6.                              Air quality

6.1                          Introduction

6.1.1.1              During the construction phase of the project, potential air quality issues may arise from fugitive dust emissions generated by construction activities such as excavation, backfilling, rock breaking and crushing, stockpiling and construction vehicle movement.  During the operation phase, as trains to be operated on the project will be electrically powered, there would be minimal dust emissions.  Tunnel ventilation exhausts and emergency smoke extraction facilities would be carefully positioned to avoid adverse air quality impacts.  Air quality impacts during operational phase are, therefore, envisaged to be insignificant. 

6.2                          Project Background

6.2.1.1              A description of the works items of the KTE project is included in Section 3 of this EIA report, including a summary of works items in Table 3.1 and details of works sites and works areas in Table 3.2.  The layout of the proposed railway alignment, stations, and the associated structures are also provided with respect to the main works items, which will potentially generate dust to the environment as summarised below and in Figures 3.1 to 3.10. 

·                     Excavation and backfilling activities at the above-ground works sites for YMT Station interfacing (Item 1A), running tunnels between YMT Station and HOM Station (Items 2A and 2C), HOM Station (Items 3A, 3D, 3I and 3J), and WHA Station (Items 5A, 5C and 5D);

·                     Blasting activities (at the above ground works sites for HOM Station (Item 3A);

·                     Loading and unloading of C&D materials at the barging point (works area for Item 6A);

·                     Wind erosion (all above ground works sites of Items 1A, 2A, 2C, 3A, 3S, 3I, 3J, 5A, 5C and 5D); and

·                     Rock crushing facilities (One rock crushing facility would be located at the work site for HOM Station (Item 3A) and two others would be located at the barging point (Item 6A)).  The rock crushing facilities are Designated Projects under Schedule 2, Part 1, Section G.5 of the EIAO.  The rock materials would be transported by trucks to the receiving point of the respective rock crushing facilities for processing. There would be no temporary storage of C&D material at the crushing facilities locations and the material will be processed directly.  The crushed rock materials would be transported by trucks to barges for loading and transportation. 

6.2.1.2              It should be noted that there would be 2 works areas (above ground works sites for Item 7A) for the formation of the temporary magazine site in TKO Area 137.  As no valid Air Sensitive Receives (ASRs) (refer to Section 6.5 for the locations of ASRs) were identified within 500m from the boundary of the temporary magazine site, these works areas have not been covered in the air quality impact assessment. However, watering will be the dust mitigation measure during the site formation of the magazine site. Nevertheless, hard surface will be formed at the temporary magazine site after the site formation so that dust generation is minimised, and no mitigation measure will be required.

6.2.1.3              In addition to the above main works sites, the barging point and temporary magazine site, there would be off-site works areas proposed for use as site offices and material storage yards during the construction period (Table 3.1).  As the activities at these works areas would be minor works during the construction phase, namely for site clearance, erection of site office structures, open storage of equipment, reinstatement, etc, no significant dust impacts would be anticipated in these works areas and they are not covered by the air quality impact assessment. 

6.3                          Environmental Legislation, Policies, Plans, Standards and Criteria

6.3.1                    Environmental Impact Assessment Ordinance (Cap 499)

6.3.1.1              Reference to the EIAO and the associated EIAO-TM has been made for the assessment of air quality impacts.  Annexes 4 and 12 of the EIAO-TM set out the criteria and guidelines for evaluating air quality impacts, which requires that for construction dust impact an hourly averaged Total Suspended Particulates (TSP) concentration of 500mgm-3 shall not be exceeded.

6.3.2                    Air Pollution Control Ordinance (Cap 311)

6.3.2.1              The principal legislation for controlling air pollutants is the Air Pollution Control Ordinance (APCO) (Cap 311) and its subsidiary regulations, which defines the statutory Air Quality Objectives (AQOs) for 7 air pollutants as shown in Table 6.1.  Notifiable and regulatory works are under the control of the Air Pollution Control (Construction Dust) Regulation.  Notifiable Works include site formation, reclamation, demolition, foundation works and superstructure construction for buildings and road construction. 

6.3.2.2              Regulatory works are building renovation, road opening and resurfacing, slope stabilisation, and other activities including stockpiling, dusty material handling, excavation, concrete works, etc.  The KTE project is expected to include both notifiable and regulatory works.  Contractors will be required to inform the EPD prior to carrying out the construction works and implement dust control measures to reduce potential impacts to the acceptable level.

Table 6.1: Hong Kong Air Quality Objectives

Pollutant

Concentration in mg m-3 [1] (ppm)

1 Hour [2]

8 Hours [3]

24 Hours [3]

3 Months [4]

1 Year [4]

Sulphur Dioxide (SO2)

800

(0.3)

 

350

(0.13)

 

80

(0.03)

Total Suspended

Particulates (TSP)

 

 

260

 

80

Respirable Suspended Particulates (RSP) [5]

 

 

180

 

55

Carbon Monoxide (CO)

30,000

(26.2)

10,000

(8.7)

 

 

 

Nitrogen Dioxide (NO2)

300

(0.16)

 

150

(0.08)

 

80

(0.04)

Photochemical

Oxidants (as Ozone, O3) [6]

240

 

 

 

 

Lead (Pb)

 

 

 

1.5

 

Notes:

[1]     Measured at 298K (25°C) and 101.325kPa (one atmosphere).

[2]     Not to be exceeded more than three times per year.

[3]     Not to be exceeded more than once per year.

[4]     Arithmetic means.

[5]     Respirable suspended particulates mean suspended particles in air with nominal aerodynamic diameter of 10 micrometres or smaller.

[6]     Photochemical oxidants are determined by measurement of ozone only.

6.3.3                    Air Pollution Control Ordinance – Control of Emission from Specified Processes

6.3.3.1              Major stationary air polluters such as power plant, incinerator and rock crushing plants, which are classified as Specified Processes (SP) under the APCO, are subject to a more stringent emission control, as follows:

·                    Operation of Stone Crushing Plant in which the processing capacity exceeds 5000 tonnes per annum and in which stones are subjected to any size reduction or grading by a process giving rise to dust, not being any works described in any other specified process.

6.3.3.2              A license is required for the operation of these processes under Part IV of the ordinance and the application for a license should be made to EPD. EPD may either grant or refuse to grant a license subject to whether the applicant can fulfill the environmental standards to avoid causing air pollution. If EPD decides to grant the license, a set of conditions will be imposed to ensure the adequate prevention of the discharge of air pollutant emissions.

6.4                          Existing Air Quality

6.4.1.1              The KTE project is located in the Kowloon Peninsula.  The existing environment of the study area is mainly a densely populated and developed area with a mix of residential, commercial and institutional (including schools, hospitals and nursing homes) development and open space areas at the vicinity of Ho Man Tin and mainly residential development at the vicinity of Whampoa.  Also, there are significant traffic activities in these areas.

6.4.1.2              The 5 year average annual TSP levels of 5 EPD stations (namely Sham Shui Po, Kwun Tong, Central/Western, Kwai Chung and Tsuen Wan) as the background level (77.4 ug/m3) and criterion for our construction dust assessment in the revised EIA report.  These stations are considered to represent the full range of landuses in the KTE project study area, given their built-up nature, similarity of population characteristics and mix of residential developments with commercial properties and open space areas, and, therefore, combined, present a reasonable representation of the background conditions of the study area.

6.4.1.3              The recent annual average concentrations of air pollutants (in mg/m3) monitored at these stations are summarised in Table 6.2 below.

Table 6.2:   Recent EPD Air Quality Monitoring Data at Sham Shui Po, Kwun Tong, Central/Western, Kwai Chung and Tsuen Wan Stations (2005 to 2009)

EPD Monitoring Station

Annual Average (mg/m3)

2005

2006

2007

2008

2009

5-year

Average

Sham Shui Po

83

79

79

81

77

79.8

Kwun Tong

81

75

82

72

70

76.0

Central/Western

81

78

77

78

73

77.4

Kwai Chung

79

81

85

79

70

78.8

Tsuen Wan

83

82

79

67

63

74.8

Overall Average:

 

 

 

 

 

77.4

TSP (AQO: 80 mg/m3)

Underlined value denotes exceedance of AQO

6.4.1.4              The average annual TSP concentration of the monitoring stations between the years 2005 and 2009 has been calculated as 77.4 mg/m3 and this has been used as the background value for assessment.

6.5                          Air Sensitive Receivers

6.5.1.1              The landuse in the vicinity of the preferred KTE alignment consists of commercial buildings, hotels, residential premises, hospitals, educational institutions and open space.  Site surveys have been carried out to identify ASRs within 500m from the site boundary in accordance with Annex 12 of the EIAO-TM, and the worst affected representative ASRs during the construction phase will be assessed.  The nearest existing ASRs have been identified and are given in Table 6.3, together with the proposed assessment heights above ground,  and depicted in Figures 6.1-6.9.  All the ASRs are relevant to the construction phase only.

Table 6.3:    Nearest Air Sensitive Receivers in the Study Area

Ref

Air Sensitive Receiver

No. of Storeys

Assessment Height in mPD

Distance from Closest Site Boundary (m)

1

Tin Hau Temple

1

7, 10, 15, 20, 25

80

2

Tang’s Mansion

9

8, 11, 16, 21, 26

32

3

Alhambra Building

14

7, 11, 16, 21, 26

30

4

Methodist College

5

17, 20, 25, 30, 35

1

5

Eaton Hotel

19

8, 12, 17, 22, 27

50

6a

Diocesan Girls’ Junior School#

7

9, 12, 17, 22, 27

139

6b

Diocesan Girls’ School#

7

10, 13, 18, 23, 28

76

7a

Queen Elizabeth Hospital – Specialist Clinic

12

17, 21, 26, 31, 36

5

7b

Queen Elizabeth Hospital – Institute of Radiotherapy and Oncology

14

17, 21, 26, 31, 36

47

8b

Parc Palais Block 3

24

41, 44, 49, 54, 59

151

8c

Parc Palais Block 6

24

41, 44, 49, 54, 59

224

9

Filipino Club

2

20, 24, 29, 34, 39

3

10

Hong Kong Chinese Civil Servants’ Association

2

16, 20, 25, 30, 35

4

11

Shun Man House, Oi Man Estate

20

35, 39, 44, 49, 54

180

12

SKH Holy Trinity Church Secondary School

6

55, 59, 64, 69, 74

105

13

Carmel Secondary School

4

53, 56, 61, 66, 71

29

14

Yee Fu Building

25

16, 19, 24, 29, 34

22

15

271-273 Chatham Road North

5

10, 13, 18, 23, 28

28

16

Caritas Bianchi College of Careers

15

7, 11, 16, 21, 26

44

17

Lok Ka House

7

6, 10, 15, 20, 25

47

18

Wing Fung Building

8

6, 10, 15, 20, 25

63

19

Marigold Mansion

20

23, 27, 32, 37, 42

85

20

Lok Do Building

13

6, 9, 14, 19, 24

10

21

Hung Hom Government Primary School

4

7, 11, 16, 21, 26

50

22

Hung Hom Government Clinic

3

7, 10, 15, 20, 25

76

23

Block Z, Ka Fu Building, Whampoa Estate

15

6, 9, 14, 19, 24

5

24

Block Y, Ki Fu Building, Whampoa Estate

15

6, 9, 14, 19, 24

5

25

Block I, Lok Wah Building, Whampoa Estate

15

6, 9, 14, 19, 24

8

26

Block H, On Wah Building, Whampoa Estate

15

7, 10, 15, 20, 25

7

27

Block 9, Bauhinia Mansions, Whampoa Garden Site 11

14

6, 9, 14, 19, 24

4

28

Block 1, Cherry Mansions, Whampoa Garden Site 2

15

6, 9, 14, 19, 24

5

29

Block 13, Bauhinia Mansions, Whampoa Garden Site 11

15

6, 9, 14, 19, 24

6

30

Block 5, Cherry Mansions, Whampoa Garden Site 2

15

6, 9, 14, 19, 24

5

31

Block 7, Cherry Mansions, Whampoa Garden Site 2

15

5, 9, 14, 19, 24

4

32

Block 1, Oak Mansions, Whampoa Garden Site 5

15

5, 9, 14, 19, 24

3

33

Block 2, Oak Mansions, Whampoa Garden Site 5

15

5, 9, 14, 19, 24

3

34

Fung Kei Millennium Primary School

7

5, 9, 14, 19, 24

6

35

Fung Kei Primary School

7

5, 9, 14, 19, 24

13

36

Alliance Primary School

6

6, 9, 14, 19, 24

52

37

GCEPSA Whampoa Primary School

6

6, 9, 14, 19, 24

0

38

Block 5, Cotton Tree Mansions, Whampoa Garden Site 7

15

6, 9, 14, 19, 24

12

39

Harbourfront Landmark

57

6, 9, 14, 19, 24

46

46

Harbourfront Horizon

18

6, 9, 14, 19, 24

14

47

Harbour Plaza Metropolis

11

24, 28, 33, 38, 43

41

48

Metropolis Residence

11

16, 20, 25, 30, 35

170

49

Hong Kong Coliseum

1

15, 19, 24, 29, 34

44

52

Fire Service Headquarters

13

6, 10, 15, 20, 25

164

Note: * Reference to Ho Man Tin OZP (S/K7/19)

# The School Redevelopment Project of Diocesan Girls’ Junior School and Diocesan Girls’ School is currently in progress and would be finished by around end of 2011. 

6.6                          Concurrent Projects

6.6.1.1              Construction of the KTE project would be on-going between 2011 and 2015, with its commissioning in 2015.  In addition to the KTE project itself, there are various other projects that are planned to be constructed concurrently and these have been taken into account in the air quality assessment. Details of the KTE project construction programme and the concurrent projects are provided in Section 3 of this EIA Report and summarised below.

·               Central Kowloon Route – the originally planned construction period of 2014-2018 is currently under review and while expected to be delayed, no further details can be provided by the Highways Department at the time of reporting.  However, even with the original programme there was only an overlap of dust generating activities with the KTE project of about 3 months and as such, given the expected delay, it has been assumed for the purposes of this assessment that the project would now not be concurrent. Therefore, the cumulative impacts from CKR do not need to be assessed.  It should be noted that, in this EIA report, all details in relation to the proposed CKR project are tentative only as it is subject to obtaining government and statutory approvals. The assessments related to the CKR project are based upon the best available information at the time of the submission of this EIA report.  The CKR is under a separate EIA study and subject to the study requirements of a separate EIA study brief under the statutory processes of the EIAO;

·               Shatin to Central Link – Tai Wai to Hung Hom Section (tentative construction period: 2011-2017) – There are proposed to be the works sites for the cut-and-cover tunnel for the construction of SCL – Tai Wai to Hung Hom Section near Chatham Road North which are in the immediate neighbourhood of the southern end of the works sites for HOM Station of the KTE project as shown in Figures 3.21 and 3.22.  Details of the modelling assumptions for the SCL – Tai Wai to Hung Hom Section are provided in Appendix 6.1, including the size of works sites, emission rates, mitigation measures, etc.  As a full overlap of construction activities for KTE and Shatin to Central Link – Tai Wai to Hung Hom Section has been assumed, worst case cumulative impacts have been predicted.  It should be noted that, in this EIA report, all details in relation to the proposed SCL project are tentative only as it is subject to obtaining government and statutory approvals. The assessments related to the SCL project are based upon the best available information at the time of the submission of this EIA report.  SCL is under a separate EIA study and subject to the study requirements of a separate EIA study brief under the statutory processes of the EIAO;

·               Shatin to Central Link – Mongkok East to Hung Hom Section (tentative construction period: 2011-2020) – There would be some works sites proposed for the cut-and-cover tunnel of the SCL – Mongkok East to Hung Hom Section near the existing East Rail Line (EAL) adjacent to Princess Margaret Road and Oi Man Estate which are close to the works sites of the KTE project for HOM Station as shown in Figure 3.23.  Details of the modelling assumptions for SCL – Mongkok East to Hung Hom Section are provided in Appendix 6.1, including the size of works sites, emission rates, mitigation measures, etc.  As a full overlap of construction activities for KTE and Shatin to Central Link – Mongkok East to Hung Hom Section has been assumed, worst case cumulative impacts have been predicted.  It should be noted that, in this EIA report, all details in relation to the proposed SCL project are tentative only as it is subject to obtaining government and statutory approvals. The assessments related to the SCL project are based upon the best available information at the time of the submission of this EIA report.  SCL is under a separate EIA study and subject to the study requirements of a separate EIA study brief under the statutory processes of the EIAO;

·               The planned dormitory of the Hong Kong Polytechnic University (construction period: 2009-2012) – There is currently no detailed information on the construction works available for the assessment and, as such, this concurrent project has not been assessed for any cumulative impacts with the KTE project (Figure 3.19); and

·               Essential Public Infrastructure Works (EPIW) for the KTE project (tentative construction period: 2011-2015) – There would be some works sites allocated for the construction of the EPIW including subways and footbridges connecting HOM Station and Oi Man Estate and Ho Man Tin Estate, Public Transport Facilities along Chung Hau Street at the northwest of HOM Station and a covered footbridge stretching from HOM Station over Yan Fung Street, Chatham Road North and above the existing footbridge as shown in Figure 3.24. Details of the modelling assumptions for the EPIW are provided in Appendix 6.1, including the size of works sites, emission rates, mitigation measures, etc.

6.7                          Identification of Pollution Sources and Emission Inventory

6.7.1.1              The running tunnels and station boxes would be constructed by drill-and-blast, soft ground tunnelling and mechanical excavation methods along the KTE alignment.  Locations of work sites and works areas for the assessment are shown in Figures 6.1-6.9.  Construction dust would be anticipated to be generated from activities, such as soil excavation, backfilling, wind erosion, transportation/handling of C&D materials, blasting, loading and unloading of excavated materials at barging point, construction of access shafts and tunnel mucking out areas, etc.  It should be noted that C&D materials will not be stored temporarily at barging point. 

6.7.1.2              It would be anticipated that the excavation and backfilling activities would involve significant quantity of earthworks and silty material handling, and hence significant dust impacts would be anticipated at the adjacent ASRs if no appropriate mitigation measures are implemented.  The ASRs nearest to the proposed barging point have also be included in the assessment, which have included ASRs 46, 47, 48, 49 and 52.

6.7.1.3              There would be access shafts at Gascoigne Road Rest Garden, Wylie Road Ancillary Building (WAB) and Fat Kwong Street Playground and there would be mucking out points at WHA Station.  Construction activities for these shafts and the mucking out points have been included in the air quality assessment.  However, during spoil removal, the dusty materials would be well covered by impervious sheeting and the trucks would be washed before leaving the work sites of the access shafts and mucking out points, no adverse dust impact from the transportation of spoil would be expected and as such, this activity has not been included in the modelling.

6.7.1.4              The potential emission sources at the rock crushing facilities would be the unloading activities (from trucks to receiving point of the rock crushing facilities) and the discharge point of the dust extraction systems.

6.7.1.5              The assessment of construction dust impacts has been carried out based on the following assumptions of the general construction activities:

·               All construction activities at all work sites and areas would be undertaken concurrently in order to assess the worst case situation;

·               Heavy construction activities will include site clearance, ground excavation, cut and fill operations, construction of the associated facilities, drill-and-blast, and construction traffic and hauling over the sites;

·               For the blasting at HOM Station, tarpaulin covers would be provided on wire mesh covered steel cages to contain the dust. Therefore, the heavy construction emission factor is considered adequate for the Fugitive Dust Model (FDM) in the air quality assessment to address the dust generated from this activity (refer to Section 6.8);

·               Wind erosion area of 30% has been assumed at any time for the hourly and daily TSP prediction and 6% at any time for annual TSP.  However, to be conservative a 100% active area screening test has been undertaken initially for the short term hourly and daily TSP assessment as detailed in the methodology section below;

·               Active operating areas of 30% have been assumed at any time for the hourly and daily TSP predictions and 6% active operating area at any time for annual TSP predictions for all sites other than the barging point where the area of the fixed haul road surface has been assumed. However, to be conservative a 100% active area screening test has been undertaken initially for the short term hourly and daily TSP assessment as detailed in the methodology section below;

·               Haul roads within the work sites would be paved and water spraying would be provided to keep the wet condition;

·               A three-sided and top cover with water spraying would be provided at the receiving point of the barging point loading and unloading locations;

·               The rock crushing facilities including haul road and unloading locations would be enclosed and a fabric baghouse/cartridge filter type dust extraction and collection system or equivalent system with 99% or more dust removal efficiency installed for the treatment of the emissions from rock crushing and screening processes; and

·               Construction periods are assumed to be 30 days per month, 6 working days per week and 12 operation hours per day from 0700 to 1900.  An addition of 17 public holidays per year with no construction works has also been assumed for the assessment.

6.7.1.6              Dust emission factors for different construction activities would be extracted from the USEPA “Compilation of Air Pollution Emission Factors (AP-42)”, 5th edition.  The key assumptions for the calculation of dust emission factors are summarised in Table 6.4 below.

Table 6.4:    Assumptions for Calculation of Dust Emission Factors

Activities

Reference [1]

Operating Sites

(Figures 3.2 – 3.9)

Equations and Assumptions [1]

Heavy construction activities including land clearing, ground excavation, cut and fill operations, construction of facilities, drill-and-blast, mucking out areas, equipment traffic and hauling over the site areas[2]

S.13.2.3.3

All above ground and open construction and excavation sites

E =

1.2 tons/acre/month of activity or

2.69Mg/hectare/month of activity

Wind erosion

S.11.9, Table 11.9.4

Area of 30% for the hourly and daily TSP prediction and 6% for annual TSP

 

E = 0.85 Mg/hectare/yr (24 hour emission)

Loading and unloading at barging point

S.13.2.4

Barging point

k is particle size multiplier

U is average wind speed

M is material moisture content

Unloading of rock materials at the receiving point of rock crushing facilities

S.11.19.2,

Table 11.19.2-1

Rock crushing facilities

E = 0.000008 kg/Mg

Crushing at rock crushing facilities

S.11.19.2,

Table 11.19.2-1

Rock crushing facilities

E = 0.0027 kg/Mg

Screening at rock crushing facilities

S.11.19.2, Table 11.19.2-1

Rock crushing facilities

E = 0.0125 kg/Mg

Note: [1]      USEPA Compilation of Air Pollution Emission Factors (AP-42)

[2]      For blasting at HOM Station, tarpaulin covers would be provided on wire mesh covered steel cages to contain the dust and therefore, the emission factors associated with heavy construction has been used for the modelling.

6.7.1.7              The dust emission from construction vehicles and the loaded/unloaded vehicles movements would be limited to within the confined works sites and barging point respectively and the equation for Heavy Construction (as in AP-42 S.13.2.3.3) would take this factor into account.  The major dust generating activities at the barging point would be assumed to mainly originate from the loading/unloading of C&D materials, which would be controlled with the following measures:

·               Road surfaces within barging point areas would be paved;

·               Installation of 3-sided screen with top and the provision of water sprays at the discharge points of the barging point;

·               Vehicles would be required to pass through designated wheel washing facilities before leaving the barging point; and

·               Regular watering would be imposed on exposed surfaces and activities (the amount of water to be used would be 1.8L/m2). 

6.7.1.8              The major dust generating activities at the rock crushing facilities at HOM Station and the barging point would be assumed to mainly originate from the unloading of rock materials, crushing and screening processes.  The rock crushing facilities would be assumed to be equipped with the following measures:

·               A dust enclosure with fabric baghouse/cartridge filter type dust extraction and collection system or equivalent system with 99% or more dust removal efficiency for the rock crushing facilities including haul road and unloading location; and

·               Watering of paved road surfaces within the area of the rock crushing facilities as good site practice.

6.8                          Assessment Methodology

6.8.1.1              The assessment approach has been based on the requirements as specified in the EIA Study Brief (ESB-188/2008).  The criteria and guidelines for assessing air quality impacts as stated in Annexes 4 and 12 of the EIAO-TM have been followed.  The requirements as stipulated under the Air Pollution Control (Construction Dust) Regulation would be followed to ensure that construction dust impacts would also be controlled within the relevant standards as stipulated in the EIAO-TM.

6.8.1.2              The quantitative assessment of construction dust impacts has been conducted using the Fugitive Dust Model (FDM) as approved by the EPD, which is a Gaussian Plume model designed for computing air dispersion model for fugitive dust sources.  Modelling parameters including the dust emission factors, particle size distribution, surface roughness, etc., are specified in the EPD’s Guideline on choice of models and model parameters and USEPA AP-42. 

6.8.1.3              The density of dust would be assumed to be 2.5g/m3.  According to S13.2.4.3 of USEPA AP-42, the particle size distribution is assumed as 1.25mm, 3.75mm, 7.5mm, 12.5mm and 22.5mm with 7%, 20%, 20%, 18% and 35% respectively.  Based upon the nature of the study area of KTE which is urban but with frequent areas of open space, the average monitoring data from the latest 5 years (i.e. 2005 to 2009) from EPD’s air quality monitoring stations in Sham Shui Po, Kwun Tong, Central/Western, Kwai Chung and Tsuen Wan (Table 6.2) has been adopted as a representative background concentration.  Based on this, the average TSP background concentration has been calculated as being 77.4 µg/m3.  A surface roughness of 100cm has been assumed in the model to represent the terrain where applicable.

6.8.1.4              The latest available sequential meteorological data for 2008 with at least 90% valid data recorded at King’s Park and Hong Kong Observatory obtained from Hong Kong Observatory (HKO) will be used to predict the 1-hour, 24-hour average and annual average TSP concentrations at representative ASRs.  The following meteorological conditions have been adopted for the calculation of 1-hour, 24-hour and annual average TSP concentrations:

·               Wind speed: hourly record of meteorological data from HKO;

·               Wind direction: hourly record from meteorological data from HKO;

·               Stability class: hourly record from meteorological data from HKO.  It should be noted that stability classes A-F have been applied;

·               Mixing height: daily record from meteorological data at King’s Park Meteorological Station in Year 2008.  The minimum mixing height would be adopted for the mixing height which were undeterminable; and

·               Temperature: hourly record of meteorological data from HKO in Year 2008.

6.8.1.5              Hourly, 24-hour and annual average TSP concentrations at the representative ASRs near the works sites and barging point have been predicted with the sequential meteorological data.  For the unavailable hourly meteorological data, the FDM has been run as usual but the corresponding modelled results will be ignored in the assessment.

6.8.1.6              Fugitive dust modelling have been conducted for heights 1.5m, 5m, 10m, 15m, 20m and 25m above local ground level.  The maximum cumulative 1-hour, 24-hour and annual average TSP concentrations at selected ASRs has been determined and pollutant contours presented at the worst hit level.  A 100x100m grid contour has been used to investigate the pollutant distribution for the assessment period.

6.8.1.7              The air quality impact assessment has been carried out in accordance with the construction programme shown in Appendix 3.1.  All the works sites (except those for the construction of the WHA Station), and works areas would be expected to have continuous works activities throughout the entire construction period.  There will be a barging point at the Hung Hom Finger Pier, comprising three loading and unloading locations, and it is proposed that the waste disposal trucks from the KTE project would be directed to this barging point.

6.8.1.8              As the WHA Station is severely constrained by the existing infrastructure and buildings, significant amounts of temporary traffic decking, temporary utility support and associated temporary traffic management (TTM) schemes will be required.  However, in order to assess the worst case scenario, the works activities of all stages of TTM have been assessed at the same time.  All works activities of all stages of TTM for the construction of WHA Station and all other works sites at Gascoigne Road Rest Garden, the WAB, HOM Station, Fat Kwong Street Playground and the barging point, have been modelled for the KTE works at the same time to represent the worst case situation. Detailed calculations of emission rates are presented in Appendix 6.1.

6.8.1.9              In terms of the construction programme, it should be noted that the sequencing of works for each works activity over each works site or area will be determined by the Contractor and is not known at this stage.  However, due to the constrained size of the works sites and areas and the tight construction programme constraints, it will be necessary for active construction activities to be undertaken at moving multiple work faces spread across each site.  Therefore, it is not feasible to identify the exact locations of individual dust emission sources.  As such, for the long term annual predictions, the dust modelling assessment has assumed that the dust emissions would be distributed across the whole area of each site to reasonably represent this mode of working and the dust emissions rates have been proportioned to produce the effect of 6% active works site. The justification for the percentage of active works areas for the long terms assessment is presented in Appendix 6.2.

6.8.1.10          However, for the barging point at the Hung Hom Finger Pier, the annual 6% active area is not applied in this case as it is more appropriate to apply the emission rates detailed in Table 6.4 above to the whole area of the access haul road surface.  Applying 100% emissions from the barging point haul road areas represents a very conservative assumption, in that it assumes a continuous use of the haul road by traffic for the full construction period as would be expected if the barging point was being used to full capacity.  The barging point with two unloading locations on the Finger Pier has been designed with capacity of 10,000 tonnes per day (5,000 tonnes for unloading point), equating to a capacity of approximately 850 trucks/day.

6.8.1.11          In terms of the short term hourly and 24-hour periods, it is assumed that a total works area of 30% on each site would be active at any one time and again active construction activities to be undertaken at moving multiple work faces spread across each site.  The justification for the percentage of active works areas for the short is presented in Appendix 6.2.  Based upon this, works activities and plant would not cover the whole site area nor be concentrated in certain areas of the site close to ASRs at any time during the construction period.  However, notwithstanding that such a scenario would not be expected to occur, for the short term TSP predictions, in order be conservative, an initial screening test has been undertaken.  The Tier 1 screening test is ultra conservative and has simulated an absolute worst case situation, whereby the whole area of each site (that is, 100%) would be active.  

6.8.1.12          The purpose of the absolute worst case Tier 1 screening assessment has been to highlight areas where construction dust may accumulate and potentially become an issue. The Tier 1 results have allowed a more focused Tier 2 assessment to be undertaken at specific hot spot locations.  The focused Tier 2 assessments have been undertaken whereby the projected actual 30% active works areas for the construction site in question, is positioned closest to the potentially worst affected ASRs, while emission from all the other sites remain at 100% as per Tier 1.  As for the long term assessment, the exception to this approach has been the barging point, where the emission rates have been applied to the whole area of the access haul road surface and not a 30% area.

6.8.1.13          Thus, the Tier 2 assessment is also very conservative as it assumes that all works activities with the associated plant would be undertaken in the closest proximity to the potentially affected ASRs at the same time, which as noted above would not occur and assumes the barging point would be working at full capacity throughout the construction period.

6.8.1.14          The locations and dimensions of the emission sources for the short and long term assessments of the KTE sites are shown in Appendix 6.1, including detailed calculations of emission rates.

6.8.1.15          For the concurrent projects, similar assumptions have been made for the calculations of the emission factors for both wind erosion and general construction activities for short and long term predictions.  The locations and dimensions of the emission sources of the concurrent projects are shown in Appendix 6.1, in which detailed calculations of emission rates are also presented.  Practical and necessary mitigation measures have been taken into consideration for the planning of the KTE project to abate the air pollution impact and alternative construction methods/phasing programmes have been considered to minimise the constructional air quality impact.  As such, measures such as regular watering are considered the necessary mitigation for all construction works, and the unmitigated scenario where no watering is applied has not been considered.

6.9                          Assessment of Results

6.9.1                    Unmitigated Results

6.9.1.1              The maximum predicted unmitigated 1-hour, 24 hour and annual average cumulative TSP levels are presented in Table 6.5 below.  The results show that exceedances of the relevant Air Quality Objectives (AQOs) are predicted to occur with no mitigation and, therefore, mitigation measures are required to control dust impacts.

Table 6.5:   1-hour, 24-hour and Annual Average Maximum Cumulative Unmitigated TSP Concentrations (µgm-3) at ASRs (Including Background Level)

Receiver Reference

Predicted Maximum 1-hour Concentration

(Criterion: 500µgm-3)

Predicted Maximum 24-hour Concentration

(Criterion: 260µgm-3)

Predicted Maximum Annual Concentration

(Criterion: 80µgm-3)

1

619

248

82.1

2

642

240

82.3

3

1933

570

86.7

4

542

195

82.2

5

790

246

83.1

6a

1256

284

82.6

6b

1613

298

82.7

7a

787

263

83.5

7b

737

248

83.9

8b

395

161

83.1

8c

408

159

84.9

9

1297

276

83.0

10

1041

236

83.4

11

1256

304

98.8

12

1250

316

102.1

13

1599

275

92.8

14

7134

1452

108.6

15

4573

1195

102.5

16

4212

1256

99.3

17

4073

1017

90.0

18

3261

740

87.6

19

4139

586

90.5

20

2622

775

90.4

21

2923

357

81.8

22

2234

369

81.6

23

2130

763

91.9

24

2278

1014

95.2

25

2288

800

90.4

26

1841

452

82.5

27

2452

782

86.4

28

2858

937

89.3

29

2516

528

84.7

30

2643

903

93.7

31

1641

543

88.8

32

3300

754

94.1

33

3499

641

89.5

34

3252

585

84.0

35

1690

480

81.9

36

1045

252

82.9

37

1885

268

82.3

38

1653

261

81.9

39

1293

227

81.6

46

7406

1804

123.6

47

5411

671

103.1

48

3917

439

85.0

49

16914

1009

99.4

52

4186

835

172.2

Note:

 

denotes TSP level in excess of criterion

6.9.2                    Mitigation Measures

6.9.2.1              The following specific mitigation measures (Appendix 6.1) and the proposed dust removal efficiencies that have been assumed in the modelling to reduce the dust generation from the KTE project to within the 1-hour (500µgm-3), 24-hour (260µgm-3) and Annual (80µgm-3) criteria at ASRs, and have been applied for both short term Tier 1 and Tier 2 assessment and the annual TSP predictions:

(i)                  For the unloading of spoil from trucks at barging point, installation of 3-sided screen with top and the provision of water sprays at the discharge point would be provided for an assumed 50% dust suppression.  This assumption is based upon USEPA AP-42 Control Techniques for Particulate Emissions form Stationary Sources Part 2 which states that watering alone would have 50% dust removal efficiency.  This is, however, considered very conservative as the barging point would also be provided with a 3 sided enclosure, which would provide additional dust containment and control which has not been allowed for in this assumption;

(ii)                Watering every working hour for 12 hours a day on exposed soil areas on active works areas and paved haul roads to reduce dust emissions by 91.7%, which is with reference to the “Control of Open Fugitive Dust Sources” (USEPA AP-42).  The amount of water to be applied would be 1.8L/m2; and

(iii)               The dust removal efficiency of fabric baghouse/cartridge filter type dust extraction and collection system or equivalent for rock crushing activities within an enclosure is assumed to be 99%, with reference to USEPA AP-42. 

6.9.2.2              In addition to the above, it is noted that tarpaulin covers would be provided on wire mesh covered steel cages to contain the dust generated by the blasting at HOM Station.   

6.9.2.3              It should be noted that the three proposed rock crushing plant facilities at HOM and the barging point are designated projects under the EIAO as noted in Section 1, and the specific mitigation for these facilities are as follows:

(i)                  A dust enclosure with fabric baghouse/cartridge filter type dust extraction and collection system or equivalent system with 99% or more dust removal efficiency for the rock crushing facilities including haul road and unloading location; and

(ii)                Watering of paved roads within the area of the rock crushing facility as good site practice.

6.9.2.4              In addition to those measures mentioned above, under the auspices of the Air Pollution Control (Construction Dust) Regulation, the Contractor will be required to ensure that dust control measures stipulated in the Regulation should be implemented control dust emissions.  The dust control measures detailed below shall also be incorporated into the Contract Specification where practicable as an integral part of good construction practice.

(i)                  Use of regular watering to reduce dust emissions from exposed site surfaces and unpaved roads, particularly during dry weather;

(ii)                Use of frequent watering for particularly dusty construction areas and areas close to ASRs;

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

(iv)              Open stockpiles shall be avoided or covered. Prevent placing dusty material storage piles near ASRs;

(v)                Tarpaulin covering of all dusty vehicle loads transported to, from and between site locations;

(vi)              Establishment and use of vehicle wheel and body washing facilities at the exit points of the site;

(vii)             Imposition of speed controls for vehicles on unpaved site roads, 8 km per hour is the recommended limit;

(viii)           Routing of vehicles and position of construction plant should be at the maximum possible distance from ASRs;

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

(x)                Cement or dry PFA delivered in bulk should be stored in a closed silo fitted with an audible high level alarm which is interlocked with the material filling line and no overfilling is allowed; and

(xi)              Loading, unloading, transfer, handling or storage of bulk cement or dry PFA should be carried out in a totally enclosed system or facility, and any vent or exhaust should be fitted with an effective fabric filter or equivalent air pollution control system.

6.9.2.5              All the mitigation measures are also summarised in the Environmental Mitigation Implementation Schedule (EMIS) in Section 16.

6.9.3                    Mitigated Results

Short Term Dust Predictions

 

6.9.3.1              The maximum predicted 1-hour and 24-hour results of the Tier 1 screening at representative ASRs in the study area with mitigation measures applied are shown in Table 6.6 and the modelling results are included in Appendix 6.3.  The mitigated Tier 1 screening test 1-hour and 24-hour cumulative (KTE + SCL + other concurrent projects + background) contours at 1.5m above ground are summarised in Table 6.6 and shown in Figures 6.10-6.17. 

6.9.3.2              According to the predicted cumulative TSP levels at different heights, the predicted maximum cumulative 1-hour and 24-hour average TSP levels would be at 10m or 15m above ground for the ASRs near HOM Station because of the elevated work sites at HOM Station.  Therefore, Figures 6.18-6.21 also show the contour plots of the mitigated 1-hour and 24-hour for cumulative (KTE + SCL + other concurrent projects + background) at 10m or 15m above ground.

Table 6.6:    Tier 1 Screening Test: 1-hour and 24-hour Maximum Cumulative TSP Concentrations (µg/m3) at ASRs (Including Background Level)

Receiver Reference

Predicted Maximum 1-hour Concentration

(Criterion: 500µg/m3)

Predicted Maximum 24-hour Concentration

(Criterion: 260µg/m3)

1

139

99

2

140

99

3

253

128

4

140

94

5

167

98

6a

207

105

6b

222

107

7a

176

105

7b

174

103

8b

110

86

8c

108

86

9

194

104

10

179

104

11

169

107

12

208

98

13

347

188

14

361

185

15

446

202

16

304

157

17

317

162

18

325

169

19

262

120

20

289

145

21

260

120

22

227

112

23

248

143

24

260

164

25

261

144

26

224

113

27

312

146

28

307

160

29

280

119

30

290

154

31

206

122

32

343

139

33

360

132

34

360

125

35

185

113

36

162

92

37

227

91

38

227

93

39

195

88

46

504

212

47

132

96

48

164

107

49

284

101

52

270

137

Note:

 

denotes TSP level in excess of criterion

 

 

6.9.3.3              The predicted Tier 1 screening test maximum cumulative TSP levels are detailed in Table 6.6.  Table 6.7 shows the predicted Tier 1 screening test maximum TSP levels only for projects under MTR Corporation (i.e. KTE + SCL, but without other concurrent projects and background).  The results indicate that, for the majority of ASRs, no exceedances of the 1-hour and 24-hour TSP criteria are predicted to occur at any of the assessed levels above ground would occur, even assuming the absolute worst case situation where 100% of every works site would be active and emitting dust.  However, the Tier 1 assessment has highlighted that ASR 46, the Harbourfront Horizon, could be subject to 1-hourly dust impacts.  As the Tier 1 assessment is for screening purposes only and would not represent the actual on-site situation for the KTE project, a more focused Tier 2 assessment has been undertaken at ASR 46 based upon the emissions from the Hung Hom Finger Pier barging point.  According to the contour plots of the mitigated 1-hour and 24-hour TSP levels, there would be no exceedances at any other locations. 

Table 6.7:    Tier 1 Screening Test: 1-hour and 24-hour Maximum TSP Concentrations (µg/m3) at ASRs for Projects under MTR Corporation (KTE + SCL) Only (Not Including Background Level)

Receiver Reference

Predicted Maximum 1-hour Concentration

Predicted Maximum 24-hour Concentration

1

51

20

2

53

20

3

173

49

4

51

15

5

81

19

6a

113

24

6b

127

27

7a

82

23

7b

70

22

8b

24

7

8c

23

7

9

93

21

10

83

22

11

30

11

12

18

6

13

19

7

14

257

102

15

314

108

16

199

74

17

238

84

18

248

89

19

166

40

20

211

67

21

166

37

22

138

31

23

170

65

24

183

86

25

183

67

26

146

35

27

222

69

28

219

82

29

202

42

30

213

76

31

129

45

32

255

62

33

272

55

34

272

48

35

108

36

36

74

15

37

140

13

38

139

15

39

108

10

46

426

135

47

54

15

48

83

25

49

207

22

52

192

60

 

6.9.3.4              The focused Tier 2 assessment has assumed that dust emissions would occur from the haul road only as opposed to the whole site and as such, emission rates have been applied to the area of the haul road surface. As noted in Section 6.8.1.10 above, this would also represent a very conservative scenario and would be an over prediction of what the actual dusts emissions that would be expected to occur.

6.9.3.5              The maximum predicted 1-hour and 24-hour results for the representative ASRs for the Tier 2 focused barging point assessment are presented in Table 6.8 and those contributed only by projects under MTR Corporation (i.e. KTE + SCL, but without other concurrent projects and background) are shown in Table 6.9 below.  The modelling results at the ASRs in the focused study area are included in Appendix 6.3.

6.9.3.6              In respect of Tier 2, according to the predicted cumulative TSP levels at different heights, the predicted maximum cumulative 1-hour average TSP levels would be at 1.5m above ground for the ASRs near the barging point.  Figure 6.22 shows the contour plots of the mitigated 1-hour for cumulative (KTE + SCL + other concurrent projects + background) at 1.5m above ground. 

Table 6.8:    Tier 2 Focused Barging Point Assessment: 1-hour and 24-hour Maximum Cumulative TSP Concentrations (µg/m3) at ASRs (Including Background Level)

Receiver Reference

Predicted Maximum 1-hour Concentration

(Criterion: 500µg/m3)

Predicted Maximum 24-hour Concentration

(Criterion: 260µg/m3)

46

209

113

47

131

96

48

164

107

49

314

101

52

184

111

Note:

 

denotes TSP level in excess of criterion

 

 

Table 6.9:    Tier 2 Focused Barging Point Assessment: 1-hour and 24-hour Maximum Cumulative TSP Concentrations (µg/m3) at ASRs for Projects under MTR Corporation Only (KTE + SCL) (Not Including Background Level)

Receiver Reference

Predicted Maximum 1-hour Concentration

Predicted Maximum 24-hour Concentration

46

132

32

47

43

15

48

71

25

49

237

21

52

107

34

 

6.9.3.7              As detailed in Table 6.8 above, the maximum predicted 1-hourly TSP results at ASR 46 would not be in excess of the criteria and as such, adverse impacts would not be predicted. 

Annual Dust Predictions

 

6.9.3.8              The maximum predicted annual average TSP concentrations at representative ASRs in the study area with mitigation measures applied are shown in Table 6.10 and the modelling results are included in Appendix 6.3.  The mitigated annual cumulative (KTE + SCL + other concurrent projects + background) contours at 1.5m above ground are provided in Figures 6.23-6.26 at which the predicted cumulative annual average TSP levels would be at their maximum. 

6.9.3.9              According to the predicted TSP levels at different heights, the predicted maximum annual average TSP levels would be at 10m and 15m above ground for the ASRs near HOM Station due to the elevated work sites at HOM Station.  As such, the contour plots of the mitigated cumulative annual average TSP levels (KTE + SCL + other concurrent projects + background) at 10m and 15m above ground near HOM Station are presented in Figures 6.27 and 6.28 respectively. 

Table 6.10:  Annual Average Maximum Cumulative TSP Concentrations (µg/m3) at ASRs (Including Background Level)

Receiver Reference

Predicted Maximum Annual Average Concentration

1

77.7

2

77.7

3

78.2

4

77.7

5

77.8

6a

77.8

6b

77.9

7a

77.9

7b

77.9

8b

77.6

8c

77.7

9

77.9

10

78.0

11

78.0

12

77.9

13

78.4

14

78.7

15

78.9

16

78.4

17

78.6

18

78.8

19

77.9

20

78.4

21

77.8

22

77.7

23

78.9

24

79.2

25

78.7

26

77.9

27

78.2

28

78.5

29

78.0

30

79.0

31

78.5

32

79.0

33

78.4

34

77.9

35

77.7

36

77.6

37

77.6

38

77.6

39

77.5

46

79.5

47

77.8

48

77.7

49

78.0

52

79.8

Note:

 

denotes TSP level in excess of criterion

 

 

6.9.3.10          The predicted maximum cumulative annual average TSP concentrations at representative ASRs detailed in Table 6.10 indicate that all ASRs are in full compliance with the criteria.  However, the contour plots shown in Figures 6.25 and 6.26 for HOM Station works sites and Finger Pier works area, respectively show that exceedances of the cumulative annual average TSP levels at 1.5m above ground level compared with the AQO would occur in some locations. 

6.9.3.11          Based on the existing landuse at the concerned HOM Station works sites and the approved Ho Man Tin OZP No. S/K7/20, the concerned zones of exceedance would cover:

(i)            Green Belt “GB” zone at east of King’s Park High Level Service Reservoir – as “Green Belt” is not classified as an ASRs, the dust level above the AQO would not be considered as an exceedance;

(ii)          North of King’s Park High Level Service Reservoir – this is not classified as ASRs and, as such, the dust level above the AQO would not be considered as an exceedance;

(iii)         King’s Park High Level Service Reservoir Playground – this would be an ASR as the people using this area would be sensitive to potential dust impacts.  However, the dust assessment has been based upon worst case assumptions and the predicted dust exceedances would be marginal only (approximately 81 µg/m3).  In addition, such impacts during the construction period of the KTE project would be transient as the users would not be permanently there and only occur when the playground was in use; and

(iv)        Area at the junction of Chung Hau Street and Fat Kwong Street (ex-Valley Road Estate site) zoned as “R(B)2” Residential (Group B) – while this is classified as an ASR, there is no known programme for the development in this area.  In addition, the predicted dust exceedances would be marginal only (approximately 81 µg/m3) and would not be expected to impose any landuse constraints in this area as any development is unlikely to be completed and occupied before the end of the KTE construction period.   

6.9.3.12          Based on the existing landuse at the concerned Hung Hom Finger Pier works areas and the draft Tsim Sha Tsui OZP No. S/K1/25, the concerned zones of exceedance would cover:

(i)            Portal of Cross Harbour Tunnel – this area is a traffic emission source (non-air sensitive land use) and not an ASR.  Therefore, the dust level above the AQO would not be considered as an exceedance;

(ii)          Podium of Hong Kong Coliseum – this is classified as an ASR as the people using this area would be sensitive to potential dust impacts.  However, the dust assessment has been based upon worst case assumptions and the predicted dust exceedances would be marginal only (approximately 80.5 µg/m3).  In addition, such impacts during the construction period of the KTE project would be transient as the users would not be permanently there would and only occur when the podium was in use; and

(iii)         International Mail Centre – this is classified as an ASR. However, the potential dust impacts during the construction period of the KTE project the predicted dust exceedances would be marginal only (approximately 81 µg/m3) and would be short-term. 

6.9.3.13          The maximum predicted annual average TSP concentrations at representative ASRs in the study area for the MTR Corporation projects (KTE + SCL) (without the background) with mitigation measures applied are shown in Table 6.11 and the modelling results are also included in Appendix 6.3.  The annual TSP contours for the MTR Corporation projects (KTE + SCL) at 1.5m above ground are provided in Figures 6.29-6.32. 

6.9.3.14          According to the predicted TSP levels at different heights, the predicted maximum annual average TSP levels would be at 10m or 15m above ground for the ASRs near HOM Station due to the elevated work sites at HOM Station.  Figures 6.33-6.34 also show the annual TSP contours for the MTR Corporation projects (KTE + SCL) at 10m and 15m above ground near HOM Station. The results show that the contribution from the projects would be small overall. 

Table 6.11:  Annual Average Maximum TSP Concentrations (µg/m3) at ASRs Contributed by the Projects under MTR Corporation (KTE + SCL) (Not Including Background Level)

Receiver Reference

Predicted Maximum Annual Concentration Projects Contribution

1

0.3

2

0.3

3

0.8

4

0.3

5

0.4

6a

0.4

6b

0.4

7a

0.5

7b

0.4

8b

0.2

8c

0.2

9

0.4

10

0.5

11

0.4

12

0.3

13

0.2

14

1.3

15

1.4

16

0.9

17

1.2

18

1.4

19

0.4

20

1.0

21

0.3

22

0.3

23

1.5

24

1.8

25

1.3

26

0.5

27

0.8

28

1.1

29

0.6

30

1.6

31

1.1

32

1.6

33

1.0

34

0.5

35

0.3

36

0.2

37

0.2

38

0.2

39

0.1

46

2.1

47

0.4

48

0.3

49

0.6

52

2.4

                                 

6.10                      Residual Impacts

6.10.1.1          No exceedances of the 1-hour and 24-hour TSP levels are predicted to occur at any of the ASRs in the study area with the recommended mitigation measures applied. 

6.10.1.2          However, there are some marginal exceedances of the AQO for the cumulative annual average TSP levels for the areas adjacent to the HOM Station works site and Finger Pier works area would occur according to the respective contour plots.

6.10.1.3          The exceedances are marginal, short-term and in most cases transient and based upon worst case assumptions.  In addition, based upon the trend of decreasing background TSP levels being recorded at the EPD monitoring station, it is reasonable to assume that when construction of the KTE project commences in 2011, the total predicted TSP levels (project plus background) could be lower than predicted as the background levels reduce and compliance with the AQO could occur at that time.  However, it is considered that the maximum practicable measures to reduce residual impacts have been made that such residual impacts may only occur on some occasions and for the short term only. 

6.10.1.4          The magnitude of the residual impacts have been assessed in accordance with Section 4.4.3 of the EIAO-TM and detailed in Table 6.12 below.

Table 6.12:  Assessment of Residual Impacts from Annual Construction Dust

Criteria

Assessment

Effects on public health and health of biota or risk to life.

The dust generated during the construction works are unlikely to contain a significant proportion of fine particulates (less than 10 µm) which are deemed to the respirable and therefore will have negligible potential to affect health if breathed in.  In addition, about 99% of inhaled particulate matter is considered to be either exhaled or trapped in the upper areas of the respiratory system and expelled and as such, would be deemed to be more of a nuisance than a health risk.

Magnitude of the adverse environmental impacts.

The contribution of the project to dust levels in the area is relatively minor, being <3% based on the AQO for annual average TSP level at all ASRs.  As such, the KTE project is not anticipated to contribute to cumulative construction dust impacts with other projects.  

Geographic extent of the adverse environmental impacts.

The geographic extent of the adverse impacts from dust will not be large and is anticipated to be limited to within about 150m from the KTE barging point works area. 

Duration and frequency of the adverse environmental impacts.

The construction dust impacts of the KTE project will be of short to moderate duration and, therefore, temporary and reversible.  

Likely size of the community or the environment that may be affected by the adverse impacts.

As the impacts will be confined to a relatively small area, only a few ASRs in the immediate vicinity will be temporarily affected. 

Degree to which the adverse environmental impacts are reversible or irreversible.

Construction phase impacts should be reversible.

Ecological context.

Not applicable

Degree of disruption to sites of cultural heritage.

Not applicable

International and regional importance.

The impacts are localised and not of international and regional importance.

Likelihood and degree of uncertainty of adverse environmental impacts.

The impacts predicted are based upon worst case assumptions and modelling parameters and as such, would not occur to the extent predicted on all occasions.  However, the assessment has been made using approved mathematical modelling techniques and the degree of certainty on the results is high. 

6.10.1.5          Based upon the above, the following factors should be considered in determining the residual impacts associated with the annual average dust levels:

·               Dust impacts are not predicted to significantly affect health or cause loss of life;

·               Predicted impacts are temporary and reversible;

·               Impacts are localised and not of international and regional importance;

·               The geographic extent of the adverse impacts is confided to a small area around the barging point works site;

·               Mitigation measures proposed will reduce the levels of impacts;

·               The study area has not shown itself to be fragile or undisturbed;

·               The KTE project itself will not trigger cumulative impacts; and

·               The contribution from the KTE project to the background levels would be small overall, based upon the worst case assumptions and modelling.

6.10.1.6          Based upon these factors, the residual impacts associated with the annual dust exceedances for the KTE project within the study area would be considered minor and acceptable.

6.11                      Environmental Monitoring and Audit

6.11.1.1          The assessment has concluded that mitigated construction dust impacts are within the acceptable levels and no adverse residual impacts will occur.  However, it is recommended that, given the close proximity of the ASRs to the works site, that construction phase environmental monitoring and audit (EM&A) is undertaken to ensure that there are no adverse impacts during the implementation of the construction activities and ensure that recommended mitigation measures are implemented.  Further details of the specific EM&A requirements are detailed in Section 13 of this report and in the EM&A Manual under separate cover.

6.12                      Conclusions

6.12.1.1          Potential air quality impacts from the construction works for the KTE project would mainly be related to construction dust from excavation, materials handling, spoil removal and wind erosion, as well as operation of the rock crushing facilities and the barging point.  With the implementation of mitigation measures in the Air Pollution Control (Construction Dust) Regulation, proposed dust suppression measures, and good site practices, no 1-hour and 24-hour residual impacts would occur.  However, some marginal annual average TSP exceedances would occur at locations around the HOM Station works sites and Finger Pier works area.  The exceedances are marginal, short-term and in most cases transient and based upon worst case assumptions.  Based upon these factors, the residual impacts associated with the annual dust exceedances for the KTE project within the study area would be considered minor and acceptable.