5                                Air Quality Impact

5.1                         Legislation and Standards

5.1.1                         The air quality impact assessment criteria shall make reference to the Hong Kong Planning Standards and Guidelines (HKPSG), the Air Pollution Control Ordinance (APCO) (Cap.311), and Annex 4 of the Technical Memorandum on Environmental Impact Assessment Process (TM-EIAO).

5.1.2                         The APCO (Cap.311) provides power for controlling air pollutants from a variety of stationary and mobile sources and encompasses a number of Air Quality Objectives (AQOs). In addition to the APCO, the Government's overall policy objectives for air pollution are also laid down in Chapter 9 of the Hong Kong Planning Standards and Guidelines (HKPSG) as follows:

·         Limit the contamination of the air in Hong Kong, through land use planning and through the enforcement of the Air Pollution Control Ordinance, to safeguard the health and well-being of the community; and

·         Ensure that the Air Quality Objectives for 7 common air pollutants are met as soon as possible.

5.1.3                         Currently, the AQOs stipulate concentrations for a range of pollutants namely sulphur dioxide (SO2), total suspended particulates (TSP), respirable suspended particulates (RSP), nitrogen dioxide (NO2), carbon monoxide (CO), photochemical oxidants, and lead (Pb).  The AQOs are listed in Table 5.1.

Table 5.1        Hong Kong Air Quality Objectives

 

Pollutant

Concentration in micrograms per cubic metre [1]

1 Hour [2]

8 Hours [3]

24 Hours [3]

3 Months [4]

1 Year [4]

Sulphur Dioxide

800

 

350

 

80

Total Suspended Particulates

500 [7]

 

260

 

80

Respirable Suspended Particulates [5]

 

 

180

 

55

Carbon Monoxide

30,000

10,000

 

 

 

Nitrogen Dioxide

300

 

150

 

80

Photochemical Oxidants (as ozone) [6]

240

 

 

 

 

Lead

 

 

 

1.5

 

Notes:

[1]   Measured at 298K and 101.325 kPa.

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

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

[4]   Arithmetic mean.

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

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

[7]   Not an AQO but is a criterion for evaluating air quality impacts as stated in Annex 4 of TM-EIAO.

5.1.4                         The Air Pollution Control (Construction Dust) Regulation specifies processes that require special dust control.  The Contractors are required to inform the EPD and adopt proper dust suppression measures while carrying out “Notifiable Works” (which requires prior notification by the regulation) and “Regulatory Works” to meet the requirements as defined under the regulation.

5.2                         Description of Existing Environment

5.2.1                         Historical air quality monitoring data from the Air Quality Monitoring Station (AQMS) in Kwun Tong operated by EPD has been examined.  The latest 5 published years of air quality monitoring data, i.e. 2007 to 2011 are tabulated in Table 5.2 below.

Table 5.2        Air Quality Monitoring Data at Kwun Tong AQMS (2007-2011)

Pollutant

Annual Concentration (μg/m3)

2007

2008

2009

2010

2011

5-year Mean

TSP

82

72

70

67

74

73

RSP

53

47

48

47

49

49

NO2

63

59

58

59

63

60

Notes: Monitoring results exceeded AQO are shown as bolded characters.

5.2.2                         It is observed from the above table that the annual TSP and RSP concentrations have shown overall improving trend from 2007 to 2011, while the ranges of annual TSP and RSP concentrations were 67 – 82µg/m3 and 47 - 53µg/m3 respectively. It should be noted that the annual TSP concentrations in Year 2007 had exceeded the criterion of 80µg/m3.

5.2.3                         For NO2 concentration, monitoring data shows that there is no obvious trend of improvement or deterioration among the last 5 years, and the concentration is well within the relevant criterion.

5.3                         Air Sensitive Receivers & Pollution Sources

5.3.1                         Study Area

5.3.1.1                    With reference to Section 3.4.1 of EIA Study Brief No. ESB-196/2008, the study area for air quality impact assessment should generally be defined by a distance of 500m from the boundary of the project site and shall be extended to include major existing and planned/committed air pollutant emission sources. The study shall also assess the air quality impacts on the air sensitive areas and other sensitive receivers, which may be potentially affected by the Project. Drawing no. 209506/EIA/AIR/001 illustrates the extent of the study area.

5.3.2                         Air Sensitive Receivers

5.3.2.1                    According to Annex 12 of the EIAO-TM, Air Sensitive Receivers (ASRs) include domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public worship, library, court of law, sports stadium or performing arts centre. Any other premises or places with which, in terms of duration or number of people affected, have a similar sensitivity to the air pollutants as the aforelisted premises and places would also be considered as a sensitive receiver. Representative ASRs within a distance of 500m from the alignment, temporary work areas, and associated barging facilities have been identified.

5.3.2.2                    These ASRs include both the existing and planned developments.  Existing ASRs are identified by means of reviewing topographic maps, aerial photos, land status plans, supplemented by site inspections. They mainly include developed high rise residential buildings, educational institution of a few storeys high and hotels etc..

5.3.2.3                    Planned/committed ASRs are identified by making reference to Tseung Kwan O Outline Zoning Plans (OZP) S/TKO/20, Outline Development Plans, Layout Plans and other published plans in the vicinity of the alignment.

5.3.2.4                    The locations of the representative ASRs for air quality assessment are illustrated in Drawing no. 209506/EIA/AIR/001, and are summarised in Table 5.3 below.

Table 5.3        Representative ASRs

ASR ID

Description

Land use [1]

No. of Storey

Affected during Construction Phase

Affected during Operational Phase

Separation distance (m)

Existing ASRs

 

 

 

 

 

A1

Lohas Park Phase II – Le Prestige Tower 1

R

49

ü

ü

60

A2

Lohas Park Phase II – Le Prestige Tower 3

R

54

ü

ü

100

A6

Lohas Park Phase I – The Capitol Tower 1

R

54

ü

ü

330

A7

Chiaphua-Shinko Centre

I

2

ü

ü

410

A8

Metrix Manufacturing (HK) Ltd

I

3

ü

ü

90

A9

HSBC Office

C

4

ü

ü

320

A10

Hong Kong Oxygen Acetylene Co. Ltd

I

4

ü

ü

450

Planned ASRs

 

 

 

 

 

A3

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

R

55

û

ü

50

A4

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

R

57

û

ü

250

A5

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

R

53

û

ü

380

A11

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

R

46

ü

ü

20

A12

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

R

55

ü

ü

70

A13

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

R

55

ü

ü

10

A14

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

R

57

ü

ü

50

A15

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

R

56

ü

ü

20

A16

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

R

52

ü

ü

10

A17

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

R

49

ü

ü

20

A18

Lohas Park Stage 3 (Planned Development in Area 86,Package 10)

R

55

ü

ü

30

A19

Tung Wah Group of Hospitals Aided Primary School & Secondary School 

E

-

ü

ü

40

A20

Planned Primary and Secondary Schools 

E

-

ü

ü

160

A21

The Beaumount (Under Construction)

R

-

ü

ü

540

A22

RTHK Broadcasting House (Planned)

GIC

-

ü

ü

70

A23

Data Centre (Planned)

C

-

ü

ü

150

Notes:

[1]           R – Residential ; E – Educational ; I – Industrial ; C – Commercial

5.3.3                         Pollution Sources

Construction Phase

5.3.3.1                    Most sections of the CBL are located above Junk Bay and adverse fugitive dust impact from the marine-based construction is considered unlikely. However, the construction of the at-grade section of Road D9 would inevitably generate fugitive dust with potential impacts on neighbouring sensitive receivers from various construction activities, including excavation, backfilling, transportation of materials, and wind erosion. Apart from these activities, a temporary stockpiling / works area is proposed on an area earmarked for GIC on the south side of Road D9, near the junction with Wan Po Road.  Stockpiling area is also proposed in the public fill in TKO Area 137 for the excavated material from the construction of Road D9. However, in consideration of its existing condition and daily load/unloading activities in the area, potential dust emission from the operation of the proposed stockpile in TKO Area 137 is considered insignificant.

5.3.3.2                    Barging facilities would also be operated near the proposed site compound during the construction stage, however, only precast concrete and other non-dusty construction material would be handled at the barging point, no associated dust impact is anticipated.

Operational Phase

5.3.3.3                    Upon completion of the Project, additional traffic would likely be generated and carried by the CBL. The associated air quality impact from vehicular emission via the CBL and induced traffic would be unavoidable.

5.4                         Potential Concurrent Projects / Sources

5.4.1                         General

5.4.1.1                    The tentative commencement year for the construction of CBL is 2017, and would take approximately 4 years for completion. All concurrent projects, which may have cumulative environmental impacts during the construction period, have been identified and summarised in Table 5.4 below.

Table 5.4        Key Concurrent Projects for Air Quality Assessment

Key Concurrent Projects

Tentative Construction Programme

Tseung Kwan O-Lam Tin Tunnel and Associated Works

End 2020

Tseung Kwan O Area 86 Development

2005-2020 (under construction)

Hong Kong Offshore Wind Farm in Sourtheastern Waters

2017

5.4.2                         TKO-LT Tunnel

5.4.2.1                    With reference to the Project Profile and the EIA Study Brief (ESB-195/2008) on TKO-LT Tunnel, the project is to construct a dual two-lane highway connecting TKO at Po Yap Road in the east with Trunk Road T2 in Kai Tak Development in the west and Lei Yue Mun Road Underpass.  The project involves a 4.8km long highway with about 3km of the highway in tunnel. The TKO-LT Tunnel will connect with CBL to form a new external road link to meet the anticipated traffic flow associated with the further population intake and development in TKO New Town. The construction sites associated with TKO-LT Tunnel are located more than 1000m away from the existing receiver in TKO Area 86, hence cumulative air quality impact during construction stage is not anticipated.

5.4.2.2                    During operational phase, vehicular emission due to the induced traffic, road network, ventilation building and tunnel portals associated with TKO-LT Tunnel would likely have cumulative air quality impact on the identified ASRs. Latest information is therefore obtained from the project proponent and is included in the operational air quality assessment.

5.4.3                         TKO Area 86 Development

5.4.3.1                    Area 86 is under construction. Potential emission sources include site excavation, trucks movement and wind erosion. The latest development schedule from MTRC has been obtained and the associated cumulative impact included in the construction dust assessment.

5.4.3.2                    Vehicular emission due to the induced traffic from the TKO Area 86 Development would also have cumulative air quality impact on nearby ASRs. As such, induced traffic has been considered in the operational air quality assessment.

5.4.4                         Hong Kong Offshore Wind Farm in Southeastern Waters

5.4.4.1                    With reference to the approved EIA Study “Hong Kong Offshore Wind Farm in Southeastern Waters” (AEIAR-140/2009), the project is to construct and operate a wind farm in the southeastern waters of Hong Kong. The project includes installation of up to 67 wind turbines, an offshore transformer platform, sub-sea collection and transmission cables, and Research Mast. There will be a landing cable area and proposed cable at the west of Junk Bay connecting the collection cables from the turbines and the CLP existing grid connection network. According to the latest information provided by CLP, the tentative construction programme indicates that the construction of the offshore wind farm project may overlap with the CCL construction programme during 2017. However, based on the ASRs identified above, it is anticipated that the distances from the proposed cable landing area and cable route in Junk Bay, to the identified ASRs for CBL project, are greater than 500m. Impact arising from the construction work for landing cable area and laying of cable route in Junk Bay to the ASRs for CBL is not expected. As such, the cumulative air impact during construction is unlikely and therefore is not included in the assessment. In addition, the operation of the offshore wind farm would unlikely to generate air emission. Hence, cumulative air quality impact during operational phase is not anticipated.

5.4.5                         Other Concurrent Sources

5.4.5.1                    Other than the emission sources associated with the abovementioned planned/ committed concurrent projects, existing industrial and marine emission sources have also been identified in the vicinity of the Tseung Kwan O Industrial Estate (TKOIE), which is within 500m study area. Cumulative air quality impacts from these concurrent sources are anticipated during the operational phase of the Project. Detailed discussions are given in Section 5.6.

5.5                         Construction Dust Assessment

5.5.1                         Identification of Pollution Sources and Representative Pollutants

5.5.1.1                    A review on the construction methodology has been conducted. Construction of the project would inevitably generate fugitive dust with potential impacts on neighbouring existing sensitive receivers. In general, construction dust, as the representative pollutants, will be potentially generated mainly from the land-based at-grade construction works including the following activities. According to HKAQO, the 1-hour, 24-hour and annual concentration would need to be considered.

·         Soil excavation;

·         Backfilling;

·         Stockpiling of dusty material;

·         Transportation of the excavated materials; and

·         Wind erosion of all open sites.

5.5.1.2                    According to Section 13.2.4.3 of USEPA AP-42, most of the particles in fugitive dust have an aerodynamic diameter of <30 μm.  Hence, it is appropriate to adopt Total Suspended Particulates (TSP) (with aerodynamic diameter ≦30 μm) as the representative pollutant for construction phase.  According to EPD’s Air Quality Report 2011, the major sources for Respirable Suspended Particulates (RSP) include power generation, road transport, etc.  Non-combustion sources only constitute about 14%.  Since construction dust is only one of the sources from non-combustion sources. It is unlikely that RSP is a representative pollutant for construction dust.

5.5.2                         Emission Inventory

5.5.2.1                    Potential air quality impact is therefore anticipated during the construction of the Project and has been assessed based on the following conservative assumptions of the general construction activities:

·         Heavy construction activities including site clearance, ground excavation, construction of the associated facilities, haul road etc;

·         Wind erosion of all active open sites;

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

·         Construction working periods of 26 days a month and 12 hours a day from 7:00am to 7:00pm, except Sundays and public holidays.

5.5.2.2                    The prediction of dust emissions is based on typical values and emission factors from United States Environmental Protection Agency (USEPA) Compilation of Air Pollution Emission Factors (AP-42), 5th Edition. References of the calculations of dust emission factors for different dust generating activities are listed in Table 5.5. Detailed calculations of emission factors are given in Appendix 5.1.

Table 5.5        Key Concurrent Projects for Air Quality Assessment

Activities

Reference

Operating Sites

Equations & Assumptions

Heavy construction activities including land clearance, ground excavation, cut and fill operations, construction of the facilities, haul road, etc

USEPA AP42 S.13.2.3.3

All construction and excavation sites

E = 1.2 tons/acre/month of activity or

   = 2.69Mg/hectare/month of activity

 

Loading/Unloading at any stockpile

 

USEPA AP42, S13.2.4

Stockpiling area

k is particle size multiplier

U is average wind speed

M is material moisture content

Wind Erosion

 

USEPA AP42 S.11.9, Table 11.9.4

All construction sites, any stockpile areas, barging area (all open sites)

E = 0.85 Mg/hectare/yr

(24 hour emission)

5.5.2.3                    Dust emission from construction vehicle movement will generally be limited within the confined worksites area and the heavy construction emission factor given in AP-42 S.13.2.3.3 has taken this factor into account.  Watering facilities will be provided at every designated vehicular exit point.  Haul roads within the work sites would be paved and water spraying would be provided to keep them in wet condition. Since all vehicles will be washed at exit points and vehicle loaded with the dusty materials will be covered entirely by clean impervious sheeting before leaving the construction site, dust nuisance from construction vehicle movement outside the worksites is unlikely to be significant. Locations and details of emission sources are illustrated in Appendix 5.1.

5.5.2.4                    In addition, construction activities associated with the development in TKO Area 86 have been considered in this assessment to assess cumulative dust impact. However, it should be noted that the construction activities on top of the MTR Depot would only involve superstructure and hence are not considered dusty.  As such, ground level construction activities only included in this assessment.

5.5.3                         Assessment Methodology

5.5.3.1                    Dust impact assessment has been undertaken using the EPD approved Fugitive Dust Model (FDM).  It is a well-known Gaussian Plume model designed for computing air dispersion for fugitive dust sources.  Modelling parameters including dust emission factors, particles size distributions, surface roughness, etc are referred to EPD’s “Guideline on choice of models and model parameters” and USEPA AP-42.  The density of dust is assumed to be 2.5g/cm3.  The 5-year annual averaged TSP concentration of 73µg/m3 is taken as the background concentrations of this study. A surface roughness of 100 cm is assumed in the model to represent the terrain.

5.5.3.2                    During daytime working hours (7am to 7pm), it is assumed that dust emissions would be generated from all dust generating activities and site erosion. During night-time non-working hours (7pm to 7am of the next day), Sunday and public holidays, dust emission source would include site erosion as construction activities during these hours will be ceased.

5.5.3.3                    The worst-case 1-hour, worst-case 24-hour average and annual TSP concentrations were calculated based on real meteorological data, including wind direction, wind speed and stability, collected from the Kai Tak meteorological station in Year 2011.  The mixing height and temperature data from the King’s Park Station in Year 2011 were adopted.

5.5.3.4                    Fugitive dust modelling was conducted at the 1.5m, 5m and 10m above ground.  Since all the dust generating sources associated with this Project are at ground level only, these assessment levels would therefore represent the worst-case scenario. Both the unmitigated and mitigated scenarios for the project are presented. A 100x100m grid has also been used to investigate the pollutant dispersion.

5.5.3.5                    A summary of modelling parameters adopted in the construction dust assessment are given in the table below:

Table 5.6        Modelling Parameters

Parameters

Input

Remark

Particle size distribution

1.25um = 7%

3.75um = 20%

7.5um = 20%

12.5um = 18%

22.5um = 35%

Reference from S13.2.4.3 of USEPA AP-42

Background Concentration

73µg/m3

5-year annual averaged value recorded at Kwun Tong  Station

Modeling mode

Flatted terrain

-

Meteorological data

Data recorded in 2011 at Kai Tak and King’s Park Meteorological Stations

-

Anemometer Height

13m

Elevation of anemometer : +16mPD

Ground level of anemometer : +3mPD

Surface Roughness

100cm

-

Emission period

General construction activities during daytime working hours (7 am to 7 pm)

Wind erosion during both day-time (7am to 7pm) and night-time (7pm to 7am of the next day)

-

Assessment height

1.5m, 5m and 10m

-

5.5.3.6                    It is understood that construction activities will not take place at all locations over the entire work sites at the same time, but to be undertaken at moving multiple work fronts spread across the work sites. The active areas on each work site were best estimated from the construction method, construction programme and number of operating plants. Based on the engineering information presented in the Appendix 5.2, it is estimated that the hourly percentage of active area is 7.4%, while the annual percentage of active areas is 4.1%. As a conservative assessment, it is assumed that the hourly and annual percentage active areas are 30% and 6% respectively.

5.5.3.7                    For short-term 1-hour and 24-hour assessment, construction and plant activity would neither take place on the entire work site/work area at the same time, nor be concentrated in certain areas of the site close to ASRs at anytime during the construction period. Notwithstanding this, a conservative initial screening test, namely “Tier 1 Screening Test” was undertaken.  The Tier 1 screening test is conservative and represented the worst case situation, whereby all the worksites would be active (i.e. 100%). The purpose of the Tier 1 screening test is to identify the potentially affected areas where construction dust may accumulate.

5.5.3.8                    For the long-term annual concentration assessment, as mentioned above, all the active construction activities would likely be moving at work fronts spreading across the whole works site. On this basis, it was assumed that the dust emissions will be distributed across the whole area of each site to reasonably represent this mode of construction works (i.e. a correction factor of 0.06 is applied to the total dust emission rate for prediction of annual concentration).

5.5.3.9                    Cumulative construction dust impact from the concurrent project (i.e. TKO Area 86 Development) has also been taken into account.  Details of the construction schedule of Area 86 were unavailable during the preparation of this assessment, but construction of TKO Area 86 Development is generally programmed to finish in Year 2020. As a conservative assumption, the active area for the short-term assessment (i.e. Tier 1) was assumed as 100%. However, given that construction activities would be undertaken at moving multiple work fronts across the site, 6% active area is assumed for the long-term (i.e. annual) TSP assessment.

5.5.3.10                In addition, in order to determine the worst case scenario impact to TKO Area 86 from the construction of the CBL project, it is assumed that the ASRs A11-A19 would exist during the construction of Road D9.

5.5.4                         Assessment Result – Unmitigated Scenario

5.5.4.1                    The maximum unmitigated 1-hour, 24-hour and annual cumulative TSP concentrations at each existing representative ASR have been assessed and are presented in Table 5.7 and Table 5.8 below. Drawing no. 209506/EIA/AIR/002-004 shows the contours of unmitigated 1-hour (Tier 1), 24-hour (Tier 1) and annual cumulative TSP concentrations at 1.5m height above ground level. Exceedances of the relevant criteria are predicted at most of the ASRs. Hence, mitigation measures are therefore required to reduce the dust impact.

Table 5.7        Predicted Cumulative Unmitigated 1-hour (Tier 1) and 24-hour (Tier 1) TSP Concentrations at ASRs (including background concentration)

ASR ID

Description

1-hour TSP Concentrations at Various Height (μg/m3)

24-hour TSP Concentrations at Various Height (μg/m3)

1.5m

5m

10m

1.5m

5m

10m

A1

Lohas Park Phase II – Le Prestige Tower 1

2020

1414

831

348

244

185

A2

Lohas Park Phase II – Le Prestige Tower 3

1488

1100

774

262

223

160

A3

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

A4

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

A5

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

A6

Lohas Park Phase I – The Capitol Tower 1

1687

1560

1046

340

325

254

A7

Chiaphua-Shinko Centre

1262

1260

1019

194

192

167

A8

Metrix Manufacturing (HK) Ltd

2335

1817

932

299

280

217

A9

HSBC Office

830

829

700

142

145

139

A10

Hong Kong Oxygen Acetylene Co. Ltd

859

884

767

141

144

136

A11

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

4879

1855

980

660

379

241

A12

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

2013

1258

776

339

273

187

A13

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

4920

2110

948

557

355

231

A14

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

2511

1394

909

438

317

217

A15

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

4605

1741

1055

768

406

238

A16

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

4154

2037

1160

552

357

239

A17

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

2781

2131

1310

361

318

250

A18

Lohas Park Stage 3 (Planned Development in Area 86,Package 10)

2997

2462

1256

375

343

257

A19

Tung Wah Group of Hospitals Aided Primary School & Secondary School 

3004

1425

866

427

329

211

A20

Planned Primary and Secondary Schools 

2257

1894

1001

347

322

240

A21

The Beaumount (Under Construction)

1403

1411

1152

134

135

124

A22

RTHK Broadcasting House (Planned)

2294

1416

929

312

250

179

A23

Data Centre (Planned)

1145

898

686

175

174

156

Notes:      Bold values mean exceedance of relevant criteria.

[1]           Not considered as an ASR during construction phase as it is assumed that the site is under construction to account for cumulative impact.

 

Table 5.8        Predicted Cumulative Unmitigated Annual TSP Concentrations at ASRs (including background concentration)

ASR ID

Description

Annual TSP Concentrations at Various Height (μg/m3)

1.5m

5m

10m

A1

Lohas Park Phase II – Le Prestige Tower 1

76.9

76.0

74.9

A2

Lohas Park Phase II – Le Prestige Tower 3

76.5

76.1

75.1

A3

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

A4

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

A5

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

A6

Lohas Park Phase I – The Capitol Tower 1

75.0

75.0

74.7

A7

Chiaphua-Shinko Centre

74.0

74.0

73.9

A8

Metrix Manufacturing (HK) Ltd

74.6

74.5

74.1

A9

HSBC Office

73.5

73.5

73.5

A10

Hong Kong Oxygen Acetylene Co. Ltd

73.5

73.6

73.5

A11

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

86.4

81.3

77.5

A12

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

80.1

78.9

76.8

A13

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

87.0

82.9

78.5

A14

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

83.0

80.8

77.8

A15

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

89.5

83.1

78.4

A16

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

86.2

82.7

78.7

A17

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

81.9

79.7

77.5

A18

Lohas Park Stage 3 (Planned Development in Area 86,Package 10)

80.7

79.2

77.2

A19

Tung Wah Group of Hospitals Aided Primary School & Secondary School 

82.2

79.9

76.8

A20

Planned Primary and Secondary Schools 

78.2

77.9

76.7

A21

The Beaumount (Under Construction)

73.8

73.8

73.7

A22

RTHK Broadcasting House (Planned)

75.6

75.2

74.5

A23

Data Centre (Planned)

74.6

74.5

74.2

Notes:      Bold values mean exceedance of relevant criteria.

[1]           Not considered as an ASR during construction phase as it is assumed that the site is under construction to account for cumulative impact.

5.5.5                         Mitigation Measures

5.5.5.1                    In order to reduce the dust emission from the Project and achieve compliance with the TSP criteria at ASRs, mitigation measures in form of regular watering under a good site practice should be adopted. In accordance with the “Control of Open Fugitive Dust Sources” (USEPA AP-42), watering once per hour on exposed worksites and haul road is recommended to achieve dust removal efficiency of 91.7%. Appendix 5.2 presents the calculation of the dust removal efficiency. The dust suppression efficiency is derived based on the average haul road traffic of 20 vehicle/hour, average evaporation rate and an assumed application intensity of 0.5 L/m2 for the respective watering frequencies.  Any potential dust impact and watering mitigation would be subject to the actual site conditions.  For example, a construction activity that produces inherently wet conditions or in cases during rainy weather, the above water application intensity may not be unreservedly applied.  While the above watering frequency is to be followed, the extent of watering may vary depending on actual site conditions but should be sufficient to maintain an equivalent intensity of no less than 0.5 L/m2 to achieve the respective dust removal efficiencies.  The dust levels would be monitored and managed under an EM&A programme as specified in the EM&A Manual.

5.5.5.2                    In addition to the watering and required intensity, the Contractor will also be obliged to follow the procedures and requirements given in the Air Pollution Control (Construction Dust) Regulation.  This stipulates the construction dust control requirements for both Notifiable (e.g. site formation) and Regulatory (e.g. road opening) Works to be carried out by the Contractor. 

5.5.5.3                    In accordance with the Air Pollution Control (Construction Dust) Regulation, the following dust suppression measures should also be incorporated by the Contractor to control the potential for dust nuisance throughout the construction phase:

·         Any excavated or stockpile of dusty material should be covered entirely by impervious sheeting or sprayed with water to maintain the entire surface wet and then removed or backfilled or reinstated where practicable within 24 hours of the excavation or unloading;

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

·         A stockpile of dusty material should not extend beyond the pedestrian barriers, fencing or traffic cones;

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

·         Where practicable, vehicle washing facilities with high pressure water jet should be provided at every discernible or designated vehicle exit point.  The area where vehicle washing takes place and the road section between the washing facilities and the exit point should be paved with concrete, bituminous materials or hardcores;

·         When there are open excavation and reinstatement works, hoarding of not less than 2.4m high should be provided as far as practicable along the site boundary with provision for public crossing. Good site practice shall also be adopted by the Contractor to ensure the conditions of the hoardings are properly maintained throughout the construction period;

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

·         Surfaces where any pneumatic or power-driven drilling, cutting, polishing or other mechanical breaking operation takes place should be sprayed with water or a dust suppression chemical continuously;

·         Any area that involves demolition activities should be sprayed with water or a dust suppression chemical immediately prior to, during and immediately after the activities so as to maintain the entire surface wet;

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

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

·         Exposed earth should be properly treated by compaction, turfing, hydroseeding, vegetation planting or sealing with latex, vinyl, bitumen, shortcrete or other suitable surface stabiliser within six months after the last construction activity on the construction site or part of the construction site where the exposed earth lies.

5.5.5.4                    For the barging facilities proposed at the site compound, the following good site practice is required:

·         All road surfaces within the barging facilities should be paved.

·         Vehicles should pass through designated wheel wash facilities.

·         Continuous water spray should be installed at the loading point.

5.5.5.5                    The above requirements should be incorporated into the Contract Specification for the civil work.  In addition, an audit and monitoring programme during the construction phase should be implemented by the Contractor to ensure that the construction dust impacts are controlled to within the HKAQO.  Detailed requirements for the audit and monitoring programme are given separately in the EM&A manual.

5.5.6                         Assessment Result – Mitigated Scenario

5.5.6.1                    With the implementation of the abovementioned mitigation measures, the maximum mitigated 1-hour (Tier 1), 24-hour (Tier 1) and annual cumulative TSP concentrations at each representative ASRs have been assessed and are presented in Table 5.9 and Table 5.10 below. In general, it is predicted that, with the recommended mitigation measures adopted, the TSP concentrations at all ASRs would comply with their respective criteria.

Table 5.9        Predicted Cumulative Mitigated 1-hour (Tier 1) and 24-hour (Tier 1) TSP Concentrations at ASRs (including background concentration)

ASR ID

Description

1-hour TSP Concentrations at Various Height (μg/m3)

24-hour TSP Concentrations at Various Height (μg/m3)

1.5m

5m

10m

1.5m

5m

10m

A1

Lohas Park Phase II – Le Prestige Tower 1

255

184

136

98

91

84

A2

Lohas Park Phase II – Le Prestige Tower 3

190

158

131

91

87

81

A3

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

A4

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

A5

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

Note [1]

A6

Lohas Park Phase I – The Capitol Tower 1

207

196

154

96

94

88

A7

Chiaphua-Shinko Centre

172

171

152

83

83

81

A8

Metrix Manufacturing (HK) Ltd

263

219

145

94

92

86

A9

HSBC Office

139

139

127

80

80

80

A10

Hong Kong Oxygen Acetylene Co. Ltd

138

140

131

79

79

79

A11

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

472

221

148

131

101

88

A12

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

240

171

131

99

92

84

A13

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

475

242

148

124

100

87

A14

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

275

183

142

106

95

86

A15

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

449

211

154

137

103

87

A16

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

412

239

163

120

99

88

A17

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

298

244

176

101

96

89

A18

Lohas Park Stage 3 (Planned Development in Area 86,Package 10)

316

271

171

101

99

91

A19

Tung Wah Group of Hospitals Aided Primary School & Secondary School 

316

186

139

106

96

85

A20

Planned Primary and Secondary Schools 

254

224

150

99

97

89

A21

The Beaumount (Under Construction)

183

184

163

79

79

78

A22

RTHK Broadcasting House (Planned)

273

197

144

100

93

84

A23

Data Centre (Planned)

169

147

124

84

83

81

Notes:     

[1]           Not considered as an ASR during construction phase as it is assumed that the site is under construction to account for cumulative impact.

 

Table 5.10      Predicted Cumulative Mitigated Annual TSP Concentrations at ASRs (including background concentration)

ASR ID

Description

Annual TSP Concentrations at Various Height (μg/m3)

1.5m

5m

10m

A1

Lohas Park Phase II – Le Prestige Tower 1

74.6

74.1

73.5

A2

Lohas Park Phase II – Le Prestige Tower 3

74.5

74.2

73.7

A3

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

A4

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

A5

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

Note [1]

Note [1]

Note [1]

A6

Lohas Park Phase I – The Capitol Tower 1

73.8

73.8

73.6

A7

Chiaphua-Shinko Centre

73.4

73.4

73.3

A8

Metrix Manufacturing (HK) Ltd

73.7

73.6

73.4

A9

HSBC Office

73.2

73.2

73.2

A10

Hong Kong Oxygen Acetylene Co. Ltd

73.2

73.2

73.2

A11

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

78.5

75.8

74.3

A12

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

76.0

75.3

74.2

A13

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

78.6

76.3

74.5

A14

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

77.0

75.7

74.3

A15

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

79.3

75.9

74.4

A16

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

78.1

76.1

74.5

A17

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

76.4

75.2

74.3

A18

Lohas Park Stage 3 (Planned Development in Area 86,Package 10)

76.0

75.2

74.3

A19

Tung Wah Group of Hospitals Aided Primary School & Secondary School 

76.9

75.5

74.0

A20

Planned Primary and Secondary Schools 

75.1

74.9

74.2

A21

The Beaumount (Under Construction)

73.3

73.3

73.3

A22

RTHK Broadcasting House (Planned)

74.2

73.9

73.5

A23

Data Centre (Planned)

73.7

73.6

73.4

Notes:     

[1]           Not considered as an ASR during construction phase as it is assumed that the site is under construction to account for cumulative impact.

5.5.6.2                    It can also be seen from Table 5.9 and Table 5.10 that the predicted 1-hour, 24-hour and annual TSP concentrations would in general decrease with increasing elevations from ground level to 10m above ground. In respect of potential construction dust impact to the nearest ASRs in TKO Area 86 (i.e. ASR A1-A2, A6, A11-A18 and A20), the air sensitive uses as well as the fresh air intake are generally located at least 5m above ground.  Fugitive dust impact generated from the construction of the at-grade section of this Project on ground level would not have significant dust impact on the ASRs at high elevation. As shown in Table 5.9 and Table 5.10, the TSP concentrations at ASR A1-A2, A6, A11-A18 and A20 at 5m and 10m above ground are far below their respective criteria.

5.5.6.3                    Drawing no. 209506/EIA/AIR/005-007 shows the contours of mitigated 1-hour (Tier 1), 24-hour (Tier 1) and annual cumulative TSP concentrations at the worst affected level (i.e. 1.5m above ground). For 1-hour and 24-hour TSP concentration, there are no air sensitive uses identified within the area of exceedance. Adverse short-term dust impact is therefore not anticipated.

5.5.6.4                    For annual TSP concentrations, exceedance is observed at the basketball court of the ASR A19 Tung Wah Group of Hospitals Aided Primary School & Secondary School. However, it is considered that there is no long-term air sensitive use at the basketball court as the school will be closed after school hours, whereas the basketball court will be vacant during non-school hours (i.e. no air sensitive use). In addition, it is assumed in this construction dust assessment that the proposed stockpiling area located opposite to the basketball court will be uncovered throughout the entire year to represent the very conservative scenario, which will not occur in reality. As a general site practice, any stockpiling of dusty material would be covered entirely by impervious sheeting within 24 hours of the excavation or unloading. With the stockpiling area covered, dust emission due to open site erosion will then be minimal and will reduce the long-term dust impact in practice.

5.5.6.5                    As such, since the predicted exceedance of annual TSP concentrations is based on the very conservative assumption mentioned above and there is no long-term air sensitive use at the basketball court of the ASR A19 Tung Wah Group of Hospitals Aided Primary School & Secondary School, adverse long-term dust impact is therefore not anticipated.

5.6                         Operational Air Quality Assessment

5.6.1                         Identification of Key/Representative Air Pollutions of Vehicular Emissions Open Road

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

(i)                           Nitrogen Dioxide (NO2)

5.6.1.2                    Nitrogen oxides (NOx) is a major pollutant from fossil fuel combustion.  According to the Emission Inventory for 2010 published on EPD’s website [1], navigation is the dominant contributor to NOx generation in Hong Kong, accounted for 32% of NOx emission in 2010.  Road transport is the second largest NOx contributor which accounted for 30% of the total in the same year.

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

(ii)             Respirable Suspended Particulates (RSP)

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

 (iii)           Sulphur Dioxide (SO2)

5.6.1.5                    Sulphur dioxide (SO2) is formed primarily from the combustion of sulphur-containing fossil fuels.  In Hong Kong, power stations and marine vessels are the major sources of SO2, followed by fuel combustion equipment and motor vehicles [2].  SO2 emission from vehicular exhaust is due to the sulphur content in diesel oil.  According to EPD’s “Cleaning the Air at Street Level” [3],ultra low sulphur diesel (ULSD) with a sulphur content of only 0.005% has been adopted as the statutory minimum requirement for motor vehicle diesel since April 2002, which is 3 years ahead of the European Union.  With the use of ULSD, according to the Emission Inventory for 2010 published on EPD’s website, road transport is the smallest share of SO2 emission sources in 2010 and only constitutes less than 1% of the total SO2 emission.  From 1 July 2010, EPD has tightened the statutory motor vehicle diesel and unleaded petrol specifications to Euro V level, which further tightens the cap on sulphur content from 0.005% to 0.001%.

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

(iv)            Carbon Monoxide (CO)

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

(v)             Ozone (O3)

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

(vi)            Lead (Pb)

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

(vii)           Toxic Air Pollutants (TAPs)

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

(viii)         Diesel Particulate Matters (DPM)

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

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

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

(ix) Polycyclic Aromatic Hydrocarbons (PAHs)

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

(x) Volatile Organic Compounds (VOCs)

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

5.6.2                         Emission Inventory

Vehicular Emission from Open Road and Tunnel Portals

5.6.2.1                    As discussed in Section 5.6.1 above, for a road project, nitrogen dioxide (NO2) and respirable suspended particulates (RSP) are the air pollutants of primary concern during operational phase of the Project and hence are assessed in the study.

5.6.2.2                    In assessing the operational air quality impact to air sensitive receivers, contribution from the following classes of emission sources will be considered:

·         Contributions induced by the project itself;

·         Vehicle emission of other existing roads within study area; and

·         Portal emission from Landscape deck of Road P2 and TKO-LT Tunnel within study area.

5.6.2.3                    Upon commencement of the CBL operation, vehicular emissions will be generated from the additional road network in the study area. Additional traffic flow would also be induced on the existing roads and therefore a corresponding increase in vehicular emissions is anticipated.  Major roads in the vicinity of the study area include Wan Po Road, Chun Yat Street etc. Drawing no. 209506/EIA/AIR/010 illustrates the locations of open roads and portals included in this assessment.

Industrial Emission

5.6.2.4                    Chimney survey and desktop study have been conducted to identify/ verify the industrial emissions within 500m of the site boundary and inside Tseung Kwan O Industrial Estate (TKOIE). Chimney data were requested from each industrial premise, however, only few premises responded. According to further information provided by the Hong Kong Science & Technology Parks Corporation (HKSTPC), who manages the TKOIE, the following assumptions are applicable:

·         The daily diesel consumption allocation available for tenants (besides Hong Kong Aero Engine Services Ltd) is 52.6 m3/day.

5.6.2.5                    To assess the potential cumulative air quality impact due to other minor emission sources, reference has been made to the approved EIA Study “Fill Bank at TKO Area 137” (AEIAR-060/2002) for the stack height, diameter, exit velocity and temperature. These chimney information adopted in this approved EIA are considered as the best available information and are adopted in this operational air quality assessment. Emission factors for the industries are calculated based on the emission limits stated in the Air Pollution Control (Fuel Restriction) Regulation. Detailed calculations are given in Appendix 5.3.

5.6.2.6                    References have also been made to the approved EIA Studies for "Development of a Biodiesel Plant at Tseung Kwan O Industrial Estate" (AEIAR-131/2009) for the planned Biodiesel Plant in TKOIE, and the “Further Development of Tseung Kwan O Feasibility Study" (AEIAR-092/2005) for the landfill gas flaring plants. For the emission from the aircraft engine testing at Hong Kong Aero Engine Service Ltd (HAESL), a sensitivity test, which has taken into account  different aircraft engine model mounted on the various large aircrafts commonly available in the market, has been conducted to determine the emissions from the engine test that might be undertaken at the HAESL. Estimation of emission from aircraft engine test has been referenced from the approved EIA study “Environmental Impact Assessment HAECO/HAESL Facilities at Tseung Kwan O” (EIA-147/BC), latest EDMS v5.1.3 developed by the Federal Aviation Administration (FAA) for determination of airport emission which includes aircraft engine emission, and the Air Quality Manual published by International Civil Aviation Organization (ICAO). Detailed calculations are given in Appendix 5.3. The highest estimated emissions from the sensitivity test have been taken for conservative operational air quality assessment.

5.6.2.7                    The locations of industrial chimneys included in this assessment are shown in Drawing no. 209506/EIA/AIR/010. Their emission characteristics are presented in Appendix 5.3. The table below lists the chimneys that are included in the operational air quality assessment.

Table 5.11      Chimneys included in the Operational Air Quality Assessment

Source ID

Description

E1 – E2

Fuel oil and biogas combustion at the planned Biodiesel Plant

E4

Aircraft engine testing at HAESL

E6 – E21

Fuel oil combustion inside the TKOIE

EP1 – EP9

Fuel oil combustion at Television Broadcasts Ltd.

FS1

Sai Tso Wan Landfill gas flaring plant

TO1 – TO2

TKO Stage I & Stage II/III Landfill gas flaring plant

Marine Emission

5.6.2.8                    Site survey and desktop study have been conducted to identify the potential marine emissions within the 500m study area. With reference to the “Study on Marine Vessels Emission Inventory, Final Report” published by EPD in February 2012, NOx and RSP emissions from large vessels (including Fully Cellular Container Vessel, Ocean Going Vessel, River Trade Vessel, Cruise and Ferry) are not identified within 500m from the identified ASRs identified. The only potential marine emission source located within 500m from the ASRs will be the barges associated with the Hong Kong Oxygen Acetylene Co. Ltd, which is about 150m away from its administration building (ASR A10) and is about 400m away from the resident development in TKO Area 86 (e.g. ASR A13 Lohas Park (Planned Development in Area 86, Package 5; Stage 1)).

5.6.2.9                    Liaison with the operator has been made to collect the latest information on the usage rate of barge, engine power and exhaust dimensions. According to the information provided by the operator, it is found that the use of vessel is infrequent (about once a week) and the vessel would only stay for a short period of time (about 30 minutes). And the engine powers of the vessel are also found to be relatively small as compared to those of typical barges stated in EPD’s “Study on Marine Vessels Emission Inventory, Final Report”. As such, it is considered that the potential air quality impact will only be transient and negligible. (i.e. significant cumulative air quality impact from this vessel during operational phase is therefore not anticipated)

5.6.2.10                In addition, it is understood that the marine emission has already been taken into account in the PATH model, in which the hourly concentration data predicted by the PATH model is taken as the background. More detailed discussion is given in Section 5.6.3.

5.6.3                         Assessment Methodology

Vehicular Emission

Determination of the Assessment Year

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

5.6.3.2                    Vehicular tailpipe emissions from open roads are calculated based on the EPD EMFAC-HK model v2.1 at the time of assessment (end 2012).  However, the latest model version EMFAC-HK v2.5 is just released by EPD in early January 2013.  As concluded in the “Outline of Changes in January 2013 Release of EMFAC-HK” in EPD website, the overall effects on emission estimates are insignificant.  There are only some changes in the output file formats due to items removal as comparing with v2.1.  Besides, one output file name is also changed and the format for input files is changed from VKT to VMT to ensure the consistency in units used in input files (US units).  The above format changes would not impose a change in the emission rate.  Therefore, the vehicular tailpipe emissions generated from v2.1 are still adopted in this assessment.   As NO2 is the pollutant of primary concern for a road project, the assessment year was determined based on the highest total NOx emission from the roads in the study area using the EMFAC-HK model.  Appendix 5.4 presents the methodology and assumptions (prepared by the EIA consultant team of TKO-LT Tunnel) adopted in estimating the emission factors and the calculated results.   Table 5.12 below summarise the total emission of NOx and RSP (in ton/year) for different road types among Year 2021, 2029 and 2036.

Table 5.12      Total Emission of NOx and RSP (in ton/year) for different Road Types among Year 2021, 2029 and 2036

Year

Total NOx Emission (ton/year)

Total RSP Emission (ton/year)

Local Road
(50kph)

Trunk Road
(70kph)

Express-
way
(80kph)

Local Road
(50kph)

Trunk Road
(70kph)

Express-
way
(80kph)

2021

77.1613

27.5650

56.6059

3.7967

1.6028

2.9677

2029

37.5575

12.2910

25.9166

2.3908

1.1432

1.9864

2036

27.8650

8.9417

19.0490

1.9282

0.9563

1.6170

5.6.3.3                    As shown in Table 5.12, it was concluded that the highest vehicular emissions will be found in Year 2021. Therefore, Year 2021 was selected as the assessment year for the operational phase air quality impact assessment. The hourly emissions of NOx and RSP in Year 2021 were divided by the number of vehicles and the distance travelled to obtain the emission factors in gram per miles per vehicle. The calculated 24-hour emission factors of 16 vehicle classes for the different road types in Year 2021 adopted in this air quality impact assessment are presented in Appendix 5.4. 

Background Pollutant Concentrations – PATH Model

5.6.3.4                    PATH model was used to quantify the background air quality during the operational phase of the Project.  The emission sources including those in Pearl River Delta Economic Zone, roads, marine, airport, power plants and industries within Hong Kong were all considered in the PATH model.  The hourly concentration data of background concentration predicted by the PATH model provided by EPD were for Year 2020. As presented in Sections 5.6.3.3, Year 2021 was selected as the assessment year for the operation phase air quality impact assessment.  Therefore, as a conservative assumption, Year 2020 background concentration were adopted in the calculation of the cumulative results. The PATH background concentrations for the concerned grids for Year 2020 and the graphical plots are presented in Appendix 5.5.

 

Vehicle Emissions from Open Roads – CALINE4

5.6.3.5                    The USEPA approved line source air dispersion model, CALINE4 developed by the California Department of Transport was used to assess vehicular emissions impact from existing and planned road network.

5.6.3.6                    The dispersion modelling was conducted based on the meteorological data extracted from the PATH model. The grid cells used for extraction of meteorological data and background pollutant concentration are summarized in Table 5.13.  Surface roughness coefficients as shown in Table 5.13 were used in the CALINE4 model.   

Table 5.13      PATH Model Grid Cells for Extraction of Meteorological Data and Background Pollutant Concentrations

Grid Cells

Surface Roughness (cm)

35_26

100

35_27

100

36_26

100

36_27

100

5.6.3.7                    The surface roughness height is closely related to the land use characteristics, and the surface roughness is estimated as 10 percent of the average height of physical structures within 1km study area.  The wind standard deviation is estimated in accordance with the “Guideline on Air Quality Models (Revised), 1986” based on the surface roughness shown in the above table, as summarized in the below

Stability Class

Wind Standard Deviation

A

32.9

B

32.9

C

25.6

D

18.3

E

11.0

F

5.6

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

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

where

[NO2]pred       is the predicted NO2 concentration

[NOX]pred       is the predicted NOX concentration

MIN                means the minimum of the two values within the brackets

[O3]bkgd         is the representative O3 background concentration

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

5.6.3.9                    Secondary air quality impacts arising from the implementation of roadside noise mitigation measures, namely, semi-enclosures were incorporated into the air quality model.  It was assumed that dispersion of traffic pollutants will in effect be similar to physically shifting the mitigated road section towards the central divider: the traffic pollutants were therefore assumed to emit from the top of the canopies.  In the CALINE4 model, the alignment of the mitigated road section was shifted by a distance equal to the covered extent, the elevation of the mitigated road section was set to the elevation of the barrier top and road type set to ‘fill’.  No correction or adjustment to the receiver heights was made in the model. In addition, owing to the constraint of the CALINE4 model in modelling elevated roads higher than 10m, the road heights of elevated road sections in excess of 10m high above local ground or water surface are set to 10m in the model as the worst-case assumption. 

5.6.3.10                The location of open road emission sources, 24-hour traffic flows and composite emission factors for each road link are presented in Appendix 5.6.

Portal Emission

5.6.3.11                The EPD approved dispersion model, the Industrial Source Complex Short Term (ISCST3) model, was used to predict the portal emission from Road P2 and TKO-LT Tunnel within the study area.

5.6.3.12                According to the information provided by the TKO-LTT EIA Study, 60% of the emissions from TKO-LTT were assumed to be emitted from ventilation building (outside the study area) and 40% from the portal; and, 50% of the emissions from the decked section of Road P2 were assumed to be emitted from the southbound portal within the study area. A summary for the mentioned portals emissions within 500m study area of CBL Project are presented in Table 5.14.

Table 5.14      Summary of Portals Emissions within 500m Study Area

Location

Daily Emission Rates in gram/second

Portal

NOx

RSP

Landscape Deck at Road P2

(Portal Name: B)

0.2280

0.0107

TKO-LT Tunnel Eastbound Main Line

(Portal Name: C)

3.6960

0.1930

40% Emission from Portal

5.6.3.13                Portal emissions were modelled in accordance with the Permanent International Association of Road Congress Report (PIARC, 1991).  Pollutants were assumed to eject from the portal as a portal jet such that 2/3 of the total emissions are dispersed within the first 50 m of the portal and 1/3 of the total emissions within the second 50 m.  The calculation and emission inventory for portal emissions are presented in Appendix 5.7.

5.6.3.14                Meteorological data extracted from the PATH model from different grid cells as listed in Table 5.13 were employed for the model run.  NOx concentrations from the open roads and the portals were firstly added together and OLM as mentioned in Section 5.6.3.7 was subsequently applied. The rural dispersion mode in the ISCST3 model was selected depending on the land uses where the ASRs are located. 

Industrial Emission

5.6.3.15                The potential air quality impact associated with the industrial emissions in the study area was assessed by the EPD approved dispersion model, ISCST3. It was assumed that all chimneys operate over a 24 hour period.  Meteorological data extracted from the PATH model from different grid cells as listed in Table 5.13 was employed for the model run.  Ozone Limiting Method (OLM) was adopted for the conversion of NOX to NO2 based on the predicted O3 level from PATH. The rural dispersion mode in ISCST3 model was selected depending on the land uses where the ASRs are located.  The NO2/NOX conversion is calculated as follows:

[NO2]pred = 0.1x[NOX]pred + MIN {0.9x[NOX]pred, or (46/48)x[O3]bkgd}

where

[NO2]pred       is the predicted NO2 concentration

[NOX]pred       is the predicted NOX concentration

MIN                means the minimum of the two values within the brackets

[O3]bkgd         is the representative O3 background concentration

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

Cumulative Impact of Criteria Air Pollutants

5.6.3.16                The PATH model outputs based on Year 2020 emission inventories were added to the sum of the CALINE4 and ISCST3 model results sequentially on an hour-by-hour basis to derive the short-term and long-term cumulative impacts at each receptor.  The highest pollutant concentration predicted at a receptor amongst the 8760 hours was taken as the worst predicted hourly pollutant concentration for that receptor.  The maximum 24-hour average pollutant concentration at a receptor amongst the 365 days will be the highest predicted daily average concentration. The annual average pollutant concentration at a receptor will be the average of 8760 hourly concentrations. Since all the vehicular emissions associated with the Project are from ground level only, the maximum predicted 1-hour, 24-hour and annual NO2 and RSP concentrations at each ASR at 5 levels (including 1.5m, 5m, 10m, 15m and 20m) will therefore represent the worst-case scenario and are then compared with the respective AQOs.

5.6.4                         Assessment Result

5.6.4.1                    The maximum cumulative 1-hour, 24-hour and annual NO2 and/or RSP concentrations at each representative ASRs have been assessed and the results are presented in Table 5.15 and Table 5.16 below and detailed in Appendix 5.8. No exceedances of the relevant AQOs are predicted at all representative ASRs. In addition, as shown in Appendix 5.8, the worst affected level of each ASRs is at 1.5m above ground. Contours of 1-hour, 24-hour and annual NO2, and 24-hour and annual RSP concentrations at 1.5m above ground are therefore plotted in Drawing no. 209506/EIA/AIR/011-015. The contour results show that no exceedance zone is predicted within the study area of CBL Project Area. Hence, adverse cumulative air quality impact during the operational phase is not anticipated.

Table 5.15      Predicted Cumulative 1-hour, 24-hour and Annual NO2 Concentrations at ASRs

ASR ID

Description

Maximum NO2 Concentrations (µg/m3)

1-hour

(AQO = 300)

24-hour

(AQO = 150)

Annual

(AQO = 80)

A1

Lohas Park Phase II – Le Prestige Tower 1

241

68

19.3

A2

Lohas Park Phase II – Le Prestige Tower 3

241

66

16.7

A3

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

252

73

16.5

A4

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

246

73

16.6

A5

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

204

62

14.6

A6

Lohas Park Phase I – The Capitol Tower 1

240

64

14.9

A7

Chiaphua-Shinko Centre

244

65

15.7

A8

Metrix Manufacturing (HK) Ltd

260

74

18.8

A9

HSBC Office

250

72

23.2

A10

Hong Kong Oxygen Acetylene Co. Ltd

237

65

18.0

A11

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

241

66

18.6

A12

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

241

65

16.6

A13

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

243

67

19.1

A14

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

244

66

17.3

A15

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

241

66

18.5

A16

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

250

76

20.5

A17

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

250

74

18.1

A18

Lohas Park Stage 3 (Planned Development in Area 86,Package 10)

249

73

17.2

A19

Tung Wah Group of Hospitals Aided Primary School & Secondary School 

241

66

17.7

A20

Planned Primary and Secondary Schools 

241

65

15.5

A21

The Beaumount (Under Construction)

204

61

14.2

A22

RTHK Broadcasting House (Planned)

248

70

18.0

A23

Data Centre (Planned)

248

69

17.2

 

Table 5.16      Predicted Cumulative 24-hour and Annual RSP Concentrations at ASRs

ASR ID

Description

Maximum RSP Concentrations (µg/m3)

24-hour

(AQO = 180)

Annual

(AQO = 55)

A1

Lohas Park Phase II – Le Prestige Tower 1

100

38.0

A2

Lohas Park Phase II – Le Prestige Tower 3

100

37.9

A3

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

102

38.2

A4

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

102

38.2

A5

Lohas Park (Planned Development in Area 86, Package 3; Stage 2)

101

37.3

A6

Lohas Park Phase I – The Capitol Tower 1

100

37.8

A7

Chiaphua-Shinko Centre

100

37.8

A8

Metrix Manufacturing (HK) Ltd

101

38.0

A9

HSBC Office

101

38.3

A10

Hong Kong Oxygen Acetylene Co. Ltd

100

37.9

A11

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

100

38.0

A12

Lohas Park Stage 1 (Planned Development in Area 86, Package 6)

100

37.9

A13

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

101

38.0

A14

Lohas Park (Planned Development in Area 86, Package 5; Stage 1)

100

37.9

A15

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

100

38.0

A16

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

102

38.4

A17

Lohas Park Stage 3 (Planned Development in Area 86,Package 11)

102

38.3

A18

Lohas Park Stage 3 (Planned Development in Area 86,Package 10)

102

38.2

A19

Tung Wah Group of Hospitals Aided Primary School & Secondary School 

100

37.9

A20

Planned Primary and Secondary Schools 

100

37.8

A21

The Beaumount (Under Construction)

101

37.3

A22

RTHK Broadcasting House (Planned)

101

38.0

A23

Data Centre (Planned)

101

37.9

 

5.7                         Residual Environmental Impacts

5.7.1                         Construction Phase

5.7.1.1                    With the implementation of the recommended mitigation measures and the dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, no adverse residual air quality impact is anticipated during construction phase.

5.7.2                         Operational Phase

5.7.2.1                    No adverse residual air quality impact is anticipated during operational phase.

5.8                         Conclusion

5.8.1                         Construction Phase

5.8.1.1                    Potential dust impact would be generated from the soil excavation activities, backfilling, site erosion, storage of spoil on site, and transportation of soil during the construction phase. Quantitative fugitive dust assessments have therefore been conducted for the construction of CBL in accordance with Annex 12, Guidelines for Air Quality Assessment, of the TM-EIAO. The assessment result concluded that watering once per hour on all exposed worksites during working hours (7am – 7pm) will be required to control the fugitive dust impact. With the implementation of recommended mitigation measures, no exceedance of criteria provided by Annex 4, Criteria for Air Quality Assessment, of the TM-EIAO is anticipated during the construction phase.

5.8.2                         Operational Phase

5.8.2.1                    Cumulative air quality impact arising from the vehicular emissions from the open roads, tunnel portals and the chimney emissions from various industries in the TKOIE has been assessed according to Annex, 12, Guidelines for Air Quality Assessment of the TM-EIAO. The assessment results concluded that all the predicted cumulative 1-hour, 24-hour and annual NO2 and RSP concentrations would comply with the relevant AQOs and Annex 4, Criteria for Air Quality Assessment, of the TM-EIAO during the operational phase.


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

[2] Air Quality in Hong Kong 2011

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