TABLE OF CONTENTS

3 Air Quality Impact.. 3-1

3.1 Introduction. 3-1

3.2 Environmental Legislation, Plans, Standards, and Guidelines. 3-1

3.3 Description of the Environment and Future Trends. 3-2

3.4 Air Sensitive Receivers. 3-5

3.5 Identification of Environmental Impacts. 3-8

3.6 Assessment Methodologies. 3-11

3.7 Prediction and Evaluation of Environmental Impacts. 3-18

3.8 Mitigation of Adverse Environmental Impacts. 3-19

3.9 Evaluation of Residual Environmental Impacts. 3-41

3.10 EM&A Requirements. 3-41

3.11 Conclusions. 3-42

LISTS OF FIGURES

NEX1062/S/SHD/ACM/Z10/120	Locations of Representative Air Quality Sensitive Receivers
NEX1062/S/SHD/ACM/Z10/121	Locations of Representative Air Quality Assessment Points under Stage 1 SHD Replanning Works (Sheet 1 of 2)
NEX1062/S/SHD/ACM/Z10/122	Locations of Representative Air Quality Assessment Points under Stage 1 SHD Replanning Works (Sheet 2 of 2)
NEX1062/S/SHD/ACM/Z10/123	Locations of Representative Air Quality Assessment Points under Stage 2 SHD Replanning Works (Sheet 1 of 2)
NEX1062/S/SHD/ACM/Z10/124	Locations of Representative Air Quality Assessment Points under Stage 2 SHD Replanning Works (Sheet 2 of 2)
NEX1062/S/SHD/ACM/Z10/125	Locations of Representative Air Quality Assessment Points under Stage 3 SHD Replanning Works (Sheet 1 of 2)
NEX1062/S/SHD/ACM/Z10/126	Locations of Representative Air Quality Assessment Points under Stage 3 SHD Replanning Works (Sheet 2 of 2)
NEX1062/S/SHD/ACM/Z10/127	Locations of Representative Air Quality Assessment Points under Stage 4 SHD Replanning Works (Sheet 1 of 2)
NEX1062/S/SHD/ACM/Z10/128	Locations of Representative Air Quality Assessment Points under Stage 4 SHD Replanning Works (Sheet 2 of 2)

LIST OF Appendices

Appendix 3.1 Calculation of Construction Dust Emission Source

Appendix 3.2 Traffic Data

Appendix 3.3 Calculation of Vehicular Emission Source

Appendix 3.4 Emission Inventory of Topside Development Construction Works

Appendix 3.5 Emission Inventory of OWTF and Marine Emission from North Lantau Refuse Transfer Station

Appendix 3.6 Summary of Surface Characteristics

Appendix 3.7 Vehicular Emission Burden of the Study Area

Appendix 3.8 Detailed Prediction of Construction Dust Impact (Unmitigated)

Appendix 3.9 Detailed Prediction of Construction Dust Impact (Tier 1)

Appendix 3.10 Construction Vehicle Routing

Appendix 3.11 Proposed Location of Reprovisioned SPS and Site Walk at Three Existing SPSs

3 Air Quality Impact

3.1 Introduction

3.1.1 This section presents the assessment of potential air quality impacts on air sensitive receivers (ASRs) arising from the construction and operation of the Project. Assessment has been conducted in accordance with the criteria and guidelines as stated in Section 1 of Annex 4 and Annex 12 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) as well as the requirements given in Clause 3.4.4 of the EIA Study Brief (ESB-296/2016).

3.1.2 The potential dust impact arising from construction activities of the Project have been assessed and appropriate mitigation measures are proposed to alleviate any adverse air quality impact.

3.1.3 During operational phase, review on the air quality impact associated with the operation of Reprovisioned SHD and SHO has been conducted. A sewage pumping station (SPS) will be reprovisioned under the podium deck to convey the sewage generated by the Reprovisioned SHD and SHO to existing public sewerage system. Potential odour impact from the operation of this SPS has been also addressed and mitigation measures are recommended as appropriate.

3.2 Environmental Legislation, Plans, Standards, and Guidelines

3.2.1 The criteria and guidelines for air quality assessment are laid down in Annex 4 and Annex 12 of the Technical Memorandum on Environmental Impact Assessment Process (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 stipulate the maximum allowable concentrations over specific periods for typical pollutants, should be met. The relevant AQOs are listed in Table 3.1.

Table 3.1 Hong Kong Air Quality Objectives

Pollutant	Averaging Time	Maximum Average Concentration (µg/m^3) ^(1)	No. of Exceedances Allowed ^(2)
Fine Suspended Particulates (PM 2.5) ^(4)	24-hr	75	9
	Annual ^(3)	35	NA
Respirable Suspended Particulates (PM10) ^(5)	24-hr	100	9
	Annual ^(3)	50	NA
Sulphur Dioxide (SO2)	10-min	500	3
	24-hr	125	3
Nitrogen Dioxide (NO2)	1-hr	200	18
	Annual ^(3)	40	NA
Carbon Monoxide (CO)	1-hr	30,000	0
	8-hr	10,000	0
Photochemical Oxidants (as ozone)	8-hr	160	9
Lead (Pb)	Annual ^(3)	0.5	NA

Notes:

(1) Measured at 293 K and 101.325 kPa.

(2) The number of exceedances allowed per year.

(3) Arithmetic mean.

(4) Suspended particulates in air with a nominal aerodynamic diameter of 2.5 mm or smaller.

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

3.2.3 The EIAO-TM stipulates that the hourly TSP level should not exceed 500 µg/m³ (measured at 25°C and one atmosphere) for construction dust impact assessment.

3.2.4 In accordance with Annex 4 of the EIAO-TM, the limit of 5 odour units based on averaging time of 5 seconds for odour emission.

Air Pollution Control (Construction Dust) Regulation

3.2.5 Notifiable and regulatory works are under the control of Air Pollution Control (Construction Dust) Regulation. Notifiable works include site formation, reclamation, demolition, foundation and superstructure construction for buildings and road construction. Regulatory works include 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 notifiable works (site formation, demolition, foundation and superstructure construction for depot facilities and station structure) and regulatory works (dusty material handling and excavation). Contractors and site agents are required to inform EPD and adopt dust reduction measures to minimize dust emissions, while carrying out construction works, to the acceptable level.

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

3.2.6 The Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation comes into operation 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.

3.3 Description of the Environment and Future Trends

3.3.1 The Project Site is located in the vicinity of North Lantau Highway and at the south-west of the existing Siu Ho Wan Wastewater Treatment Works (SHWWTW). The Project Site is in a predominantly rural area. The potential air pollutants in the study area would be traffic emissions from existing North Lantau Highway and future emission from nearby Organic Wastes Treatment Facilities Phase 1 (OWTF).

3.3.2 The nearest EPD fixed air quality monitoring station is located at Tung Chung Health Centre. The annual average monitoring data recorded at EPD’s Tung Chung air quality monitoring station has shown steady trend of pollutants’ concentration in the past five years. The recent five years (2012 - 2016) annual average concentrations are summarized in Table 3.2.

Table 3.2 Average Concentrations of Pollutant in the Recent Five Years (Year 2012 – 2016) at Tung Chung EPD Air Quality Monitoring Station

Pollutant	2016	2015	2014	2013	2012	Mean
10th Highest Daily Average PM10 Concentration (µg/m^3)	92	93	101	108	106	100.0
Annual Average PM10 Concentration (µg/m^3)	33	36	39	42	45	39.0
10th Highest Daily Average PM2.5 Concentration (µg/m^3)	63	65	65	76	74	68.6
Annual Average PM2.5 Concentration (µg/m^3)	21	22	24	26	28	24.2

3.3.3 The operation year background concentrations are made reference to the EPD’s PATH modelling results. The PATH model is a regional air quality model developed by EPD to simulate air quality over Hong Kong against the Pearl River Delta (PRD) as background. Since the tentative commencement year of the construction work for SHO and Stage 1 SHD Replanning Works would be in Year 2019, the PATH Model results for future year would be made reference to Year 2019 for assessment on Stage 1 works and Year 2020 for assessment on Stage 2, Stage 3 and Stage 4 works. The particulates concentrations of the study area extracted from Year 2016, 2019 and 2020 PATH results are presented in Table 3.3.

Table 3.3 Relevant Air Pollutant Concentrations extracted from PATH-2016 Model

Pollutant	Averaging Time	AQO^[1]	Data Summary	PATH Grid Cell ^[2] ^[3]
				Year 2016			Year 2019			Year 2020
				(20, 32)	(21, 32)	(22, 32)	(20, 32)	(21, 32)	(22, 32)	(20, 32)	(21, 32)	(22, 32)
Fine Suspended Particulates (PM2.5) ^[4][5]	24-hr	75 (9)	Max.	106	110	116	100	104	109	97	101	107
			10th Max.	61	60	62	60	59	60	59	58	59
			No. of Exceedance(s)	4	4	4	4	3	4	4	2	3
	Annual	35	-	24	24	25	24	23	24	23	23	24
Respirable Suspended Particulates  (PM10)^[5]	24-hr	100 (9)	Max.	142	147	155	133	138	146	130	135	142
			10th Max.	82	81	83	80	78	80	79	77	79
			No. of Exceedance(s)	4	4	4	4	3	4	4	2	3
	Annual	50	-	34	34	35	33	33	34	33	32	34

Notes:

[1] Values in ( ) mean the number of exceedances allowed per year.

[2] Bolded values mean exceedance of the AQOs.

[3] N/A – Not Available.

[4] Since PM_2.5 is not available from PATH model outputs, 24-hour average PM2.5 and annual average PM_2.5 are estimated by 0.75 x PM₁₀ and 0.71 x PM₁₀ respectively with reference to Guidelines on the Estimation of PM_2.5 for Air Quality Assessment in Hong Kong.

[5] 10th highest daily and annual RSP concentration is adjusted by adding 26.5 µg/m³ and 15.6 µg/m³ respectively with reference to Guidelines on Choice of Models and Model Parameters. Same adjustment is applied to estimation of PM_2.5 as well.

3.4 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 air sensitive receivers (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. As stated in the EIA Study Brief, the boundary of the assessment area for air quality assessment should be 500 m from the Project boundaries of all associated areas under the Project.

3.4.2 The construction programme for the Reprovisioned SHD would be divided into four stages, while the construction of SHO would be conducted during Stage 1 SHD Replanning Works. Upon completion of construction of podium deck in each respective Stage 1 to 4, construction of Proposed SHD Topside Development would be commenced (Table 3.4 refers).

3.4.3 The representative ASRs (existing / planned) that may be affected by the Project within the 500 m assessment area have been identified based on the latest Outline Zoning Plans, Layout Plan, Outline Development Plans, Layout Plans and other relevant published land use plans.

3.4.4 The locations of the representative existing and planned ASRs including the proposed assessment points are shown in Figure Nos. NEX1062/S/SHD/ACM/Z10/120 - 128. The details of the representative ASRs for assessment in different stages are presented in Table 3.4.

Table 3.4 Representative Air Sensitive Receivers

ASR	Description	Land Use^(1)	Approx. Distance between ASR and closest works front (m)	No. of Storey
Stage 1 SHD Replanning Works (Year 2019 – 2023)
A1	Discovery Bay Tunnel Administration Building	Commercial	190	2
A2	Siu Ho Wan Government Maintenance Depot	GIC	240	3
A3	Siu Ho Wan Sewage Treatment Works Administration Building	GIC	100	3
A4	Siu Ho Wan Water Treatment Works Administration Building	GIC	300	3
A5	Organic Waste Treatment Facilities Main Building	GIC	330	N/A
A6	North Lantau Refuse Transfer Station Office	GIC	700	3
Stage 2 SHD Replanning Works (Year 2024 – 2026)
A1	Discovery Bay Tunnel Administration Building	Commercial	860	2
A2	Siu Ho Wan Government Maintenance Depot	GIC	780	3
A3	Siu Ho Wan Sewage Treatment Works Administration Building	GIC	1450	3
A4	Siu Ho Wan Water Treatment Works Administration Building	GIC	1700	3
A5	Organic Waste Treatment Facilities Main Building	GIC	1750	N/A
A6	North Lantau Refuse Transfer Station Office	GIC	1950	3
A101	Proposed Development atop Siu Ho Wan Depot (Phase 1a)	R	60	17
A104			80	18
A107			60	18
A108			70	18
A113			160	18
A115			200	18
A118			270	19
A125	Proposed Development atop Siu Ho Wan Depot (Phase 1b)		200	16
A128			130	16
A131			80	17
A135			80	17
A136	Proposed Development atop Siu Ho Wan Depot (Phase 1c)		300	19
A139			370	19
A142			430	20
A143			500	20
A146			570	20
A149			640	21
Stage 3 SHD Replanning Works (Year 2028 – 2030)
A101	Proposed Development atop Siu Ho Wan Depot (Phase 1a)	R	150	17
A104			100	18
A107			70	18
A108			70	18
A113			70	18
A115			70	18
A118			60	19
A125	Proposed Development atop Siu Ho Wan Depot (Phase 1b)		450	16
A128			370	16
A131			300	17
A135			220	17
A136	Proposed Development atop Siu Ho Wan Depot (Phase 1c)		65	19
A139			72	19
A142			55	20
A143			94	20
A146			50	20
A149			20	21
A209	Proposed Development atop Siu Ho Wan Depot (Phase 2a)	R	250	18
A501		E	350	7
A211	Proposed Development atop Siu Ho Wan Depot (Phase 2b)	R	200	17
A212			100	17
A215			5	17
A219			80	19
A1	Discovery Bay Tunnel Administration Building	Commercial	100	2
A2	Siu Ho Wan Government Maintenance Depot	GIC	80	3
A3	Siu Ho Wan Sewage Treatment Works Administration Building	GIC	480	3
A4	Siu Ho Wan Water Treatment Works Administration Building	GIC	730	3
A5	Organic Waste Treatment Facilities Main Building	GIC	760	N/A
A6	North Lantau Refuse Transfer Station Office	GIC	1020	3
Stage 4 SHD Replanning Works (Year 2032 – 2034)
A101	Proposed Development atop Siu Ho Wan Depot (Phase 1a)	R	580	17
A104			530	18
A107			470	18
A108			430	18
A113			320	18
A115			280	18
A118			205	19
A125	Proposed Development atop Siu Ho Wan Depot (Phase 1b)		900	16
A128			820	16
A131			750	17
A135			660	17
A136	Proposed Development atop Siu Ho Wan Depot (Phase 1c)		170	19
A139			140	19
A142			80	20
A143			70	20
A146			50	20
A149			40	21
A209	Proposed Development atop Siu Ho Wan Depot (Phase 2a)	R	690	18
A501		E	800	7
A211	Proposed Development atop Siu Ho Wan Depot (Phase 2b)	R	640	17
A212			540	17
A215			440	17
A219			522	19
A303	Proposed Development atop Siu Ho Wan Depot (Phase 3a)	R	200	19
A307			90	19
A308			60	21
A310	Proposed Development atop Siu Ho Wan Depot (Phase 3b)		410	18
A313			400	20
A318			200	20
A601		E	350	7
A1	Discovery Bay Tunnel Administration Building	Commercial	130	2
A2	Siu Ho Wan Government Maintenance Depot	GIC	100	3
A3	Siu Ho Wan Sewage Treatment Works Administration Building	GIC	500	3
A4	Siu Ho Wan Water Treatment Works Administration Building	GIC	730	3
A5	Organic Waste Treatment Facilities Main Building	GIC	760	N/A
A6	North Lantau Refuse Transfer Station Office	GIC	1020	3

Note:

(1) R – residential; E – educational; G – government; IC – Institution and Community; E – Educational

3.5 Identification of Environmental Impacts

Construction Phase

Construction Works

3.5.1 Maintenance of a safe depot operation condition without any disturbance to the operating railway is an overriding consideration factor in the determination and selection of construction sequences and method. Relevant railway safety regulations shall be followed throughout the construction period.

3.5.2 For the construction works to be conducted in proximity to the operating depot tracks or the operating AEL and TCL tracks, the boundaries of these works areas should be erected with protective barriers and hoarding such that labour, plant and materials would not have uncontrolled access to any part of the operating tracks.

3.5.3 Major construction works of the Project would include the following activities:

· Demolition of existing depot facilities;

· Pipe jacking works for installation of underground utilities and associated excavation and lateral support (ELS) works;

· Piling works, pile cap construction and ELS works related to the construction of planned SHD Topside Development;

· Pad footing foundation works;

· Construction of SHO and modification of existing AEL/TCL tracks; as well western access and local access;

· Construction of concrete slab; and

· Reprovision of SHD facilities by stages (under the concrete slab).

Tentative Construction Programme

3.5.4 The tentative programme of construction works to be conducted at SHD, including the construction progamme of SHD Replanning Works, SHO and SHD Topside Development, is summarised in Table 3.5. The locations of works front in different stages and detailed construction programme are provided in Appendix 2.4.

Table 3.5 Tentative Construction Programme

SHD Replanning Works				SHO and Associated Trackworks	Planned SHD Topside Development ^(1)
Stage	Works Programme^(1)		Completion of works & Operation	Works programme	Phase	Commencement of Super-structure Works	Population Intake^(4)
	Start	Slab Completion^(2)
1	2019	2023	2024	2019 – 2026^(^3^)	1	2023	2026-2027
2	2024	2026	2028	-	2	2027	2030
3	2028	2030	2032	-	3	2031	2034
4	2032	2034	2036	-	4	2032 for Phase 4a^(4) 2035 for Phase 4b & 4c	2035 - 2038

Notes:

(1) The foundation of SHD Topside Development including piling and excavation works will be conducted in parallel with replanning works in respective phasing.

(2) Upon completion of concrete slab in respective phasing area, the contractor(s) of SHD Topside Development would be on board to commence the superstructure works.

(3) Civil construction works for SHO will be completed in 2023 while building services (BS) and electrical and mechanical (E&M) works will be conducted in 2024-2026. Operation of SHO would commence in 2026.

(4) Population intake year of different phases of SHD Topside Development is shown in Appendix 2.6. Phase 4a SHD Topside Development is located above Stage 3 SHD Replanning Works. 

Identification of Key Air Pollutants of Emission from Construction Activities

3.5.5 The major potential air quality impact during construction phase of the Project, including SHD Replanning Works and construction of SHO, would be dust arising from below construction activities for substructure works:

· Excavation, materials handling, spoil removal, piling and backfilling works;

· Haul road; and

· Wind erosion of the exposed site area.

3.5.6 The construction of SHD Topside Development including access road, Topside Development SPS and superstructure works for Topside Development will be conducted concurrently with the SHD Replanning Works and SHO. However, superstructure works are not considered as dusty generating activities because no excavation or intense spoil handling would be involved. No cumulative dust impact from the superstructure works for SHD Topside Development would be expected. Based on the available information, there are no concurrent dusty construction activities of other projects undertaken within 500 m assessment area during construction phase of the Project, therefore no cumulative dust impact from other projects would be anticipated.

3.5.7 Construction vehicles on the haul road within the work areas would also cause construction dust impact. Dust mitigation measures such as paving and regular watering will be provided to abate the dust emission. Construction vehicle will be required to pass through the wheel washing facilities upon site exit. Thus the construction vehicle movements outside the work area would not cause any significant dust impact.

3.5.8 Although these construction vehicles, as additional traffic induced by the construction of SHO and SHD Replanning Works, would contribute in vehicular emission along their routes, the number of construction vehicle including dump trucks and concrete trucks is estimated to be less than 50 nos. per hour, 7am to 7pm, throughout the construction phase, based on the current engineering design. Upon leaving the construction site, construction vehicles will enter the North Lantau Highway (NLH) westbound, turn around at Tung Chung Interchange and enter Tuen Mun- Chek Lap Kok (TM-CLK) Link, or enter the NLH eastbound and heading to Tsing Yi. It is anticipated that construction vehicles would not enter the existing Tung Chung New Town and the planned extension. The routing of construction vehicles is illustrated in Appendix 3.10. NLH has an AADT of 68,930 in 2015, thus the amount of additional traffic induced on the highway is insignificant, which is less than 1% of minimum hourly traffic along NLH between 7am to 7pm. The air quality impact due to construction vehicle movement outside the worksite is expected to be insignificant.

3.5.9 OWTF would be commissioned in 2017 and 3RS system would be fully functional starting from 2023. Vehicular emission from the road traffic within 500m study area and marine emission from North Lantau Refuse Transfer Station (NLRTS), and emission from OWTF and Hong Kong International Airport with Three-Runway System are the contributors to the cumulative construction dust impact in the assessment.

3.5.10 As mentioned above, major construction activities with significant particulate emission include excavation work, material handling, spoil removal, piling, backfilling and wind erosion of exposed site area. On-site use of diesel-powered engines is the potential source for other gaseous pollutants such as NO₂ and SO₂ and smoke. The Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation came into effect in June 2015 to control emissions from diesel-powered engines. In addition, the number of such equipment required on-site will be limited and the equipment would be under normal operation with proper maintenance which is unlikely to cause significant smoke and gaseous emissions. Thus, particulates from construction activities would be the major air pollutant during construction phase. According to Annex 4 of the EIAO-TM, Total Suspended Particulates (TSP) is the criteria pollutant for construction dust impact assessment. Quantitative assessment of TSP emission impact as well as other particulates, Respirable Suspended Particulates (RSP) and Fine Suspended Particulates (FSP) stipulated in AQOs, is conducted for assessing construction dust impact due to the Project.

Operation Phase

3.5.11 According to assessment findings of Lantau and Airport Railway (LAR) Environmental Impact Study (EIA-029/BC), gaseous and particulate emissions generated from exhaust emissions of equipment used for maintenance operations are expected to be insignificant as the equipment is operated on a routine but infrequent basis. With the operation activities at Reprovisioned SHD same as those at existing SHD, it is anticipated that there would be no additional and insignificant air quality impact arising from the operation of Reprovisioned SHD.

3.5.12 No air quality impact is expected from the operation of SHO with emission free electric-powered rail system and thus the exhaust air from railway operations would be insignificant. Non-road mobile machinery (NRMM) if any for the operation of SHO, shall comply with prescribed emission standards and obtain a proper label in a prescribed format issued by EPD, according to the Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation. The air quality impact due to the use of NRMM is expected to be minimum. No adverse operational air quality impact is anticipated.

3.5.13 A sewage pumping station (SPS) with a total sewage flow of around 1,229m³/day will be reprovisioned at Works Front 1C-7 under the podium deck to handle the sewage generated by the Reprovisioned SHD and SHO. Odour is originated from hydrogen sulphide gas (H₂S) and the potential sources of odour at the reprovisioned SPS would be the wet well, inlet chamber and screen chamber. These are the odour sources and would be properly covered. The air vent from these sources would be treated by deodorizer before discharging to the atmosphere. With proper implementation of these odour mitigation measures, it is anticipated that the odour impact from the reprovisioned SPS would be insignificant.

3.6 Assessment Methodologies

Construction Phase

General Approach

3.6.1 According to “Guidelines on Assessing the ‘TOTAL’ Air Quality Impacts”, three components of contribution should be considered in evaluating the air quality impact due to the Project upon ASRs, namely primary, secondary and background contributions.

· Primary contributions: Project induced;

· Secondary contributions: pollutant-emitting activities in the immediate neighbourhood. Any emission sources in an area within 500 m radius of the Project area with notable impacts are identified and included in an air quality assessment to cover the short-range contributions using EPD’s approved local-scale Gaussian type model; and

· Background contributions: Background concentrations from Pollutants in the Atmosphere and their Transport over Hong Kong (PATH-2016) model released from EPD will be adopted to estimate future concentrations.

Emission Inventory

Primary Contributions

3.6.2 Primary contributions are the project-induced emission which contributes to the local air quality impact. Thus, construction dust emission associated with the construction work of the Project is the primary contributions during the construction phase.

3.6.3 The major dusty construction activities for the Project to be concerned and considered in the modelling assessment include:

· Excavation, material handlings and spoil removal within the construction site modelled as heavy construction activities; and

· Wind erosion of open active and inactive work site during working and non-working hours.

3.6.4 According to United States Environmental Protection Agency (USEPA) AP-42[[1]], construction dust particles may be grouped into five particle size classes. The particle size distribution as referenced to AP-42, Section 13.2.4 (Aggregate Handling Emission), is normalised to obtain the particle size distribution in PM30 (TSP). Details are shown in Table 3.6. The mass of RSP, which is defined as suspended particulates in air with aerodynamic size of 10 µm or smaller, is estimated to be 47% of PM30, i.e. RSP emission = 47% × TSP emission. Similarly, the mass of FSP is estimated to be 7% of PM30.

Table 3.6 Particle Size Distribution

Size Range (µm)	Average size(µm)	Distribution	Normalized Distribution
15 – 30	22.5	26%	35%
10 – 15	12.5	13%	18%
5 – 10	7.5	15%	20%
2.5 – 5	3.75	15%	20%
< 2.5	1.25	5%	7%

3.6.5 According to the preliminary engineering design information, dust control measures would been incorporated into the design, as presented in Table 3.7. These dust control measures would also been taken into account in the assessment.

Table 3.7 Dust Emission Design Control Measures

Process	Description	Dust Emission Design Control Measures
Haul road within construction sites facilities	Transportation of spoil	All road surfaces within the construction sites would be paved and watering frequently along the haul road during the working hours.
Unloading of materials	Unloading of spoil materials	The unloading process would be undertaken within a 3-sided screen with top tipping hall. Water spraying and flexible dust curtains would be provided at the discharge point for dust suppression.
Trucks	Vehicles leaving the loading/unloading facility	Vehicles would be required to pass through the wheel washing facilities provided at the site exit.

3.6.6 The emission rates of dusty construction activities are estimated based on emission factors of United States Environmental Protection Agency (USEPA) Compilation of Air Pollution Emission Factors (AP-42), 5th edition and activity data from the engineer design. Activity data includes, but not limited to, excavation rate, material handling rate, percentage active area, moisture content, silt content, number of construction trucks and truck speed. The emission factors for identified dust sources are summarized in Table 3.7. The detailed calculation of construction dust sources are presented in Appendix 3.1.

Table 3.8 Emission Factors for Dusty Construction Activities

Source	Activity	Emission Factor	Remarks
Works Area of SHD Replanning Works and SHO Construction	Heavy Construct-ion Activities (including Excavation, materials handling, spoil removal, backfilling and piling works)	E(TSP)=2.69 Mg/hectare /month of activity E(RSP) = 2.69 x 47% Mg/hectare/month^(1) E(FSP) = 2.69 x 7% Mg/hectare/month^(1)	100% area actively operating for hourly and daily concentration prediction AP-42, Section 13.2.3, 1/95 ed.
	Wind Erosion	E(TSP)=0.85 Mg/hectare /year E(RSP) = 0.85 x 47% Mg/hectare/month^(1) E(FSP) = 0.85 x 7% Mg/hectare/month^(1)	100% area actively operating for hourly and daily concentration prediction AP-42, 5^th ed., Table 11.9.4

Note:

(1) USEPA AP-42, 5th ed. 11/06 ed. S13.2.3

3.6.7 For the prediction of the highest hourly average TSP, the 10th highest daily average and annual average RSP and FSP concentrations, 12-hour (07:00-19:00) per normal working day would be assumed for the construction period in the assessment. Wind erosion would be assumed for working hours (07:00 to 19:00) and non-working hours (19:00 to 07:00 of the following day). All days are considered as working days for assessment purpose.

3.6.8 Works activities and plant would not be concentrated in certain areas of the site close to ASRs for an extended period of time during the construction period. However, notwithstanding that such a scenario would not be expected to occur, a hypothetical Tier 1 screening test assuming 100% active area of construction site of the Project with mitigation measures in place has been undertaken for predicting hourly average TSP, daily average RSP and FSP levels. It aims to highlight the hot spot locations where construction dust may potentially become an issue. However, it should be emphasised that Tier 1 screening test is a hypothetical one which is very conservative and does not occurred in reality.

3.6.9 The Tier 1 results have allowed a more focused Tier 2 assessment to be undertaken at the specific hot spot locations where TSP/ RSP/FSP non-compliance is predicted under the Tier 1 screening test. A focused Tier 2 assessment is undertaken whereby the percentage of maximum active works areas, which is calculated based on total number of operating plant for dusty construction activities, for each stage of the Project are positioned closest to the potentially worst affected ASRs. The calculation of the monthly average works areas of each stage is presented in Appendix 3.1. A more conservative percentage of active works area of 10% is assumed for the Tier 2 assessment, which is confirmed by the Engineer as a practicable assumption. Wind erosion is also assumed for the whole works area.

3.6.10 Active construction activities might be undertaken at multiple works faces spreading across each site. It is not feasible to determine the exact location of individual dust emission source at a specific time. As such, for the purpose of predicting annual concentrations and in conservative approach, it is assumed that dust emissions would be distributed across the whole area of each site with all activities operating at the same time for a complete year. The dust emission rates would be estimated based on the annual average percentage active works area of 10%. Wind erosion is assumed for the whole works area.

Secondary Contributions

3.6.11 Secondary contributions are the air pollutant emissions immediate neighbourhood of the Project Site contributing further to the local air quality impact. Any particulate emission sources within 500m of the project boundary with notable impact are identified and considered in the construction phase impact assessment. Potential sources for secondary contribution in particulates include construction of access road and Topside Development SPS under Planned SHD Topside Development Project, emissions from nearby OWTF and the Hong Kong International Airport, marine emission and vehicular emission, in particular North Lantau Expressway. However, as mentioned in Section 3.5.6, the superstructure work of SHD Topside Development Project which is not dusty construction activities is not considered as secondary contributions. .

Emission from Open Road Traffic

3.6.12 The principal pollutants associated with traffic emission are RSP and FSP in cumulative dust impact assessment. The projected 24-hour traffic flows and vehicle compositions are adopted in this air quality assessment. A Technical Note illustrating the methodology to produce the traffic data (include 24-hr traffic flow, trips, daily vehicle-kilometer-travelled (VKT) & speed fraction) has been issued to Transport Department (TD) for comment. TD has no comment on the Technical Note and the correspondence is attached in Appendix 3.2.

3.6.13 EMFAC-HK v3.1.1 model is adopted to estimate the vehicle emission rates of particulate matters, both RSP and FSP. The “vehicle fleet” refers to all motor vehicles operating on roads within this assessment area. The modelled fleet is broken down into 16 vehicle classes based on the information in the Transport Monthly Digest and vehicle population provided by EPD. The detailed input parameters and model assumptions made in EMFAC-HK model are summarized in Appendix 3.3.

3.6.14 The hourly emissions of RSP and FSP are divided by the number of vehicles and the distance travelled to obtain the emission factors in gram per miles per vehicle. The calculated 24-hour emission factors of 16 vehicle classes for each road type are adopted in this air quality impact assessment. The detailed calculation of vehicular emission source is presented in Appendix 3.3.

3.6.15 Both Railway EIA and SHD Topside Development EIA have conducted the assessment on the vehicular emission impact on Year 2026. By adoption of the assumptions in SHD Topside Development EIA, the assessment results showed that the RSP and FSP levels at ASRs due to vehicular emission impact would only have minor difference by less than 1µg/m³. Thus the large margin for AQO compliance would remain substantially unchanged.

Emission from Topside Development Construction Works

3.6.16 The emission inventory for the construction of access road and SPS under Planned SHD Topside Development Project follows its EIA Study. Superstructure works are not considered as major construction dust sources as discuss in Section 3.5.6. Details on emissions strengths, emission characteristics and modelling parameters of the construction dust sources are presented in Appendix 3.4. All construction works are assumed to be conducted simultaneously as a worst-case assumption.

Emission from Industrial Source (OWTF)

3.6.17 The EIA Report for OWTF was approved under EIAO in February 2010 and an Environmental Permit (Environmental No.: EP-395/2010) was granted in June 2010. Variations of Environmental Permit (VEP), VEP Application No. VEP-394/2013 was subsequently applied for the change of the chimney emission information. VEP-488/2015 involved the change in the site layout and the chimney design. Therefore, the emission inventory (particulates) and the chimney design of the OWTF follow the latest design information (including emission inventory and chimney parameters and its location) in the relevant attachments under VEP Application No. VEP 394/2013 and VEP 488/2015. The emission inventory of the OWTF and its design assumption are presented in Appendix 3.5.

Emission from Hong Kong International Airport

3.6.18 Emission inventory for the operation of the Airport considered in the assessment follows the approved EIA Study for Expansion of Hong Kong International Airport into Three-Runway System (3RS EIA) (AEIAR-185/2014). The worst scenario with highest aircraft emission was identified to be Year 2031. Details on emissions strengths, emission characteristics and modelling parameters refers to the 3RS EIA Study.

Emission from Marine Vessels

3.6.19 The marine emission from NLRTS presented in the approved EIA Study “Organic Waste Treatment Facilities, Phase 1” (AEIAR-149/2010) is adopted for the cumulative air quality impact assessment. There is no change in locations and emission rates of marine sources in the subsequent variation of Environmental Permit VEP-394/2013, VEP-403/2013 and VEP-488/2015. It is noted that from site observation that the barges arriving and leaving the NLRTS would take a generally north bound route towards Urmston Road to leave NLRTS, and vice versa. Such route has been confirmed by the NLRTS operator. However, according to the assessments associated with the EIA and sequent VEPs, marine source locations are aligned in the southwesterly direction which would represent a more conservatiove case as far as the receivers in the Topside Development is concernted. The southwestern route is therefore adopted, instead of the northern route. The emission inventory of the marine emission is presented in Appendix 3.5.

Background Contributions

3.6.20 According to “Guidelines on Assessing the ‘TOTAL’ Air Quality Impacts”, an integrated modelling system PATH which is developed and maintained by EPD is applied to estimate the background pollutant concentrations. Year 2019 and Year 2020 background concentrations from PATH-2016 (Pollutants in the Atmosphere and their Transport over Hong Kong) model are adopted to estimate future concentrations for scenario in Year 2019, and scenario in Year 2020 and afterwards, respectively.

3.6.21 As dataset of PATH consist only the background concentration of RSP, daily and annual average FSP background concentrations are estimated by a factor of 0.75 and 0.71 to RSP concentration respectively, as suggested by “Guidelines on the Estimate of PM_2.5 for Air Quality Assessment in Hong Kong”.

3.6.22 Dataset of PATH has no TSP background either. TSP background concentration is assumed to constitute of 100% of RSP concentration. RSP concentration from PATH will be directly adopted as TSP background concentration for the assessment.

3.6.23 The study area covers 6 grid cells of PATH, namely grid (20, 31), (20, 32), (21, 31), (21, 32), (22, 32) and (22, 33). PATH dataset (Year 2019 or 2020 subject to the results of emission burden rate calculation) of these six grid cells are adopted as the background concentration for the assessment.

Dispersion Modelling & Modelling Approach

Emissions from Construction Activities, Marine Vessels, OWTF and Airport

3.6.24 American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD), the EPD approved air dispersion model, is employed to predict the air quality impacts due to emission from construction activities and OWTF. For the emissions from the Hong Kong International Airport, CALINE4 and AERMOD are applied to assess the air quality impact from airside vehicles and sources other than airside vehicles respectively. The air pollutants concentrations are predicted at each identified ASRs at various assessment height at 1.5 mAG, 5.0 mAG, 10 mAG, 13.6 mAG, 20 mAG and so forth up to 80 mAG of the respective ASRs.

3.6.25 Hourly meteorological conditions including wind data, temperature, relative humidity, pressure cloud cover and mixing height of Year 2010 are extracted from the WRF meteorological data adopted in the PATH-2016 system. The minimum wind speed is capped at 1 metre per second. The mixing height is capped between 121 metres and 1667 metres according to the observation in Year 2010 by HKO. The height of the input data is assumed to be 9 above ground for the first layer of the WRF data as input.

3.6.26 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 landuse are then suggested by AERMET by default according to its land use characteristics. The detailed assumptions are discussed in Appendix 3.6.

Emission from Open Road Traffic

3.6.27 CALINE4, the USEPA approved line source air dispersion model developed by the California Department of Transport is used to assess the secondary contribution due to vehicular emission from road networks within 500m study area.

3.6.28 The surface roughness is dependent on the land use characteristics, which is estimated to be 10% of average height of physical structure within 1 km radius of the Project site. The surface roughness for the area of proposed development (Grid (21, 32)) is taken as 100 cm. More than 50% of area outside proposed development is sea and flat land, the surface roughness applied in the model is thus taken as 50 cm in general for other grid cell.

3.6.29 Under the current EPD guideline, the hourly meteorological data including wind speed, wind direction, and air temperature from the relevant grids from the WRF Meteorological data (same basis for PATH-2016 model), are employed for the model run. PCRAMMET is applied to generate Pasquill-Gifford stability class for the meteorological input to CALINE4 model based on the WRF meteorological data.

3.6.30 There is a height limitation for line sources in CALINE4, i.e. road height higher than 10 metres above ground should be considered as 10 metres high above ground. Thus the height of elevated roads higher than 10 metres above ground is input as 10 metres in the model for assessment purpose.

3.6.31 The principle pollutants associated with traffic emission are NO₂, RSP and FSP. As the best estimation, the hourly TSP concentration are assumed to be the same as that for RSP in the assessment.

Cumulative Air Quality Impact

3.6.32 Cumulative dust impacts upon ASRs are derived from the sum of predictions by local air quality models and background concentration from PATH-2016 system on hour-by-hour basis. Averaging results, namely hourly, daily and annual, are derived from the cumulative hour-by-hour results in accordance with Title 40, Code of Federal Regulations, US Environmental Protection Agency (USEPA 40 CFR) Part 51 “Revision to the Guideline on Air Quality Models, Version 2005”. Cumulative average predictions at each ASR amongst 365 days are ranked by highest concentration and compared with the maximum allowable concentration to determine the number of exceedance throughout a year. The dust impact upon ASRs is evaluated by number of exceedance per annum against the AQO criteria.

Determination of the Assessment Year

3.6.33 The assessment year of each stage for construction phase impact assessment shall consider the programme of dusty construction activities (Appendix 2.4), number of operating plants (Appendix 3.1) and the population intake year of the planned development (Appendix 2.6) and the environ in each stage.

3.6.34 The assessment for each stage is conducted because each stage has its distinct works area. As a conservative approach, the secondary impact (vehicular emission impacts) considered in each stage of the construction programme, adopts the highest emission burden year in the assessment. Vehicular emission burden for RSP are calculated based on the traffic forecast and EMFAC-HK v3.1.1 model, the latest version released from EPD. The vehicular emission burdens for different years, 2019, 2020, 2021, 2022, 2026, 2028, 2029, 2030, 2032, 2033 and 2034 are presented in Appendix 3.7. Results indicate that Year 2019 would be the worst affected year for Stage 1 and Year 2026 for Stage 2. Year 2026, the first year of population intake of SHD Topside Development, would have higher vehicular emission burden than the years of Stage 3 works (i.e. 2028 – 2030) and Stage 4 works (i.e. 2032 – 2034), and thus it is selected as the assessment year for Stage 3 and Stage 4 as a conservative assumption. Table 3.9 summarizes the assessment scenarios for construction dust impact assessment.

Table 3.9 Assessment Scenarios in the Construction Dust Impact Assessment

Project Works	Works Duration	Affected ASRs	Other Concurrent Sources
Stage 1	Year 2019 – 2023	Existing ASR	· HKIA · OWTF · Open Road (Year 2019) · Marine Source of NLRTS · Topside Development (All)
Stage 2	Year 2024 – 2026	Existing ASR, Planned SHD Topside Development at Phase 1	· HKIA · OWTF · Open Road (Year 2026) · Marine Source of NLRTS · Topside Development (All)
Stage 3	Year 2028 – 2030	Existing ASR, Planned SHD Topside Development at Phase 1, Phase 2a and 2b
Stage 4	Year 2032 – 2034	Existing ASR, Planned SHD Topside Development at Phase 1, Phase 2a and 2b and Phase 3

Operation Phase

3.6.35 As mentioned in Section 3.5.11 to 3.5.13, no air quality impact from the operation of SHO and Reprovisioned SHD and insignificant odour impact from the reprovisioned SPS would be expected. Therefore, the assessment for air quality during operational phase of the Project adopts qualitative assessment approach.

3.7 Prediction and Evaluation of Environmental Impacts

Construction Phase

3.7.1 The cumulative dust impacts due to construction of the Project, construction of Topside Development, vehicle emission, marine emission from NLRTS, emission from OWTF and Hong Kong Airport at the representative ASRs in 4 stages of Replanning Works have been evaluated. In all 4 stage of Replanning Works, exceedance in cumulative maximum hourly average TSP, 10^th highest daily average RSP and FSP would be predicted at the representative ASRs. The predicted unmitigated cumulative maximum hourly average TSP, 10^th highest daily and annual average RSP and FSP concentrations at the representative ASRs are summarized in Table 3.10. The detailed predictions and contour plots are presented in Appendix 3.8.

Table 3.10 Predicted Construction Dust Impact during Stages of Replanning Works (Unmitigated)

Stage	Maximum Hourly TSP Conc. (µg/m^3)	10^th Highest Daily RSP Conc, (µg/m^3)	Annual RSP Conc. (µg/m^3)	10^th Highest Daily FSP Conc, (µg/m^3)	Annual FSP Conc. (µg/m^3)
1	290 – 8792	78 – 136	33 – 34	58 – 66	23 – 24
2	193 – 3516	77 – 116	32 – 34	58 – 62	23 – 24
3	196 – 7015	71 – 218	33 – 36	58 – 81	23 – 25
4	193 – 11799	77 – 259	32 – 37	58 – 82	23 – 25

Remark: Bolded value shows exceedance of relevant criteria of EIAO-TM/AQO.

Operation Phase

3.7.2 As discussed in Section 3.5.11, gaseous and particulate emissions generated from exhaust emissions of equipment used for maintenance operations are expected to be insignificant as the equipment is operated on a routine but infrequent basis. With the operation activities at Reprovisioned SHD same as those at existing SHD, it is anticipated that there would be no additional and insignificant air quality impact arising from the operation of Reprovisioned SHD.

3.7.3 No air quality impact is expected from the operation of SHO with emission free electric-powered rail system and thus the exhaust air from railway operations would be insignificant. In addition, exhausts for general ventilation and smoke extraction facilities will be carefully positioned to avoid causing nuisance to the surrounding environment. Thus, air quality impact during operation phase of SHO is considered insignificant.

3.7.4 A sewage pumping station (SPS) with a total sewage flow rate of around 1,229m³ per day (i.e. 0.01422m³ per second) will be reprovisioned at Works Front 1C-7 under the podium deck to handle the sewage generated by the Reprovisioned SHD and SHO. The location of reprovisioned SPS is illustrated in Appendix 3.11. Odour is originated from hydrogen sulphide gas (H₂S) and the potential sources of odour at the reprovisioned SPS would be the wet well, inlet chamber and screen chamber. According to the preliminary design of the SPS, the exposed area of these odour emission sources of approximate 2.6 m² would be fully enclosed and vented to the deodorizer with at least 95% odour removal efficiency. The deodorizer will be operating properly by regular maintenance. A slight negative pressure of the ventilation system within the facility will be maintained. Exhaust outlets of the deodorizer will be carefully positioned to avoid nearby ASRs, as far as practicable. It is anticipated that potential odour impact from the reprovisioned SPS would be properly controlled with the implementation of the above mitigation measures. Site walk have been conducted at three existing Drainage Services Department (DSD) sewage pumping stations with larger sewage flow rate, including Chinese University SPS, Pak Shak Kok No. 3 SPS and A Kung Kok SPS. Deodourizors have been installed in these SPS except A Kung Kok SPS. No perceptible odour was detected at the boundary of Chinese University SPS and A Kung Kok SPS (about 10m from the plant), and approximately 19 metres from Pak Shak Kok No. 3 SPS during site walk. The details of the site walk are summarized in Appendix 3.11. In accordance with the preliminary design, the reprovisioned SPS will locate under the podium deck and the travelling distance to the closest ASR, ASR 142 (on podium deck), would be at least 100 metres, from the SPS to the edge of the podium and from the edge to the ASR. If the odour emission point is assumed to position at the edge of the podium, the ASR will be more than 25 metres away from the odourous source. Therefore, no adverse odour impact from reprovisioned SPS is expected at the closest ASRs.

3.7.5 There is no existing odour emission rate data available for assessment. It therefore adopts the odour emission rate of 8.79 OU/m²·s for fresh sewage at channel/chamber, with reference from Appendix 3-2 of approved EIA Report of Harbour Area Treatment Scheme (HATS) Stage 2A (Register No. AEIAR-121/2008). The adoption of this value in this assessment as both sewage sources are dominantly from domestic sewage and the retention period from the sources to the channel/chamber of Stonecutter Island STW is the longest time in Hong Kong which would induce the sewage with a higher odour emission rates. With the assumption of odour emission rate of 8.79 OU/m²·s for the sewage at the reprovisioned SPS and installation of deodorizer with a conservative odour removal efficiency of 95%, the odour emission rate of the reprovisioned SPS is estimated to be only about 1.14 OU/s which is very low as comparing with the other emission sources within the study area, such as OWTF (approx. 7,040 OU/s), SHW STW (approx. 3,860 OU/s) and the proposed SPS for topside development (approx. 24.6 OU/s). Furthermore, the reprovisioned SPS will be located under the podium deck to be completed by Stage 1 Works. Owing to the insignificant odour emission strength and its location under the podium deck, no adverse cumulative odour impact due to the reprovisioned SPS is anticipated.

3.8 Mitigation of Adverse Environmental Impacts

Construction Phase

3.8.1 In order to minimize the construction dust impact, the following dust mitigation measures shall be implemented:

· Watering once per hour on active works areas, inactive works area with wind erosion, exposed areas and unpaved haul roads during working hours to reduce dust emission by 91.7%. The estimation of dust suppression efficiency by water is presented in Appendix 3.1. Any potential dust impact and watering mitigation would be subject to the actual site condition. For example, a construction activity that produces inherently wet conditions or in cases under rainy weather, the above water application intensity may not be unreservedly applied. While the above watering frequency is to be followed, the extent of watering may vary depending on actual site conditions but should be sufficient to achieve the removal efficiency. The dust levels would be monitored and managed under an EM&A programme as specified in the EM&A Manual.

Stage 1 Replanning Works

Tier 1 Assessment

3.8.2 With the implementation of the above measures, the predicted mitigated cumulative maximum hourly average TSP, 10^th highest daily and annual average RSP and FSP concentrations at the representative ASRs are summarized in Table 3.11. The detailed prediction results and contour plots are presented in Appendix 3.9. It is noted that the daily and annual average RSP and FSP concentrations at the representative ASRs would comply with the AQOs. However the exceedance of hourly average TSP would still exceed at A2. Tier 2 assessment is required for this ASR.

Table 3.11 Worst Predicted Construction Dust Impact during Stage 1 Works (Mitigated, Tier 1)

ASR ID	Maximum 1-hr TSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	224	225
A2	4	736	2	<1	<1	<1	57	800
A3	<1	<1	<1	2	<1	<1	224	227
A4	<1	<1	<1	2	<1	<1	224	226
A5	3	336	<1	<1	<1	67	39	445
A6	<1	<1	<1	<1	<1	<1	220	220

ASR ID	10^th Highest 24-hr RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	<1	<1	<1	<1	<1	79	81
A2	2	2	<1	<1	<1	2	79	84
A3	<1	1	<1	1	<1	1	80	82
A4	<1	<1	<1	<1	<1	1	79	81
A5	<1	<1	<1	<1	<1	<1	78	79
A6	<1	<1	<1	<1	<1	1	78	79

ASR ID	Annual RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	34	35
A2	1	1	<1	<1	<1	<1	33	34
A3	<1	<1	<1	<1	<1	<1	34	35
A4	<1	<1	<1	<1	<1	<1	34	35
A5	<1	<1	<1	1	<1	<1	33	34
A6	<1	<1	<1	<1	<1	<1	33	34

ASR ID	10^th Highest 24-hr FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	<1	<1	<1	<1	<1	60	61
A2	1	9	<1	<1	<1	<1	50	61
A3	<1	<1	<1	1	<1	<1	60	61
A4	<1	<1	<1	<1	<1	<1	60	60
A5	<1	<1	<1	<1	<1	<1	59	59
A6	<1	<1	<1	<1	<1	<1	59	59

ASR ID	Annual FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	24	25
A2	1	<1	<1	<1	<1	<1	23	24
A3	<1	<1	<1	<1	<1	<1	24	25
A4	<1	<1	<1	<1	<1	<1	24	25
A5	<1	<1	<1	1	<1	<1	24	25
A6	<1	<1	<1	<1	<1	<1	24	25

Remark: Bolded value shows exceedance of relevant AQO

Tier 2 Assessment

3.8.3 The ASR with non-compliance in particulates levels under Tier 1 screening during the construction of the Project is A2 at 1.5 mAG which is selected to undergo Tier 2 assessment accordingly as discussed in Section 3.6. The active work areas of concurrent work contracts are positioned closest to the potentially worst affected ASR. The individual affected ASR would be influenced by one active work area. The predicted cumulative maximum hourly average TSP at the ASR of Tier 2 assessment are summarized in Table 3.12 and comply with the criterion. The contour plot of maximum hourly average TSP at 1.5 mAG concerning A2 is presented in Appendix 3.9.

Table 3.12 Predicted Construction Dust Impact during Stage 1 Works (Mitigated, Tier 2)

ASR ID	Maximum 1-hr TSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A2	3	142	<1	<1	<1	<1	102	247

Stage 2 Replanning Works

Tier 1 Assessment

3.8.4 With the implementation of the above measures, the predicted mitigated cumulative maximum hourly average TSP, 10^th highest daily and annual average RSP and FSP concentrations at the representative ASRs are summarized in Table 3.13. The detailed prediction results and contour plots are presented in Appendix 3.9. It is noted that the hourly average TSP and the daily and annual average RSP and FSP concentrations at the representative ASRs would comply with the AQOs.

Table 3.13 Worst Predicted Construction Dust Impact during Stage 2 Works (Mitigated, Tier 1)

ASR ID	Maximum 1-hr TSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	224	225
A2	4	293	2	<1	<1	<1	56	355
A3	<1	<1	<1	2	<1	<1	224	227
A4	<1	<1	<1	2	<1	<1	224	226
A5	2	130	<1	<1	<1	67	49	249
A6	<1	<1	<1	<1	<1	<1	220	220
Planned ASRs
A101	<1	37	<1	<1	<1	<1	182	219
A104	<1	<1	<1	<1	<1	<1	219	219
A107	<1	<1	<1	<1	<1	<1	219	219
A108	<1	<1	<1	<1	<1	<1	219	219
A113	<1	<1	<1	<1	<1	<1	219	219
A115	<1	<1	<1	<1	<1	<1	219	219
A118	<1	<1	<1	<1	<1	<1	219	219
A125	<1	57	<1	<1	<1	<1	171	228
A128	<1	57	<1	<1	<1	<1	171	228
A131	<1	47	<1	<1	<1	<1	182	229
A135	<1	47	<1	<1	<1	<1	182	229
A136	<1	<1	<1	<1	<1	<1	219	219
A139	<1	<1	<1	<1	<1	<1	219	219
A142	<1	<1	<1	<1	<1	<1	219	219
A143	<1	<1	<1	<1	<1	<1	219	219
A146	<1	<1	<1	<1	<1	<1	219	219
A149	<1	<1	<1	<1	<1	<1	219	219

ASR ID	10^th Highest 24-hr RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	<1	<1	<1	<1	<1	79	80
A2	<1	<1	<1	<1	<1	<1	81	81
A3	<1	<1	<1	<1	<1	1	78	80
A4	<1	<1	<1	<1	<1	1	78	80
A5	<1	<1	<1	<1	<1	<1	78	78
A6	<1	<1	<1	<1	<1	<1	78	78
Planned ASRs
A101	<1	4	<1	<1	<1	<1	75	79
A104	<1	3	<1	<1	<1	<1	75	79
A107	<1	3	<1	<1	<1	<1	75	78
A108	<1	2	<1	<1	<1	<1	75	78
A113	<1	<1	<1	<1	<1	<1	77	78
A115	<1	<1	<1	<1	<1	<1	77	78
A118	<1	<1	<1	<1	<1	<1	77	78
A125	<1	1	<1	<1	<1	<1	79	81
A128	<1	1	<1	<1	<1	<1	79	81
A131	<1	2	<1	<1	<1	<1	77	79
A135	<1	4	<1	<1	<1	<1	75	79
A136	<1	<1	<1	<1	<1	<1	77	78
A139	<1	<1	<1	<1	<1	<1	77	78
A142	<1	<1	<1	<1	<1	<1	77	78
A143	<1	<1	<1	<1	<1	<1	77	78
A146	<1	<1	<1	<1	<1	<1	77	78
A149	<1	<1	<1	<1	<1	<1	77	78

ASR ID	Annual RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	34	34
A2	1	<1	<1	<1	<1	<1	32	33
A3	<1	<1	<1	<1	<1	<1	34	34
A4	<1	<1	<1	<1	<1	<1	34	34
A5	<1	<1	<1	1	<1	<1	33	34
A6	<1	<1	<1	<1	<1	<1	33	33
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	32	33
A104	<1	<1	<1	<1	<1	<1	32	33
A107	<1	<1	<1	<1	<1	<1	32	33
A108	<1	<1	<1	<1	<1	<1	32	33
A113	<1	<1	<1	<1	<1	<1	32	33
A115	<1	<1	<1	<1	<1	<1	32	33
A118	<1	<1	<1	<1	<1	<1	32	33
A125	<1	<1	<1	<1	<1	<1	33	33
A128	<1	<1	<1	<1	<1	<1	33	33
A131	<1	<1	<1	<1	<1	<1	32	33
A135	<1	<1	<1	<1	<1	<1	32	33
A136	<1	<1	<1	<1	<1	<1	32	33
A139	<1	<1	<1	<1	<1	<1	32	33
A142	<1	<1	<1	<1	<1	<1	32	33
A143	<1	<1	<1	<1	<1	<1	32	33
A146	<1	<1	<1	<1	<1	<1	32	33
A149	<1	<1	<1	<1	<1	<1	32	33

ASR ID	10^th Highest 24-hr FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	<1	<1	<1	<1	<1	59	60
A2	1	<1	<1	<1	<1	<1	58	59
A3	<1	<1	<1	1	<1	<1	59	60
A4	<1	<1	<1	1	<1	<1	59	60
A5	<1	<1	<1	<1	<1	<1	58	59
A6	<1	<1	<1	<1	<1	<1	58	58
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	58	58
A104	<1	<1	<1	<1	<1	<1	58	58
A107	<1	<1	<1	<1	<1	<1	58	58
A108	<1	<1	<1	<1	<1	<1	58	58
A113	<1	<1	<1	<1	<1	<1	58	58
A115	<1	<1	<1	<1	<1	<1	58	58
A118	<1	<1	<1	<1	<1	<1	58	58
A125	<1	<1	<1	<1	<1	<1	60	60
A128	<1	<1	<1	<1	<1	<1	60	60
A131	<1	<1	<1	<1	<1	<1	58	58
A135	<1	<1	<1	<1	<1	<1	58	58
A136	<1	<1	<1	<1	<1	<1	58	58
A139	<1	<1	<1	<1	<1	<1	58	58
A142	<1	<1	<1	<1	<1	<1	58	58
A143	<1	<1	<1	<1	<1	<1	58	58
A146	<1	<1	<1	<1	<1	<1	58	58
A149	<1	<1	<1	<1	<1	<1	58	58

ASR ID	Annual FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	24	24
A2	1	<1	<1	<1	<1	<1	23	24
A3	<1	<1	<1	<1	<1	<1	24	24
A4	<1	<1	<1	<1	<1	<1	24	24
A5	<1	<1	<1	1	<1	<1	23	25
A6	<1	<1	<1	<1	<1	<1	23	24
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	23	23
A104	<1	<1	<1	<1	<1	<1	23	23
A107	<1	<1	<1	<1	<1	<1	23	23
A108	<1	<1	<1	<1	<1	<1	23	23
A113	<1	<1	<1	<1	<1	<1	23	23
A115	<1	<1	<1	<1	<1	<1	23	23
A118	<1	<1	<1	<1	<1	<1	23	23
A125	<1	<1	<1	<1	<1	<1	23	24
A128	<1	<1	<1	<1	<1	<1	23	24
A131	<1	<1	<1	<1	<1	<1	23	23
A135	<1	<1	<1	<1	<1	<1	23	23
A136	<1	<1	<1	<1	<1	<1	23	23
A139	<1	<1	<1	<1	<1	<1	23	23
A142	<1	<1	<1	<1	<1	<1	23	23
A143	<1	<1	<1	<1	<1	<1	23	23
A146	<1	<1	<1	<1	<1	<1	23	23
A149	<1	<1	<1	<1	<1	<1	23	23

Remark: Bolded value shows exceedance of relevant AQO

Stage 3 Replanning Works

Tier 1 Assessment

3.8.5 With the implementation of the above measures, the predicted mitigated cumulative maximum hourly average TSP, 10th highest daily and annual average RSP and FSP concentrations at the representative ASRs are summarized in Table 3.14. The detailed prediction results and contour plots are presented in Appendix 3.9. It is noted that the daily and annual average RSP and FSP concentrations at the representative ASRs would comply with the AQOs. However the exceedance of hourly average TSP would still exceed at A2. Tier 2 assessment is required for this ASR.

Table 3.14 Worst Predicted Construction Dust Impact during Stage 3 Works (Mitigated, Tier 1)

ASR ID	Maximum 1-hr TSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	316	4	<1	<1	<1	103	424
A2	3	584	21	<1	<1	<1	68	676
A3	<1	<1	<1	2	<1	<1	224	227
A4	<1	<1	<1	2	<1	<1	224	226
A5	2	277	<1	<1	<1	67	49	396
A6	<1	<1	<1	<1	<1	<1	220	220
Planned ASRs
A101	<1	48	<1	<1	<1	<1	181	229
A104	<1	40	<1	<1	<1	<1	182	222
A107	<1	49	<1	<1	<1	<1	182	231
A108	<1	49	<1	<1	<1	<1	182	231
A113	<1	45	<1	<1	<1	<1	182	227
A115	<1	45	<1	<1	<1	<1	182	227
A118	<1	45	<1	<1	<1	<1	182	227
A125	<1	<1	<1	<1	<1	<1	221	221
A128	<1	<1	<1	<1	<1	<1	221	221
A131	<1	<1	<1	<1	<1	<1	219	219
A135	<1	<1	<1	<1	<1	<1	219	219
A136	<1	<1	<1	<1	<1	<1	219	219
A139	<1	<1	<1	<1	<1	<1	219	219
A142	<1	<1	<1	<1	<1	<1	219	219
A143	<1	<1	<1	<1	<1	<1	219	219
A146	<1	<1	<1	<1	<1	<1	219	219
A149	<1	<1	<1	<1	<1	<1	219	219
A209	<1	199	<1	<1	<1	4	32	235
A211	<1	41	<1	1	<1	<1	197	239
A212	<1	63	<1	<1	<1	<1	181	245
A215	<1	54	<1	1	<1	<1	197	252
A219	<1	58	<1	<1	<1	<1	197	256
A501	<1	<1	<1	<1	<1	<1	221	221

ASR ID	10^th Highest 24-hr RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	3	<1	<1	<1	<1	79	83
A2	1	26	<1	<1	<1	<1	63	90
A3	<1	<1	<1	<1	<1	1	78	80
A4	<1	<1	<1	<1	<1	1	78	80
A5	<1	<1	<1	<1	<1	<1	78	78
A6	<1	<1	<1	<1	<1	1	77	77
Planned ASRs
A101	<1	1	<1	<1	<1	<1	77	78
A104	<1	1	<1	<1	<1	<1	77	79
A107	<1	2	<1	<1	<1	<1	77	79
A108	<1	2	<1	<1	<1	<1	77	79
A113	<1	2	<1	<1	<1	<1	77	79
A115	<1	4	<1	<1	<1	<1	75	79
A118	<1	4	<1	<1	<1	<1	75	79
A125	<1	<1	<1	<1	<1	<1	79	80
A128	<1	<1	<1	<1	<1	<1	79	80
A131	<1	<1	<1	<1	<1	<1	77	78
A135	<1	<1	<1	<1	<1	<1	77	78
A136	<1	4	<1	<1	<1	<1	75	79
A139	<1	4	<1	<1	<1	<1	75	79
A142	<1	3	<1	<1	<1	<1	75	78
A143	<1	<1	<1	<1	<1	<1	77	78
A146	<1	<1	<1	<1	<1	<1	77	78
A149	<1	<1	<1	<1	<1	<1	77	78
A209	<1	<1	<1	<1	<1	<1	77	78
A211	<1	1	<1	<1	<1	<1	77	78
A212	<1	1	<1	<1	<1	<1	77	79
A215	<1	1	<1	<1	<1	<1	77	78
A219	<1	1	<1	<1	<1	<1	77	79
A501	<1	<1	<1	<1	<1	<1	79	80

ASR ID	Annual RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	34	35
A2	1	1	<1	<1	<1	<1	32	34
A3	<1	<1	<1	<1	<1	<1	34	34
A4	<1	<1	<1	<1	<1	<1	34	34
A5	<1	<1	<1	1	<1	<1	33	34
A6	<1	<1	<1	<1	<1	<1	33	33
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	32	33
A104	<1	<1	<1	<1	<1	<1	32	33
A107	<1	<1	<1	<1	<1	<1	32	33
A108	<1	<1	<1	<1	<1	<1	32	33
A113	<1	<1	<1	<1	<1	<1	32	33
A115	<1	<1	<1	<1	<1	<1	32	33
A118	<1	<1	<1	<1	<1	<1	32	33
A125	<1	<1	<1	<1	<1	<1	33	33
A128	<1	<1	<1	<1	<1	<1	33	33
A131	<1	<1	<1	<1	<1	<1	32	33
A135	<1	<1	<1	<1	<1	<1	32	33
A136	<1	<1	<1	<1	<1	<1	32	33
A139	<1	<1	<1	<1	<1	<1	32	33
A142	<1	<1	<1	<1	<1	<1	32	33
A143	<1	<1	<1	<1	<1	<1	32	33
A146	<1	<1	<1	<1	<1	<1	32	33
A149	<1	<1	<1	<1	<1	<1	32	33
A209	<1	<1	<1	<1	<1	<1	32	33
A211	<1	<1	<1	<1	<1	<1	32	33
A212	<1	<1	<1	<1	<1	<1	32	33
A215	<1	<1	<1	<1	<1	<1	32	33
A219	<1	<1	<1	<1	<1	<1	32	33
A501	<1	<1	<1	<1	<1	<1	33	33

ASR ID	10^th Highest 24-hr FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	<1	<1	<1	<1	<1	59	60
A2	<1	<1	<1	<1	<1	<1	60	61
A3	<1	<1	<1	1	<1	<1	59	60
A4	<1	<1	<1	1	<1	<1	59	60
A5	<1	<1	<1	<1	<1	<1	58	59
A6	<1	<1	<1	<1	<1	<1	58	58
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	58	58
A104	<1	<1	<1	<1	<1	<1	58	58
A107	<1	<1	<1	<1	<1	<1	58	58
A108	<1	<1	<1	<1	<1	<1	58	58
A113	<1	<1	<1	<1	<1	<1	58	58
A115	<1	<1	<1	<1	<1	<1	58	58
A118	<1	<1	<1	<1	<1	<1	58	58
A125	<1	<1	<1	<1	<1	<1	60	60
A128	<1	<1	<1	<1	<1	<1	60	60
A131	<1	<1	<1	<1	<1	<1	58	58
A135	<1	<1	<1	<1	<1	<1	58	58
A136	<1	<1	<1	<1	<1	<1	58	58
A139	<1	<1	<1	<1	<1	<1	58	58
A142	<1	<1	<1	<1	<1	<1	58	58
A143	<1	<1	<1	<1	<1	<1	58	58
A146	<1	<1	<1	<1	<1	<1	58	58
A149	<1	<1	<1	<1	<1	<1	58	58
A209	<1	<1	<1	<1	<1	<1	58	58
A211	<1	<1	<1	<1	<1	<1	58	58
A212	<1	<1	<1	<1	<1	<1	58	58
A215	<1	<1	<1	<1	<1	<1	58	58
A219	<1	<1	<1	<1	<1	<1	58	58
A501	<1	<1	<1	<1	<1	<1	60	60

ASR ID	Annual FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	24	24
A2	1	<1	<1	<1	<1	<1	23	24
A3	<1	<1	<1	<1	<1	<1	24	24
A4	<1	<1	<1	<1	<1	<1	24	24
A5	<1	<1	<1	1	<1	<1	23	25
A6	<1	<1	<1	<1	<1	<1	23	24
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	23	23
A104	<1	<1	<1	<1	<1	<1	23	23
A107	<1	<1	<1	<1	<1	<1	23	23
A108	<1	<1	<1	<1	<1	<1	23	23
A113	<1	<1	<1	<1	<1	<1	23	23
A115	<1	<1	<1	<1	<1	<1	23	23
A118	<1	<1	<1	<1	<1	<1	23	23
A125	<1	<1	<1	<1	<1	<1	23	24
A128	<1	<1	<1	<1	<1	<1	23	24
A131	<1	<1	<1	<1	<1	<1	23	23
A135	<1	<1	<1	<1	<1	<1	23	23
A136	<1	<1	<1	<1	<1	<1	23	23
A139	<1	<1	<1	<1	<1	<1	23	23
A142	<1	<1	<1	<1	<1	<1	23	23
A143	<1	<1	<1	<1	<1	<1	23	23
A146	<1	<1	<1	<1	<1	<1	23	23
A149	<1	<1	<1	<1	<1	<1	23	23
A209	<1	<1	<1	<1	<1	<1	23	23
A211	<1	<1	<1	<1	<1	<1	23	23
A212	<1	<1	<1	<1	<1	<1	23	23
A215	<1	<1	<1	<1	<1	<1	23	23
A219	<1	<1	<1	<1	<1	<1	23	23
A501	<1	<1	<1	<1	<1	<1	23	24

Remark: Bolded value shows exceedance of relevant AQO

Tier 2 Assessment

3.8.6 The ASR with non-compliance in particulates levels under Tier 1 screening during the construction of the Project is A2 at 1.5 mAG which is selected to undergo Tier 2 assessment accordingly as discussed in Section 3.6. The active work areas of concurrent work contracts are positioned closest to the potentially worst affected ASR. The individual affected ASR would be influenced by one active work area. The predicted cumulative maximum hourly average TSP at the ASR of Tier 2 assessment are summarized in Table 3.15 and comply with the criterion. The contour plot of maximum hourly average TSP at 1.5 mAG concerning A2 is presented in Appendix 3.9.

Table 3.15 Predicted Construction Dust Impact during Stage 3 Works (Mitigated, Tier 2)

ASR ID	Maximum 1-hr TSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A2	1	14	<1	<1	<1	4	219	238

Stage 4 Replanning Works

Tier 1 Assessment

3.8.7 With the implementation of the above measures, the predicted mitigated cumulative maximum hourly average TSP, 10^th highest daily and annual average RSP and FSP concentrations at the representative ASRs are summarized in Table 3.16. The detailed prediction results and contour plots are presented in Appendix 3.9. It is noted that the daily and annual average RSP and FSP concentrations at the representative ASRs would comply with the AQOs. However the exceedance of hourly average TSP would still exceed at A1 and A2. Tier 2 assessment is required for this ASR.

Table 3.16 Worst Predicted Construction Dust Impact during Stage 4 Works (Mitigated, Tier 1)

ASR ID	Maximum 1-hour TSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	3	989	14	<1	<1	<1	41	1047
A2	3	632	<1	<1	<1	<1	63	698
A3	<1	<1	<1	2	<1	<1	224	227
A4	<1	<1	<1	2	<1	<1	224	226
A5	2	333	<1	<1	<1	67	49	452
A6	<1	<1	<1	<1	<1	<1	220	220
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	219	219
A104	<1	<1	<1	<1	<1	<1	219	219
A107	<1	<1	<1	<1	<1	<1	219	219
A108	<1	<1	<1	<1	<1	<1	219	219
A113	<1	<1	<1	<1	<1	<1	219	219
A115	<1	<1	<1	<1	<1	<1	219	219
A118	<1	20	<1	1	<1	1	197	220
A125	<1	<1	<1	<1	<1	<1	221	221
A128	<1	<1	<1	<1	<1	<1	221	221
A131	<1	<1	<1	<1	<1	<1	219	219
A135	<1	<1	<1	<1	<1	<1	219	219
A136	1	20	<1	1	<1	1	197	220
A139	1	19	<1	1	<1	2	197	220
A142	<1	27	<1	1	<1	2	197	227
A143	<1	45	<1	<1	<1	<1	181	227
A146	<1	44	<1	<1	<1	<1	181	225
A149	<1	46	<1	<1	<1	<1	181	227
A209	<1	<1	<1	<1	<1	<1	219	219
A211	<1	<1	<1	<1	<1	<1	219	219
A212	<1	<1	<1	<1	<1	<1	219	219
A215	<1	<1	<1	<1	<1	<1	219	219
A219	<1	<1	<1	<1	<1	<1	219	219
A303	<1	33	<1	1	<1	1	197	231
A307	<1	37	<1	1	<1	1	197	236
A308	<1	50	<1	1	<1	0	197	248
A310	<1	<1	<1	<1	<1	<1	219	219
A313	<1	<1	<1	<1	<1	<1	219	219
A318	<1	24	<1	1	<1	<1	197	223
A501	<1	<1	<1	<1	<1	<1	221	221
A601	<1	20	<1	1	<1	1	197	219

ASR ID	10^th Highest 24-hr RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	5	<1	<1	<1	<1	88	96
A2	2	16	<1	<1	<1	1	75	94
A3	<1	<1	<1	<1	<1	1	78	80
A4	<1	<1	<1	<1	<1	1	78	80
A5	<1	<1	<1	<1	<1	<1	78	78
A6	<1	<1	<1	<1	<1	1	77	78
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	77	78
A104	<1	<1	<1	<1	<1	<1	77	78
A107	<1	<1	<1	<1	<1	<1	77	78
A108	<1	<1	<1	<1	<1	<1	77	78
A113	<1	<1	<1	<1	<1	<1	77	78
A115	<1	<1	<1	<1	<1	<1	77	78
A118	<1	1	<1	<1	<1	<1	77	78
A125	<1	<1	<1	<1	<1	<1	79	80
A128	<1	<1	<1	<1	<1	<1	79	80
A131	<1	<1	<1	<1	<1	<1	77	78
A135	<1	<1	<1	<1	<1	<1	77	78
A136	<1	1	<1	<1	<1	<1	77	78
A139	<1	2	<1	<1	<1	<1	77	79
A142	<1	2	<1	<1	<1	<1	77	79
A143	<1	1	<1	<1	<1	<1	77	79
A146	<1	1	<1	<1	<1	<1	77	79
A149	<1	3	<1	<1	<1	<1	75	79
A209	<1	<1	<1	<1	<1	<1	77	78
A211	<1	<1	<1	<1	<1	<1	77	78
A212	<1	<1	<1	<1	<1	<1	77	78
A215	<1	<1	<1	<1	<1	<1	77	78
A219	<1	<1	<1	<1	<1	<1	77	78
A303	<1	1	<1	<1	<1	<1	77	78
A307	<1	1	<1	<1	<1	<1	77	79
A308	<1	1	<1	<1	<1	<1	77	78
A310	<1	<1	<1	<1	<1	<1	77	78
A313	<1	<1	<1	<1	<1	<1	77	78
A318	<1	1	<1	<1	<1	<1	77	78
A501	<1	<1	<1	<1	<1	<1	79	80
A601	<1	<1	<1	<1	<1	<1	77	78

ASR ID	Annual RSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	1	<1	<1	<1	<1	34	35
A2	1	1	<1	<1	<1	<1	32	35
A3	<1	<1	<1	<1	<1	<1	34	34
A4	<1	<1	<1	<1	<1	<1	34	34
A5	<1	<1	<1	1	<1	<1	33	34
A6	<1	<1	<1	<1	<1	<1	33	33
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	32	33
A104	<1	<1	<1	<1	<1	<1	32	33
A107	<1	<1	<1	<1	<1	<1	32	33
A108	<1	<1	<1	<1	<1	<1	32	33
A113	<1	<1	<1	<1	<1	<1	32	33
A115	<1	<1	<1	<1	<1	<1	32	33
A118	<1	<1	<1	<1	<1	<1	32	33
A125	<1	<1	<1	<1	<1	<1	33	33
A128	<1	<1	<1	<1	<1	<1	33	33
A131	<1	<1	<1	<1	<1	<1	32	33
A135	<1	<1	<1	<1	<1	<1	32	33
A136	<1	<1	<1	<1	<1	<1	32	33
A139	<1	<1	<1	<1	<1	<1	32	33
A142	<1	<1	<1	<1	<1	<1	32	33
A143	<1	<1	<1	<1	<1	<1	32	33
A146	<1	<1	<1	<1	<1	<1	32	33
A149	<1	<1	<1	<1	<1	<1	32	33
A209	<1	<1	<1	<1	<1	<1	32	33
A211	<1	<1	<1	<1	<1	<1	32	33
A212	<1	<1	<1	<1	<1	<1	32	33
A215	<1	<1	<1	<1	<1	<1	32	33
A219	<1	<1	<1	<1	<1	<1	32	33
A303	<1	<1	<1	<1	<1	<1	32	33
A307	<1	<1	<1	<1	<1	<1	32	33
A308	<1	<1	<1	<1	<1	<1	32	33
A310	<1	<1	<1	<1	<1	<1	32	33
A313	<1	<1	<1	<1	<1	<1	32	33
A318	<1	<1	<1	<1	<1	<1	32	33
A501	<1	<1	<1	<1	<1	<1	33	33
A601	<1	<1	<1	<1	<1	<1	32	33

ASR ID	10^th Highest 24-hr FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	1	<1	<1	<1	<1	59	61
A2	1	1	<1	<1	<1	<1	58	61
A3	<1	<1	<1	1	<1	<1	59	60
A4	<1	<1	<1	1	<1	<1	59	60
A5	<1	<1	<1	<1	<1	<1	58	59
A6	<1	<1	<1	<1	<1	<1	58	58
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	58	58
A104	<1	<1	<1	<1	<1	<1	58	58
A107	<1	<1	<1	<1	<1	<1	58	58
A108	<1	<1	<1	<1	<1	<1	58	58
A113	<1	<1	<1	<1	<1	<1	58	58
A115	<1	<1	<1	<1	<1	<1	58	58
A118	<1	<1	<1	<1	<1	<1	58	58
A125	<1	<1	<1	<1	<1	<1	60	60
A128	<1	<1	<1	<1	<1	<1	60	60
A131	<1	<1	<1	<1	<1	<1	58	58
A135	<1	<1	<1	<1	<1	<1	58	58
A136	<1	<1	<1	<1	<1	<1	58	58
A139	<1	<1	<1	<1	<1	<1	58	58
A142	<1	<1	<1	<1	<1	<1	58	58
A143	<1	<1	<1	<1	<1	<1	58	58
A146	<1	<1	<1	<1	<1	<1	58	58
A149	<1	<1	<1	<1	<1	<1	58	58
A209	<1	<1	<1	<1	<1	<1	58	58
A211	<1	<1	<1	<1	<1	<1	58	58
A212	<1	<1	<1	<1	<1	<1	58	58
A215	<1	<1	<1	<1	<1	<1	58	58
A219	<1	<1	<1	<1	<1	<1	58	58
A303	<1	<1	<1	<1	<1	<1	58	58
A307	<1	<1	<1	<1	<1	<1	58	58
A308	<1	<1	<1	<1	<1	<1	58	58
A310	<1	<1	<1	<1	<1	<1	58	58
A313	<1	<1	<1	<1	<1	<1	58	58
A318	<1	<1	<1	<1	<1	<1	58	58
A501	<1	<1	<1	<1	<1	<1	60	60
A601	<1	<1	<1	<1	<1	<1	58	58

ASR ID	Annual FSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	<1	<1	<1	<1	<1	<1	24	25
A2	1	<1	<1	<1	<1	<1	23	24
A3	<1	<1	<1	<1	<1	<1	24	24
A4	<1	<1	<1	<1	<1	<1	24	24
A5	<1	<1	<1	1	<1	<1	23	25
A6	<1	<1	<1	<1	<1	<1	23	24
Planned ASRs
A101	<1	<1	<1	<1	<1	<1	23	23
A104	<1	<1	<1	<1	<1	<1	23	23
A107	<1	<1	<1	<1	<1	<1	23	23
A108	<1	<1	<1	<1	<1	<1	23	23
A113	<1	<1	<1	<1	<1	<1	23	23
A115	<1	<1	<1	<1	<1	<1	23	23
A118	<1	<1	<1	<1	<1	<1	23	23
A125	<1	<1	<1	<1	<1	<1	23	24
A128	<1	<1	<1	<1	<1	<1	23	24
A131	<1	<1	<1	<1	<1	<1	23	23
A135	<1	<1	<1	<1	<1	<1	23	23
A136	<1	<1	<1	<1	<1	<1	23	23
A139	<1	<1	<1	<1	<1	<1	23	23
A142	<1	<1	<1	<1	<1	<1	23	23
A143	<1	<1	<1	<1	<1	<1	23	23
A146	<1	<1	<1	<1	<1	<1	23	23
A149	<1	<1	<1	<1	<1	<1	23	23
A209	<1	<1	<1	<1	<1	<1	23	23
A211	<1	<1	<1	<1	<1	<1	23	23
A212	<1	<1	<1	<1	<1	<1	23	23
A215	<1	<1	<1	<1	<1	<1	23	23
A219	<1	<1	<1	<1	<1	<1	23	23
A303	<1	<1	<1	<1	<1	<1	23	23
A307	<1	<1	<1	<1	<1	<1	23	23
A308	<1	<1	<1	<1	<1	<1	23	23
A310	<1	<1	<1	<1	<1	<1	23	23
A313	<1	<1	<1	<1	<1	<1	23	23
A318	<1	<1	<1	<1	<1	<1	23	23
A501	<1	<1	<1	<1	<1	<1	23	24
A601	<1	<1	<1	<1	<1	<1	23	23

Remark: Bolded value shows exceedance of relevant AQO

Tier 2 Assessment

3.8.8 The ASRs with non-compliance in particulates levels under Tier 1 screening during the construction of the Project are A1 at 1.5 mAG and A2 at 1.5 mAG which are selected to undergo Tier 2 assessment accordingly as discussed in Section 3.6. The active work areas of concurrent work contracts are positioned closest to the potentially worst affected ASRs. The individual affected ASR would be influenced by one active work area. The predicted cumulative maximum hourly average TSP at the ASRs of Tier 2 assessment are summarized in Table 3.17 and comply with the criterion. The contour plot of maximum hourly average TSP at 1.5 mAG concerning A1 and A2 is presented in Appendix 3.9.

Table 3.17 Predicted Construction Dust Impact during Stage 4 Works (Mitigated, Tier 2)

ASR ID	Maximum 1-hr TSP Concentrations (µg/m^3)
	Vehicles	Dust from SHO & SHD Replanning Works	Airport	Industrial	Marine	Dust from Topside Development	Ambient Background	Total
Existing ASRs
A1	1	130	3	<1	<1	<1	120	254
A2	1	5	<1	<1	<1	4	219	229

3.8.9 In addition to the dust control measures described above, dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation and good site practices should be carried out to further minimize construction dust impact.

· Use of regular watering, with complete coverage, 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 should be applied to aggregate fines.

· Open stockpiles should 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.

· Establishment and use of vehicle wheel and body washing facilities at the exit points of the site.

· Provision of wind shield and dust extraction units or similar dust mitigation measures at the loading points, 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.

· Imposition of speed controls for vehicles on unpaved site roads. 8 kilometres per hour is the recommended limit.

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

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

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

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

Operation Phase

3.8.10 No mitigation measure is required for the operation of the SHO and Reprovisioned SHD. For the reprovisioned SPS, with enclosing the odorous facilities including wet well, inlet chamber and screen chamber and installation of the deodorizer (95% odour removal efficiency) for the treatment of the vented exhaust from these enclosed facilities, negligible odour impact from this SPS is anticipated, no further mitigation measure is required.

3.9 Evaluation of Residual Environmental Impacts

Construction Phase

3.9.1 With the implementation of the mitigation measures as stipulated in the Air Pollution Control (Construction Dust) Regulation, dust control measures and good site practices, no adverse dust impact at the ASRs would be expected.

Operation Phase

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

3.10 EM&A Requirements

Construction Phase

3.10.1 EM&A for potential dust impacts should be conducted during the construction phase of the Project 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.

Operation Phase

3.10.2 No adverse impact would be generated during the operation phase of the Project, and therefore specific EM&A for air quality impact during operation phase would not be necessary.

3.11 Conclusions

Construction Phase

3.11.1 The potential air quality impacts from the construction works of the Project would mainly be related to construction dust from excavation, material handling, spoil removal, piling, backfilling and wind erosion. With the implementation of mitigation measures specified in the Air Pollution Control (Construction Dust) Regulation together with the recommended dust suppression measures, good site practices, and EM&A programme, the predicted dust impact at the ASRs would comply with the hourly, daily and annual particulate criteria stipulated in the AQOs and EIAO-TM.

Operation Phase

3.11.2 The operation of SHO and Reprovisioned SHD would not generate air quality impact. The odour impact from the reprovisioned SPS would also be negligible with the implementation of designed odour control measures.

---

^[1] USEPA, AP-42 Compilation of Air Pollution Emission Factors (AP-42), Section 13.2.4.3, 1^st Table, November 2006