TABLE OF CONTENTS

3 Air Quality Impact.. 3-1

3.1 Introduction. 3-1

3.2 Environmental Legislation, Standards and Guidelines. 3-1

3.3 Description of Environment 3-3

3.4 Identification of Air Sensitive Receivers. 3-5

3.5 Identification of Environmental Impact 3-6

3.6 Assessment Methodology. 3-9

3.7 Prediction and Evaluation of Environmental Impacts. 3-19

3.8 Mitigation of Adverse Environmental Impacts. 3-22

3.9 Evaluation of Residual Impacts. 3-24

3.10 Environmental Monitoring and Audit 3-24

3.11 Conclusion. 3-24

List of tables

Table 3.1 Prevailing Hong Kong Air Quality Objectives. 3-1

Table 3.2 Proposed Hong Kong Air Quality Objectives. 3-2

Table 3.3 Average Concentrations of Pollutants in the Recent Three Years (Year 2021 – 2023) at Southern EPD Air Quality Monitoring Station. 3-4

Table 3.4 Background Air Pollutants in Year 2030 (Extracted from the PATH-v3.0) 3-4

Table 3.5 Representative Air Sensitive Receivers. 3-6

Table 3.6 Method Adopted in the Assessment for the Identified Parking Sites, PTI, Bus and Shuttle Bus Terminus. 3-11

Table 3.7 Stability-dependent Multiplicative Factors. 3-19

Table 3.8 Predicted Cumulative Concentrations at Representative Air Sensitive Receivers During the Operation Phase. 3-20

Table 3.9 Summary of Exceedance Zone Occurrences in the Contour Plots. 3-22

LIST OF FIGURES

Figure 3.1	Locations of Concerned PATH Grids and Representative Air Sensitive Receivers
Figure 3.2	The Extent of Dredging
Figure 3.3a	Closest Separation Distances from ASRs to Construction Vessels and Works Area During Peak Construction Period
Figure 3.3b	Closest Separation Distances from ASRs to Construction Vessels and Works Area During the Minimum Vessel Utilisation Period
Figure 3.4	Emission Sources Within 500 m Assessment Area
Figure 3.5a	Marine Emission Locations (Maneuvering) - Existing and Proposed Marine Routes Entering/Leaving Aberdeen Typhoon Shelter
Figure 3.5b	Marine Emission Locations (Maneuvering) - Proposed Marine Route Adjacent to Ap Lei Chau Praya Road Within Aberdeen Typhoon Shelter
Figure 3.5c	Marine Emission Locations (Maneuvering) - Proposed Marine Route Adjacent to Sham Wan Road Within Aberdeen Typhoon Shelter
Figure 3.5d	Marine Emission Locations (Maneuvering) - Ferry Services at the Proposed Landing Facility at Proposed Eastern Breakwater
Figure 3.5e	Marine Emission Locations – Adventure Ship
Figure 3.5f	Locations of Hotelling Emissions
Figure 3.6	Contours of Cumulative 10^th Highest Daily Average RSP Concentration at 1.5mAG during Operation Phase
Figure 3.7	Contours of Cumulative Annual Average RSP Concentration at 1.5mAG during Operation Phase
Figure 3.8	Contours of Cumulative 19^th Highest Daily Average FSP Concentration at 1.5mAG during Operation Phase
Figure 3.9	Contours of Cumulative Annual Average FSP Concentration at 1.5mAG during Operation Phase
Figure 3.10	Contours of Cumulative 19^th Highest Hourly Average NO2 Concentration at 1.5mAG during Operation Phase
Figure 3.11	Contours of Cumulative 10^th Highest Daily Average NO2 Concentration at 1.5mAG during Operation Phase
Figure 3.12	Contours of Cumulative Annual Average NO2 Concentration at 1.5mAG during Operation Phase
Figure 3.13	Contours of Cumulative 4^th Highest 10-mins Average SO2 Concentration at 1.5mAG during Operation Phase
Figure 3.14	Contours of Cumulative 4^th Highest Daily Average SO2 Concentration at 1.5mAG during Operation Phase
Figure 3.15	Contours of Cumulative 10^th Highest Daily Average RSP Concentration at 5mAG during Operation Phase
Figure 3.16	Contours of Cumulative Annual Average RSP Concentration at 5mAG during Operation Phase
Figure 3.17	Contours of Cumulative 19^th Highest Daily Average FSP Concentration at 5mAG during Operation Phase
Figure 3.18	Contours of Cumulative Annual Average FSP Concentration at 5mAG during Operation Phase
Figure 3.19	Contours of Cumulative 19^th Highest Hourly Average NO2 Concentration at 5mAG during Operation Phase
Figure 3.20	Contours of Cumulative 10^th Highest Daily Average NO2 Concentration at 5mAG during Operation Phase
Figure 3.21	Contours of Cumulative Annual Average NO2 Concentration at 5mAG during Operation Phase
Figure 3.22	Contours of Cumulative 4^th Highest 10-mins Average SO2 Concentration at 5mAG during Operation Phase
Figure 3.23	Contours of Cumulative 4^th Highest Daily Average SO2 Concentration at 5mAG during Operation Phase
Figure 3.24	Contours of Cumulative 19^th Highest Hourly Average NO2 Concentration at 10mAG during Operation Phase
Figure 3.25	Contours of Cumulative 10^th Highest Daily Average NO2 Concentration at 10mAG during Operation Phase
Figure 3.26	Contours of Cumulative Annual Average NO2 Concentration at 10mAG during Operation Phase
Figure 3.27	Contours of Cumulative 19^th Highest Hourly Average NO2 Concentration at 15mAG during Operation Phase
Figure 3.28	Contours of Cumulative 10^th Highest Daily Average NO2 Concentration at 15mAG during Operation Phase
Figure 3.29	Contours of Cumulative Annual Average NO2 Concentration at 15mAG during Operation Phase

LIST OF appendiCES

Appendix 3.1	Traffic Forecast for Air Quality Assessment
Appendix 3.2	EMFAC-HK Model Assumptions
Appendix 3.3	Summary of Source Parameters for Open Road Vehicular Emission Using AERMOD
Appendix 3.4	Detailed Calculation of Emissions Associated with Bus and Minibus Termini, Heavy Goods Vehicle and Coach Parking Sites
Appendix 3.5	Detailed Calculation of Industrial Emissions
Appendix 3.6	Detailed Calculation of Marine Emissions
Appendix 3.7	Determination of Surface Characteristics Parameters for AERMET
Appendix 3.8	Derivation of Cumulative Annual Average NOx to NO2 Conversion Equation using Jenkin Method
Appendix 3.9	Detailed Assessment Results under With Project Scenario

3 Air Quality Impact

3.1 Introduction

3.1.1 This section presents the assessment on potential air quality impacts on the air sensitive receivers (ASRs) arising from construction and operation of the Project.  Assessment has been conducted in accordance with the criteria and guidelines as stipulated in Annex 4 and Annex 12 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) as well as the requirements given in Clause 3.4.3 of the EIA Study Brief (No. ESB-357/2022). 

3.1.2 The assessment has taken into consideration the latest project layout, including the proposed breakwaters alignments with marine access in the form of landing facilities, the proposed land access and the proposed wave wall in the form of floating breakwater, as discussed in Section 2 and as shown in Figure 2.1.

3.2 Environmental Legislation, Standards and Guidelines

3.2.1 The criteria for evaluating air quality impacts and the guidelines for air quality assessment are laid down in Annex 4 and Annex 12 of the EIAO-TM.

Air Quality Objectives & Technical Memorandum on EIA Process

3.2.2 The Air Pollution Control Ordinance provides the statutory authority for controlling air pollutants from a variety of sources.  The Hong Kong Air Quality Objectives (AQOs), which stipulate the maximum allowable concentrations over specific periods for typical pollutants, should be met.  The prevailing AQOs are listed in Table 3.1. Subject to the effective date of the proposed AQOs as shown in Table 3.2, the proposed AQOs are also considered as the benchmark for conducting air quality impact assessment of this EIA study.

Table 3.1    Prevailing Hong Kong Air Quality Objectives

Pollutants	Averaging Time	Concentration Limit (µg/m^3)^[1]	Number of Exceedance Allowed per Year
Respirable Suspended Particulates (RSP or PM10) ^[2]	24-hour	100	9
	Annual ^[4]	50	N/A
Fine Suspended Particulates (FSP or PM2.5) ^[3]	24-hour	50	18 ^[5]
	Annual ^[4]	25	N/A
Nitrogen Dioxide (NO2)	1-hour	200	18
	Annual ^[4]	40	N/A
Sulphur Dioxide (SO2)	10-min	500	3
	24-hour	50	3
Carbon Monoxide (CO)	1-hour	30,000	0
	8-hour	10,000	0
Ozone	8-hour	160	9
Lead (Pb)	Annual ^[4]	0.5	N/A

Notes:

[1] All measurements of the concentration of gaseous air pollutants, i.e., sulphur dioxide, nitrogen dioxide, ozone and carbon monoxide, are to be adjusted to a reference temperature of 293 Kelvin and a reference pressure of 101.325 kilopascal.

[2] Suspended particulates in air with a nominal aerodynamic diameter of 10µm or smaller.

[3] Suspended particulates in air with a nominal aerodynamic diameter of 2.5µm or smaller.

[4] Arithmetic mean

[5] The number of allowable exceedances of 18 days per calendar year as the benchmark for conducting air quality impact assessment under Government Project Environmental Impact Assessment studies.

Table 3.2    Proposed Hong Kong Air Quality Objectives

Pollutants	Averaging Time	Concentration Limit (µg/m^3)^[1]	Number of Exceedance Allowed per Year
Respirable Suspended Particulates (RSP or PM10) ^[2]	24-hour	75	9
	Annual ^[4]	30	N/A
Fine Suspended Particulates (FSP or PM2.5) ^[3]	24-hour	37.5	18
	Annual ^[4]	15	N/A
Nitrogen Dioxide (NO2)	1-hour	200	18
	24-hour^[5]	120	9
	Annual ^[4]	40	N/A
Sulphur Dioxide (SO2)	10-min	500	3
	24-hour	40	3
Carbon Monoxide (CO)	1-hour	30,000	0
	8-hour	10,000	0
	24-hour^[5]	4,000	0
Ozone	8-hour	160	9
	Peak Season ^[5]	100	N/A
Lead (Pb)	Annual^[4]	0.5	N/A

Notes:

[1] All measurements of the concentration of gaseous air pollutants, i.e., sulphur dioxide, nitrogen dioxide, ozone and carbon monoxide, are to be adjusted to a reference temperature of 293 Kelvin and a reference pressure of 101.325 kilopascal.

[2] Suspended particulates in air with a nominal aerodynamic diameter of 10µm or smaller.

[3] Suspended particulates in air with a nominal aerodynamic diameter of 2.5µm or smaller.

[4] Arithmetic mean

[5] 24-hour level for NO₂, peak season level for Ozone and 24-hour level for CO are the new parameters in the World Health Organisation (WHO) Global Air Quality Guidelines (AQGs) and AQO.

3.2.3 The Annex 4 of pre-amended EIAO-TM stipulated that hourly Total Suspended Particulates (TSP) level should not exceed 500 µg/m³ measured at 298K and 101.325 kPa (one atmosphere) for construction dust impact assessment.

Air Pollution Control (Construction Dust) Regulation

3.2.4 The Air Pollution Control (Construction Dust) Regulation (Cap. 311R) specifies processes that require special air quality control.  Contractors and site agents are required to inform Environmental Protection Department (EPD) and adopt air quality control 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.

Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation

3.2.5 The Air pollution Control (Non-road Mobile Machinery) (Emission) Regulation comes into effect on 1 June 2015.  Under the Regulation, Non-Road mobile machinery (NRMMs), except those exempted, are required to comply with the prescribed emission standards.  From 1 September 2015, all regulated machines sold or leased for use in Hong Kong must be approved or exempted with a proper label in a prescribed format issued by EPD.  Starting from 1 December 2015, only approved or exempted NRMMs with a proper label are allowed to be used in specified activities and locations including construction sites.  The Contractor is required to ensure the adopted machines or non-road vehicle under the Project could meet the prescribed emission standards and requirement.

Air Pollution Control (Fuel Restriction) Regulation

3.2.6 The Air Pollution Control (Fuel Restriction) Regulation was enacted in 1990 to impose legal control on the type of fuels allowed for use and their sulphur contents in commercial and industrial processes to reduce sulphur dioxide (SO₂) emissions. In June 2008 and April 2025, the Regulation was amended to tighten the control requirements of liquid fuels.

Air Pollution Control (Marine Light Diesel) Regulation

3.2.7 Since 1 April 2014, a statutory cap of 0.05% m/m on the sulphur content of locally supplied marine light diesel has been imposed to reduce air pollution from the marine sector under the Air Pollution Control (Marine Light Diesel) Regulation.

3.3 Description of Environment

3.3.1 The Project is located at Aberdeen Channel. The existing breakwaters fall within an area shown as ‘Typhoon Shelter’ on the OZP. The land connecting to the existing western breakwater is zoned “GB” and the land connecting to the existing eastern breakwater is partly zoned “G/IC”, partly zoned “OU(Ocean Park)” and partly shown as ‘Road’ on the OZP. The shoreline at Ap Lei Pai, Ap Lei Chau and Tai Shue Wan are zoned “CPA” on the OZP.

3.3.2 The nearest EPD air quality monitoring station (AQMS) is Southern monitoring station.  As Southern monitoring station commissioned on 10 July 2020, the recent three years (2021 – 2023) averaged concentrations of air pollutants relevant to the Project are recorded and summarised in Table 3.3. No exceedances of the 19^th highest hourly NO₂ and annual NO₂, the 4^th highest daily SO₂, the 4^th highest 10-minute SO₂, the 10^th highest daily RSP and annual RSP, as well as the 19^th highest daily FSP and annual FSP were recorded at the Southern EPD AQMS during the period of 2021-2023.

Table 3.3    Average Concentrations of Pollutants in the Recent Three Years (Year 2021 – 2023) at Southern EPD Air Quality Monitoring Station

Pollutant	Averaging Time		Prevailing AQOs (µg/m^3)	2021	2022	2023
SO2	10-min	4^th Highest	500	36	40	31
	24-hour	4^th Highest	50	8	6	8
RSP	24-hr	10^th Highest	100	53	48	53
	Annual		50	26	24	25
FSP	24-hr	19^th Highest	50	26	26	24
	Annual		25	13	12	12
NO2	1-hr	19^th Highest	200	123	105	114
	Annual		40	30	25	26
CO	1-hr	Maximum	30,000	1,230	1,140	1,150
	8-hr	Maximum	10,000	1,014	1,073	1,123

Notes:

[1] All data is calculated from the hourly data provided in EPD’s website (http://epic.epd.gov.hk/EPICDI/air/station/?lang=en)

[2] Reference conditions of gaseous pollutants concentration data: 293K and 101.325 kPa.

3.3.3 Apart from the air quality monitoring data, EPD has released a set of background levels from “Pollutants in the Atmosphere and their Transport over Hong Kong” (PATH) model (version 3.0).  The PATH model is a regional air quality model developed by EPD to simulate future background air quality concentrations in Hong Kong. At the time of this assessment, PATH v3.0 is available in Smart Air Model Platform (SAMP) v2.1 for Year 2026-2030, 2035 and 2040.  Given the proposed Project will be completed in Year 2030, the air quality predicted by PATH v3.0 for Year 2030 will be adopted.  Year 2030 data of the assessment area for NO₂, RSP, FSP, and SO₂ extracted from PATH v3.0 is presented in Table 3.4.  The predicted background concentrations of NO₂, RSP, FSP and SO₂ at various averaging times would be lower than the prevailing / proposed new AQOs.

Table 3.4    Background Air Pollutants in Year 2030 (Extracted from the PATH-v3.0)

Pollutant	Averaging Time		Prevailing AQOs (µg/m^3)	Proposed AQOs (µg/m^3)	Concentration in PATH v3.0 (Year 2030)
					(40,25)	(40,24)	(38,25)	(39,25)	(38,24)
SO2	10-mins	4^th Highest^[1]	500	500	22	24	24	23	25
	24-hour	4^th Highest	50	40	6	6	6	6	7
RSP	24-hr	10^th Highest	100	75	49	49	50	49	50
	Annual		50	30	18	18	19	18	18
FSP	24-hr	19^th Highest	50	37.5	28	28	29	28	28
	Annual		25	15	11	11	11	11	11
NO2	1-hr	19^th Highest	200	200	65	71	81	71	85
	24-hr	10^th Highest	-	120	27	30	34	30	41
	Annual		40	40	12	13	16	13	17

Pollutant	Averaging Time		Prevailing AQOs (µg/m^3)	Proposed AQOs (µg/m^3)	Concentration in PATH v3.0 (Year 2030)
					(39,24)	(39,23)	(38,23)	(40,23)
SO2	10-mins	4^th Highest^[1]	500	500	25	27	28	25
	24-hour	4^th Highest	50	40	6	7	7	7
RSP	24-hr	10^th Highest	100	75	49	50	50	50
	Annual		50	30	18	18	18	18
FSP	24-hr	19^th Highest	50	37.5	28	28	28	28
	Annual		25	15	11	11	11	11
NO2	1-hr	19^th Highest	200	200	79	84	87	81
	24-hr	10^th Highest	-	120	35	39	44	35
	Annual		40	40	14	16	19	15

Notes:

[1]      Values are given as highest 10-minute SO₂ concentrations, which are estimated based on EPD’s “Guidelines on the Estimation of 10-minute Average SO₂ Concentration for Air Quality Assessment in Hong Kong”.

[2]      The 10th highest daily NO₂ concentration is only included in the proposed new AQO.

3.4 Identification of Air Sensitive Receivers

3.4.1 In accordance with Annex 12 of the EIAO-TM, any domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public worship, library, court of law, sports stadium or performing arts centre are considered as ASRs. Any other premises or place with which, in terms of duration or number of people affected, has a similar sensitivity to the air pollutants as the aforelisted premises and places is also considered to be a sensitive receiver.

3.4.2 In accordance with the EIA Study Brief, the assessment area for air quality impact assessment should be defined by a distance of 500 m away from the boundary of the Project site.  Illustration of the proposed assessment area is presented in Figure 3.1.

3.4.3 For identification of the representative ASRs within the assessment area that would likely be affected by the potential impacts from the construction and operation of the Project, a review has been conducted based on relevant available information including topographic maps, OZPs and other published plans from Planning Department and Lands Department, along with any land use and development applications approved by the Town Planning Broad, as well as a site survey conducted on 7 August 2023 and 24 August 2024, in the vicinity of the Project site. The representative ASRs within the assessment area are presented in Table 3.5 and illustrated in Figure 3.1.

Table 3.5    Representative Air Sensitive Receivers

ID	Description	Land use	The Shortest Distance between the ASR and the Project Boundary, m	Assessment Height Above Ground (mAG)^[1]
Existing ASRs
A1	Broadview Court Block 4	Residential	443	25 -140 ^[2]
A2	Larvotto	Residential	284	15-125 ^[3]
A3a	Shipyards and workshops	Industrial	208	1.5-5
A3b	Shipyards and workshops	Industrial	225	1.5-5
A4	Shipyard and Temporary Industrial Area	Industrial	75	1.5-5
A5	Canadian International School	Education	435	1.5-50
A6	Hong Kong Juvenile Care Centre Chan Nam Cheong Memorial School	Education	403	1.5-30
A7	Victoria Shanghai Academy	Education	324	5-55 ^[4]
A8	Water World Ocean Park Hong Kong	Other Specified Uses (Ocean Park)	84	1.5-10
A9	Ocean Park Hong Kong	Other Specified Uses (Ocean Park)	213	1.5
A10a	Fullerton Ocean Park Hotel	Hotel	13	1.5-50
A10b	Fullerton Ocean Park Hotel	Hotel	22	1.5-50
A11	Shipyard and Temporary Industrial Area	Industrial	180	1.5-5
Planned ASRs
PA01	The Proposed Open Space at the Proposed Eastern Breakwater	Open Space	Within Project Boundary	1.5-5
PA02	The Proposed Open Space at the Proposed Eastern Breakwater	Open Space	Within Project Boundary	1.5-5
PA03	The Proposed Open Space at the Proposed Eastern Breakwater	Open Space	Within Project Boundary	1.5-5

Notes:

[1] The lower bound of assessment height shown in the table is the lowest level with air-sensitive uses, full range of assessment heights for each ASR has been listed in the table.

[2] ASR is located on podium. No air-sensitive uses below 25 mAG.

[3] ASR is located on podium. No air-sensitive uses below 15 mAG.

[4] Carpark is located at the ground floor. No air-sensitive uses below 5 mAG.

3.5 Identification of Environmental Impact

Construction Phase

3.5.1 According to the construction programme, the construction works of the Project is tentatively scheduled to commence in 2026 and completed in 2030. Air quality impact may arise from various construction activities of the Project, including:

· Construction of the proposed eastern and western breakwaters which include dredging operations and other construction works including Deep Cement Mixing (DCM) and rubble mound filling.  The dredging operations and other construction works will utilise barges and will last for approximately 40 months;

· Construction of proposed land access and proposed wave wall in the form of floating breakwater lasting for approximately 12 months;

· Modification works of the existing breakwaters lasting for approximately 12 months; and

· Material handling.

3.5.2 Based on the preliminary construction programme and the estimated volume breakdown presented in Table 6.5 of Section 6, the construction of the proposed breakwater includes a dredging operation lasting approximately 9 months, with an estimated volume of approximately 241,263 m³ material to be dredged. The dredging locations are illustrated in Figure 3.2. As illustrated in Figure 3.2, the shortest separation distance between the dredging extent and the nearest ASR is approximately 322 m. During the dredging operation, a maximum of 6 barges would be utilised. However, as advised by the Project Engineer the project involves three work fronts, each work front utilising two barges - one for transferring the dredged material and another stationed on-site to support the dredging operations. Therefore, a maximum of 3 barges would be used per day for the transfer of the dredged material, and there will not be overnight storage of dredging material. The remaining 3 barges would be stationed on-site to assist with the dredging works, and they will not store dredging material. The dredged material would be placed on barges for transfer from the works area for disposal. As dredging operations are marine-based activities, and the moisture content of the dredged material is very high, fugitive dust emissions are therefore expected to be minor during the construction period. The potential odour impact from the dredging activities would be short-term as the dredged material is transported away from the Project site once excavated and is appropriately covered before transportation. Referring to Section 6.4.31, the dredged material will be disposal to South Cheung Chau and East of Ninepin, the potential transportation routing would be via East Lamma Channel, West Lamma Fairway and South Shek Kwu Chau Fairway (for South Cheung Chau) and via East Lamma Channel, south of Hong Kong Island and Tathong Channel (for East of Ninepin). The navigation route of barges/construction vessels will be located away from any ASR as far as practicable.  With the implementation of mitigation measures during the construction period to minimise the potential odour mentioned in Section 3.8.2 and considering the large separation distance between the dredging extent and the nearest ASR, adverse odour impact from the dredged material is not expected.

3.5.3 Phasing of construction works at multiple work fronts at different construction period would be considered. Construction vessels would be involved at each construction activities, such as construction of breakwater. As outlined in Section 3.5.1, the dredging operation and other construction works are expected to take approximately 40 months and would occur in different construction periods. Two construction periods are highlighted: one representing the peak construction period, which will utilise the highest number of construction vessels, and the other representing the period with the minimum number of construction vessels employed. The number of construction vessels for other construction periods will be in-between the number of construction vessels of the two highlighted construction periods. The peak construction period is anticipated to last around 200 days, involving a maximum of 24 vessels per day, including 9 hopper barges, 10 dump lighters and 1 DCM barge (which are not propelled by an engine) and 4 tugboats that facilitate the movement of the barges but will not be stationed on-site, as illustrated in Figure 3.3a. the minimum vessel utilisation period will last approximately 100 days, with a maximum of 9 vessels will operate daily. This includes 3 dump lighter barges, 3 hopper barges and 1 DCM barge, which are not engine-propelled, along with 2 tugboats that assist in moving the barges but will not be stationed on-site, as illustrated in Figure 3.3b. During the construction period, tugboats would not stay at one works area but would be distributed across different works area of the Project. In summary, the number of construction vessels utilised during all the construction periods ranges from 9 to 24 vessels. As shown in Figure 3.3b, the shortest separation distance from construction vessels to the nearest ASR (A10a) during the minimum vessel utilisation period is approximately 109 m, and this case represents the worst-case scenario, having the shortest distance to ASRs among all construction periods. These marine vessels would operate using fuel that complies with the Air Pollution Control (Marine Light Diesel) Regulation, which requires that the sulphur content of locally supplied marine light diesel (MLD) used in marine vessels shall not exceed 0.05% by weight. Additionally, under the Air Pollution Control (Fuel for Vessels) Regulation, vessels are prohibited from using any fuel other than compliant fuel for combustion purposes while operating any specified machinery in the waters of Hong Kong. These construction vessels would be operated throughout the works area and would be stay away from any existing ASRs as far as practicable. With the implementation of mitigation measures listed in Section 3.8, adverse air quality impacts are not anticipated from the construction vessels.

3.5.4 Fuel combustion from the use of powered mechanical equipment (PME) during construction works could be a source of PM, NO₂, SO₂ and CO. As advised by Project Engineer, only a small number of PMEs (approximately 4 PMEs) will be in operation at the same time.  Minor number of construction vehicles (i.e., approximately two return trips of dump trucks per day) are anticipated during construction phases. With the implementation of the requirements and measures stipulated in the Air Pollution Control (Non-Road Mobile Machinery (NRMM)) (Emission) Regulation and Air Pollution Control (Fuel Restriction) Regulation, the emissions from construction equipment and dump trucks are not expected to cause adverse air quality impact to the surrounding ASRs.

3.5.5 Based on the best available information at time of preparation of this EIA, there is no concurrent project within the assessment area of the Project.

Operation Phase

3.5.6 Potential air quality impacts during the operation phase of the Project would be associated with the following pollution sources located within the assessment area:

· Background pollutant concentrations;

· Vehicular emissions from open sections of existing and proposed roads within 500 metres from the Project boundary;

· Industrial emissions from Hospital Authority Shum Wan Laundry (locations shown in Figure 3.4);

· Emissions associated with the coach parking, bus and minibus termini, and shuttle bus terminus at Water World Ocean Park Hong Kong, shuttle bus terminus at Fullerton Ocean Park Hotel, bus and minibus termini at Shum Wan Road public transport interchange (PTI), and on-street heavy goods vehicle (HGV) and non-franchised bus (NFB) parking at Ap Lei Chau Praya Road (locations shown in Figure 3.4); and

· Marine emissions from Aberdeen Typhoon Shelter (ATS).

3.6 Assessment Methodology

Construction Phase

3.6.1 Considering the nature of the construction activities for the Project, the potential air quality impact during the construction phase should be limited with the implementation of mitigation measures stipulated in Air Pollution Control (Construction Dust) Regulation and good site practices recommended in Section 3.8. Therefore, adverse construction air quality impact to surrounding ASRs is not anticipated and qualitative assessment approach is adopted for construction air quality impact assessment.

Operation Phase

3.6.2 PATH and AERMOD models are used to simulate the dispersion of emission from the sources identified in Section 3.5.6. The future background concentrations for air pollutants from the PATH v3.0 model for the Year 2030, available in the SAMP, are adopted. AERMOD model, the EPD approved air dispersion model, is used to simulate vehicular emission associated with the coach parking sites/termini (AREA, AREAPOLY and VOLUME sources), open road emissions within the assessment area (LINE source), marine emission (POINT source) and industrial emission (POINT source) within the assessment area.

Background concentrations

3.6.3 As suggested by “Guidelines on Assessing the ‘TOTAL’ Air Quality Impacts”, an integrated modelling system, PATH v3.0, which is developed and maintained by EPD, is applied to estimate the background pollutant concentrations. The PATH model simulates local emission sources such as open road emission, marine emission, point sources, and aviation as well as regional transport through meteorological processes at 1km x 1km resolution.

3.6.4 The assessment area covers 9 grid cells of PATH v3.0, namely grid (38,23), (38,24), (38,25), (39,23), (39,24), (39,25), (40,23), (40,24) and (40,25). The construction of the Project is tentatively scheduled in Year 2026 to 2030 and the Project will be commissioned in Year 2030. The PATH v3.0 for the Year 2030 is adopted for estimating the background pollutant concentrations during operation phase.  The location of PATH v3.0 model grids are shown in Figure 3.1.

Vehicular emissions from open road

3.6.5 Ocean Drive, Shum Wan Road, Nam Long Shan Road and Ap Lei Chau Praya Road would contribute to vehicular emissions within the assessment area. The traffic data of the abovementioned roads, which is provided by traffic consultant appointed under this study, including the projected 24-hour traffic flows, vehicle compositions, and travelling speeds for operation phase are adopted in this air quality assessment, and presented in Appendix 3.1. The traffic data was submitted to Transport Department with no comment received, and the endorsement is also supplemented in Appendix 3.1.

3.6.6 EMFAC-HK v4.3 model was adopted to estimate the vehicular emission rates of NOx (i.e., initial NO + initial NO₂), RSP and FSP for vehicular emission arising from open road and PTI and shuttle bus terminus and on-street parking within the assessment area. The “vehicle fleet” refers to all motor vehicles operating on roads within this assessment area. The modelled fleet is broken down into 18 vehicle classes based on the vehicle population provided by EPD. The detailed input parameters and model assumptions made in EMFAC-HK model are summarised in Appendix 3.2.

3.6.7 The vehicular emission burdens of NOx, RSP, and FSP from commencement year to 15 years afterward, namely Years 2030, 2038 and 2045, were estimated by using EMFAC-HK model and shown in Appendix 3.2. The vehicular emission attained the highest in Year 2030. Year 2030 was therefore selected as the representative assessment year for the vehicular emission.

3.6.8 Open sections of all existing roads (e.g., Ocean Drive, Shum Wan Road, Nam Long Shan Road and AP Lei Chau Praya Road) were included in this assessment.  An EPD recommended air dispersion model, AERMOD, was used to assess the contribution due to vehicular emissions (e.g., NO, NO₂, RSP and FSP) from the open roads within the assessment area. 

3.6.9 The resulting hourly emissions of NO, NO₂, RSP and FSP were divided by the hourly traffic flow, the distance travelled to obtain the emission factors in gram per km per vehicle.  The calculated 24-hour initial NO, initial NO₂, RSP and FSP emission factors of 18 vehicle classes for each road type were adopted in the subsequent air dispersion model, AERMOD. The AERMOD vehicular input files are generated from SAMP v2.1 developed by EPD. The scenario with zero-emission vehicles is considered in the composite emission factors output by SAMP v2.1.

3.6.10 The methodology for configuring AERMOD to assess vehicular emissions, including parameters such as source release heights, road width, and initial vertical dimension coefficient, follows the guidelines outlined in the "Technical Note for Modelling Vehicular Emission Using AERMOD" issued by EPD. The relevant parameters utilised in this assessment are provided in Appendix 3.3.

Emissions associated with the coach parking, bus and minibus termini, and shuttle bus terminus

3.6.11 According to the desktop study and site survey conducted on 7 August 2023 and 24 August 2024, bus depots are not identified in the assessment area. The locations, the distance from Project boundary, and methods used to assess the start emissions from the identified parking sites, PTI, bus and shuttle bus terminus, and coach bus parking site are detailed in Table 3.6. These locations are also illustrated in Figure 3.4.

Table 3.6    Method Adopted in the Assessment for the Identified Parking Sites, PTI, Bus and Shuttle Bus Terminus

ID	Name	Distance from Project Boundary (m)	Approach for Considering the Start Emission
E1	The Fullerton Ocean Park Hotel – Shuttle Bus Terminus	25	Precise approach ^[1]
E2	Water World Ocean Park Hong Kong – Shuttle Bus Terminus	16	Precise approach ^[1]
E3	Water World Ocean Park Hong Kong – Public Light Bus Terminus	16	Broad-brush approach
E4	Water World Ocean Park Hong Kong – Franchised Double Deck Bus Terminus	17	Broad-brush approach
E5	Water World Ocean Park Hong Kong – Coach Parking Site	33	Precise approach ^[1]
E6	Shum Wan Road PTI	500	Precise approach ^[1]
E7	On-street HGV and NFB parking spaces at Ap Lei Chau Praya Road	256	Precise approach ^[1]

Note:

[1] The detail of the precise approach is outlined in the Technical Note on Calculation of Start Emissions in Air Quality Impact Assessment published by EPD.

3.6.12 The franchised bus and public light bus terminus of the Water World Ocean Park Hong Kong (hereinafter referred to as “WWOP”) (E3 and E4) are small scale, with only 2 bus routes and 3 minibus routes. According to the bus schedules on Citybus’ website, bus routes 629M and 629 (Central (Star Ferry) – Ocean Park (Main Entrance/Water World)) are operated on specific days only. While bus route 629 is only served once a day. Based on the public light bus schedules provided by the service provider, there are a total of 9 headways for two routes (29A and 29X) and total of 12 headways on Saturdays, Sundays and public holidays for another minibus route (59S). Given that the limited number of franchised bus and public light bus routes in the WWOP are provided, the start emission in the WWOP (i.e., E3 and E4) are considered minor. Start emissions of all vehicle types from these termini and all the roads leading to and leaving from the bus and PLB termini is considered by broad-brush approach in which the emission is allocated to the local roads.

3.6.13 The start emissions, running exhaust emissions, and idling emissions (i.e., NO, NO₂, RSP, and FSP) associated with the shuttle bus termini at WWOP (E2) and Fullerton Ocean Park Hotel (E1), coach bus parking site in the WWOP (E5),  Shum Wan Road PTI (E6) and on-street HGV and NFB at Ap Lei Chau Praya Road (E7) are calculated based on the start emission and running exhaust emission factors predicted by EMFAC-HK model, cold idling emission factors from Calculation of Start Emissions in Air Quality Impact Assessment published by EPD, warm idling emission factors from Road Tunnels: Vehicle Emissions and Air Demand for Ventilation published by World Road Association and traffic data including the idling time and no. of trips provided by the traffic consultant based on at least 24 hour site survey on normal day and 1 public holiday day.

3.6.14 A site survey conducted on 7 August 2023 and 24 August 2024 revealed that the shuttle bus terminus at the Fullerton Ocean Park Hotel (E1) is semi-enclosed without mechanical ventilation. In contrast, the shuttle bus terminus and coach bus parking at the WWOP (E2 and E5), as well as the on-street HGV and NFB parking spaces at Ap Lei Chau Praya road (E7), are open. On-site observations indicated that there was no overnight parking of coaches at shuttle bus termini. Additionally, the Shum Wan Road PTI (E6) is semi-enclosed and has been equipped with mechanical ventilation systems for exhaust. The emissions (i.e., start, running and idling emissions) associated with E1, E2, E5, E6 and E7 were evaluated using the precise approach outlined in the Technical Note on Calculation of Start Emissions in Air Quality Impact Assessment published by EPD. For diesel vehicles equipped with selective catalytic reduction (SCR) devices, start emissions were adjusted based on the idling emission and would be released over total spread distance of 700 m from where the start takes place, start emissions for liquefied petroleum gas (LPG) minibus were adjusted based on the idling emission and would be released over a total spread distance of 150 m from where the start takes place, while running exhaust and idling emissions would be released on the spot. At identified coach parking sites and shuttle bus parking, running exhaust and idling emissions from terminating and non-terminating vehicles, and adjusted start emission from terminating vehicles are considered for emissions inside coach bus/shuttle bus parking sites while the remaining adjusted start emission from terminating vehicles is considered for emissions outside coach bus/shuttle bus parking sites.

3.6.15 Since the shuttle bus parking at Fullerton Ocean Park Hotel (E1) is semi-confined and does not have any mechanical ventilation for exhaust, the starting emissions are modelled as “AREAPOLY” sources, distributed at the side openings, ingress and egress at E1. However, Shum Wan Road PTI (E6) is also semi-confined but is equipped with the mechanical ventilation for exhaust, which is modelled as “VOLUME” Sources in AERMOD. To avoid any underestimation, 100% of emission within E6 is assigned to the openings, ingress and egress (“AREAPOLY” source) and additional 100% of emission is distributed via the exhaust points (“VOLUME” source). Emissions within open shuttle bus terminus (E2) and coach bus parking sites at WWOP (E5), as well as the on-street parking sites at Ap Lei Chau Praya Road (E7) are also modelled as “AREAPOLY” sources in AERMOD. Start emissions on spread distance outside the identified parking sites/PTI/shuttle bus terminus are modelled as “AREA” sources. The location of emission sources and the detailed calculation of the emission are presented in Appendix 3.4. The meteorological data and modelling parameters adopted in AERMOD are detailed in Sections 3.6.30 to 3.6.31.

Industrial Emissions within the Assessment Area and Major Point Sources within 4 km

3.6.16 According to chimney survey conducted on 7 August 2023 and 24 August 2024, Hospital Authority Shum Wan Laundry (HASWL) is identified as the only source of industrial emissions within the assessment area, and the location is illustrated in Figure 3.4. The chimney parameters such as stack height, stack temperature, stack exit velocity, stack diameter, and emission inventory of HASWL are referred to the approved EIA report on Repositioning and Long-Term Operation Plan of Ocean Park (Register No.: AEIAR-101/2006) and the response from the chimney owner/operator dated 16 June 2023 and the site surveys. The correspondence from the chimney owner/operator is provided in Appendix 3.5. As a worst-case scenario, it is assumed that these three chimneys operate 24 hours a day. The emission sources are modelled as “POINT” sources in AERMOD, and the detailed calculations of chimney emission are presented in Appendix 3.5. The meteorological data adopted in AERMOD are detailed in Sections 3.6.30 to 3.6.31.

3.6.17 According to the Guidelines on Assessing the ‘TOTAL’ Air Quality Impacts and Centralised Environmental Database (CED) published by EPD, there are no major point emission sources within 4 km of the Project boundary and no Specified Process (SP) Licence within the assessment area.

Marine emissions from Aberdeen Typhoon Shelter

3.6.18 The vessels accessing the existing ATS and the Project would generate the marine emission. NO₂, RSP, FSP and SO₂ are the key major marine emission pollutants.  For CO, the monitored CO background concentration is notably low, measuring only approximately 4% of the AQO for the maximum 1-hour CO concentrations, approximately 10% for the maximum 8-hour CO concentrations and approximately 11% for the maximum 24-hour CO concentrations from 2021 to 2023.  Consequently, CO is not considered a critical air pollutant of concern for this Project.  Various marine vessels such as pleasure vessels, fishing vessels, Police Launches of the Hong Kong Police Force (HKPF) and Adventure Ship[1] enter and leave the ATS. Based on the site observations conducted on 7 August 2023, 13 November 2023, 18-19 November 2023 and 24 August 2024, no emissions are expected as the engines from all types of vessels such as pleasure vessels, fishing vessels, police launches and adventure ship, are turned off while moored or berthed at ATS. Additionally, no ferries were observed mooring or berthing at ATS.

3.6.19 According to the Plan of Passage Area in Aberdeen South Typhoon Shelter[2] published by the Hong Kong Marine Department (MD), the existing marine route (represented by the grey shaded area in Appendix 3.6) falls within the assessment area of the Project.  Emissions from all vessels are dispersed along the existing marine route and modelled as “POINT” sources in AERMOD. The location of emissions (ID M24-M63 and M101-M102) along the existing marine route outside the proposed expansion of ATS for rivertrade vessel (RTM), barge (TTBM), tugboat (TTTM), fast launches (FLM) and small craft (SCM) are presented in Figure 3.5a.

3.6.20 According to the latest available information, the ferry service time is as follows: 9:30 and 10:30 (departures from Aberdeen to the temporary landing facility at Tai Shue Wan), and 19:00 and 20:00 (departures from the temporary landing facility at Tai Shue Wan to Aberdeen)[3]. Since the proposed Landing Facility at the proposed eastern breakwater (hereinafter referred to as “The Proposed Landing Facility”) is schedule to be completed by 2030, the ferry service will be relocated to the Proposed Landing Facility.

3.6.21 Apart from the Proposed Landing Facility, three existing landing facilities (HP015 Shum Wan Landing No.1, HP011 Po Chong Wan Landing Nol.1 and HP023 Ap Lei Chau Landing No.5) and one Marine Police Aberdeen Base (MPAB) are located within the assessment area, there are no other existing and planned landing points within the assessment area of the Project. The locations of the existing/temporary landing facilities and the Proposed Landing Facility are presented in Figure 3.4. The annual growth rates of different vessel classes for hotelling are referenced to the Marine Traffic Impact Assessment (MTIA) report. Vessel counts of each existing/temporary landing facilities, as well as the Proposed Landing Facility for hotelling, are provided in Tables D2 – D7 of Appendix 3.6. The marine traffic data and annual growth rates adopted in the assessment have been endorsed by MD and supplemented in Appendix 3.6. Additional hotelling and maneuvering emissions from vessels due to marine vessel growth within the assessment area are anticipated.

3.6.22 The MTIA report contains the vessel count survey for the existing marine traffic, indicating approximately 326 vessel movements per day entering and leaving the ATS. The average annual growth rate of different vessel classes is taken into account in the marine emission calculations and considered as the marine traffic during the operation phase. According to the latest available information provided by CEDD, the Proposed Landing Facility is expected to be completed in 2030 and will serve various types of ferry and small craft vessels (e.g., ferry and kaito) to other key destinations/attractions and the islands nearby in Southern District for the purpose of promoting marine tourism, as well as ferry services between Aberdeen and proposed eastern breakwater (re-route from the existing Tai Shue Wan Temporary Landing Facility).  The Proposed Landing Facility will serve 68 single-trip vessels daily including 64 single-trip vessels for marine tourism from 10am to 6 pm and 4 single-trip ferries between Aberdeen and the Proposed Landing Facility.  These vessels will include ferry and small craft vessel types (e.g., ferry and kaito).  Emissions resulting from the hoteling and maneuvering activities of these vessels were modelled as a “POINT” source. Figures 3.5d and 3.5f shows the marine emission sources during the hotelling and maneuvering for these vessels. The routing of ferry services to Aberdeen is based on on-site observations, while the routing for marine tourism is based on the advice of the Project Engineer. 

3.6.23 As advised by Marine Traffic Consultant appointed under this study, for marine traffic activities beyond 2040, it is assumed that there will be no major expansion of container terminal development, or port facilities including typhoon shelters and Public Cargo Working Areas (PCWA) in Hong Kong and marine traffic growth of all vessel types is assumed to reach a peak in 2040. Therefore, the year 2040 is considered a worst-case scenario for marine emissions, based on the maximum forecasted marine traffic. The annual growth rates of different vessel classes are referenced to the MTIA report and provided in Table D1 of Appendix 3.6. The marine traffic data and annual growth rates adopted in the assessment have been endorsed by MD and supplemented in Appendix 3.6[4].

3.6.24 Due to the lack of available information on the potential marine route within, as well as entering and leaving the expanded ATS, indicative marine routes have been assumed, subject to the future expanded typhoon shelter arrangement. For the worst-case scenario in the assessment, the marine route is assumed to be in close proximity to the identified representative ASRs. Upon entering and leaving ATS (i.e., emission ID M1 – M23), the assumed marine route is near Ocean Park, as shown in Figure 3.5a[5]. Within the expanded ATS, one of the assumed marine routes (depicted in Figure 3.5c) is situated on the eastern side of the Project and has a higher impact on the identified ASRs such as A1, A4, A5, A6, A7, A8, A9, A10, and A11 on the eastern side. Similarly, another assumed marine route (depicted in Figure 3.5b) is located on the western side of the Project and has a higher impact on the identified ASRs such as A2, A3a and A3b on the western side. For rivertrade vessel (RTM), barge (TTBM), tugboat (TTTM), fast launches (FLM) and small craft (SCM), accounting for 100% of the total number of vessels, navigate along the proposed marine routes. In other words, 100 % of the vessels navigate the eastern side of the proposed marine route and an additional 100% of vessels navigate the western side of the proposed marine route as a conservative scenario. Emissions from all vessels are dispersed along the assumed marine routes within the Project and modelled in AERMOD as “POINT” sources. Emissions during hoteling at the piers (i.e., Sham Wan Landing, Po Chong Wan Landing, Ap Lei Chau Landing, MPAB and the Proposed Landing Facility) were modelled as “POINT” source with AERMOD. The parameters such as the exit temperature, stack height, are referenced to the approved Lei Yue Mun Waterfront Enhancement Project EIA Report (Register No.: AEIAR-219/2018) and on-site observation or other information.

3.6.25 According to the available information from Adventure ship, the vessel operates from 9:30 am to 4:30 pm, with two round trips passing through the ATS. The routing of maneuvering within the existing ATS is based on on-site observations. Due to the lack of information regarding potential marine routes within the expanded ATS, a conservative approach is adopted, as outlined in Section 3.6.24. This approach involves using two marine routes located on the eastern and western sides of the Project. The marine emission sources during maneuvering for the Adventure Ship are illustrated in Figure 3.5e.  There is no hotelling of adventure ships within the assessment area, as confirmed by the site visit.

3.6.26 With reference to the Study on Marine Vessels Emission Inventory (MVEIS) by the Hong Kong University of Science and Technology (HKUST), marine emission is estimated by an activities-based approach. The emission factors were derived in units of work (gram per kilowatt-hour), dependent on the fractional load of the equipment during different vessel activity modes. The calculation can be summarised below:

Emission = P × FL × T × EF

where P is the installed power of equipment;

                                    FL is a fractional load of equipment in a specific mode;

                                    T is operation time-in-mode; and

                                    EF is a fractional load emission factor of equipment.

3.6.27 Typical power equipment installed on marine vessels are Main Engine (ME) for propulsion, Auxiliary Engine (AE) for electricity and Auxiliary Boiler (AB) for fuel pre-heating and pumping. Subject to the vessel type, different combinations of engines are equipped on a vessel. Typical engine power rating, engine type, and fuel type of each vessel type were adopted from MVEIS or other relevant information.

3.6.28 Typical engine load factor by vessel type and by operation mode refers to MVEIS. The engine load factor of the marine source was then determined according to its vessel type and its operation mode. The time-in-mode was estimated by the distance and vessel speed travelled in the corresponding mode (i.e., Fairway Cruise – over 12 knots; Slow Cruise – 8 to 12 knots; Maneuvering – 1 to 8 knots and Hoteling – below 1 knot). According to the Shipping and Port Control Regulations (CAP 313A), the maximum permitted speed at the entrance to or within a typhoon shelter is 5 knots. As such, for a route within the typhoon shelter area, the average travelling speed is assumed to be 5 knots.

3.6.29 Stack height, diameter, exit temperature, and exit velocity of the vessels are made reference to the stack parameters for vessels in the approved EIA Lei Yue Mun Waterfront Enhancement Project (Register No.: AEIAR-219/2018) and on-site observation or other information. The detailed calculation of the marine emission is presented in Appendix 3.6.

3.6.30 Hourly meteorological conditions for Year 2019 including wind data, temperature, relative humidity, pressure, cloud cover, and mixing height, were extracted from the Weather Research and Forecasting (WRF) meteorological data under PATH v3.0 system was adopted for the meteorological input to AERMET (the meteorological pre-processor of AERMOD). The minimum wind speed was capped at 0.5 metre per second. The mixing height was capped between 119 metres and 2009 metres according to the observation in Year 2019 by Hong Kong Observatory (HKO). The height of the input data was assumed to be 9 metres above ground for the first layer of the WRF data as input. The input file to AERMET has been obtained from EPD’s SAMP v2.1. The output files from AERMET were also obtained from SAMP, which are subsequently used as input in AERMOD.

3.6.31 Surface characteristic parameters such as albedo, Bowen ratio, and surface roughness are required in the AERMET (the meteorological pre-processor of AERMOD).  The land use characteristics of the surrounding are classified, and these parameters of each land use are then determined by default on SAMP according to its land use characteristics. The detailed assumptions are discussed in Appendix 3.7. Given that the Project is situated in a complex terrain, the 'terrain' option and urban mode were utilised in AERMOD, and the base elevation of receptors and emission sources were inputted.

Conversion of NO_x to NO₂

3.6.32 The conversion from NO_x to NO₂ is necessary to compare the operation phase cumulative results against AQOs. The conversion method follows the approaches stated in the ‘Guidelines on Choice of Models and Model Parameters’ published by EPD.  Two approaches, namely Ozone Limiting Method and Jenkin Method, were adopted for the conversion from NO_x to NO_2.

Ozone Limiting Method for Short-term Cumulative NO₂ Assessment

3.6.33 For the short-term cumulative NO₂ assessment (i.e., predictions of hourly average NO₂ concentration), Ozone Limiting Method (OLM) was adopted for conversion of NO from vehicle-related sources (i.e., emissions from open roads, coach parking sites and shuttle bus termini in Water World Ocean Park Hong Kong and Fullerton Ocean Park Hotel) and NOx from industrial and marine sources to NO₂ based on the predicted O₃ level from PATH v3.0. According to the Heathrow Airport EIA report, the initial NO₂/NOx ratios of marine and industrial emission sources are 10%. The NO₂/NOx conversion was calculated as follows:

[NO₂]_predicted = [NO₂]_vehicular  + 0.1 ´ [NO_x]_{marine/chimney +} MIN {[NO]_vehicular + 0.9 ´ [NOx]_{marine /chimney}, or (46/48) ´ [O₃]_PATH}

where

[NO2]predicted	is the predicted NO2 concentration
[NO2]vehicular	is the sum of predicted initial NO2 concentration from open roads, coach parking sites and shuttle bus termini in Water World Ocean Park Hong Kong and Fullerton Ocean Park Hotel
[NOx]marine/chimney	is the sum of predicted initial NOx concentration from the marine and industrial emission sources
[NO]vehicular	is the sum of predicted initial NO concentration from open roads, coach parking sites and shuttle bus termini in Water World Ocean Park Hong Kong and Fullerton Ocean Park Hotel
MIN	means the minimum of the two values within the brackets
[O3]PATH	is the representative O3 from PATH concentration (from other contribution)
(46/48)	is the molecular weight of NO2 divided by the molecular weight of O3

3.6.34 For the long-term cumulative NO₂ assessment (i.e., predictions of annual average NO₂ concentration), Jenkin method was adopted for the conversion of cumulative NO_x to NO₂ by using the functional form of an annual mean of NO₂-to-NO_x with reference to the Review of Methods for NO to NO₂ Conversion in plumes at short ranges[6]. The mentioned functional form is referenced from Jenkin, 2004a[7] and is presented as follows:

where

[NO2]	is the NO2 concentration
[NOx]	is the NOx concentration
[OX]	is the sum of NO2 concentration and O3 concentration (i.e. [OX] = [NO2] + [O3])
J	is the photolysis rate of NO2
k	is the rate coefficient for reaction between NO and O3

3.6.35 The annual mean data obtained from the EPD’s AQMS, including the Southern general station, Tap Mun general station, and three roadside stations (Causeway Bay, Central, and Mong Kok), were analysed using the functional form provided above. The Southern general station was initially chosen as the representative station due to its proximity. However, since the Southern general station was commissioned on 10 July 2020, data from the Southern general station was also available starting from 2021. The Tap Mun general station and three roadside stations were included to cover a wider range of NOx concentration. The function from curve would fit the annual mean data when [OX] = 95.57 µg/m³ and J/K = 17.114 µg/m³. The obtained functional form curve was adopted for the cumulative annual average NO_x to NO₂ conversion. As shown in Appendix 3.8, the curve is higher than all the annual mean data obtained from AQMS and on-site measurement data, underestimation of the annual average NO₂ concentration is not expected. The cumulative annual average NO_x to NO₂ conversion equation for this assessment was calculated as follows:

where

[NO2] c	is the predicted cumulative NO2 concentration in µg/m^3
[NOx] c	is the predicted cumulative NOx concentration (i.e., the sum of the total predicted NOx concentration from AERMOD and PATH v3.0) in µg/m^3

Cumulative Air Quality Impact

3.6.36 Cumulative air quality impacts upon ASRs were derived from the sum of predictions by local air quality models (i.e. AERMOD model) and background concentration from PATH v3.0 for Year 2030 on hour-by-hour basis.

3.6.37 Time-averaged results, namely hourly, daily and annual, are derived from the cumulative hour-by-hour results. For annual average, the sum of all hourly concentrations is divided by the number of hours during the year to obtain the annual-averaged concentration. The air quality impact upon ASRs is evaluated by respective concentration limits specified in the AQO.  For daily average, cumulative daily-averaged results at each ASR amongst 365 days are ranked by the concentration and the ranked daily-averaged concentrations are compared with the maximum allowable concentration to determine the number of exceedances throughout a year. The air quality impact upon ASRs was evaluated by number of exceedances per annum against the number of exceedances allowed as specified in the AQO or EIAO-TM for hourly and daily averaged result.

3.6.38 According to “Guidelines on the Estimation of 10-min average SO₂ Concentration for Air Quality Assessment in Hong Kong”, the 10-min SO₂ concentration is determined by multiplying the 1-hour average of the SO₂ concentrations by the conversion factors specific to corresponding stability classes, as provided in Table 3.7.

Table 3.7    Stability-dependent Multiplicative Factors

Stability Class	A	B	C	D	E	F
Conversion Factor	2.45	2.45	1.82	1.43	1.35	1.35

3.7 Prediction and Evaluation of Environmental Impacts

Construction Phase

3.7.1 As mentioned in Sections 3.5.1-3.5.4, the potential air quality impact from the construction activities would be limited during the construction phase. Hence, there would be no adverse air quality impact anticipated from the works area to the surrounding ASRs. Nevertheless, air quality mitigation measures recommended in Section 3.8 and mitigation measures stipulated in Air Pollution Control (Construction Dust) Regulation shall be implemented to minimise the potential air quality impact from the construction of the Project.

3.7.2 The potential odour impact from the dredging activities would be short-term as the dredged material is transported away from the Project site once excavated and is appropriately covered before transportation. As such, adverse odour impact from the dredged material is not expected. As mentioned in Section 3.5.4, the emissions from PMEs and dump trucks are considered minor. The travel distance of dump trucks would be minimised, and the use of highways would be maximised as much as possible to shorten the duration of transport.  In addition, vehicles loaded with the dusty materials will be covered by clean and impervious sheeting to minimise air quality impact to the nearby ASRs before leaving the work sites.  Hence, adverse air quality impact arising from the use of PME and dump trucks to the surrounding ASRs is not anticipated.

3.7.3 For the marine traffic arising from the Project, based on the advice from Project Engineer, it is assumed that maximum 24 vessels will operate per day during the peak construction period of approximately 200 days. This includes 9 hopper barges, 10 dump lighter barges, 1 DCM barge (which is not propelled by an engine), and 4 tugboats that facilitate the movement of the barges but will not be stationed on-site. The separation distance from the construction vessel to the nearest ASR (A10b) is approximately 421m (distance shown in Figure 3.3a). Another period, representing the minimum number of construction vessels employed, will last approximately 100 days, which a maximum of 9 vessels will operate daily. This includes 3 dump lighter barges, 3 hopper barges and 1 DCM barge, which are not engine-propelled, along with 2 tugboats that assist in moving the barges but will not be stationed on-site. The separation distance to the nearest ASR (A10a) is approximately 109 m (as shown in Figure 3.3b). These two construction periods are scheduled to occur within a specific timeframe in the overall construction timeline from 2026 to 2030. The number of construction vessels utilised during all construction periods and the shortest separation distance from construction vessels to the nearest ASRs during all construction periods are given in Section 3.5.3. According to Section 3.5.2, a maximum of 3 barges would be used per day for the transfer of the dredged materials and another 3 barges would be stationed on-site to assist with the dredging work. Given the large separation distance between the dredging extent and the nearest ASR (approximately 322m), and with the implementation of the requirements and measures stipulated in the in the Air Pollution Control (Non-Road Mobile Machinery (NRMM)) (Emission) Regulation and Air Pollution Control (Fuel Restriction) Regulation, adverse air quality impact associated with barges used for dredging works is not expected. Vessels are not expected to be all present at the same time due to the phasing of construction activities, and idle vessels shall be avoided in the construction area.  Effective planning of construction vessel activities can help minimise the number of vessels on site, it is unlikely that air quality impact from construction vessels will be adverse.

Operation Phase

3.7.4 The cumulative air quality impacts at the representative ASRs have been evaluated. Detailed assessment results of all relevant assessment heights of the identified representative ASRs are provided in Appendix 3.9.

3.7.5 According to the predicted cumulative NO₂, RSP, FSP and SO₂ concentrations at the representative ASRs during the operation of the Project, the prediction indicated that the 10^th highest daily average and the annual average of RSP concentrations, the 19^th highest daily average and the annual average of FSP concentrations and the 19^th highest hourly average, 10^th highest daily average and the annual average of NO₂ concentrations, the 4^th highest 10-min and daily SO₂ concentrations at all representative ASRs would comply with both prevailing and proposed AQOs. The predicted results are presented in Table 3.8.

Table 3.8    Predicted Cumulative Concentrations at Representative Air Sensitive Receivers During the Operation Phase

ASR	NO2 Concentration (µg/m^3)			RSP Concentration (µg/m^3)		FSP Concentration (µg/m^3)		SO2 Concentration (µg/m^3)
	19^th Highest Hourly Average	10^th Highest Daily Average	Annual Average	10^th Highest Daily Average	Annual Average	19^th Highest Daily Average	Annual Average	4^th Highest 10-min Average	4^th Highest Daily Average
Prevailing AQO	200	-	40	100	50	50	25	500	50
Proposed AQO	200	120	40	75	30	37.5	15	500	40
Existing ASRs
A1	72 - 106	33 - 43	14 - 19	49 - 50	18 - 19	28	11	23 - 24	6
A2	80 - 97	40 - 42	16 - 20	50	18	28	11	25	7
A3a	106 - 116	44 - 45	22 - 23	50	18 - 19	28 - 29	11	25	7
A3b	126 - 146	49	23 - 24	50	19	29	11	25	7
A4	98 - 103	47	20	50	18	28	11	28	7
A5	81 - 87	37 - 40	15 - 16	50	18	28	11	23	6
A6	77 - 80	35 - 36	14 - 15	50	18	28	11	23	6
A7	91 - 104	38 - 40	15 - 16	50	18	28	11	23	6
A8	97 - 110	44 - 48	17 - 19	50	18	28	11	25	7
A9	76	32	13	49	18	28	11	24	6
A10a	88 - 125	45 - 48	18 - 21	50	18	28	11	25 - 27	7
A10b	88 - 121	45 - 50	18 - 24	50	18	28	11	25 - 26	7
A11	91 - 97	40	18	50	18	28	11	24	6
Planned ASRs
PA01	114 - 120	42 - 43	-	50	-	28	-	27	7
PA02	116 - 128	42	-	50	-	28	-	26 - 27	7
PA03	123 - 138	42	-	50	-	28	-	26	7

Note:

[1] Long-term AQOs (i.e., annual NO2, annul RSP and annual FSP) are not applicable to PA01, PA02 and PA03 in consideration of short retention time at these kinds of uses.

3.7.6 According to the discrete results listed in Appendix 3.9, the worst affected levels for all ASRs, except A10a and A10b, would be 1.5 mAG and 5 mAG. For ASRs A10a and A10b, the worst affected level for the 19^th highest hourly NO₂ would be 15 mAG. Contour plots are presented to illustrate various pollutant concentrations including the 19^th highest hourly average, the 10^th highest daily average and annual average NO₂ concentrations, the 10^th highest daily average and annual average RSP concentrations, 19^th highest daily average and annual average FSP concentrations, as well as 4^th highest 10-min average and daily average SO₂ concentrations within the assessment area at the worst affected level. These plots at the worst affected levels, are presented in Figure 3.6 to Figure 3.23 for 1.5 mAG and 5 mAG, Figure 3.27 to Figure 3.29 for the pollutant of NO₂ at 15 mAG. To evaluate potential exceedances of NO₂ at 10 mAG, the 19^th highest hourly NO₂, the 10^th highest daily NO₂, and the annual average NO₂ at 10 mAG are presented in Figure 3.24 to Figure 3.26.

3.7.7 Under the prevailing AQOs and the proposed AQOs, exceedance zones were identified in the contour plots for the 19^th highest hourly NO₂ at 1.5 mAG, 5 mAG and 10 mAG, as well as for the annual average NO₂ at 1.5 mAG, 5 mAG, 10 mAG and 15 mAG. The occurrences of exceedance zones in the contour plots are summarised in Table 3.9.

Table 3.9     Summary of Exceedance Zone Occurrences in the Contour Plots

Pollutant^[2]			Assessment Height (mAG)
			1.5	5	10 ^[3]	15 ^[4]
			Figures 3.6 – 3.14	Figures 3.15 – 3.23	Figures 3.24 – 3.26	Figures 3.27 – 3.29
RSP	10^th Highest Daily	Prevailing AQO			N/A	N/A
		Proposed AQO			N/A	N/A
	Annual	Prevailing AQO			N/A	N/A
		Proposed AQO			N/A	N/A
FSP	19^th Highest Daily	Prevailing AQO			N/A	N/A
		Proposed AQO			N/A	N/A
	Annual	Prevailing AQO			N/A	N/A
		Proposed AQO			N/A	N/A
NO2	19^th Highest Hourly	Prevailing AQO	✔	✔	✔
		Proposed AQO	✔	✔	✔
	10^th Highest Daily^[5]	Prevailing AQO	N/A	N/A	N/A	N/A
		Proposed AQO
	Annual	Prevailing AQO	✔	✔	✔	✔
		Proposed AQO	✔	✔	✔	✔
SO2	4^th Highest 10-mins	Prevailing AQO			N/A	N/A
		Proposed AQO			N/A	N/A
	4^th Highest Daily	Prevailing AQO			N/A	N/A
		Proposed AQO			N/A	N/A

Notes:

[1] “✔” indicates that an exceedance zone was identified for specific pollutants.

[2] The criteria for the prevailing AQO and the proposed AQO are detailed in Table 3.1 and Table 3.2, respectively.

[3] To evaluate potential exceedances of NO₂ at 10 mAG, the 19^th highest hourly NO₂, the 10^th highest daily NO₂, and the annual average NO₂ at 10 mAG are presented in Figures 3.24 to 3.26. Contours for RSP, FSP, and SO₂ are not plotted at 10 mAG.

[4] According to Section 3.7.6, the worst affected level for the 19^th highest hourly NO₂ is 15 mAG. Contours for RSP, FSP, and SO₂ are not plotted at 15 mAG.

[5] The 10^th highest daily NO₂ is applicable only in the proposed AQO.

3.7.8 According to Table 3.9, the exceedance zones in the contour plots were identified. It is confirmed that no air sensitive uses shall be located within the exceedance zones. Therefore, no adverse air quality impact is anticipated from the operation of the Project.

3.8 Mitigation of Adverse Environmental Impacts

Construction Phase

3.8.1 The approved NRMMs under NRMM Regulation (excluding exempted NRMMs) would be used on site and NRMMs supplied with mains electricity instead of diesel-powered shall be adopted as far as possible to minimise the potential emission from NRMMs.

3.8.2 In addition, air quality mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation and good site practices listed below shall be carried out to further minimise construction air quality impact.

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

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

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

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

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

• The engine of the PMEs during idling shall be switched off.

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

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

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

• Instigation of an environmental monitoring and auditing program during the construction phase in order to enforce controls and modify method of work if dusty conditions arise and to ensure no adverse air quality impact during Construction phase.

• Locate all the dusty activities away from any nearby ASRs as far as practicable.

• For construction vessels, the number of trips would be monitored and minimised and vessel travelling route would be kept away from the ASRs as far as possible.

• Engine of construction vessels shall be switched off while not in use.

• All malodorous materials shall be placed as far as possible from any ASRs.

• The stockpiled malodorous materials shall be covered entirely by plastic tarpaulin sheets.

• The malodorous materials shall be removed from site as soon as possible and shall not be stockpiled overnight at the site.

• Dredged materials onto the barges should be properly covered as far as practicable to minimise the exposed area and potential fugitive dust and odour emissions during its transportation.

3.8.3 With the implementation of the mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation and the above air quality mitigation measures, adverse construction air quality impact would not be anticipated.

Operation Phase

3.8.4 No adverse air quality impact during the operation of the Project is anticipated. Mitigation measures are thus considered not necessary during the operation phase. No air sensitive use shall be located within the exceedance zones identified in the Contour plots.

3.9 Evaluation of Residual Impacts

Construction Phase

3.9.1 With the implementation of the mitigation measures as stipulated in the Air Pollution Control (Construction Dust) Regulation together with the recommended air quality control measures and good site practices on the work sites, no adverse residual impact would be expected from construction of the Project.

Operation Phase

3.9.2 No adverse residual impact is expected during the operation phase of the Project.

3.10 Environmental Monitoring and Audit

Construction Phase

3.10.1 Environmental monitoring and audit (EM&A) for potential air quality impacts shall be conducted during construction phase so as to check compliance with the legislative requirements.  Details of the monitoring and audit programme are contained in a stand-alone EM&A Manual.

3.10.2 Regular site audit for potential air quality and odour impact, dust monitoring is recommended to be conducted during the entire construction phase of the Project to ensure the air quality and odour mitigation measures and the mitigation measures stipulated in Air Pollution Control (Construction Dust) Regulation are implemented in order and to ensure no adverse air quality and odour impact at the ASRs.

Operation Phase

3.10.3 No adverse residual air quality impact arising from the Project is anticipated during the operation of the Project. Therefore, the EM&A works for the operation phase are considered unnecessary.

3.11 Conclusion

Construction Phase

3.11.1 The potential air quality impacts which may arise from the construction works of the Project include filling for the proposed breakwater, construction of the proposed wave wall in the form of floating breakwater, construction of the proposed land access, as well as the modification of existing eastern and western breakwaters, and material handling.  With the implementation of mitigation measures specified in the Air Pollution Control (Construction Dust) Regulation together with the recommended air quality mitigation measures, good site practices, and EM&A programme, no adverse air quality impact at ASRs is anticipated due to the construction activities of the Project.

Operation Phase

3.11.2 Cumulative air quality impact arising from vehicular emission from open road, emission associated with parking site/termini, industrial and marine emissions within the assessment area, as well as background concentrations, has been assessed for the operation phase of the Project. The results concluded that the predicted cumulative air quality concentrations on the identified ASRs comply with both the prevailing and the proposed AQOs during the operation phase and no air sensitive use shall be located within the exceedance zones identified in the Contour plots. As such, adverse air quality impact due to the operation of the Project is not anticipated.

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[1] https://adventureship.org.hk/en/

[2] Plan of passage area in Aberdeen South Typhoon Shelter (mardep.gov.hk)

[3] Based on the information adopted in Tai Shue Wan (TSW) Pier project as provided by CEDD and endorsed by MD, 4 movements per day was identified for the usage of the TSW temporary landing facilities. With reference to the previous ferry schedule and information adopted in TSW Pier project, 1 way trip (4 in total) which is in total of 4 movements per day is adopted for the ferry service from Aberdeen to the proposed landing facility in the air quality assessment. For future forecast, the ferry service will be subject to Ocean Park Corporation (OPC) development and with the best available information, 1 way trip which is in total of 4 movements per day is adopted.

[4] The assessment has excluded adverse weather and extreme conditions such as typhoon events due to their infrequent occurrence throughout the year and the short duration of each event.

[5] The proposed marine routes entering and leaving ATS as shown in Figure 3.5a are based on vessel tracks from Automatic Identification System (AIS) and radar data.

[6] Environment Agency. 2007. Review of methods for NO to NO₂ conversion in plumes at short range. Prepared by Environmental Agency.

[7] Jenkin. 2004a. Analysis of sources and partitioning of oxidant in the UK – Part 1: The NOx-dependence of annual mean concentrations of nitrogen dioxide and ozone. Atmospheric Environment, 38, 5117-5129.