3 aIR qUALITY.. 1

3.1 Introduction. 1

3.2 Environmental Legislation, Policies, Plans, Standards and Criteria. 1

3.3 Description of the Environment 2

3.4 Sensitive Receivers. 2

3.5 Identification of Environmental Impacts. 2

3.6 Assessment Methodology. 2

3.7 Prediction and Evaluation of Environmental Impacts. 2

3.8 Mitigation of Adverse Environmental Impacts. 2

3.9 Evaluation of Residual Impacts. 2

3.10 Environmental Monitoring and Audit 2

3.11 Conclusion. 2

3 aIR qUALITY

3.1 Introduction

3.1.1 This section presents an air quality impact assessment of air quality during the reclamation works including associated dredging works (DP3) of the Wan Chai Development Phase II project. Compared to the previous scheme, the size of reclamation has been decreased in the latest scheme. Potential construction dust impact is expected to be less. Potential odour impacts from contaminated sediment during dredging at Causeway Bay Typhoon Shelter (CBTS) would also be another issue. Appropriate mitigation measures for the proposed works are identified under this Study where necessary.

3.1.2 In view of the project nature, no adverse air quality impact during the operation phase would be anticipated. Thus, this section would only focus on construction air quality impact assessment.

3.2 Environmental Legislation, Policies, Plans, Standards and Criteria

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

Air Quality Objective & EIAO-TM

3.2.2 The Air Pollution Control Ordinance (APCO) provides the statutory authority for controlling air pollutants from a variety of sources. The Hong Kong Air Quality Objectives (AQOs), which must be satisfied, stipulate the maximum allowable concentrations of certain pollutants over specific periods. The relevant AQOs are listed in Table 3.1.

Table 3.1 Hong Kong Air Quality Objectives

Notes:

(1) Measured at 298 K and 101.325 kPa.

(2) Not to be exceeded more than three times per year.

(3) Not to be exceeded more than once per year.

(4) Arithmetic mean.

(5) Suspended particulates in air with a nominal aerodynamic diameter of 10 mm or smaller.

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

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

3.2.4 In accordance with the EIAO-TM, odour level at an air sensitive receiver should meet 5 odour units based on an averaging time of 5 seconds for odour prediction assessment.

Air Pollution Control (Construction Dust) Regulation

3.2.5 Notifiable and regulatory works are under the control of the Air Pollution Control (Construction Dust) Regulation. Notifiable works are site formation, reclamation, demolition, foundation and superstructure construction for buildings and road construction. Regulatory works are building renovation, road opening and resurfacing slope stabilisation, and other activities including stockpiling, dusty material handling, excavation, concrete production etc. This Project is expected to include both notifiable and regulatory works. Contractors and site agents are required to inform the Environmental Protection Department (EPD) on carrying out construction works and to adopt dust reduction measures to reduce dust emission to the acceptable level.

3.3 Description of the Environment

Baseline Conditions

3.3.1 The study area is in Wan Chai, Causeway Bay and North Point. The nearest EPD air quality monitoring stations are in Central and Central/Western. The annual average concentrations of the pollutants measured at EPD’s Central / Western and Central air quality monitoring stations in 2006 adjacent to the WDII development area are summarised in Table 3.2.

Table 3.2 Annual Average Concentrations of Pollutants in 2006

Pollutant	Annual Average Concentration in 2006 (mg m^-3)	Monitoring Stations
CO	862	Central
NO2	54	Central / Western
RSP	53	Central / Western
TSP	78	Central / Western

3.4 Sensitive Receivers

3.4.1 The study area is within 500m from the project boundary. The study area of air quality assessment is shown in Figure 3.1. The Air Sensitive Receivers (ASRs) including domestic premises, commercial buildings, educational institutions, and recreational and leisure facilities have been identified for air quality impact assessment.

3.4.2 The identified representative ASRs are listed in Table 3.3 and the corresponding locations are shown in Figures 3.2 and 3.3.

Table 3.3 Details of Air Sensitive Receivers

ASRs	Section	Location	Existing / Planned Land Use	No. of floors
A25	Wanchai	Police Headquarters	G/IC	7
A26	Wanchai	HK Academy for Performing Arts (Office/Performance Hall)	G/IC	9
A27	Wanchai	Arts Centre	G/IC	10
A28	Wanchai	Citic Tower	Commercial	42
A29	Wanchai	Servicemen's Guides Association	Commercial	3
A30	Wanchai	HK Academy for Performing Arts (Open Space)	G/IC	9
A31	Wanchai	Shui On Centre	Commercial	34
A32	Wanchai	Hong Kong Convention & Exhibition Centre (HKCEC)	Commercial	46
A33	Wanchai	Pedestrian plaza	Recreation	0
A34	Wanchai	HKCEC Extension	Commercial	8
A35	Wanchai	Great Eagle Centre	Commercial	27
A36	Wanchai	Causeway Centre	Residential	42
A37	Wanchai	Wanchai Swimming Pool	Recreation	3
A38	Wanchai	Wanchai Sports Ground	Recreation	0
A39	Wanchai	SPCA	G/IC	6
A40	Wanchai	Gloucester Road 169-170	Residential	12
A41	Wanchai	Gloucester Road 210	Residential	18
A42	Wanchai	Gloucester Road 226	Residential	22
A43	Causeway Bay	Elizabeth House	Residential	21
A44	Causeway Bay	Sino Plaza	Commercial	33
A45	Causeway Bay	World Trade Centre	Commercial	34
A46	Causeway Bay	Excelsior Hotel	Commercial	28
A47	Causeway Bay	Riviera Mansion	Residential	15
A48	Causeway Bay	Marco Polo Mansion (northern façade)	Residential	15
A49	Causeway Bay	Marco Polo Mansion (eastern façade)	Residential	15
A50	Causeway Bay	Royal Hong Kong Yacht Club	Recreation	3
A51	Causeway Bay	Police Officers Club (Tennis Courts)	Recreation	0
A52	Causeway Bay	Police Officers Club (Bowling Green)	Recreation	0
A53	Causeway Bay	Police Officers Club	Recreation	3
A54	Causeway Bay	Bowling Green, Victoria Park	Recreation	0
A55	Causeway Bay	Victoria Park Public Swimming Pool	Recreation	0
A56	Causeway Bay	Viking Garden	Residential	25
A57	Causeway Bay	Victoria court	Residential	18
A58	Causeway Bay	Mayson Garden	Residential	24
A59	Causeway Bay	Gorden House	Residential	15
A60	Causeway Bay	Belle House	Residential	24
A61	Causeway Bay	Citicorp Centre	Commercial	36
A62	Causeway Bay	Hoi Tao Building	Residential	30
A63	Causeway Bay	Victoria Centre	Residential	30
A64	Causeway Bay	Seaview Estate	Industrial/ commercial	13
A65	Causeway Bay	Harbour Heights	Residential	44
A66	Causeway Bay	Whitfield Road Rest Garden	Recreation	0
A93	North Point	City Garden (Block 11) (the height of 1^st Sensitive Receiver is located at 5m above ground)	Residential	27
A94	North Point	City Garden (Block 6) (the height of 1^st Sensitive Receiver is located at 5m above ground)	Residential	27
A95	North Point	Hong Kong Baptist Church Henrietta Secondary School	Educational	N/a
A96	North Point	Provident Centre (Block 1)	Residential	25
A97	North Point	Provident Centre (Block 6)	Residential	25
A98	North Point	Provident Centre (Block 17)	Residential	25
Future
A70	Central	Central Government Complex	G/IC	N/a

3.4.3 The planned ASR A70 is Central Government Complex which may be occupied during the construction period of WDII Project. As a conservative approach, ASR A70 was considered in the construction dust impact assessment.

3.5 Identification of Environmental Impacts

Air Quality Impact from Construction Activities

3.5.1 Construction of seawall and filling works are the major construction works during reclamation. Materials handling, wind erosion, truck haulage on unpaved roads are other major sources of dust impact. SO₂, NO₂ and smoke emitted from diesel-powered equipment may also affect the air quality of the study area.

3.5.2 Potential marine traffic emissions from the dredgers would be expected. However, given that only a maximum of 10 dredgers would be concurrently operated at CBTS and Wan Chai waterfront, the associated emissions should be limited. In addition, the nearest distance between the dredgers and ASR (A50) at CBTS is 66m while the nearest distance at Wan Chai waterfront is 27m (ASR A32). Therefore, marine traffic emission impact arising from the Project is anticipated to be insignificant.

3.5.3 The concurrent works for the CRIII project has also been taken into account in assessing the impacts.

Odour Impact from Dredging Activities

3.5.4 The water quality in the typhoon shelter has been polluted by sewage discharges in the past and sediments deposited on the seabed in the vicinity of storm outfalls. These sediments may contain high concentrations of organic matter and heavy metals. The sediments in CBTS would be dredged away when carrying out the temporary reclamation.

3.5.5 For the dredging activities carried out in the vicinity of Police Officers’ Club, the dredging operation will be restricted to only 1 small close grab dredger to minimise the odour impact during the dredging activity. The dredging rate should be reduced as much as practicable for the area in close proximity to the Police Officers’ Club. As the sediments may contain highly contaminated mud which may be disposed with the use of geosynthetic containers (details shall refer to Section 6), grab dredger has to be used for filling up the geosynthetic containers on barges. As there is no programme constraint for the removal of the sediments at the south-west corner of the typhoon shelter in the vicinity of Police Officers’ Club for mitigating the existing odour problem, the dredging rate can be slowed down or restricted to specific non-popular hours in weekdays when it is necessary during construction.

3.6 Assessment Methodology

3.6.1 There is potential for SO₂, NO₂ and smoke to be emitted from the diesel-powered equipment and dredgers being used during the construction phase. However, the number of such plant required on-site (land based and water based) will be limited and under normal operation, equipment with proper maintenance is unlikely to cause significant dark smoke emissions and gaseous emissions are expected to be minor. Thus, the AQOs are not expected to be exceeded. Notwithstanding, plant should be regularly maintained to minimise emissions.

3.6.2 The principal source of air pollution during the construction phase will be dust from the dusty activities as mentioned in Section 3.5.1. The impact of fugitive dust sources on air quality depends upon the quantity as well as the drift potential of the dust particles emitted into the atmosphere. Large dust particles (i.e. over 100 mm in diameter) will settle out near the source and particles that are between 30 and 100 mm in diameter are likely to undergo impeded settling. The main dust impacts are likely to arise from particles less than 30 mm in diameter, which have a greater potential to disperse over greater distances.

3.6.3 According to the USEPA AP-42, construction dust particles may be grouped into nine particle size classes. Their size ranges are 0 - 1 mm, 1 - 2 mm, 2 - 2.5 mm, 2.5 - 3 mm, 3 - 4 mm, 4 - 5 mm, 5 - 6 mm, 6 - 10 mm and 10 - 30 mm, and the percentage of particles in each class was estimated to be 4%, 7%, 4%, 3%, 7%, 5%, 4%, 17% and 49%, respectively.

3.6.4 The emission rates adopted in the WDII project assessment for different construction activities were based on the USEPA Compilation of Air Pollutant Emission Factors (AP-42), 5th edition. Table 3.4 gives the relevant clauses for emission factors used in this assessment in AP-42. Detailed calculation of emission rate is presented in Appendix 3.1.

Table 3.4 Emission Factors for Construction Activities

Construction Activities	Emission Rate (g/m^2/s)	Remark
Road Construction, Building Construction and Material Handling (as Heavy Construction)	E = 3.113426E-05	- 50% work area - 75% reduction by water suppression (watering four times a day) -USEPA AP-42 5^th ED., S.13.2.3.3
Wind Erosion	E = 1.347666E-06	- 50% work area - AP-42 5^th ED., S.11.9 Table 11.9.4

3.6.5 The Air Pollution Control (Construction Dust) Regulation specifies that dust suppression measures such as watering should be applied for the construction site. Dust emission from the site would be reduced by 75% if watering with complete coverage of active construction area four times a day. This assumption was adopted in the construction dust impact assessment.

3.6.6 As confirmed with the Project Proponent, 10 working hours per day (08:00-18:00) was assumed for the dusty construction works in the assessment. Wind erosion of open work sites would take place over the whole day.

3.6.7 The following summarises the construction activities during the construction stage of the DP3 Project and other construction activities under WDII Project. The locations of the different reclamation sites are shown in Figure 3.4.

Causeway Bay Temporary Reclamation (CBR)

· Temporary Relocation Causeway Bay Typhoon Shelter (CBTS)

· CBTS Temporary Reclamation Stage 1 (TCBR1W & TCBR1E)

· CBTS Temporary Reclamation Stage 2 (TCBR2)

· CBTS Temporary Reclamation Stage 3 (TCBR3)

· CBTS Temporary Reclamation Stage 4 (TCBR4)

· Slip Road 8 & Victoria Park Reprovisioning

Ex-PCWA Temporary Reclamation

· Temporary Reclamation PCWA Stage 1 (TPCWAE)

· Temporary Reclamation PCWA Stage 2 (TPCWAW)

Wan Chai Reclamation (WCR)

· Wan Chai Reclamation Stage 1 (WCR1)

· Wan Chai Reclamation Stage 2 (WCR2)

· Wan Chai Reclamation Stage 3 (WCR3)

· Wan Chai Reclamation Stage 4 (WCR4)

· New Ferry Pier Reprovisioning & Demolish Existing Pier

· Helipad Reprovisioning at HKCEC

· Roads

HKCEC Reclamation

· HKCEC Reclamation Stage 1 (Water Channel) (HKCEC1)

· HKCEC Reclamation Stage 2 (HKCEC2E & HKCEC2W)

· MTR Tunnel Crossing

· HKCEC Reclamation Stage 3 (HKCEC3E & HKCEC3W)

· Roads

Cross Harbour Watermains

· Submarine Pipeline

· Land Section

North Point Reclamation (NPR)

· North Point Reclamation Stage 1 (NPR1)

· North Point Reclamation Stage 2 (NPR2E & NPR2W)

Construction of IECL

· IECL Connection Work

· East Portal and IEC Connection

Construction of Central Interchange

Tunnel Building and Installation

· East Ventilation Building

· Administration Building

· Central Ventilation Building

3.6.8 Beside the Wan Chai development, some construction activities would be undertaken within 500m from the boundary of WDII development area. The construction period of whole CRIII Project is from February 2003 to September 2012. The interfacing of CRIII dusty construction activities would be from end 2008 to the 1^st quarter of 2012. The concurrent dusty construction activities undertaken within 500 m from the boundary of the WDII development area are summarized as follows.

Construction of CWB Tunnel Under CRIII Project

· CWB Tunnel at Initial Reclamation Area East

· CWB Tunnel at Final Reclamation Area East

3.6.9 Based on the construction programme (Appendix 2.5) and the number of dusty activities on site, four worst-case scenarios for the DP3 Project have been identified throughout the construction period and are shown in Table 3.5. Overall, the scenarios presented can be considered to be representative of the worst case. The figures showing locations of dusty construction site areas for each scenario are presented in Figure A3.1 to A3.4 in Appendix 3.1.

Table 3.5 Different Major Dust Generating Activities in the Worst Case Scenarios during Construction Phase

Period	2009 – Early 2010	Mid 2010 – Early 2011	Mid 2011 – Early 2012	Mid 2012 – Early 2013
Worst month	Jan 2010	Aug 2010	April 2012	Feb 2013
Activities	Scenario 1	Scenario 2	Scenario 3	Scenario 4
1	TCBRIE– Filling	TCBR1E – CWB Tunnel	TCBR1W – CWB Tunnel	TCBR3 – CWB Tunnel
2	TCBRIW – Filling	TCBR1W – CWB Tunnel	TCBR2 – CWB Tunnel	TCBR4 – Filling
3	TCBRIE – CWB Tunnel	TCBR2 – CWB Tunnel	TCBR3 – CWB Tunnel	TPCWAW – CWB Tunnel
4	TCBR2 – Filling	TPCWAE – CWB Tunnel	TPCWAE – CWB Tunnel	WCR2 – Promenade
5	TPCWAE – CWB Tunnel	WCR1 - Drainage	WCR2 – CWB Tunnel	WCR3 – Filling
6	WCR1 – Filling	WCR1 – Cooling Water	HKCEC2E – Filling	WCR4 – Filling
7	WCR1 – CWB Tunnel	WCR1 – CWB Tunnel	HKCEC2W – Filling	WCR4 – Drainage
8	New Ferry Piers	HKCEC1 – Cooling Water	HKCEC3E – Filling	HKCEC2W – CWB Tunnel
9	HKCEC1 – Cooling Water	MTR - Piling	HKCEC3E – Drainage	HKCEC3W – CWB Tunnel
10	HKCEC2E - Filling	NPR1 – CWB Tunnel	HKCEC3W – Drainage	HKCEC3E – CWB Tunnel
11	Cross Harbour Watermains – Land Sections	NPR2E – Filling	HKCEC3E – CWB Tunnel	IEC Connection Work
12	NPR1 – CWB Tunnel	CRIII – CWB Tunnel at Initial Area East	NPR2W – CWB Tunnel	East Ventilation Building
13	NPR2E – Filling	CRIII – CWB Tunnel at Final Area West
14	NPR2W – CWB Tunnel	CRIII – CWB Tunnel at Final Area East
15	CRIII – CWB Tunnel at Initial Area East
16	CRIII-CWB Tunnel at Final East

3.6.10 Fugitive Dust Model (FDM) (1993 version) was used to assess potential dust impact from the construction works. The worst case meteorological data was used to predict the 1-hour and 24-hour average TSP concentrations at representative discrete ASRs close to the construction works. Since the construction activities would be undertaken at ground level and underground level, the worst dust impact on the ASRs would be at the ground floor of the ASRs. The height of 1.5m above ground, which is the breathing level of human, was adopted for the construction dust impact assessment. As there are some ASRs at the podium level, assessment for ASRs at 5m above ground was also included in the assessment. The meteorological data used in the model were:

· Wind speed: 1 m/s

· Wind direction: 360 wind direction

· Stability class: D (daytime) & F (night time)

· Surface roughness: 1m

· Mixing height: 500 m

3.6.11 Daily TSP concentrations were calculated as follows:

Daily TSP concentration = (number of working hour)/24 ´ (1-hour average maximum TSP concentration during working hours) + (number of non-working hour)/24 ´ (1-hour average maximum TSP concentration during non-working hours) + Background

3.6.12 The background TSP concentration of 77 mg/m³, based on the latest five years average monitoring data from EPD Central/Western monitoring station, was adopted as an indication of the future TSP background concentration. As the monitoring data in year 2001 and 2002 were below their respective minimum data requirement of 66% for number of data within the period, therefore, the annual average concentration of TSP was calculated based on the data in Year 2000 and 2003-2006.

Level of Uncertainty in the Assessment

3.6.13 The emission rates adopted in the construction dust impact assessment are in accordance with the USEPA Compilation of Air Pollutant Emission Factors (AP-42), which had previously been applied in similar situations in other EIA studies.

3.6.14 The Fugitive Dust Model (FDM) for construction dust impact assessment is generally accepted models for use in assessing construction dust impacts.

3.6.15 There would be some limitations such as the accuracy of the predictive base data for future conditions e.g. plant inventory for the proposed construction works and sequences of construction activities. Uncertainties in the assessment of impacts have been considered when drawing conclusions from the assessment.

3.7 Prediction and Evaluation of Environmental Impacts

3.7.1 Dredging and reclamation activities would overlap some construction activities of WDII, Trunk Road and CRIII Project will cause a cumulative dust impact on the nearby sensitive receivers.

3.7.2 Since most of the construction activities are at ground level, the likely cumulative dust impacts of the WDII on the ASRs at 1.5 m and 5 m above ground were modelled.

3.7.3 The predicted cumulative maximum 1-hour average TSP and 24-hour average TSP during construction are shown in Tables 3.6 - 3.7.

Table 3.6 Predicted Cumulative Maximum 1-hour Average TSP Concentrations at 1.5m above ground

ASR	Predicted Concentration (mg m^-3) *
	Scen. 1	Scen. 2	Scen. 3	Scen. 4	Max.
A25	123	107	172	162	172
A26	151	130	252	247	252
A27	195	135	199	196	199
A28	132	120	222	204	226
A29	170	154	409	402	409
A30	216	175	277	276	277
A31	208	138	193	192	208
A32	221	186	394	434	434
A33	378	232	367	269	378
A34	246	173	328	224	328
A35	141	126	240	278	278
A36	124	121	175	205	205
A37	214	213	329	414	414
A38	241	228	235	292	292
A39	225	206	199	238	238
A40	113	112	131	152	152
A41	120	118	129	150	150
A42	121	120	129	147	147
A43	127	125	125	138	138
A44	150	149	149	163	163
A45	189	189	189	218	218
A46	193	193	193	230	230
A47	180	180	180	226	226
A48	158	158	158	224	224
A49	151	150	151	219	219
A50	306	306	306	193	306
A51	212	212	212	210	212
A52	201	199	200	191	201
A53	280	277	277	216	280
A54	147	145	156	185	320
A55	125	123	129	153	237
A56	111	108	113	133	148
A57	116	114	119	141	194
A58	123	121	128	148	277
A59	129	128	137	154	183
A60	148	147	160	166	167
A61	183	182	193	181	193
A62	166	162	162	155	166
A63	221	212	174	195	221
A64	194	175	165	223	223
A65	185	172	166	254	254
A66	170	170	184	184	184
A70	217	210	168	162	217
A95	225	220	102	238	238
A96	167	162	99	185	185
A97	149	145	98	167	167
A98	121	117	95	132	132

Note: * Background concentration is included.

Hourly TSP criteria (EIAO-TM): 500 mg m^-3

Table 3.7 Predicted Cumulative Maximum 24-hour Average TSP Concentrations for at 1.5m above ground

ASR	Predicted Concentration (mg m^-3) *
	Scen. 1	Scen. 2	Scen. 3	Scen. 4	Max.
A25	98	91	122	117	122
A26	111	102	158	156	158
A27	131	105	134	133	134
A28	102	98	145	136	147
A29	119	113	229	226	229
A30	141	124	169	169	169
A31	137	106	131	130	137
A32	143	129	221	241	241
A33	213	149	210	168	213
A34	154	122	193	145	193
A35	106	101	152	169	169
A36	99	98	122	136	136
A37	140	140	192	231	231
A38	152	146	151	178	178
A39	145	137	136	154	154
A40	94	94	103	112	112
A41	97	97	102	111	111
A42	97	98	102	110	110
A43	100	100	100	107	107
A44	111	111	111	119	119
A45	129	129	129	143	143
A46	130	130	130	148	148
A47	124	124	124	146	146
A48	114	115	115	144	144
A49	111	111	112	142	142
A50	180	183	183	132	183
A51	139	141	141	139	141
A52	134	134	135	132	135
A53	171	170	170	144	171
A54	109	108	113	127	187
A55	99	99	101	113	151
A56	92	92	94	103	110
A57	95	94	97	107	132
A58	98	97	101	111	170
A59	101	100	105	114	126
A60	109	109	116	120	120
A61	125	125	132	127	132
A62	118	117	118	115	118
A63	142	142	124	132	142
A64	130	124	119	145	145
A65	126	122	118	159	159
A66	120	120	127	129	129
A70	141	139	121	118	141
A95	144	145	89	153	153
A96	117	118	88	128	128
A97	109	110	87	119	119
A98	97	97	86	103	103

Note: * Background concentration is included.

24-hour TSP criteria (AQO): 260 mg m^-3

Table 3.8 Predicted Cumulative Maximum 1-hour Average TSP Concentrations at 5m above ground

ASR	Predicted Concentration (mg m^-3) *
	Scen. 1	Scen. 2	Scen. 3	Scen. 4	Max.
A25	125	104	175	163	175
A26	153	122	248	242	248
A27	194	125	199	196	199
A28	135	115	226	207	230
A29	173	142	364	354	364
A30	213	155	266	266	266
A31	206	127	192	195	206
A32	219	167	318	390	390
A33	323	187	312	270	323
A34	229	151	308	224	308
A35	143	120	234	259	259
A36	125	114	178	203	203
A37	203	182	258	371	371
A38	222	186	234	291	291
A39	214	176	202	241	241
A40	115	108	134	155	155
A41	122	114	132	153	153
A42	124	115	132	150	150
A43	130	120	128	141	141
A44	152	138	151	167	167
A45	185	167	185	221	221
A46	188	170	188	231	231
A47	176	160	176	226	226
A48	158	145	157	221	221
A49	152	139	152	216	216
A50	259	230	259	195	259
A51	202	179	200	208	208
A52	199	178	197	196	199
A53	265	233	263	220	265
A54	148	134	156	188	209
A55	127	117	130	157	216
A56	113	105	115	136	151
A57	118	109	121	144	191
A58	124	115	131	152	223
A59	130	121	140	159	179
A60	148	136	163	171	171
A61	180	163	196	186	196
A62	168	150	166	158	168
A63	219	190	177	196	219
A64	194	161	167	222	222
A65	186	157	167	248	248
A66	169	154	186	189	189
A70	201	174	173	167	201
A93	410	354	115	432	432
A94	301	258	106	299	301
A95	228	199	104	239	239
A96	171	152	101	189	189
A97	152	137	99	171	171
A98	124	113	96	135	135

Note: * Background concentration is included.

Hourly TSP criteria (EIAO-TM): 500 mg m^-3

Table 3.9 Predicted Cumulative Maximum 24-hour Average TSP Concentrations at 5m above ground

ASR	Predicted Concentration (mg m^-3) *
	Scen. 1	Scen. 2	Scen. 3	Scen. 4	Max.
A25	100	90	122	117	122
A26	112	98	154	152	154
A27	131	100	133	132	133
A28	105	95	146	137	147
A29	122	108	205	200	205
A30	140	114	162	162	162
A31	136	100	129	132	136
A32	142	119	185	219	219
A33	186	126	182	167	186
A34	145	111	181	144	181
A35	108	98	148	158	158
A36	99	95	123	134	134
A37	134	125	160	209	209
A38	142	126	149	176	176
A39	139	123	136	155	155
A40	95	92	104	113	113
A41	99	95	103	112	112
A42	100	96	103	111	111
A43	103	98	101	108	108
A44	112	106	111	120	120
A45	126	119	126	144	144
A46	127	119	127	148	148
A47	122	115	122	145	145
A48	114	109	114	142	142
A49	112	106	112	140	140
A50	158	145	157	132	158
A51	136	126	135	138	138
A52	133	124	132	134	134
A53	163	149	161	145	163
A54	110	104	113	128	137
A55	100	96	102	115	140
A56	94	90	95	104	111
A57	96	92	98	109	129
A58	99	95	102	113	144
A59	101	97	106	116	125
A60	110	104	117	122	122
A61	124	117	132	129	132
A62	119	111	119	116	119
A63	143	131	125	132	143
A64	132	118	119	143	143
A65	128	115	119	155	155
A66	118	112	128	131	131
A70	134	122	123	120	134
A93	224	200	95	235	235
A94	181	162	91	179	181
A95	148	135	90	152	152
A96	122	114	89	129	129
A97	113	106	88	121	121
A98	99	95	86	105	105

Note: * Background concentration is included.

24-hour TSP criteria (AQO): 260 mg m^-3

3.7.4 Based on results indicated in Tables 3.6 and 3.7, no exceedance of 1-hour average and 24-hour average TSP guideline and AQO is predicted at the ASRs 1.5m and 5m above ground. The predicted cumulative maximum 1-hour average and 24-hour average TSP concentration contours at 1.5m and 5.m above local ground are shown in Figures 3.6 to 3.15. Exceedances of the 1-hour average TSP guideline of 500 mg/m³ and the 24-hour average TSP AQO of 260 mg/m³ are noted in some areas at 1.5m above ground including:

Exceedance of the 1-hour average TSP guideline of 500 mg/m³

Scenario 1 – sea area, area next to Cross Harbour Tunnel and area next to HKCEC, IEC;

Scenario 2 – sea area and IEC

Scenario 3 – sea area, area next to Cross Harbour Tunnel, area next to HKCEC, area underneath New Atrium Link (Extension of HKCEC)

Scenario 4 - sea area, IEC, part of waterfront in the vicinity of Causeway Bay Flyover, area underneath New Atrium Link (Extension of HKCEC), area in the vicinity of existing Wan Chai Pier and nearby PTI, area next to Servicemen’s Guides Association

Exceedance of the 24-hour average TSP AQO of 260 mg/m³

Scenario 1 – sea area, area next to Cross Harbour Tunnel and area next to HKCEC, IEC;

Scenario 2 – sea area, IEC and area next to Cross Harbour Tunnel

Scenario 3 – sea area, area next to Cross Harbour Tunnel, areas next to Servicemen’s Guides Association and HKCEC, area underneath New Atrium Link (Extension of HKCEC)

Scenario 4 - sea area, IEC, part of waterfront in the vicinity of Causeway Bay Flyover, GFS Helipad, area underneath New Atrium Link (Extension of HKCEC), area in the vicinity of existing Wan Chai Pier and nearby PTI, area next to Servicemen’s Guides Association

3.7.5 Exceedances were noted at the above identified areas but they are not ASRs and no air sensitive areas are located within these exceedance areas

3.8 Mitigation of Adverse Environmental Impacts

Construction Phase

3.8.1 As shown in Tables 3.10 to 3.12, the cumulative maximum 1-hour average and 24-hour average TSP concentrations are predicted to comply with the TSP criteria at all representative ASRs with watering on the active works area four times a day. The area within study area of WDII Project would also meet the TSP criteria. In order to further ensure compliance with the AQOs at the ASRs at all time, requirements of the Air Pollution Control (Construction Dust) Regulation shall be adhered to during the construction period. In addition, the following mitigation measures, good site practices and a comprehensive dust monitoring and audit programme are recommended to minimise cumulative dust impacts.

· Strictly limit the truck speed on site to below 10 km per hour and water spraying to keep the haul roads in wet condition;

· Watering during excavation and material handling;

· Provision of vehicle wheel and body washing facilities at the exit points of the site, combined with cleaning of public roads where necessary; and

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

3.9 Evaluation of Residual Impacts

3.9.1 With the implementation of the proposed mitigation measures and the dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation during the construction phase, no adverse residual air quality impact would be expected.

3.9.2 No adverse odour impact from contaminated sediment during dredging would be anticipated with the implementation of proposed mitigation measures.

3.10 Environmental Monitoring and Audit

3.10.1 With the implementation of the proposed dust suppression measures, good site practices and dust monitoring and audit programme, acceptable dust impact would be expected at the ASRs. Details of the monitoring requirements such as monitoring locations, frequency of baseline and impact monitoring are presented in the stand-alone EM&A Manual.

3.11 Conclusion

3.11.1 During construction, reclamation, filling and surcharging were identified as the major dust sources. Trunk Road tunnel works would also generate dust and contribute cumulative dust impacts. Due to the complex sequencing of the construction activities, six worst case scenarios of the construction schedules have been identified and assessed. The findings of the construction phase air quality assessment indicate that no exceedence of the 1-hour and 24-hour total TSP criteria are predicted at ASRs in the vicinity of the construction sites. In order to ensure compliance with the TSP criteria at the ASRs at all times, the dust suppression measures and requirements of the Air Pollution Control (Construction Dust) Regulation should be adhered to during the construction period. In addition, a comprehensive dust monitoring and audit programme are recommended to ensure the effective implementation of dust suppression measures. Therefore, no adverse residual air quality impacts due to the dredging and reclamation activities would be anticipated.

3.11.2 Potential odour impacts from contaminated sediment would be expected when the dredging activities carrying out in the vicinity of Police Officers’ Club. As the dredging operation will be restricted to only 1 small close grab dredger, the odour impact during the dredging activity would be minimised. With the implementation of proposed mitigation measures, no adverse odour impacts from contaminated sediment would be anticipated.