building have been modelled by the ISCST3 model as point sources. Key inputs to the model include:

¡           Hourly meteorological data in 2008 as measured at HKO’s Ta Kwu Ling station.

¡           Discharge parameters such as dimensions, discharge flow/velocity and temperature in accordance with the ventilation system design

¡           Pollutant emission rates, which are calculated based on the worst case emissions obtained from EMFAC-HK (see Table 3.6), the linear lengths of the tunnels and traffic flow

As confirmed by the Engineer, the ventilation systems have been designed to operate continuously to extract all emissions from within the tunnels for discharge to the atmosphere via the ventilation shafts at tunnel portals and the mid-ventilation building (for long tunnel).   The designed splits of emissions are summarized as follows.

¡           For the long tunnel, 22% of the vehicle emissions inside the tunnel will be removed from the mid-ventilation building, while the remaining 33% and 45% of the emissions will be discharged from the ventilation shafts near Fanling (Figure 3-1.9) and Sha Tau Kok Road – Wo Hang (Figure 3-1.6), respectively.

¡           For the short tunnel, 43% of the emissions inside the tunnel will be discharged from the ventilation shaft at the southern portal while the remaining 57% of the emission will be discharged from the ventilation shaft at the northern portal (Figures 3-1.4). 

Based on the above designed split of emissions, the Engineer has accordingly developed the preliminary design of the ventilation shafts/building including the locations, numbers and specifications of the fans for each of the tunnels, which will form parts of the key requirements for the subsequent detailed design.

As a conservative approach, it is assumed that the total hourly emission rates of ventilation shafts and mid-ventilation building (for the long tunnel) throughout each of the 4 model years would be the same as the emission rates estimated based on the aforementioned worst case emissions. The calculation of emission rates at the ventilation shafts/building, as well as the relevant dimension and specifications are provided in Appendices 3.9a and 3.9b.

3.4.5           Emission from Tunnel Portals

As confirmed by the Engineer, all the emissions within both tunnels are designed to be extracted by the ventilation shafts and mid-ventilation building (for the long tunnel), and therefore there will be no emission from all tunnel portals.  Hence, modelling of tunnel portal emissions is not required in this assessment.

3.4.6           In-tunnel Air Quality

According to the Engineer, each of the two tunnels (i.e., short tunnel and long tunnel) will be constructed as separate tubes for northbound and southbound traffic, with dual-lane in each tube, and both tunnels will be equipped with mechanical ventilation systems that are designed to meet the criteria recommended in EPD’s “Practice Note on Control of Air Pollution in Vehicle Tunnels”.  The proposed ventilation system will mainly consist of axial and jet fans (with standby capacities), instruments installed within the tunnels to monitor concentrations of air pollutants (NO2 and CO) and the associated control system.   Air pollutant levels recorded inside the tunnels will be used as ones of the input parameters to the control system, for which interlock control algorithms will be developed to control operation of the exhaust fans in order to ensure maintenance of air quality within the tunnels to levels in compliance with the relevant criteria. 

3.4.7           Emission from kiosks, loading and unloading areas and PTI

The emissions from kiosks, loading and unloading (L&UL) areas and PTI have been considered as idling emissions. The worst-case forecast of numbers of idling vehicles in kiosks, L&UL and PTI in peak hour as provided by the Traffic Consultant are provided in Table 3.7. The composite NOx and RSP idling emissions factors of different vehicle types are extracted respectively from the Feasibility Study[1] and the approved EIA for Improvement to San Tin Interchange[2] ,and are as summarized in Table 3.8.  The average lengths of goods vehicle, coach/bus and passenger car/taxi are assumed to be 12m, 12m and 6m, respectively1 when calculating the idling emissions per unit length and the total queue lengths of the vehicles.  In the Caline4 model, idling emissions from vehicles have been modelled as “parking lot”, and the lengths of idling emissions of individual vehicle types are taken as the corresponding total queue lengths. Detailed calculations of the idling emissions and queue lenghts are provided in Appendix 3.10a.  Relevant information about the determination of idling emission factors as extracted from the Feasibility Study is given in Appendix 3.10b.

Table 3.7:      Forecast of Idling Vehicles in Kiosks, L&UL and PTI in Peak Hour

Location

Vehicle Type

Level

(m AGL)

Total Idling Time in an Hour

(veh-minutes)(a)

Equivalent No. of Idling Vehicles in an Hour(b)

PTI

Bus

0

30

0.5

Green Mini Bus (GMB)

0

12

0.2

Taxi

0

2880

48

L&UL: Cross-Boundary Coach Boarding Area (to Hong Kong)

Cross-Boundary Coach

10

1392

23.2

L&UL: Cross-Boundary Coach Boarding Area (to PRC)

Cross-Boundary Coach

10

348

5.8

Kiosks (to Hong Kong)

Coach (3 Channels)

10

50 per channel

0.8 per channel

Passenger Car/taxi (3 Channels)

10

205 per channel

3.4 per channel

Goods Vehicle (9 Channels)

0

602 per channe)

10.0 per channel

Kiosks (to PRC)

Coach (3 Channels)

10

50 per channel

0.8 per channel

Passenger Car/taxi (3 Channels)

10

171 per channel

2.9 per channel

Goods Vehicle (9 Channels)

0

602 per channel

10.0 per channel

Notes:

(a)            The total idling time in an hour was estimated by the Traffic Consultant based on the total number of vehicles that would idle in each location in the hour multiplied with the corresponding idling time (in minutes) of the vehicle.

(b)            The equivalent number of idling vehicles in an hour is equal to the total idling time in an hour divided by 60 minutes.  In other words, it is the equivalent number of vehicles that were idling in each location for the entire hour.

Table 3.8:      Idling Emissions from Kiosks, L&UL areas and PTI

Vehicle Type

Composite Idling Emission Factor (g/min-veh)

 

NOx

RSP

Goods Vehicle

1.317

0.06

Coach/Bus

1.317

0.06

Passenger Car/taxi

0.2

Negligible

The composite NOx idling emission factors adopted in the Feasibility Study were estimated based on the implementation of emission standards (as of July 2005) and vehicle population distribution (as of 2003) available at the time of completing the Study (see Appendix 3.10b).  In view of the updated implementation schedule of emission standards (as of June 2010) and the latest available vehicle population data (as of 2008), it is necessary to accordingly update the NOx idling emission factors as detailed below. 

Based on Tables II.3-20 to II.3-27 and Tables II.3-46 to II.3-50, Appendix 2 of the “Road Tunnels: Vehicle Emissions and Air Demand for Ventilation” published by the Permanent International Association of Road Congresses (PIARC) in November 2004 (see the Attachment to Appendix 3.10b), the NOx idling emission factors of relevant vehicle types for different Euro emission standards are as follows:

 

Emission Standard

NOx Idling Emission Factor for Heavy Goods Vehicle (g/h-veh)

NOx Idling Emission Factor for Private Car (g/h-veh)

Pre-Euro

73.0

1.00

Euro I

61.3

1.00

Euro II

40.8

0.38

Euro III

27.5

0.27

Euro IV

18.0

0.14

According to Tables II.3-22, II.3-24, II.3-26 and II.3-51, Appendix 2 of the above-mentioned publication by PIARC (see the Attachment to Appendix 3.10b), all the above NOx idling emission factors for heavy goods vehicles should be adjusted by a mass factor of 2.5 to account for the vehicle mass variation whereas the NOx idling emission factors for private cars should be adjusted by the aging factors of 3 for Euro I; 1.82 for Euro II and 2 for Euro III.    As the aging factor for Euro IV private cars is not provided in the PIARC publication, it is assumed to be the same as that for Euro III, i.e., 2.  The adjusted emission factors therefore become:

 

Emission Standard

Adjusted NOx Idling Emission Factor for Heavy Goods Vehicle (g/h-veh)

Adjusted NOx Idling Emission Factor for Private Car (g/h-veh)

Pre-Euro

182.50

1.00

(no adjustment needed)

Euro I

153.25

3.00

Euro II

102.00

0.69

Euro III

68.75

0.54

Euro IV

45.00

0.28

Based EPD’s published vehicle population data in 2008 and EPD’s updated Guideline on Modelling Vehicle Emissions, Appendix II – Implementation Schedule of Vehicle Emission Standards in Hong Kong (June 2010), the estimated population distributions of heavy goods vehicles and private cars complying with various Euro emission standards in the assessment year of 2018 can be estimated and the results are as follows:

 

Emission Standard

% of Population of Heavy Goods Vehicle

% of Population of Private Car

Pre-Euro

0.2%

0.2%

Euro I

0.9%

0.1%

Euro II

8.7%

0.5%

Euro III

26.3%

8.2%

Euro IV

31.9%

47.4%

Euro V

31.9%

43.6%

Details of the population distribution estimation are given in Appendix 3.10c.   With the adjusted NOx idling emission factors and the estimated population distribution in 2018, the composite NOx idling emission factors for heavy goods vehicle and private car have been calculated by taking the population-weighted average of the corresponding emission factors (see Appendix 3.10c).    Since there is no NOx idling emission factor for Euro V engines in the PIARC publication, it is conservatively assumed to be the same as that for Euro IV engines for the purpose of calculating the composite emission factors.  Finally, with reference to the Feasibility Study, the composite emission factors are multiplied by the factors of 1.05 and 1.3 to respectively account for the China fuel usage and the additional air-conditioning loading.  The resulting composite NOx idling emission factors for heavy goods vehicle and private car are respectively 1.308 g/min-veh and 0.007 g/min-veh (see Appendix 3.10c for the detailed calculation).

From the above, it can be seen that the composite emission factor for heavy goods vehicle (i.e., 1.308 g/min-veh) estimated based on the latest vehicle population and implementation schedule is very close to (only about 1% below) the corresponding factor used in the Feasibility Study (i.e., 1.317 g/min-veh).  For the estimated composite emission factor for passenger cars (i.e., 0.007 g/min-veh), as it is substantially lower than the factor used in the Feasibility Study (i.e., 0.2 g/min-veh), the factor used in the Feasibility Study is adopted in this EIA in order to be conservative.   Therefore, despite the updated vehicle population and implementation schedule of emission standards, the composite NOx idling emission factors of the Feasibility Study for both heavy goods vehicle and private car (see Table 3.8) remain applicable and have been adopted for this EIA.

During the detailed design stage, it is proposed to explore the feasibility and arrangement for administrative measures whereby vehicle idling emissions could be reduced within the BCP area, for example, administrative means to encourage switching off engines while waiting.  Nevertheless, as a conservative approach, the effects of such administrative measures (if any) are not taken into account in the modelling exercise.

3.4.8           Cumulative Impacts

There are a number of identified major concurrent projects in the vicinity of this Project, the details of which are given in Section 2.10 and Appendix 2.2.  The concurrent projects that are considered to have cumulative impacts on the identified ASRs during the operational phase of this Project are the North East New Territories New Development Area (including Fanling Bypass) and the Widening of Tolo Highway / Fanling Highway projects whereas all other identified concurrent projects would not contribute to cumulative operational phase impacts.  For the former concurrent project, no sufficient information is available during the preparation of the submission and this concurrent project has not been included in the assessment.   For the latter concurrent project, while the implementation of the project is currently under review, the traffic data of the Fanling Highway section adopted in this assessment has already taken into account of the concurrent project.

Within the 500m assessment area, it has been identified that there would be pollution sources from the Shenzhen Liantang BCP, Luo Sha Road and Luo Fong Road in Shenzhen. Cumulative impacts due to these sources have been taken into account in the assessment, where it is considered appropriate as discussed below.

The layout of the Shenzhen BCP as provided by the Shenzhen Authority (深圳市建築工務署) has been used in the cumulative impact assessment.  However, as information about the emission sources of the Shenzhen BCP is not available, it is assumed that they are similar to those of the BCP on Hong Kong side.  Therefore, the emission sources at Shenzhen BCP have included those from kiosks, loading and unloading areas and PTI.

According to the information provided by the Shenzhen Authority, it is planned to commence the EIA for the Shenzhen BCP in the 4th quarter of 2010 and to complete the EIA in 6 to 9 months.  Therefore, information regarding the vehicular emissions from Luo Sha Road and Luo Fong Road in Shenzhen for assessing the associated air quality impact is currently not available (though it may probably be available in the 1st or 2nd quarters of 2011, subject to the scope of that EIA).  Due to the unavailability of such information for carrying out the EIA of this BCP Project, quantitative assessment of the cumulative air quality impacts due to traffic emissions from the proposed connecting roads of this Project and the two Roads in Shenzhen cannot be made.  Nevetheless, it is proposed to adopt the following qualitative approach to review the potential air quality impacts that may arise from the two Roads in Shenzhen.

For Luo Sha Road, based on the layout of the BCP in Hong Kong, the nearest ASR BDG1 in the BCP is at least 450m away from the road, while it is located at least 600m away from the second nearest ASR TYHP.  According to the “GB17691-2005 Limits and Measurement Methods for Exhaust Pollutants from Compression Ignition and Gas Fuelled Positive Ignition Engines (III, IV V)” issued by the relevant authorities in China[3], vehicles in the Mainland China have been required to meet the equivalent emission standards of Euro IV since 1 January 2010, which would be further tightened to the equivalent emission standards of Euro V with effect from 1 January 2012.  In view of the large buffer distances between Luo Sha Road and the nearby ASRs and the increasingly stringent vehicle emission standards in China, it is considered that vehicular emissions from the Road would not have significant contributions to the pollution levels of the ASRs.

For Luo Fong Road, it is at least 350m and 550m from the ASRs BDG1 and TYHP, respectively.  As it is only a two-lane local road, small peak traffic flow is expected for this type of road (less than 500 vehicles/hour), with reference to the traffic flows of Sha Tau Kok Road and Route Twisk in 20081. As such, low vehicular emissions are expected. In view of the large buffer distances between Luo Fong Road and the nearby ASRs as well as the low vehicular emissions of the Road, it is considered that vehicular emissions from the Road would not have significant contributions to the pollution levels of the ASRs.

3.4.9           Calculation of Total Concentration 

The cumulative pollution levels at the identified ASRs during the operational phase have been calculated by adding up the contribution of emissions from all the major open roads within the 500m assessment area  of the Project in Hong Kong and from idling vehicles in kiosks/L&UL/PTI of the BCPs on both Hong Kong and Shenzhen sides which are predicted by the Caline4 model; the emissions from ventilation building/shafts which are predicted by the ISCST3 model as well as the background concentrations (50.4 μg/m3 for NO2 and 49.9 μg/m3 for RSP). The assessment levels of 1.5m, 5m and 10m AGL are assumed for all ASRs. However, the assessment height of the air intake points for the BCP (i.e. ASR BDG1) is assumed as 35m AGL only. 

3.5               Identification, Prediction and Evaluation of Environmental Impact

3.5.1           Construction Phase

3.5.1.1         Hourly TSP Levels

For the purpose of Tier 1 screening, the predicted hourly TSP concentrations at all identified ASRs are summarized in Tables 3.9 to 3.12 for unmitigated scenario and Tables 3.13 to 3.16 for mitigated scenario.   For clarity, the ASRs are split into four groups: (1) near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan; (2) Sha Tau Kok, (3) Po Kak Tsai, and (4) Fanling.  The Tier 1 contours of cumulative hourly TSP levels at 1.5m AGL are shown in Figures 3-4.1a to 3-4.9a and Figures 3-4.1b to 3-4.9b for respectively the unmitigated and mitigated scenarios..

Table 3.9:      Predicted Cumulative Hourly Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TYHP

4018

3975

3096

TYH

4876

4639

3338

V1

9270

6870

3845

V2

6177

4845

3242

CY3

3531

3091

2216

KL1

4444

4456

3690

TKL1

3802

3870

3307

TKL2

4943

3600

3091

KTW6

3586

3646

3122

TF1

2209

2348

2139

FWW1

2877

3061

2760

KTW1

3336

3267

2563

KTW2

3931

3660

2625

KTW4

4710

3305

2111

KTW5

2373

2040

1589

NYH1

1636

1564

1310

PY1

2870

2104

1225

PY3

1911

1894

1544

PY6

2084

1897

1382

WKS1

2177

1881

1329

WKS2

1653

1306

1149

WKS3

1160

1186

1011

WKS4

2787

2375

1370

WKS5

2570

2159

1602

WKS7

3529

2230

1853

Note:        Bold value: The predicted value exceeds the 1-hour average TSP criterion, i.e. 500 μg/m3

Table 3.10:            Predicted Cumulative Hourly Average TSP Concentration in Sha Tau Kok (Tier 1– Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

ST1

1042

1001

735

ST2

1426

1267

906

ST3

2910

2533

1608

ST4

2822

2244

1584

TTW1

4340

1996

1159

TTW2

2518

2157

1216

TTW3

4445

2407

1246

LT1

2204

1645

1254

LT2

1914

1786

1287

Note:        Bold value: The predicted value exceeds the 1-hour average TSP criterion, i.e. 500 μg/m3

Table 3.11:            Predicted Cumulative Hourly Average TSP Concentration in Po Kak Tsai (Tier 1– Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

PKT1

490

456

318

PKT2

1048

816

379

PKT3

891

684

311

Note:        Bold value: The predicted value exceeds the 1-hour average TSP criterion, i.e. 500 μg/m3

Table 3.12:            Predicted Cumulative Hourly Average TSP Concentration in Fanling (Tier 1 – Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TH1

4825

2320

1482

TH4

3154

3066

2319

KT1

3680

3081

1676

KT2

3555

2432

1355

KT3

5290

3366

1825

NWP1

5465

4120

2233

NWP2

5309

4508

2785

NWP3

5129

2634

1497

KLH1

5030

3872

2117

Note:        Bold value: The predicted value exceeds the 1-hour average TSP criterion, i.e. 500 μg/m3

Table 3.13:    Predicted Cumulative Hourly Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TYHP

569

562

447

TYH

673

640

470

V1

1133

871

547

V2

770

684

473

CY3

479

421

345

KL1

572

574

487

TKL1

496

505

448

TKL2

668

496

417

KTW6

491

497

433

TF1

320

337

312

FWW1

403

426

390

KTW1

447

438

356

KTW2

558

519

384

KTW4

660

469

312

KTW5

377

333

247

NYH1

278

268

226

PY1

444

323

211

PY3

301

298

251

PY6

380

308

231

WKS1

468

384

255

WKS2

324

309

242

WKS3

238

243

216

WKS4

457

403

265

WKS5

436

383

271

WKS7

533

352

302

Note:        Bold value: The predicted value exceeds the 1-hour average TSP criterion, i.e. 500 μg/m3

Table 3.14:            Predicted Cumulative Hourly Average TSP Concentration in Sha Tau Kok (Tier 1– Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

ST1

199

193

157

ST2

251

229

180

ST3

450

399

274

ST4

438

360

271

TTW1

643

327

214

TTW2

397

348

221

TTW3

657

382

225

LT1

355

279

227

LT2

316

298

231

Note:        Bold value: The predicted value exceeds the 1-hour average TSP criterion, i.e. 500 μg/m3

Table 3.15:            Predicted Cumulative Hourly Average TSP Concentration in Po Kak Tsai (Tier 1– Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

PKT1

176

167

132

PKT2

318

260

147

PKT3

279

226

130

Table 3.16:            Predicted Cumulative Hourly Average TSP Concentration in Fanling (Tier 1 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TH1

708

370

257

TH4

485

472

370

KT1

554

473

283

KT2

537

385

240

KT3

770

511

304

NWP1

794

613

359

NWP2

773

665

433

NWP3

749

413

259

KLH1

736

579

343

Note:        Bold value: The predicted value exceeds the 1-hour average TSP criterion, i.e. 500 μg/m3

The Tier 1 screening results have identified that with the mitigation measures in place 20 ASRs would potentially be subject to adverse dust impacts, i.e., exceedance of the 1-hour TSP criterion.  These ASRs were then selected to undergo the Tier 2 assessment, the results of which are as shown in Table 3.17.  The locations of 30% active areas of the dust emission sources assumed to be closest to the identified ASRs are shown in Figures 3-3.1 to 3-3.17.  It can be seen that the Tier 2 results at all the selected ASRs would comply with the 1-hour TSP criterion (500 μg/m3). The Tier 2 contours of cumulative hourly TSP levels at such ASRs at 1.5m AGL (mitigated) are shown in Figures 3-5.1 to 3-5.17.    

Table 3.17:    Predicted Cumulative Hourly Average TSP Concentration at Selected ASRs (Tier 2 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TYHP

260

222

156

TYH

249

230

170

V1

300

289

230

V2

303

287

222

KL1

194

185

171

TKL1

184

170

159

TKL2

303

178

153

KTW2

315

270

177

KTW4

485

282

156

WKS7

201

148

102

TTW1

315

186

127

TTW3

268

173

122

TH1

361

228

163

KT1

321

274

166

KT2

396

288

156

KT3

462

283

153

KLH1

415

333

197

NWP1

409

309

179

NWP2

344

301

207

NWP3

472

259

170

3.5.1.2         Daily TSP Levels

For the purpose of Tier 1 screening, the predicted daily TSP concentrations at all identified ASRs are summarized in Tables 3.18 to 3.21 for unmitigated scenario and Tables 3.22 to 3.25 for mitigated scenario..   The Tier 1 contours of cumulative daily TSP levels at 1.5m AGL are shown in Figures 3-6.1a to 3-6.9a. and Figures 3-6.1b to 3-6.9b for respectively the unmitigated and mitigated scenarios.

Table 3.18:    Predicted Cumulative Daily Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TYHP

619

576

431

TYH

631

606

478

V1

2592

1991

1151

V2

1993

1737

1215

CY3

1051

954

778

KL1

628

634

577

TKL1

538

544

486

TKL2

819

592

482

KTW6

519

524

465

TF1

362

381

369

FWW1

343

359

340

KTW1

1022

1028

889

KTW2

998

937

751

KTW4

1294

956

679

KTW5

514

463

417

NYH1

383

375

356

PY1

846

633

414

PY3

499

488

412

PY6

547

511

401

WKS1

620

549

380

WKS2

420

416

351

WKS3

234

246

236

WKS4

722

639

448

WKS5

731

612

424

WKS7

506

447

375

Note:        Bold value: The predicted value exceeds the daily average TSP criterion, i.e. 260 μg/m3

Table 3.19:    Predicted Cumulative Daily Average TSP Concentration in Sha Tau Kok (Tier 1 – Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

ST1

249

246

210

ST2

335

315

250

ST3

424

388

290

ST4

540

436

289

TTW1

895

633

399

TTW2

555

499

336

TTW3

915

573

352

LT1

439

364

292

LT2

391

379

309

Note:        Bold value: The predicted value exceeds the daily average TSP criterion, i.e. 260 μg/m3

Table 3.20:    Predicted Cumulative Daily Average TSP Concentration in Po Kak Tsai (Tier 1 – Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

PKT1

103

102

94

PKT2

146

132

108

PKT3

147

128

102

Table 3.21:    Predicted Cumulative Daily Average TSP Concentration in Fanling (Tier 1 – Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TH1

1475

648

381

TH4

576

447

293

KT1

632

582

422

KT2

938

752

447

KT3

1023

787

541

NWP1

1124

722

421

NWP2

831

724

576

NWP3

1213

812

488

KLH1

1509

1262

782

Note:        Bold value: The predicted value exceeds the daily average TSP criterion, i.e. 260 μg/m3

Table 3.22:    Predicted Cumulative Daily Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Tier 1 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TYHP

137

131

114

TYH

140

136

120

V1

362

293

202

V2

316

281

212

CY3

201

187

162

KL1

134

137

130

TKL1

129

124

119

TKL2

162

133

118

KTW6

121

122

116

TF1

105

107

106

FWW1

101

103

99

KTW1

190

191

172

KTW2

192

183

157

KTW4

235

187

148

KTW5

131

123

112

NYH1

112

106

103

PY1

176

142

112

PY3

124

122

112

PY6

134

126

110

WKS1

149

139

114

WKS2

122

122

112

WKS3

100

102

99

WKS4

169

158

130

WKS5

169

152

125

WKS7

129

121

111

Note:        Bold value: The predicted value exceeds the daily average TSP criterion, i.e. 260 μg/m3

Table 3.23:    Predicted Cumulative Daily Average TSP Concentration in Sha Tau Kok (Tier 1 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

ST1

93

92

87

ST2

105

102

93

ST3

117

112

97

ST4

135

118

97

TTW1

185

147

112

TTW2

134

126

104

TTW3

185

140

107

LT1

119

109

97

LT2

111

109

100

Table 3.24:    Predicted Cumulative Daily Average TSP Concentration in Po Kak Tsai (Tier 1 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

PKT1

76

76

74

PKT2

87

83

77

PKT3

88

83

76

Table 3.25:    Predicted Cumulative Daily Average TSP Concentration in Fanling (Tier 1 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TH1

266

148

111

TH4

138

121

99

KT1

147

140

116

KT2

188

162

121

KT3

203

169

131

NWP1

222

161

118

NWP2

172

162

140

NWP3

235

173

124

KLH1

271

236

167

Note:        Bold value: The predicted value exceeds the daily average TSP criterion, i.e. 260 μg/m3

The Tier 1 screening results have identified that with the mitigation measures in place 4 ASRs would potentially be subject to adverse dust impacts, i.e., exceedance of the daily TSP criterion.  The ASRs were then selected to undergo the Tier 2 assessment, the results of which are as shown in Table 3.26.  The locations of 30% active areas of the dust emission sources assumed to be closest to the identified ASRs are shown in Figures 3-3.7, 3-3.8, 3.3.12, 3.3.13, 3.3.16 and 3.3.17.  It can be seen that the Tier 2 results at the selected ASR would comply with the daily TSP criterion (260 μg/m3). The Tier 2 contours of cumulative daily TSP levels at such ASRs at 1.5m AGL (mitigated) are shown in Figures 3-7.1 to 3-7.6.   

Table 3.26:    Predicted Cumulative Daily Average TSP Concentration at Selected ASRs (Tier 2 – Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

V1

103

101

96

V2

130

119

104

TH1

163

97

83

KLH1

158

138

105

3.5.1.3         Annual TSP Levels

The predicted annual TSP concentrations are summarized in Tables 3.27 to 3.30 for unmitigated scenario and Tables 3.31 to 3.34 for mitigated scenario.  It can be seen that with the mitigation measures in place the annual TSP concentrations at all ASRs would comply with the corresponding AQO (80 μg/m3). The contours of cumulative annual TSP levels at 1.5m AGL (mitigated) are shown in Figures 3-8.1a to 3-8.9a and Figures 3-8.1b to 3-8.9b for respectively the unmitigated and mitigated scenarios.

Table 3.27:  Predicted Cumulative Annual Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TYHP

74

74

73

TYH

75

75

74

V1

108

101

90

V2

87

86

82

CY3

76

76

74

KL1

84

83

80

TKL1

85

82

78

TKL2

83

79

76

KTW6

75

75

74

TF1

71

72

71

FWW1

71

71

71

KTW1

77

77

76

KTW2

85

83

80

KTW4

89

85

80

KTW5

79

77

75

NYH1

75

74

73

PY1

85

81

76

PY3

73

73

72

PY6

78

77

75

WKS1

83

80

75

WKS2

78

77

75

WKS3

68

68

68

WKS4

82

79

75

WKS5

87

82

75

WKS7

73

72

70

Note:        Bold value: The predicted value exceeds the annual average TSP criterion, i.e. 80 μg/m3

Table 3.28: Predicted Cumulative Annual Average TSP Concentration in Sha Tau Kok (Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

ST1

68

68

68

ST2

70

70

69

ST3

74

73

71

ST4

79

77

74

TTW1

78

76

73

TTW2

78

78

76

TTW3

94

88

81

LT1

70

70

69

LT2

70

70

70

Note:        Bold value: The predicted value exceeds the annual average TSP criterion, i.e. 80 μg/m3

Table 3.29: Predicted Cumulative Annual Average TSP Concentration in Po Kak Tsai (Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

PKT1

67

67

67

PKT2

73

70

68

PKT3

68

67

67

Table 3.30:    Predicted Cumulative Annual Average TSP Concentration in Fanling (Unmitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TH1

69

69

68

TH4

69

69

68

KT1

68

68

68

KT2

68

68

68

KT3

69

69

68

NWP1

72

71

69

NWP2

71

70

68

NWP3

73

71

69

KLH1

68

68

68

Table 3.31:  Predicted Cumulative Annual Average TSP Concentration in near the BCP, Lin Ma Hang to Frontier Closed Area and Ping Yeung to Wo Keng Shan (Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TYHP

68

68

68

TYH

68

68

68

V1

72

71

70

V2

69

69

69

CY3

68

68

68

KL1

69

69

68

TKL1

69

69

68

TKL2

69

68

68

KTW6

68

68

68

TF1

67

67

67

FWW1

67

67

67

KTW1

68

68

68

KTW2

69

69

69

KTW4

70

69

68

KTW5

68

68

68

NYH1

68

68

68

PY1

69

69

68

PY3

68

68

67

PY6

68

68

68

WKS1

69

69

68

WKS2

68

68

68

WKS3

67

67

67

WKS4

69

69

68

WKS5

70

69

68

WKS7

68

67

67

Table 3.32: Predicted Cumulative Annual Average TSP Concentration in Sha Tau Kok (Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

ST1

67

67

67

ST2

67

67

67

ST3

68

68

67

ST4

69

68

68

TTW1

68

68

68

TTW2

68

68

68

TTW3

71

70

69

LT1

67

67

67

LT2

67

67

67

Table 3.33: Predicted Cumulative Annual Average TSP Concentration in Po Kak Tsai (Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

PKT1

67

67

67

PKT2

68

67

67

PKT3

67

67

67

Table 3.34:    Predicted Cumulative Annual Average TSP Concentration in Fanling (Mitigated)

ASRs

1.5m AGL

5m AGL

10m AGL

TH1

67

67

67

TH4

67

67

67

KT1

67

67

67

KT2

70

67

67

KT3

68

68

67

NWP1

67

67

67

NWP2

68

67

67

NWP3

71

70

68

KLH1

67

67

67

3.5.2           Operational Phase

3.5.2.1         Vehicular Emissions

During the operational phase, the predicted hourly and daily NO2 as well as daily RSP concentrations at all the identified ASRs are presented in Tables 3.35 and 3.36 for stability class D and stability class F respectively.   The predicted annual NO2 and RSP concentrations at all ASRs are presented in Table 3.37. The contours of cumulative hourly NO2, daily NO2 and daily RSP levels at 1.5m AGL are given respectively in Figures 3-10.1 to 3-10.9, Figures 3-11.1 to 3-11.9 and Figures 3-12.1 to 3-12.9 for stability class D whereas the similar sets of contours for stability class F are given in Figures 3-13.1 to 3-13.9, Figures 3-14.1 to 3-14.9 and Figures 3-15.1 to 3-15.9.   The contours for annual NO2 and RSP concentrations at 1.5m AGL are given respectively in Figures 3-16.1 to 3-16.9 and Figures 3-17.1 to 3-17.9.  As discussed earlier, the predicted results have included the background pollutant levels and the cumulative impacts of the following emissions:

¡      Open roads on the Hong Kong side;

¡      Idling vehicles in kiosks/L&UL/PTI from the BCPs of both Hong Kong side and Shenzhen side; and

¡      Ventilation building/shafts of the vehicle tunnels.

Table 3.35:    Predicted Cumulative Hourly and Daily NO2 and Daily RSP concentrations for Stability Class D

 

Hourly NO2 Concentration (μg/m3)

Daily NO2 Concentration (μg/m3)

Daily RSP Concentration (μg/m3)

 

(Criterion: 300 μg/m3)

(Criterion: 150 μg/m3)

(Criterion: 180 μg/m3)

ASRs

1.5m AGL

5m AGL

10m AGL

1.5m AGL

5m AGL

10m AGL

1.5m AGL

5m AGL

10m AGL

TYHP

121

120

116

76

76

74

55

55

54

TYH

125

123

120

78

77

76

55

55

55

V1

132

130

124

81

80

78

56

56

56

V2

118

117

114

76

75

74

55

55

55

CY3

97

97

97

67

67

67

53

53

53

KL1

97

97

97

67

67

66

53

53

53

TKL1

91

91

91

65

64

64

53

53

53

TKL2

87

87

87

63

63

63

52

52

52

KTW6

84

84

84

62

62

62

52

52

52

TF1

78

78

79

59

59

59

51

51

51

FWW1

75

76

76

58

58

58

51

51

51

KTW1

101

101

101

68

68

68

53

53

53

KTW2

130

129

127

80

80

79

56

56

55

KTW4

134

133

130

82

81

80

56

56

55

KTW5

140

138

135

84

83

82

56

56

55

KTW7

83

83

83

61

61

61

52

52

52

NYH1

124

123

121

77

77

76

55

54

54

PY1

167

162

149

95

93

87

57

57

56

PY3

96

96

95

66

66

66

53

53

53

PY6

117

116

114

74

74

73

54

54

54

WKS1

99

98

97

67

67

66

53

53

53

WKS2

85

85

85

61

61

61

52

52

52

WKS3

99

99

99

67

67

67

53

53

53

WKS4

102

95

92

69

66

64

53

53

52

WKS5

107

106

103

70

70

69

53

53

53

WKS7

106

105

103

70

70

69

53

53

53

WKS8

132

131

129

80

80

79

55

55

55

ST1

65

65

66

55

55

55

51

51

51

ST2

69

69

70

57

57

57

51

51

51

ST3

75

75

76

59

59

59

52

52

52

ST4

79

79

79

60

60

60

52

52

52

TTW1

81

80

79

62

61

61

52

52

52

TTW2

77

76

75

60

60

59

52

52

52

TTW3

81

79

74

61

60

59

53

52

51

LT1

77

77

76

60

60

60

52

52

52

LT2

78

77

76

61

60

60

52

52

52

PKT1

68

68

69

55

55

55

51

51

51

PKT2

68

68

68

55

55

55

51

51

51

PKT3

67

67

68

54

54

54

51

51

51

TH1

109

105

103

72

70

69

54

54

54

TH4

107

107

107

71

71

71

54

54

54

KT1

115

114

111

74

73

72

54

54

54

KT2

115

114

113

74

74

73

54

54

54

KT3

128

126

122

79

79

77

56

56

56

NWP1

137

135

128

83

82

79

57

57

56

NWP2

152

150

144

89

88

86

58

58

58

NWP3

116

115

112

75

74

73

55

55

55

KLH1

118

118

117

75

75

75

57

57

57

BDG1 (at 35m AGL)

-

-

90

-

-

62

-

-

52

Table 3.36:    Predicted Cumulative Hourly and Daily NO2 and Daily RSP concentrations for Stability Class F

 

Hourly NO2 Concentration (μg/m3)

Daily NO2 Concentration (μg/m3)

Daily RSP Concentration (μg/m3)

 

(Criterion: 300 μg/m3)

(Criterion: 150 μg/m3)

(Criterion: 180 μg/m3)

ASRs

1.5m AGL

5m AGL

10m AGL

1.5m AGL

5m AGL

10m AGL

1.5m AGL

5m AGL

10m AGL

TYHP

172

168

158

96

95

91

59

58

58

TYH

183

179

168

101

100

95

59

59

58

V1

229

223

206

120

117

111

64

64

63

V2

201

197

187

108

107

103

62

62

61

CY3

158

157

153

91

91

89

57

57

57

KL1

165

164

160

94

93

92

59

58

58

TKL1

154

153

150

90

89

88

58

57

57

TKL2

146

146

143

87

86

85

57

57

57

KTW6

138

137

135

83

83

82

56

56

56

TF1

120

119

118

76

76

75

55

55

55

FWW1

116

116

115

75

74

74

55

54

54

KTW1

170

169

165

96

96

94

58

58

58

KTW2

207

205

200

111

110

108

61

61

61

KTW4

192

190

186

105

104

102

59

59

59

KTW5

193

192

187

105

105

103

59

59

59

KTW7

135

134

132

82

82

81

56

56

56

NYH1

170

168

164

96

95

94

58

58

57

PY1

210

205

193

112

110

105

61

60

60

PY3

125

124

120

78

77

76

55

55

55

PY6

152

151

147

88

88

87

57

57

56

WKS1

124

124

122

77

77

76

55

55

55

WKS2

107

107

106

70

70

70

54

54

53

WKS3

134

134

132

81

81

80

55

55

55

WKS4

122

116

111

76

74

72

55

54

54

WKS5

122

119

125

76

75

78

54

55

54

WKS7

140

138

135

83

83

81

56

56

55

WKS8

193

191

186

105

104

102

59

59

59

ST1

87

87

87

64

64

63

52

52

52

ST2

97

96

97

68

68

67

53

53

53

ST3

101

101

102

69

69

69

53

53

53

ST4

91

90

90

65

65

65

53

53

52

TTW1

99

98

93

69

68

66

54

54

53

TTW2

83

82

80

63

62

61

52

52

52

TTW3

96

92

85

67

66

63

53

53

52

LT1

92

91

88

66

66

65

54

54

53

LT2

91

90

87

66

66

64

54

54

54

PKT1

90

90

90

63

63

63

53

53

53

PKT2

89

89

89

63

63

63

52

52

52

PKT3

88

88

88

62

62

62

52

52

52

TH1

122

129

126

77

80

78

56

56

55

TH4

138

138

137

84

83

83

58

58

57

KT1

146

144

138

86

85

83

57

57

57

KT2

143

142

138

85

85

83

57

57

56

KT3

156

153

142

91

90

85

59

59

59

NWP1

172

168

159

97

95

92

61

60

59

NWP2

184

181

173

102

101

98

60

60

59

NWP3

136

135

129

83

82

80

57

57

57

KLH1

146

146

144

87

86

86

61

60

60

BDG1 (at 35m AGL)

-

-

87

-

-

61

-

-

52

 


Table 3.37:    Predicted Cumulative Annual NO2 and RSP concentrations

 

Annual Average NO2 Concentration (μg/m3)

Annual Average RSP Concentration (μg/m3)

 

(Criterion:  80 μg/m3)

(Criterion:  55 μg/m3)

ASRs

1.5m AGL

5m AGL

10m AGL

1.5m AGL

5m AGL

10m AGL

TYHP

57

55

55

51

51

51

TYH

61

60

58

53

52

52

V1

59

58

57

54

53

52

V2

55

55

54

52

52

52

CY3

55

55

55

51

51

51

KL1

55

54

54

51

51

51

TKL1

54

54

54

51

51

51

TKL2

54

54

54

51

51

51

KTW6

53

53

53

51

51

51

TF1

53

53

53

51

51

51

FWW1

56

56

55

51

51

51

KTW1

61

60

59

53

53

52

KTW2

63

62

59

54

54

53

KTW4

60

59

58

54

53

53

KTW5

55

55

55

52

52

52

KTW7

57

56

56

51

51

51

NYH1

67

64

60

54

53

52

PY1

67

64

60

55

54

53

PY3

60

59

58

52

52

52

PY6

58

58

57

52

52

52

WKS1

61

60

57

52

52

51

WKS2

57

57

56

51

51

51

WKS3

52

52

52

50

50

50

WKS4

63

60

57

52

52

51

WKS5

63

61

57

53

52

51

WKS7

55

54

53

51

51

51

WKS8

53

53

53

51

51

51

ST1

52

52

52

50

50

50

ST2

52

52

52

50

50

50

ST3

52

52

52

51

51

50

ST4

52

52

52

51

51

51

TTW1

54

54

53

51

51

51

TTW2

55

55

54

51

51

51

TTW3

57

56

55

52

51

51

LT1

52

52

52

50

50

50

LT2

53

53

52

50

50

50

PKT1

51

51

51

50

50

50

PKT2

51

51

51

50

50

50

PKT3

51

51

51

50

50

50

TH1

54

54

54

51

51

51

TH4

54

54

53

51

51

51

KT1

55

55

55

51

51

51

KT2

55

55

55

51

51

51

KT3

57

57

56

51

51

51

NWP1

66

65

63

53

53

53

NWP2

72

69

64

55

54

53

NWP3

65

65

63

54

54

53

KLH1

57

57

56

52

52

51

BDG1 (at 35m AGL)

-

-

52

-

-

51

As indicated in the above Tables, the predicted hourly, daily and annual NO2 as well as daily and annual RSP concentrations at all ASRs are in compliance with the corresponding AQOs. The maximum hourly NO2, daily NO2 and daily RSP levels are respectively 229 μg/m3, 120 μg/m3 and 64 μg/m3 as predicted at V1.  The maximum annual NO2 and annual RSP are respectively 72 μg/m3 and 55 μg/m3 as predicted at NWP2.

As shown in Figure 3.17.2, three patches of the land near KTW1, KTW2 and KTW4 are within the annual RSP criterion line where the annual AQO for RSP would be exceeded.  However, there are currently no ASRs in these patches of land.  As these areas are within the Ta Kwu Ling North Development Permission Area (DPA), the relevant government authority has been notified about the potential air quality issues of the areas, which will be taken into account when developing the Outline Zoning Plan (OZP) for the DPA.  Therefore, presence of ASRs within such affected areas would be avoided in future.

Similarly, it can be seen from Figure 3.17.3 that other three patches of the land near NYH1, PY1 and PY6 are within the annual RSP criterion line where the annual AQO for RSP would be exceeded.  However, there are currently no ASRs in these patches of land.  According to the Ping Che & Ta Kwu Ling OZP, these areas are intended for either agricultural or green belt use and development of such sensitive uses as village houses in these areas will require planning approval by relevant government authority, which has been notified about the potential air quality issues of the areas.   Therefore, presence of ASRs within these affected areas would be avoided in future.

From Figures 3.16.9 and 3.17.9, two patches of the land on the south and north sides of NWP2 are within the annual NO2/RSP criteria lines where the annual AQOs for NO2/RSP would be exceeded.  However, there are currently no ASRs in these patches of land.  According to the Kau Lung Hang OZP, the affected area on the south side of NWP2 is intended for open storage use and is, based on site inspection, currently paved and used for storage facilities.  As such, it is very unlikely to have ASRs in this affected area in future.  The other affected area on the north side of NWP2 is zoned as green belt based on the OZP and there are currently underground drainage facilities in the area.  Therefore, future development of such sensitive uses as village houses in the area would very unlikely be allowed.  On the north side of NWP3, there is another patch of land within the annual NO2/RSP criteria lines.  However, as this area is a part of the government land on hillside and has not been zoned for any specific land uses, there are no existing ASRs and presence of future ASRs in the area would be avoided through the planning process.

 

3.5.2.2         Odour from the Proposed Sewage Treatment Works

As can be seen from Figures 3-1.1 and 3-1.2, ASRs BDG1, TYHP, TYH and V1 are relatively closer to the sewage treatment works at the BCP than the other ASRs and would be subject to potential odour impact.  However, all these 4 ASRs are at a buffer distance of at least 490 m from the sewage treatment works.  In addition, the following odour containment and control measures will be provided for the treatment works:

(a)            The treatment works will be totally enclosed. Negative pressure ventilation will be provided within some of the enclosures to avoid any fugitive odorous emission from the treatment works. In addition, the tanks will be connected to deodorisation facilities directly to eliminate the odour problem.

(b)            Further odour containment will be achieved by using air-tight cover to cover or confine the sewage channels, sewage tanks, and equipment with potential odour emission. Where covers are used, the trapped gases would be collected by air handling equipment for containing and directing odorous gases to treatment systems.

(c)            The gravity sewers, equalization and sludge holding tanks will be designed with suitable sewer distance and retention time to prevent sewage septicity.

(d)            Deodorisation facilities by chemical, biological or physical methods (e.g. adsorption by activated carbon) with a minimum odour removal efficiency of 95% will be provided to treat potential odorous emissions from the treatment plant including sewage channels / tanks, filter press and screening facilities so as to minimize any potential odour impact to the nearby ASRs.

With the large buffer distance and the above odour containment and control measures in place to substantially confine and reduce the potential odour emissions at sources, it is anticipated that there would not be significant odour impact on the nearby ASRs.

3.6               Mitigation of Adverse Environmental Impact

3.6.1           Construction Phase

To ensure compliance with the TSP criteria during the construction phase, the relevant requirements stipulated in the Air Pollution Control (Construction Dust) Regulation and good practices for dust control should be implemented to reduce the dust impact. The dust control measures are detailed as follows.

3.6.1.1         General Dust Control Measures

Dust emissions could be suppressed by regular water spraying on site. In general, water spraying twice a day could reduce dust emission from active construction area by 50%. However, for this Project, more frequent water spraying, i.e., 8 times a day (or about once every 1.5 hours for 12 hours per day), is required for heavy construction activities and slope cutting activities at all active works area, except the active works area in Po Kak Tsai (see Figure 3-1.8), in order to achieve a higher dust suppression efficiency of 87.5% to reduce the dust impacts to acceptable levels. For the active works area in Po Kak Tsai, a water spraying frequency of 4 times a day (or about once every 3 hours for 12 hours per day) would be adequate to achieve a dust suppression efficiency of 75% to mitigate the dust impacts to acceptable levels.  Heavy construction activities include construction of buildings or roads, drilling, ground excavation, cut and fill operations (i.e., earth moving), etc.  The dust suppression efficiencies were estimated by making reference to the “Control of Open Fugitive Dust Sources Final Report” published by USEPA, as detailed in Appendix 3.1f. 

For stockpiling activities, it is recommended that 80% of the stockpiling area should be covered by impervious sheets and all dusty materials should be sprayed with water immediately prior to any loading or transfer operation so as to keep the dusty material wet during material handling at the stockpile areas.

It is anticipated that the number of construction trucks approaching and leaving the works sites would be limited. The speed of the trucks within the site should be controlled to about 10km/hour in order to reduce adverse dust impacts and secure the safe movement around the site.  It is also recommended that all haul roads within the site should be paved to avoid dust emission due to vehicular movement.

With implementation of the above dust mitigation measures, it has been assessed in Section 3.5.1 that the predicted hourly TSP (Tier 2), daily TSP (Tier 2) and annual TSP concentrations at all the identified ASRs would comply with the corresponding TSP criteria (i.e., respectively 500μg/m3, 260μg/m3  and 80μg/m3).

3.6.1.2         Best Practices for Dust Control

In addition to implementing the recommended dust control measures mentioned above, it is recommended that the relevant best practices for dust control as stipulated in the Air Pollution Control (Construction Dust) Regulation should also be adopted to further reduce the construction dust impacts of the Project.  These best practices include:

Good Site Management

¡                Good site management is important to help reducing potential air quality impact down to an acceptable level. As a general guide, the Contractor should maintain high standard of housekeeping to prevent emission of fugitive dust. Loading, unloading, handling and storage of raw materials, wastes or by-products should be carried out in a manner so as to minimize the release of visible dust emission. Any piles of materials accumulated on or around the work areas should be cleaned up regularly. Cleaning, repair and maintenance of all plant facilities within the work areas should be carried out in a manner minimizing generation of fugitive dust emissions. The material should be handled properly to prevent fugitive dust emission before cleaning.

Disturbed Parts of the Roads

¡                Each and every main temporary access should be paved with concrete, bituminous hardcore materials or metal plates and kept clear of dusty materials; or

¡                Unpaved parts of the road should be sprayed with water or a dust suppression chemical so as to keep the entire road surface wet.

Exposed Earth

¡                Exposed earth should be properly treated by compaction, hydroseeding, vegetation planting or seating with latex, vinyl, bitumen within six months after the last construction activity on the site or part of the site where the exposed earth lies.

Loading, Unloading or Transfer of Dusty Materials

¡                All dusty materials should be sprayed with water immediately prior to any loading or transfer operation so as to keep the dusty material wet.

Debris Handling

¡                Any debris should be covered entirely by impervious sheeting or stored in a debris collection area sheltered on the top and the three sides.

¡                Before debris is dumped into a chute, water should be sprayed so that it remains wet when it is dumped.

Transport of Dusty Materials

¡                Vehicle used for transporting dusty materials/spoils should be covered with tarpaulin or similar material.  The cover should extend over the edges of the sides and tailboards.

Wheel washing

¡                Vehicle wheel washing facilities should be provided at each construction site exit.   Immediately before leaving the construction site, every vehicle should be washed to remove any dusty materials from its body and wheels.

Use of vehicles

¡                Immediately before leaving the construction site, every vehicle should be washed to remove any dusty materials from its body and wheels.

¡                Where a vehicle leaving the construction site is carrying a load of dusty materials, the load should be covered entirely by clean impervious sheeting to ensure that the dusty materials do not leak from the vehicle.

Site hoarding

¡                Where a site boundary adjoins a road, street, service lane or other area accessible to the public, hoarding of not less than 2.4m high from ground level should be provided along the entire length of that portion of the site boundary except for a site entrance or exit.

Blasting

¡                The areas within 30m from the blasting area should be wetted with water prior to blasting.

3.6.2           Operational Phase

3.6.2.1         Vehicular Emission

Since there will be no exceedance of the 1-hour, 24-hour and annual AQOs for NO2 and the 24-hour and annual AQOs for RSP at all the ASRs, no mitigation measure is required during the operational phase.

3.6.2.2         Odour from the Proposed Sewage Treatment Works

With the large buffer distance (over 490m) and the odour containment and control measures in place to substantially confine and reduce the potential odour emissions at sources (see Section 3.5.2.2), it is anticipated that the sewage treatment works would not have significant odour impact on the nearby ASRs.  Hence, no further mitigation measure is required.

3.7               Evaluation of Residual Impact

3.7.1           Construction Phase

With implementation of the recommended mitigation measures as well as the relevant control requirements as stipulated in the Air Pollution Control (Construction Dust) Regulation, no adverse residual impacts are predicted at all the ASRs during the construction phase.  

3.7.2           Operational Phase

3.7.2.1         Vehicular Emission

Since there will be no exceedance of the 1-hour, 24-hour and annual AQOs for NO2 and the 24-hour and annual AQOs for RSP at all the ASRs, no adverse residual impacts are predicted during the operational phase.

3.7.2.2         Odour from the Proposed Sewage Treatment Works

With the large buffer distance (over 490m) and the odour containment and control measures in place to substantially confine and reduce the potential odour emissions at sources (see Section 3.5.2.2), no adverse residual impacts due to the sewage treatment works are anticipated during the operational phase. 

3.8               Environmental Monitoring and Audit

3.8.1           Construction Phase

Regular dust monitoring is considered necessary during the construction phase of the Project and regular site audits are also required to ensure that the dust control measures are properly implemented. Details of the environmental monitoring and audit (EM&A) programme will be presented in the stand-alone EM&A Manual.

3.8.2           Operational Phase

Since it has been assessed that there will be no adverse air quality impacts due to vehicular emissions or odour from the sewage treatment works during the operational phase, EM&A is considered not necessary.

3.9               Conclusion

With implementation of the recommended mitigation measures as well as the relevant control requirements as stipulated in the Air Pollution Control (Construction Dust) Regulation, no exceedance of the TSP criteria is predicted at all the ASRs during the construction phase.

No adverse impacts are predicted during the operational phase of the Project.  



[1] Planning Study on Liantang/Heung Yuen Wai Cross-boundary Control Point and its Associated Connecting Roads in Hong Kong – Feasibility Study

[2] Improvements to San Tin Interchange – EIA (EIA-093/2004)

[3] The “GB17691-2005” document can be found from the website of the Vehicle Emission Control Centre of Ministry of Environmental Protection, China (www.vecc-mep.org.cn/policys/gjbz/GB17691-2005b.pdf).