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 of the Project. Assessment was conducted in accordance with criteria and guidelines as stipulated in Annex 4 and Annex 12 of the EIAO-TM as well as the requirements given in Clause 3.4.3 and Appendix B of the EIA Study Brief (No. ESB-346/2021).

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

3.1.3 The rail system to be employed in the Project will be electric-powered, and air-emission free during the normal operation. The potential air quality impact during operation phase was thus considered insignificant and was not assessed in this section.

3.2 Environmental Legislations, Standards and Guidelines

Air Quality Objectives & Technical Memorandum on EIA Process

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 prevailing AQOs are listed in Table 3.1.

Table 3.1 Hong Kong Air Quality Objectives

Pollutant	Averaging Time	Maximum Average Concentration (µg/m³) ⁽¹⁾	No. of Exceedances Allowed ⁽²⁾
Fine Suspended Particulates (PM_2.5) ⁽⁴⁾	24-hr	50	35
Fine Suspended Particulates (PM_2.5) ⁽⁴⁾	Annual ⁽³⁾	25	NA
Respirable Suspended Particulates (PM₁₀) ⁽⁵⁾	24-hr	100	9
Respirable Suspended Particulates (PM₁₀) ⁽⁵⁾	Annual ⁽³⁾	50	NA
Sulphur Dioxide (SO₂)	10-min	500	3
Sulphur Dioxide (SO₂)	24-hr	50	3
Nitrogen Dioxide (NO₂)	1-hr	200	18
Nitrogen Dioxide (NO₂)	Annual ⁽³⁾	40	NA
Carbon Monoxide (CO)	1-hr	30,000	0
Carbon Monoxide (CO)	8-hr	10,000	0
Ozone	8-hr	160	9
Lead (Pb)	Annual ⁽³⁾	0.5	NA

Notes:

(1) Gaseous pollutant is 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.

Air Pollution Control (Construction Dust) Regulation

3.2.3 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. The Project is expected to include notifiable works (site formation, demolition, foundation and superstructure construction for 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

3.2.4 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.

Air Pollution Control (Fuel Restriction) Regulation

3.2.5 The Air Pollution Control (Fuel Restriction) Regulation was enacted in 1990 to impose legal control on the types of fuel allowed for use and their sulphur contents in commercial and industrial processes to reduce sulphur dioxide (SO₂) emissions. Since 1 October 2008, liquid fuel with a sulphur content not exceeding 0.005% by weight such as Ultra Low Sulphur Diesel (ULSD) shall be used, unless a valid certificate of compliance with emission limits issued by a competent examiner.

Air Pollution Control Ordinance – Specified Processes and the Licensing of Premises

3.2.6 Process stipulated in Schedule 1 of Air Pollution Control Ordinance (APCO) is classified as Specified Process (SP). A licence is required to conduct the process in a premises under Part IV of the ordinance. SP relevant to the Project is summarized as follows:

· Cement Works (Concrete Batching Plant) – Works in which the total silo capacity exceeds 50 tonnes and in which cement is handled or in which argillaceous and calcareous materials are used in the production of cement clinker, and works in which cement clinker is ground.

3.2.7 Grant of a SP licence by EPD is subject to whether the applicant can fulfil the environmental standards to avoid causing air pollution. A Guidance Note on the Technical, Management and Monitoring Requirements for Specified Process – Cement Works (Concrete Batching Plant) BPM 3/2 (16) sets out the minimum requirements for the provision and maintenance of the best practical means for an individual plant. Apart from the suggested control measures in the BPM, particulates emission concentration limit of 10 mg/m³ (expressed at reference condition, 0°C, 101.325 kPa) shall be satisfied by 1 January 2018 by all plants.

3.3 Description of the Environment and Future Trends

Existing Environment

3.3.1 The Project Site is located in the northern part of New Territories. The proposed NOL alignment runs from the proposed Kam Sheung Road (KSR)(NOL) Station, passing via three intermediate stations at Au Tau (AUT), Ngau Tam Mei (NTM) and San Tin (SAT), and ends at Kwu Tung (KTU)(NOL) Station. The existing environment adjacent to the proposed alignment is rural, with variety of land uses comprising residential developments, villages, industrial, agricultural, recreational, comprehensive development area, open storage, government, institution or community (G/IC), green belt, conservation area and open space.

3.3.2 The dominant existing air pollutants sources within the 500m assessment area of the NOL alignment are the vehicular emission from major open roads including Tsing Long Highway, Kam Tin Road, Kam Tin Bypass, San Tin Highway, Castle Peak Road and Fanling Highway.

3.3.3 The closest EPD’s air quality monitoring station to the assessment area is the North Air Quality Monitoring Station (AQMS) situated at the Po Wing Road Sports Centre which is operating since July 2020 and is under the land use type “New Town”. Owing to insufficient data for time before Year 2020 and in Year 2020, the background observation refers to the next closest station with the same land use type instead, i.e. Yuen Long AQMS at Yuen Long District Office Building as published in Air Quality in Hong Kong. The major air pollutants induced from the construction of the Project would be the particulates emissions during the construction phase, while there will be no air pollutant emission arising from the operation of electrically powered trains during operation of the Project. Therefore, the Fine Suspended Particulates (FSP) and Respirable Suspended Particulates (RSP) monitoring data recorded between Year 2018 to 2022 are examined and summarized in Table 3.2. It is observed that daily and annual averages of RSP and FSP concentration complied with prevailing AQOs during Year 2018 to 2022.

Table 3.2 The Air Quality Monitoring Data Recorded at EPD’s Yuen Long in Year 2018 – 2022

Pollutant	Averaging Time	AQO^[1]	Data Summary	Year ^[2]
Pollutant	Averaging Time	AQO^[1]	Data Summary	2018	2019	2020	2021	2022
Fine Suspended Particulates (FSP) ^[3]	24-hr	50 (35)	Max.	80	81	44	75	64
			36th Max.	34	34	28	31	30
			No. of Exceedance(s)	5	5	0	3	5
	Annual	25	-	20	20	16	17	16
Respirable Suspended Particulates (RSP)^[3]	24-hr	100 (9)	Max.	121	125	97	109	81
			10th Max.	75	83	77	73	56
			No. of Exceedance(s)	4	2	0	1	0
	Annual	50	-	37	37	30	30	25

Notes:

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

[2] Bolded values mean exceedance of the AQO limit values.

[3] All concentration units are in microgram per cubic metre (µg/m³).

3.3.4 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 (PATHv2.1). Year 2025 data of the assessment area extracted from PATHv2.1 model are presented in Table 3.3. With reference to the predictions by PATHv2.1, the future air pollutant concentrations in these areas are lower than the prevailing AQOs.

Table 3.3 PATHv2.1 Model - Air Pollutant Concentrations in Year 2025

Pollutant	Aver-aging Time	AQO^[1]	Data Summary	PATH Grid Cell ^[2]
Pollutant	Aver-aging Time	AQO^[1]	Data Summary	Year 2025
Fine Suspended Particulates (PM_2.5) ^[3]	24-hr	50 (35)	Max.	73 - 87
			36th Max.	24 – 29
			No. of Exceedance(s)	9 – 11
	Annual	25	-	15 – 18
Respirable Suspended Particulates (PM₁₀)^[4]	24-hr	100 (9)	Max.	91 - 105
			10th Max.	63 – 71
			No. of Exceedance(s)	0 – 1
	Annual	50	-	26 - 30

Notes:

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

[2] Bolded values mean exceedance of the AQO limit values.

[3] Annual FSP concentration is adjusted by adding 3.5 µg/m³ with reference to Guidelines on Choice of Models and Model Parameters.

[4] Daily and annual RSP concentration is adjusted by adding 11.0 µg/m³ and 10.3 µg/m³ respectively with reference to Guidelines on Choice of Models and Model Parameters.

[5] All concentration units are in microgram per cubic metre (µg/m³).

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 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 aforementioned premises and places is also considered to be a sensitive receiver. As stated in the EIA Study Brief (No. ESB-346/2021), the boundary of the assessment area for air quality assessment should be 500m from the Project boundaries of all associated areas under the Project.

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

3.4.3 Concurrent projects are expected in the vicinity of the proposed stations and would introduce planned ASRs upon their completion as well as cumulative impacts from concurrent projects at these planned ASRs, subject to the completion year of the concurrent projects.

3.4.4 The locations of the representative ASRs along NOL are shown in Figure Nos. C1603/C/NOL/ACM/M51/303 to 317. The details of the representative ASRs for assessment are presented in Table 3.4.

Table 3.4 Representative Air Sensitive Receivers along NOL

ASR	Description	Land Use⁽¹⁾	Approx. Distance between ASR and closest works area/works site (m)	No. of Storey
KSR-A01	Taoist Temple	W	140	1
KSR-A02	Go Green Farm	A	259	2
KSR-A03	Dude Ranch	A	160	2
KSR-A04	Chui Yee Garden	R	42	3
KSR-A05	Kut Hing Garden	R	91	3
KSR-A06	Noble Park	R	166	3
KSR-A07	Kam Fung Garden	R	314	3
KSR-A08	Kam Fung Garden	R	430	3
KSR-A09	Kam Tin Mung Yeung Public School	E	484	3
KSR-A10	Village House	R	30	2
KSR-A11	Shek Wu Tong	R	93	1
KSR-A12	Strong Sing Garden	R	288	2
KSR-PA01	Planned Public Housing in Kam Tin South Development (Site 1)	R	11	-⁽²⁾
KSR-PA02	Planned G/IC site in Kam Tin South Development (Site 1)	GIC	9⁽³⁾	-⁽²⁾
KSP-PA03	Planned G/IC site in Kam Tin South Development (Site 6)	GIC	25	-⁽²⁾
KSR-PA04	Grand Mayfair (Planned)	R	32	-⁽²⁾
KSR-PA05	Planned Residential Use under Kam Tai Road Residential Development	R	344	-⁽²⁾
SMA-A01	Park Vista Tower 9A	R	22	19
SMA-A02	Park Yoho Tower 8B	R	10	16
SMA-A03	Cheung Chun San Tsuen	R	150	1
SMA-A04	Au Tau Fisheries Office, AFCD	GIC	13	1
SMA-A05	Riva Helorus Boulevard	R	398	25
SMA-A06	Crescent Green Tower 1	R	316	13
SMA-A07	Cheung Chun San Tsuen	R	77	3
AUT-A01	Park Yoho Genova Tower 12	R	128	19
AUT-A02	Sha Po Tsuen	R	251	3
AUT-PA03	Planned Public Housing in Sha Po Housing Development	R	21	-⁽²⁾
AUT-A04	Open Storage at Castle Peak Road – Tam Mei	OS	140	2
AUT-A05	Shum Residence	R	58	2
AUT-A06	Mo Fan Heung	R	0	1
AUT-A07	Wing Kei Tsuen	R	179	3
PWA-A01	Village House	R	1	2
PWA-A02	Pok Wai	R	2	3
PWA-A03	Elite Garden	R	72	3
PWA-A04	Elite Garden	R	113	3
LHA-A01	Village House	R	17	1
LHA-A02	Village House	R	106	1
LHA-A03	Merry Garden	R	166	3
LHA-A04	Village House	R	15	1
NTM-A01	Village House	R	32	2
NTM-A02	Fuk Hing Lei	R	172	3
NTM-A03	Hongtai Home for the Aged Limited	HA	9	3
NTM-A04	Village House	R	3	1
NTM-A05	Village House	R	193	3
NTM-A06	Village House	R	10	1
NTM-A07	China Bible Seminary	E	182	3
NTM-A08	Village House	R	59	1
NTM-A11	Yau Tam Mei Tsuen	R	31	3
NTM-A12	Greenacres Villa House A	R	96	3
NTM-A13	Yau Tam Mei Tsuen Village House	R	0	2
NTM-A14	Yau Tam Mei Tsuen	R	0	1
SAT-A01	Christian New Life Association	GIC	11	1
SAT-A02	San Tin Barracks	GIC	288	6
SAT-A03	Shek Wu Wai	R	56	1
SAT-A04	Hung Yat Farm	A	51	2
SAT-A05	Shek Wu Wai	R	14	3
SAT-A06	Shun Sum Yuen Farm	A	7	2
SAT-A07	San Tin Barracks	GIC	211	6
SAT-A08	Luk Mei Tsuen	R	280	1
SAT-A09	Farmers’ Cooperative	A	11	2
SAT-A10	Village House	R	42	1
SAT-A11	Open Storage at Kwu Tung Road	OS	90	1
SAT-A12	Wah Sang Yuen	A	60	1
SAT-A13	Village House	V	54	1
SAT-A14	Man Tin Cheung Park	O	142	1
SAT-A15	Fan Tin Tsuen	R	150	3
SAT-A16	Village House	V	169	2
SAT-A17	Siu Hum Tsuen	R	185	3
SAT-A18	Siu Hum Tsuen	R	207	3
SAT-PA01	Potential Housing Development in STLMC DN	R	44	-⁽²⁾
KTU-A01	Chau Tau Tsuen	R	288	3
KTU-A02	Village Meeting Place	O	33	1
KTU-A03	Open Storage at Kwu Tung Road	OS	14	1
KTU-A05	Village House	GB	35	2
KTU-PA01	Planned Housing Development at Kwu Tung North	R	10	-⁽²⁾
KTU-PA02	Planned Housing Development at Kwu Tung North	R	10	-⁽²⁾
KTU-PA03	Planned Housing Development at Kwu Tung North	R	19	-⁽²⁾
KTU-PA04	Planned Housing Development at Kwu Tung North	R	43	-⁽²⁾
KTU-PA05	Planned Hospital at Kwu Tung North	GIC	171	-⁽²⁾
KTU-PA07	Purpose-built Multi-welfare Services Complex in Area 29	GIC	41	40

Notes:

(1) A – Agricultural; E – Educational; GIC - Government, institution and community; I – Industrial; O – Open Space; OS – Open Storage; R – Residential; HA – Home for the Aged; W – Place of Public Worship; GB – Green Belt.

(2) Information subject to the design of planned development.

(3) A reserve zone of 8m wide will be provided at the south-western boundary of Site 1 for provision of CLP cable.

3.4.5 The locations of the representative ASRs near the temporary explosive magazine site at Tai Shu Ha (Yuen Long) are shown in Figure No. C1603/C/NOL/ACM/M51/317. The details of the representative ASRs for assessment are presented in Table 3.5.

Table 3.5 Representative Air Sensitive Receivers near Temporary Explosive Magazine Site at Tai Shu Ha (Yuen Long)

ASR	Description	Land Use	Approx. Distance between ASR and closest works area/works site (m)	No. of storey
TSH-A01	Hong Kong Model Engineering Club (HKMEC) International Model Aviation Centre	Institutional	126	1
TSH-A02	Village House	Village	307	3

3.5 Identification of Environmental Impacts

Construction Phase

Construction Works Site along NOL

3.5.1 The NOL runs underground in tunnel between KSR and KTU with three intermediate stations at Au Tau (AUT), Ngau Tam Mei (NTM) and San Tin (SAT). An at-grade depot is proposed at Ngau Tam Mei area. Southern extension enabling works under NOL is also proposed under the Project. The locations of the proposed alignment, stations and the associated ancillary buildings are presented in Figure Nos. C1603/C/NOL/ACM/M50/302 to 303.

3.5.2 The major construction works under the Project include:

· Construction of 5 stations including KSR(NOL), AUT, NTM, SAT and KTU(NOL) by cut-and-cover; Construction of tunnel connecting KSR(NOL), AUT, NTM, SAT and KTU(NOL) Stations by Tunnel Boring Machine (TBM);

· Construction of branching tunnel connecting to Ngau Tam Mei Depot (NTD) by cut-and-cover, mined and drill-and-blast tunnelling method;

· Construction of NTD;

· Construction of overrun tunnel section at KSR and crossover box and bifurcation at SAT by cut-and-cover;

· Demolition of EAP aboveground structure under Existing EAL at Kwu Tung;

· Site clearance and construction of temporary explosive magazine at Tai Shu Ha (Yuen Long) and reinstatement; and

· Construction of Ancillary Buildings for EAP/EEPs/VBs.

3.5.3 The tunnelling works for certain sections will be excavated and constructed by TBM 24-hour a day. Either or both types of TBM, namely Earth Pressure Balance (EPB) and Mixshield Slurry Type, would be employed for the tunneling works, subject to the detailed design during which detailed geological conditions would be available for further geological studies.

· For an EPB, excavated materials will be collected in the excavation chamber and treated with foams and polymers, transforming into a flowing material (muck) to achieve pressure balance at the cutterhead. The muck which is wet in nature will be removed through a screw conveyor to the stockpiling area for mucking-out. Given the closed system of EPB and the use of conveyor belt system within the tunnel, the dust emission associated with the tunneling works by EPB would be expected minimum. Limited dust emission would only arise from the mucking-out operation.

· For a Mixshield Slurry Type TBM, excavated boulders will be crushed inside the TBM, mixed with the slurry and then hydraulicly removed through a closed slurry circuit. The excavated material is wet in nature and conveyed by conveyor system to the stockpiling area for mucking-out. Given the closed system of TBM and wet nature of the slurry generated, the dust emission associated with the tunneling works by slurry type and the subsequent conveying and handling of excavated material is also expected minimum.

3.5.4 For the tunnelling works by drill-and-blast, in addition to the regular watering at spoiling handing and unpaved / paved haul roads, a blast door should be installed at the opening to avoid the escape of fugitive dust from the blasting. The blast door should remain closed and ventilation stopped during blasting. Water spaying should be also applied to facilitate dust settlement. A filtration system comprising watering and dust collector, etc. with overall dust removal efficiency of at least 80% should be provided at the ventilation exhaust to treat dust-laden exhaust before release to the ambient. The exhaust vents will be located at the tunnel portals at the sites of NTD, LHA and PWA.

3.5.5 The excavated material from the tunneling works by TBM and drill-and-blasts would be transported with dump trucks out of the works sites to receiving sites. The induced traffic would cause vehicle emission along the routes. Dump trucks would collect spoils from separate sites, including KSR(NOL) Station, AUT, NTM Station and NTD, SAT Station and KTU(NOL) Station, eventually via Yuen Long Highway, Tuen Mun Road to Tuen Mun Area 38 Fill Bank, with the tentative transportation routes discussed in Section 8.4.48. Maximum number of trucks per hour were estimated based on the current engineering design and are discussed in the following sections. Comparing with the high traffic flow of Yuen Long Highway and Tuen Mun Road, the additional dump trucks generated from the isolated works sites along NOL would not cause significant increment in traffic. Dump truck to be employed would be equipped with water-tight containers and mechanical cover, and fugitive dust emission on the road is anticipated to be limited. It is anticipated that the transportation of excavated spoils would not cause adverse air quality impact along the routes with the implementation of appropriate mitigation measures.

3.5.6 A concrete batching plant (CBP) will be provided at works sites of SAT Station under NOL for supporting the construction of NOL, in order to meet the concrete demand by the constructions of tunnel and stations. According to the preliminary engineer design, the maximum production of each CBP would be 3,000 m³ per day. The CBP uses electricity as the power supply for operation, thus no gaseous pollutants by fuel combustion is anticipated. Potential dust impact would arise from the operation of the CBP and is addressed qualitatively in the assessment. The CBP would have total silo capacity exceeding 50 tonnes which is classified as Specified Process and requires a licence to operate pursuant to Air Pollution Control Ordinance (APCO).

3.5.7 The temporary explosive magazine site is proposed to be located at Tai Shu Ha (Yuen Long) and the location is presented in Figure No. C1603/C/NOL/ACM/M51/317. The site was formerly used as temporary explosive magazine site for the tunnel construction works by MTR Corporation in the Hong Kong Section of Guangzhou-Shenzhen-Hong Kong Express Rail Link under EP-349/2009/N and CEDD’s Liantang/Heung Yuen Wai Boundary Control Point Project under EP-502/2015/A and had been reinstated for about 5 years. Minor non-dusty works would be required to set up the magazine site, such as vegetation clearance, brick-built magazine, fencing, sandbag mounds and the existing access road. During the construction of NOL, there would be maximum of 2 trucks per hour accessing the site. The temporary explosive magazine site from Tai Shu Ha Road West would be reinstated as per the requirement from relevant government department upon completion of tunnelling works. Based on the preliminary design information, considering no excavation works and only limited traffic to be involved, its potential dust impact is considered minor, thus it was addressed qualitatively.

Tentative Construction Programme

3.5.8 The construction of the Project would tentatively commence in 2025 for target completion in 2034, in which the major civil works would be between 2025 and 2033. The detailed construction programme along the alignment is presented in Appendix 2.2.

Identification of Potential Emission Sources and Key Air Pollutants

3.5.9 The potential dust impact would arise from the construction activities of the Project. The major construction activities causing dust emission include site clearance, site formation, demolition works, excavation, tunnelling works (e.g. TBM, cut-and-cover, drill-and-blast and mining), backfilling, spoil handling, vehicle movement on haul roads within works area/works sites and wind erosion of the exposed site area. Watering at regular time interval will be provided over all the active works sites and exposed areas. As a proven effective dust suppression measures in the past approved EIA reports, regular watering would reduce the dust impact due to the major construction activities to an acceptable level.

3.5.10 Construction vehicles on the haul road within the works areas/works sites would also cause construction dust impact. Dust suppression measures such as paving and regular watering will be provided to abate the dust emission from open haul roads. Underground haul roads, i.e. inside tunnel, would be unpaved but wetted regularly for dust suppression. Construction vehicle will be required to pass through the wheel washing facilities upon site exit. Thus, the construction vehicle movements outside the works areas/works sites would not cause any significant dust impact.

3.5.11 On-site use of diesel-powered engines is the potential source for other gaseous pollutants such as NO₂, 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. Fuel with sulphur content not exceeding 0.005% by weight will be used to minimize SO₂ emission in accordance with the Air Pollution Control (Fuel Restriction) Regulation. In addition, the use of NRMMs with exempted label under the Air Pollution Control (NRMM) Regulation will be avoided as far as practicable. The equipment would also be properly maintained to minimize any emissions. Also, the use of electrified NRMMs, as well as the TBM, electric excavator, etc. will be employed as far as practicable, which is unlikely to cause significant smoke and gaseous emissions. Alternative power supply such as off-grid power storage, e.g. AMPD Enertainer, will also be considered where feasible. In view of the minor impact by NRMMs, particulates from dusty construction activities would be the major air pollutant during construction phase.

Concurrent Projects

3.5.12 There would be minor modification works at existing PHD required to meet future operational and maintenance requirements of TML after the commissioning of Tuen Mun South Extension (TME). The modification works including installation of 2 stabling tracks and the associated overhead lines, and erection of an annex on top of the existing IMB structure would commence in Q2 2024 for completion in Q2 2027. Considering that the nature of the modification works, i.e. limited works area and small in scale, without substantial excavation works, in addition to adoption of dust suppression measures, only minor construction dust impact would be anticipated and would not induce significant cumulative construction dust impact.

3.5.13 There are five planned housing development in vicinity of the proposed KSR(NOL) Station, with their details discussed below:

· Kam Tin South Housing Development – It is now under construction and would be completed in 2030, thus cumulative construction dust impact is expected.

· Kam Sheung Road Package 2 Property Development – It is now under planning, and no construction programme is available for the assessment.

· Grand Mayfair – It is now under construction and would be completed in 2024, before the commencement of the Project, and thus no concurrent construction works is expected.

· Kam Tai Road Residential Development – It is now under construction and would be completed in Q3 2025, and thus no concurrent construction works is expected.

3.5.14 A planned project, Park Yoho Phase 2 and 3, would be adjacent to Shui Mei Road Ancillary Building (SMA). However, Park Yoho Phase 2 and 3 are under planning and no construction programme is available, therefore it was not addressed in this assessment.

3.5.15 There is also a planned project in vicinity of the AUT Station, namely Sha Po Public Housing Development. The construction works of Sha Po Public Housing Development would be commence in 2025 and its foundation works would be completed in 2027. Its cumulative construction dust impact was addressed in this assessment.

3.5.16 Two projects are in the vicinity of NTM, namely Land Use Review Study for Ngai Tam Mei Area – Feasibility Study (NTM LUR) and Proposed Fresh Water Trunk Main under Ngau Tam Mei Water Treatment Works Extension. However, both projects are under planning and no detailed construction programme is available for the assessment, thus they were not considered in the assessment.

3.5.17 There would be new developments in San Tin under First Phase Development of the New Territories North – San Tin / Lok Ma Chau Development Node – Investigation (STLMC DN) respectively. The study areas would be located in the vicinity of SAT Station. The construction works would commence in 2024 and target for completion in 2034. The cumulative construction dust impact was addressed in this assessment.

3.5.18 The KTU(NOL) Station situates in the Kwu Tung North New Development Area (KTN NDA) and adjoins with the Kwu Tung Station on Lok Ma Chau Spur Line of East Rail Line (KTU(EAL) Station). The construction periods of first and remaining phases in KTN NDA is 2019 – 2026, and 2024 – 2031 respectively. Construction works for KTU(EAL) Station would commence in 2023 and the major construction works to be completed in 2026 for completion in 2027. Concurrent construction works of KTN NDA and KTU(EAL) Station would be expected and were considered in the cumulative construction dust impact assessment based on best available information.

Review of Dust Monitoring Data of Past Projects

3.5.19 Based on the nature and scale of the Project, it is considered that the Project is similar to a railway project, i.e. High Speed Rail (Hong Kong Section) (HSR) (formerly named as “the Hong Kong Section of Guangzhou-Shenzhen-Hong Kong Express Rail Link (XRL)”), which comprises 26-km long high-speed rail railway running underground from West Kowloon to boundary at Huanggang, a terminus in West Kowloon, nine tunnel ventilation buildings/emergency access point, stabling siding and maintenance facilities, on-site concrete batching plant, etc. The underground tunnels of HSR were built by various methods, namely drill-and-blast, cut-and-cover and TBM, while the ventilation buildings/emergency access point were constructed by cut-and-cover, and Shek Kong Stabling Sidings by cut-and-fill method. The construction of HSR commenced in Year 2011 and its operation commenced on 23 September 2018.

3.5.20 Based on the approved HSR EIA Report (Register No.: AEIAR-143/2009), it was estimated that the total approximate quantities of excavated rock and soft inert materials would be 2,776,500 m³ and 5,378,800 m³ respectively, while the NOL Project would generate about 431,840 m³ and 3,675,300 m³ of rock and soft inert materials respectively. It is therefore anticipated that the Project would generate lesser dust impact than that from HSR due to excavation works and associated activities (e.g. spoil handling).

3.5.21 Given the similarities in nature of HSR and NOL, components and construction methods, the actual dust impact by HSR has been reviewed. Various construction activities were carried out near the dust monitoring stations and their actual dust impact was recorded, according to the EM&A manual of the approved HSR EIA Report. Dust monitoring stations were generally placed near the surface works sites of station, stabling sidings and shafts/ventilation buildings/emergency access point. The actual dust impact was recorded during the abovementioned construction activities and the detailed dust monitoring results refer to its EM&A data website^{^[1]}. During the construction period of HSR, the measured 24-hr TSP levels at all monitoring stations located at about 6m to 153m from the works site boundary complied with limit level of 260 µg/m³, except two measurement events of exceedance recorded which was not related to the construction of the HSR project. In addition, over 99% of the measured 24-hr TSP levels at all monitoring stations were below the Action Level (i.e. 146 - 217 µg/m³) throughout the construction period, indicating that no significant dust impact arising from the construction of HSR. Therefore, it is anticipated that no significant dust impact would arise from the construction of the NOL which has similar nature and scope of HSR.

3.5.22 In view of insignificant dust impact caused by past railway project of similar nature and scope, the potential construction dust impact by the Project is evaluated by qualitative approach. A comprehensive EM&A programme with RSP and FSP real-time monitoring would be conducted to ensure the proper implementation of dust suppression measures and the compliance of AQOs during the construction of NOL.

Operational Phase

3.5.23 As electrically powered trains will be operated for the Project, no air pollutants emissions will arise from the train operations. The seven ancillary buildings will serve as Emergency Egress Point, Emergency Access Point and/or Ventilation Building, which have no emissions. Exhaust for general ventilation and smoke extraction facilities will be carefully positioned to avoid causing any nuisance to the ambient. Train inspection/maintenance/repairing services will be provided at Ngau Tam Mei Depot, which would not cause any emission. Electrified equipment for maintenance will be deployed as far as practicable, and NRMM (Non-Road Mobile Machinery), if any, to be used in the depot would comply with the prescribed emission standard (i.e. approved NRMM) with relevant labels under the requirements of the Air Pollution Control (NRMM) (Emission) Regulation, such that limited air emission is anticipated, while exempted NRMM will also be avoided as far as practicable. Therefore, no air quality issue is envisaged from operation of the Project.

3.6 Prediction and Evaluation of Environmental Impacts

Construction Works Sites along NOL

3.6.1 NOL comprises five stations, connecting underground railway tunnels and seven ancillary buildings along NOL alignment. As referred to Figure No. C1603/C/NOL/ACM/M50/305, the station boxes, ancillary buildings, KSR(NOL) overrun tunnels and crossover box and bifurcation at SAT are to be constructed by cut-and-cover (Table 3.6 refers) while the underground railway tunnel is to be constructed by TBM, cut-and-cover and drill-and-blast methods (Table 3.7 refers). Construction works to be conducted in different locations are also summarized in Table 3.6. These major construction works would be carried out in open-air or completely underground subject to their construction methods. Based on the latest design, the works sites would scatter along the alignment and separate from each other more than 500 meters apart. The evaluation of potential construction dust impact for these distinct locations are discussed separately in the following sections, together with the identified concurrent works within 500 metres where applicable.

Table 3.6 Summary of Major Aboveground Construction Works of NOL

Location	Aboveground Construction Works	Concurrent Project(s) Considered in the Assessment
Kam Sheung Road	Construction of KSR(NOL) Station and overrun tunnels (Cut-and-Cover)	Kam Tin South Housing Development
Shui Mei Road	Construction of Shui Mei Road Ancillary Building (SMA) (Cut-and-Cover)	Nil
Shui Mei Road	TBM Launching & Mucking-out (Tunnels towards KSR and Tunnels towards AUT / NTM)	Nil
Au Tau	Construction of AUT Station (Cut-and-Cover)	Sha Po Housing Development
Pok Wai and Long Ha	Construction of Pok Wai Ancillary Building (PWA) (Cut-and-Cover)	Nil
Pok Wai and Long Ha	Construction of Long Ha Ancillary Building (LHA) (Cut-and-Cover)	Nil
Ngau Tam Mei	Construction of NTM Station (Cut-and-Cover)	Nil
Ngau Tam Mei	Construction of Ngau Tam Mei Depot (NTD) (Cut and Fill)	Nil
San Tin	Construction of SAT Station, crossover box, bifurcation, San Tin Ancillary Building (SNA) (Cut-and-Cover)	STLMC DN
	TBM Launching & Mucking-out (Tunnel towards NTM)
	Construction of Ka Lung Road Ancillary Building (KLA) (Cut-and-Cover)
	Construction of Kwu Tung Ancillary Building (KTA) (Cut-and-Cover)
Pak Shek Au	Construction of Pak Shek Au Ancillary Building (PAA) (Cut-and-Cover)	STLMC DN
Kwu Tung	Construction of KTU(NOL) Station (Cut-and-Cover)	KTN NDA & KTU(EAL) Station
Kwu Tung	TBM Launching & Mucking-out (Tunnel towards SAT)	KTN NDA & KTU(EAL) Station

Table 3.7 Summary of Tunnelling Works of NOL

Tunnel Section	Construction Methods
Tunnels between KSR Station and AUT Station	TBM
Tunnels between AUT Station and NTM Station	TBM
Tunnels for crossover and tunnels between PWA and LHA, and tunnels between LHA and NTD	Drill-and-Blast, Mined and Cut-and-Cover
Tunnels between NTM Station and SAT Station	TBM
Tunnels between SAT Station and KTU(NOL) Station	TBM

Kam Sheung Road (KSR) (NOL) Station / Kam Sheung Road Area

3.6.2 KSR(NOL) Station adjacent to the existing KSR(TML) and KSR(NOL) overrun tunnel would be built in the area by cut-and-cover method. Also, the works sites of KSR(NOL) Station would be utilized for the retrieval of TBMs from SMA for the construction of underground tunnel north of the station. Potential dust impact would arise from the associated construction activities at these works sites, including site formation, excavation, backfilling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area. The locations of works sites are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/303 to 304. Major excavation works would be confined to station box. The construction of KSR(NOL) would also adopt top-down construction method in certain section where some of works sites would be covered up by the casted slab after the uppermost floor level is excavated. The exposed area in the works site would therefore be reduced and only limited openings would be left for transport of spoil out of the works sites. At the peak construction year of 2028 at KSR, an averaged hourly traffic of about 26 trucks would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design.

3.6.3 Village and planned residential uses are found in the vicinity of KSR(NOL) works sites. ASRs within 500 metres from NOL works sites have been identified and are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/303 to 304. The nearest ASRs to the works sites would be the planned Kam Tin South GIC sites (KSR-PA02) where the site boundary is 9 metres away from the works site, as the building layout is yet to be finalized or available. The construction works of this planned public housing site would be completed by phases, i.e. in 2027, 2028 and 2030 (Table 2.11 refers).

3.6.4 To further reduce the fugitive dust emission from the works sites, dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation would be implemented as far as practicable. Regular watering would be provided at works sites with excavation works and exposed areas, and at sites of spoil handling. Haul roads within works sites and works areas would be paved as appropriate and regularly wetted to suppress the fugitive dust emission caused by the travel of construction vehicles. Wheel washing facility would also be provided at each exit of works sites such that no significant dust impact would be caused by outbound construction vehicles on public roads. With the implementation of appropriate dust suppression measures and good site practices, the fugitive dust emission from the construction works would be reduced to minimum.

3.6.5 Construction works under Kam Tin South Housing Development would be carried out concurrently with the Project. The location of the concurrent project is illustrated in Figure Nos. C1603/C/NOL/ACM/M51/303 to 304. According to its construction programme, most of the site formation and foundation works would be completed by the time NOL works fully commencing in the area. Also, it is anticipated that appropriate dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, such as regularly watering and paved haul road, would be implemented by the contractor of concurrent works and it would result in minimum fugitive dust emission from the construction activities.

3.6.6 Should there be any intensive construction works conducted in close vicinity of an ASR, the ASR would suffer from significant dust impact. In order to avoid intensive works at a location in works sites, KSR(NOL) Station and KSR(NOL) overrun tunnels would be constructed in several workfronts by design of construction works. Construction activities would scatter among these workfronts, as well as the associated fugitive dust emission. Furthermore, coordination or collaboration with the contractor(s)/project proponent of other concurrent projects would be conducted such that any concurrent construction works in close vicinity of ASRs could be adjusted / well-planned as far as practicable for minimisation of potential dust impact.

3.6.7 The works sites of KSR(NOL) would be located at about 9 metres away from boundary of planned GIC sites (KSR-PA02) of Kam Tin South, and 11 metres away from planned public housing (KSR-PA01) under Kam Tin South Public Housing Development. Dusty activities would be taken place progressively across each work front with moving construction plant according to work requirements to be determined at the time of construction. Hence, construction dust emission is expected to be transient in nature. Dust impact to these concerned ASRs should be limited with the adoption of dust suppression measures such as regular watering and erection of hoarding with a combined height of up to 3m (i.e. 2.4m hoarding with 0.6m dust screen on top) (subject to site constraints and the required setback from CLP cable reserve zone) in front of the air sensitive façade facing to the work site to shield off the concerned ASRs from nearby dust emission sources. Dust monitoring is recommended to ensure the potential dust impact complying with AQOs during the construction phase. Detailed requirements of the dust monitoring are specified in the EM&A Manual.

3.6.8 With the implementation of the abovementioned effective dust suppression measures and good site practices, no adverse dust impact on nearby ASRs in the area due to the construction of KSR(NOL) Station, its overrun tunnel and other concurrent projects is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

Shui Mei Road Ancillary Building (SMA)

3.6.9 Shui Mei Road Ancillary Building (SMA) locates at the immediate south of Park Yoho and would be built by cut-and-cover method. As discussed in Section 2, the potential disturbance and impact to the public and environment has been minimised through utilization of works site for stations/ABs as TBM launching/retrieval shafts. The works sites of SMA would be used to launch TBM towards KSR(NOL) Station and NTM Station. The location of works sites are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/305 to 306. Potential construction dust impact would arise from the associated construction activities in the works sites, including site formation, excavation, backfilling, mucking out for TBM tunneling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area. Major excavation works is confined within the shaft area. Upon completion of shaft construction, the dust emission associated with the TBM tunneling works is expected minimum due to its adoption of a closed system (Section 3.5.3 refers). At the peak construction year of 2028 at SMA, an averaged hourly traffic of about 15 trucks would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design.

3.6.10 Villages and existing residential use are found in the vicinity of SMA. ASRs within 500 metres from SMA works sites have been identified and are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/305 to 306. Park Yoho (SMA-A02) would be the nearest ASR to the works sites, which is around 10 metres away.

3.6.11 Similarly, dust suppression measures for the construction works of other stations as discussed in Section 3.6.4 is also applicable to the works sites of SMA. With the implementation of appropriate dust suppression measures, for example regular watering at excavation works, exposed areas and sites of spoil handling, paved and regularly wetted haul roads, wheel washing facilities upon exit of works sites/works areas, and good site practices, the fugitive dust emission from the construction works would be reduced to minimum.

3.6.12 With the implementation of the abovementioned effective dust suppression measures at the works site and dust control measures at TBM tunnel works as stated in Section 3.5.3, no adverse dust impact on nearby ASRs in the area due to the construction of SMA and mucking out for TBM tunneling is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

Au Tau (AUT) Station / Au Tau Area

3.6.13 AUT Station locates adjacent to the planned Sha Po Public House Development, north of Sha Po Tsuen, and it would be constructed by cut-and cover method. Potential construction dust impact would arise from the associated construction activities in the works sites, including site formation, excavation, backfilling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area. The locations of works sites are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/306. At the peak construction year of 2028 at AUT, an averaged hourly traffic of about 24 trucks would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design.

3.6.14 There are a few existing villages and planned public housing in the vicinity of the NOL works, namely Sha Po Tsuen in the south and Mo Fan Heung in the north and adjacent Sha Po Housing Development. ASRs within 500 metres from AUT works sties have been identified and are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/306. Mo Fan Heung (AUT-A06) would be the nearest ASR to the works site, which is adjacent to the site hoarding of the works site. Planned public housing under Sha Po Housing Development adjacent to AUT Station is to be completed in Year 2031. Referring the construction programme, major dusty construction works of AUT Station, e.g. excavation works, is to be completed by mid of 2029, thus only minor dust impact on the adjacent planned public house is expected due to the remaining works of AUT Station.

3.6.15 Similarly, dust suppression measures for the construction works of other stations as discussed in Section 3.6.4 is also applicable to the works sites of AUT Station. With the implementation of appropriate dust suppression measures, for example regular watering at excavation works, exposed areas and sites of spoil handling, paved and regularly wetted haul roads, wheel washing facilities upon exit of works sites/works areas, and good site practices, the fugitive dust emission from the construction works would be reduced to minimum.

3.6.16 Construction works under Sha Po Housing Development would be the concurrent works near the Project. According to its construction programme, its foundation works would be completed by end of 2027 while the excavation works of AUT Station commences in early 2027. Dusty construction activities of Sha Po Housing Development would overlap with those of AUT Station in Year 2027. It is also anticipated that appropriate dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, such as regularly watering and paved haul road, would also be implemented by the contractors of concurrent works and it would result in minimum fugitive dust emission from the construction activities.

3.6.17 Should there be any intensive construction works conducted in close vicinity of an ASR, the ASR would suffer from significant dust impact. In order to avoid intensive works at a location in works sites, AUT Station is to be constructed in several workfronts by design. Construction activities scatter among these smaller workfronts and thereby minimising the associated fugitive dust emission. Furthermore, coordination or collaboration with the contractor(s)/project proponent of other concurrent projects would be conducted such that any concurrent construction works in close vicinity of ASRs could be adjusted / well-planned as far as practicable for minimisation of potential dust impact.

3.6.18 The works sites of AUT would exist in immediate proximity to the village house of Mo Fan Heung (AUT-A06) which is adjacent to site hoarding of the works site. Dusty activities would be taken place progressively across each work front with moving construction plant according to work requirements to be determined at the time of construction. Hence, construction dust emission is expected to be transient in nature. Dust impact to these concerned ASRs should be limited with the adoption of dust suppression measures such as regular watering and erection of hoarding with a combined height of up to 3m (i.e. 2.4m hoarding with 0.6m dust screen on top) in front of the air sensitive façade facing to the work site to shield off the concerned ASRs from any dust emission sources. Dust monitoring at these locations is recommended to ensure the potential dust impact complying with AQOs during the construction phase.

3.6.19 With the implementation of the abovementioned effective dust suppression measures and good site practices, no adverse dust impact on nearby ASRs in the area due to the construction of AUT Station and other concurrent projects is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

Pok Wai Ancillary Building (PWA) and Long Ha Tsuen Ancillary Building (LHA)

3.6.20 Pok Wai Ancillary Building (PWA) and Long Ha Tsuen Ancillary Building (LHA) locate east of Kai Kung Shan, between AUT and NTM Stations along the NOL alignment. These two ABs would be built by cut-and-cover method and the works sites would also be utilized for export of spoil from the drill-and-blast underground tunnel towards the NTD Portal, and exhaust vent for the underground works. The locations of works sites are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/307. Potential construction dust impact would arise from the associated construction activities in the works sites, including site formation, excavation, backfilling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area. Major excavation works would be confined to small shaft areas. Upon completion of shaft construction, the dust emission associated with the drill-and-blast works is expected minimum with adoption of regular watering, filtration system and blast door for confining the dust within the shaft (Section 3.5.4 refers). At the peak construction year of 2029 at PWA and LHA, an averaged hourly traffic of about 11 ad 19 trucks respectively would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design.

3.6.21 Villages and existing residential use are found in the vicinity of PWA and LHA. ASRs within 500 metres from the works sites have been identified and are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/307. The nearest ASRs to the works sites of PWA would be the village houses (PWA-A01 & PWA-A02) adjacent to the site hoarding of works sites, while the village house (LHA-A01) is 17 metres away from the works site of LHA. With careful planning of work sequence and design optimization of workfronts, the fugitive dust emission from the works sites could be reduced.

3.6.22 In addition, dust suppression measures for the construction works of other stations as discussed in Section 3.6.4 is applicable to the works sites of PWA and LHA. A filtration system comprising watering and dust collector, etc. with overall dust removal efficiency of at least 80% should be provided at the ventilation exhaust. Together with the implementation of appropriate dust suppression measures, for example regular watering at excavation works, exposed areas and sites of spoil handling, paved and regularly wetted haul roads, wheel washing facilities upon exit of works sites/works areas, and good site practices, the fugitive dust emission from the construction works would be reduced to minimum.

3.6.23 The works sites of PWA would exist in immediate proximity to nearby village houses (PWA-A01 & PWA-A02) which are adjacent to the site hoarding of the works site. Dusty activities would be taken place progressively across each work front with moving construction plant according to work requirements to be determined at the time of construction. Hence, construction dust emission is expected to be transient in nature. Dust impact to these concerned ASRs should be limited with the adoption of dust suppression measures such as regular watering and erection of hoarding with a combined height of up to 3m (i.e. 2.4m hoarding with 0.6m dust screen on top) in front of the air sensitive façade facing to the works site to shield off the concerned ASRs from any dust emission sources. Dust monitoring at these locations is recommended to ensure the potential dust impact complying with AQOs during the construction phase.

3.6.24 With the implementation of the abovementioned effective dust suppression measures, no adverse dust impact on nearby ASRs in the area due to the construction of PWA and LHA, and export of spoil from drill-and-blast tunneling works is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

Ngau Tam Mei (NTM) Station and Ngau Tam Mei Depot (NTD)

3.6.25 Several components of NOL are to be constructed in Ngau Tam Mei, namely Ngau Tam Mei (NTM) Station, Ngau Tam Mei Depot (NTD), and NTD Portal. NTM Station and NTD Portal would be constructed by cut-and-cover, while NTD would involve mostly cut slope and backfilling. NTD Portal would also be utilized for export of spoil from the drill-and-blast underground tunnel in the south, and exhaust vent for the underground works. The locations of works sites are illustrated in Figure No. C1603/C/NOL/ACM/M51/309. Potential dust impact would arise from the associated construction activities at the works sites, including site formation, excavation, backfilling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area. Major excavation works would be confined to station box and portal area for initial tunneling works. Also, the works sites of NTM Station would be utilized for the retrieval of TBMs from KTU(NOL) Station and from SMA for the construction of northbound and southbound underground tunnel respectively. Upon completion of shaft construction, the dust emission associated with the drill-and-blast works is expected minimum with adoption of regular watering, filtration system and blast door for confining the dust within the shaft (Section 3.5.4 refers). At the peak construction year of 2027 at NTM and NTD, an averaged hourly traffic of about 58 trucks would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design.

3.6.26 Existing village house and low-rise residential uses are found in the vicinity of NOL works in the area. ASRs within 500 metres from works sites have been identified and are illustrated in Figure No. C1603/C/NOL/ACM/M51/309. The land uses in the area are being reviewed under NTM LUR of which the proposed land uses and their implementation programme are not available during the course of this EIA study. The nearest ASRs to the works sites would be the village house (NTM-A13 & NTM-A14) which are adjacent to the site hoarding of works sites. With careful planning of work sequence and design optimization of workfronts in Ngau Tam Mei area, dispersion of construction dust out of works sites to the nearby ASRs could be reduced.

3.6.27 In addition, dust suppression measures for the construction works of other stations as discussed in Section 3.6.4 is also applicable to the works sites of NTM Station and NTD. A filtration system comprising watering and dust collector, etc. with overall dust removal efficiency of at least 80% should be provided at the ventilation exhaust. Together with the implementation of appropriate dust suppression measures, for example regular watering at excavation works, exposed areas and sites of spoil handling, paved and regularly wetted haul roads, wheel washing facilities upon exit of works sites/works areas, and good site practices, the fugitive dust emission from the construction works is reduced to minimum.

3.6.28 It is assumed that appropriate dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, such as regularly watering and paved haul road, would be implemented properly by the contractors of concurrent works and it results in minimum fugitive dust emission from their construction activities.

3.6.29 In order to avoid intensive works at a location near ASR, NTM Station is to be constructed by several workfronts in design. The cut and fill works of NTD would be conducted by stages, from north to south. With the implementation of workfronts in design, construction activities scatter among these smaller workfronts and thereby minimising the associated fugitive dust emission.

3.6.30 The works sites of NTM station would exist in close proximity to two ASRs, e.g. at 9 metres away from Hongtai Home for the Aged Limited (NTM-A03) and at 3 metres away from the village house (NTM-A04). The village houses (NTM-A13 & NTM-A14) are adjacent to the site hoarding of the NTD works site. Dusty activities would be taken place progressively across each work front with moving construction plant according to work requirements to be determined at the time of construction. Hence, construction dust emission is expected to be transient in nature. Dust impact to these concerned ASRs should be limited with the adoption of dust suppression measures such as regular watering and erection of hoarding with a combined height of up to 3m (i.e. 2.4m hoarding with 0.6m dust screen on top) in front of the air sensitive façade facing to the works site to shield off the concerned ASRs from nearby dust emission sources. Dust monitoring at these locations is recommended to ensure the potential dust impact complying with AQOs during the construction phase.

3.6.31 With the implementation of the abovementioned effective dust suppression measures and good site practices, no adverse dust impact on nearby ASRs in the area due to the construction of NTM Station, NTD and NTD Portal is anticipated. A comprehensive EM&A programme would be required to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

San Tin (SAT) Station / SNA / KLA / KTA / San Tin Area

3.6.32 San Tin (SAT) Station locates within the planned San Tin / Lok Ma Chau Development Nodes (STLMC DN). The works sites would be used for the launch of TBMs, tunneling towards NTM Station. There are also three ancillary buildings (i.e. SNA, KLA, KTA) within STLMC DN. SAT Station and the three ancillary buildings would be built by cut-and-cover method. A CBP is also proposed at the works site of SAT Station, adjacent SNA, to meet the concrete demand by the constructions of tunnel and stations. Potential construction dust impact would arise from the associated construction activities in the works sites, including site formation, excavation, backfilling, mucking out for TBM tunneling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area and concrete batching. The location of works sites are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/310, 312 to 315. Major excavation works would be confined to station box and shaft areas. Upon completion of launching shaft, the dust emission associated with the TBM tunneling works is expected minimum due to its adoption of a closed system (Section 3.5.3 refers). At the peak construction year of 2030 at SAT and SNA, an averaged hourly traffic of about 54 trucks would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design. Similarly, an averaged hourly traffic of about 3 and 2 trucks would be required during the peak construction year of 2028 at KLA and 2029 at KTA respectively.

3.6.33 Existing village house and low-rise structures for brownfield operations are found in the vicinity of NOL works in the area. Under STLMC DN, most of the San Tin area are to be redeveloped except the existing villages to be retained, namely Shek Wu Wai, Fan Tin Tsuen, Wing Ping Tsuen and Siu Hum Tsuen, etc. The redevelopment in STLMC DN would be completed in three phases: Initial Phase for northeastern and southwestern areas of STLMC DN, Main Phase for the southeastern and northwestern parts, and Remaining Phase for sites with the completed NOL works. The first population intake in STLMC DN Initial Phase would be expected in Year 2031, while the population intake in STLMC DN Main Phase would appear in Year 2034. SAT Station of NOL is designed to support the population in STLMC DN, thus major construction works of SAT Station and ABs in this area should be completed by the first population intake in STLMC DN Main Phase. Planned uses under STLMC DN Main Phase and Remaining Phase should therefore not be affected by the dust impact due to remaining works of SAT Station and ABs. ASRs within 500 metres from works sites have been identified and are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/310, 312 to 314. The nearest ASR to works site of SAT Station and ABs during the construction phase would include Christian New Life Association (SAT-A01) which is 11 metres away from the works sites of SAT, the retained village Shek Wu Wai (SAT-A03 & SAT-A05) which is 56 and 14 metres away from the works site of SAT respectively. Shun Sum Yuen Farm (SAT-A06) is 7 metres away from the works site of SAT and SNA. The planned residential uses (SAT-PA01) will commission under STLMC Initial Phase, which is 44 metres away from the south portal of SAT station. With careful planning of work sequence and design optimization of workfronts, the fugitive dust emission from the works sites could be reduced.

3.6.34 In addition, dust suppression measures for the construction works of other stations as discussed in Section 3.6.4 is applicable to the works sites of SAT Station, SNA KLA and KTA. With the implementation of appropriate dust suppression measures, for example regular watering at excavation works, exposed areas and sites of spoil handling, paved and regularly wetted haul roads, wheel washing facilities upon exit of works sites/works areas, and good site practices, the fugitive dust emission from the construction works would be reduced to minimum.

3.6.35 For the potential cumulative impact, the construction programme of STLMC DN has also been reviewed. Site formation works of STLMC DN Initial Phase would commence in late 2024 and target for first population intake by Year 2031. Site formation works of STLMC DN Main Phase would commence in Year 2026 and target for population intake by Year 2034. Major construction works of SAT Station and ABs including excavation and backfilling works would be carried out concurrently with STLMC DN Main Phase, and would be completed by the first population intake in STLMC DN Main Phase. It is anticipated that appropriate dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, such as regularly watering and paved haul road, would also be implemented by the contractors of STLMC DN and it would result in minimum fugitive dust emission from their construction activities.

3.6.36 The operation of the proposed CBP would last longer, until Year 2034 to support the overall construction of NOL. Dust control measures should be implemented in the CBP as required in A Guidance Note on the Technical, Management and Monitoring Requirements for Specified Process – Cement Works (Concrete Batching Plant) (BPM 3/2 (16)). Best practicable means such as dust collectors at silos / mixers, 3-side and top enclosure at aggregate receiving hopper, regularly wetting on paved haul roads, etc. are proven effective measures in suppressing fugitive dust emission arising from concrete batching. The proposed CBP is classified as a Specified Process, thus its operation, dust control measures and resulting dust impact are regulated under APCO and a licence under the regulations should be applied by the responsible contractor as appropriate. With the implementation of effective dust control measures and good site practice, it is expected that the significant dust impact due to the operation of CBP would be confined within the boundary of the plant.

3.6.37 In order to avoid intensive works at a location near ASR, SAT Station, crossover box and bifurcation would be constructed in several workfronts by design. Owing to the large extent of STLMC DN, the construction works under Initial and Main Phases are also expected to be conducted in numerous workfronts, subject to the land resumption schedule. With the implementation of workfronts in the works sites, construction activities scatter among these smaller workfronts and thereby minimising the associated fugitive dust emission. Furthermore, coordination or collaboration with the contractor(s)/project proponent of other concurrent projects would be conducted such that any concurrent construction works in close vicinity of ASRs could be adjusted / well-planned as far as practicable for minimisation of potential dust impact.

3.6.38 The works sites in San Tin area would exist in close proximity to one ASR, i.e. Shun Sum Yuen Farm (SAT-A06) at 7 metres away from works sites of SAT station and SNA. The concerned ASR is subject to development under the STLMC DN. Dusty activities would be taken place progressively across each work front with moving construction plant according to work requirements to be determined at the time of construction. Hence, construction dust emission is expected to be transient in nature. Dust impact to the concerned ASR should be limited with the adoption of dust suppression measures such as regular watering and erection of hoarding with a combined height of up to 3m (i.e. 2.4m hoarding with 0.6m dust screen on top) in front of the air sensitive façade facing to the works site to shield off the concerned ASR from nearby dust emission sources. Dust monitoring at the concerned ASR is recommended to ensure the potential dust impact complying with AQOs during the construction phase.

3.6.39 With the implementation of the abovementioned effective dust suppression measures and good site practices, no adverse dust impact on nearby ASRs in the area due to the construction of SAT Station, ABs, and other concurrent projects is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

Pak Shek Au Ancillary Building (PAA)

3.6.40 Pak Shek Au Ancillary Building (PAA) locates between STLMC DN and KTU NDA and would be built by cut-and-cover method. The locations of works sites are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/315 to 316. Potential construction dust impact would arise from the associated construction activities in the works sites, including site formation, excavation, backfilling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area. Major excavation works will be limited to relatively small shaft area. At the peak construction year of 2026 at PAA, an averaged hourly traffic of about 2 trucks would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design.

3.6.41 Existing villages and planned uses under STNLMC DN and KTU NDA are found in the vicinity of PAA. ASRs within 500 metres from the works sites have been identified and are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/315 to 316. The nearest ASR to the works site would be a village house (i.e. KTU-A05) which is approximately 35 metres away from the works site. With careful planning of work sequence and design optimization of workfronts, the fugitive dust emission from the works sites could be reduced.

3.6.42 In addition, dust suppression measures for the construction works of other stations as discussed in Section 3.6.4 is applicable to the works sites of PAA. With the implementation of appropriate dust suppression measures, for example regular watering at excavation works, exposed areas and sites of spoil handling, paved and regularly wetted haul roads, wheel washing facilities upon exit of works sites/works areas, and good site practices, the fugitive dust emission from the construction works would be reduced to minimum.

3.6.43 For the potential cumulative impact, the construction programme of KTN NDA has also been reviewed. Site formation works of KTN NDA Advance Works would be completed in 2025/2026 and target for first population intake by Year 2026. Site formation works of Remaining Phase would commence in Year 2024 and target for population intake by Year 2034. The construction works of PAA including site formation and excavation works would start in Year 2025 and to be completed by Year 2027, which are to be carried out concurrently with KTN NDA. It is assumed that appropriate dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, such as regularly watering and paved haul road, would be implemented properly by the contractors of KTN NDA and it would result in minimum fugitive dust emission from their construction activities.

3.6.44 With the implementation of the abovementioned effective dust suppression measures, no adverse dust impact on nearby ASRs in the area due to the construction of PAA is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

Kwu Tung (KTU) Station (NOL) / Kwu Tung Area

3.6.45 Kwu Tung (KTU) Station (NOL) is to be constructed by cut-and-cover method, which locates next to KTU(EAL) station and within the planned Kwu Tung North New Development Area (KTN NDA). The works sites of KTU(NOL) Station would also be used to launch TBMs, tunnelling towards SAT Station. The location of works sites are illustrated in Figure Nos. C1603/C/NOL/ACM/M51/316. Potential construction dust impact would arise from the associated construction activities in the works sites, including site formation, excavation, backfilling, mucking out for TBM tunneling, spoil handling, vehicle movement on haul roads, wind erosion of the exposed site area. Major excavation works would be confined to station box. Top-down construction method is adopted for part of the station in which the uppermost floor level is excavated first, followed by casting a slab above, and repeat this process until the bottom level is reached. With such method, the exposed area of the works sites would be covered up by the slab with the subsequent construction activities to be conducted underneath. It would result in less fugitive dust emitted from the works sites and only confined at the openings of the slab. Upon completion of launching area of TBM, the dust emission associated with the TBM tunneling works is expected minimum due to its adoption of a closed system (Section 3.5.3 refers). At the peak construction year of 2030 at KTU(NOL), an averaged hourly traffic of about 34 trucks would be required for these construction works based on the maximum daily spoiling rate estimated under the current engineering design.

3.6.46 KTN NDA would be constructed by two phases, namely Advance Works and Remaining Phase. The site formation works and infrastructure works under Advance Works already commenced in Year 2019 and the ones of Remaining Phase will commence in coming 2024. The area of KTU NDA is expected to be under construction by the time KTU(NOL) Station construction works commence. Existing land use in vicinity of KTU(NOL) Station would no longer exist. The existing residential uses would be south of KTU NDA across Fanling Highway. Planned public housing under KTN NDA would appear in around Year 2027 and Year 2030 under the two phases respectively. ASRs within 500 metres from works sites have been identified and are illustrated in Figure No. C1603/C/NOL/ACM/M51/316. The nearest ASR to works site of KTU(NOL) Station would be the planned public and private housing under KTN NDA (KTU-PA02) which is 10 metres away from the works site of KTU(NOL) Station. As mentioned in Section 3.6.39, the proposed top-down construction method for the construction of KTU(NOL) Station would limit the exposed area of the works sites and cover the subsequent construction activities to be conducted underneath.

3.6.47 In addition, dust suppression measures for the construction works of other stations as discussed in Section 3.6.4 is applicable to the works sites of KTU(NOL) Station. With the implementation of appropriate dust suppression measures, for example regular watering at excavation works, exposed areas and sites of spoil handling, paved and regularly wetted haul roads, wheel washing facilities upon exit of works sites/works areas, and good site practices, the fugitive dust emission from the construction works would be reduced to minimum.

3.6.48 For the potential cumulative impact, the construction programme of KTN NDA has also been reviewed. Site formation works of KTN NDA Advance Works would be completed in 2025/2026 and target for first population intake by Year 2026. Site formation works of Remaining Phase would commence in Year 2024 and target for population intake by Year 2034. Construction works of KTU(EAL) would commence in Year 2023 and with major works to be completed before Year 2026. Meanwhile, major construction works of KTU(NOL) Station including excavation and backfilling works would be concurrent with KTN NDA and KTU(EAL), and to be completed by Year 2031. It is assumed that appropriate dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, such as regularly watering and paved haul road, would be implemented properly by the contractors of KTN NDA and it would result in minimum fugitive dust emission from their construction activities. Furthermore, coordination or collaboration with the contractor(s)/project proponent of other concurrent projects would be conducted such that concurrent construction works, if any, in close vicinity of ASRs could be adjusted / well-planned as far as practicable for minimisation of potential dust impact.

3.6.49 The works sites KTU(NOL) would be located at about 10 metres away from planned housing development (KTU-PA01 & KTU-PA02). These concerned ASRs are under the development of KTN NDA. These ASRs would adopt podium design which causes their first level of air sensitive use further away from the ground. Dusty activities would be taken place progressively across each work front with moving construction plant according to work requirements to be determined at the time of construction. Hence, construction dust emission is expected to be transient in nature. Dust impact to these concerned ASRs should be limited with the adoption of dust suppression measures such as regular watering. Dust monitoring at these locations is recommended to ensure the potential dust impact complying with AQOs during the construction phase.

3.6.50 With the implementation of the abovementioned effective dust suppression measures, no adverse dust impact on nearby ASRs in the area due to the construction of KTU(NOL) is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL in the area.

Offsite Explosive Magazine Site

3.6.51 The offsite works area at Tai Shu Ha, Yuen Long is proposed to be used as temporary explosive magazine site. The site was formerly used as temporary explosive magazine site by HSR and Liantang/Heung Yuen Wai Boundary Control Point Project and had been reinstated for about 5 years. The closest ASR, TSA01, is located at more than 125 metres away from the boundary of the magazine site. Minor non-dusty works would be required to prepare the magazine site, such as vegetation clearance, brick-built magazine, fencing, sandbag mounds and access road, where no excavation works would be anticipated for these preparation works. Vehicle access to the site is expected to be a maximum of about 2 trucks per hour during the construction of NOL. Given no excavation works and minor traffic induced, the associated potential air quality impact on the ambient is considered negligible.

3.6.52 The temporary magazine site will be decommissioned and reinstated after the construction of the Project. The decommissioning works would include minor dismantling, demolition and removal of temporary structures. Owing to the nature and the small scale of decommissioning works, the potential dust impact is expected to be minimum. With the implementation of dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation, no adverse dust impact due to the decommissioning works is expected.

3.7 Summary of Dust Suppression Measures

3.7.1 Based on the above discussion, a summary of key dust suppression measures to be implemented during the construction phase is provided below:

· Regular watering on construction works sites and exposed site surface should be conducted.

· Paving should be provided to open haul road within works sites / works areas.

· For the works sites close to the ASRs with the air sensitive facades at a separation distance of less than 10 m, provide hoarding with a combined height of up to 3m (i.e. 2.4m hoarding with 0.6m dust screen on top) from ground level along the site boundary, subject to site constraints and status of ASRs; for the other work sites in general, provide hoarding of not less than 2.4m high from ground level along site boundary except for site entrance or exit.

· Dust control measures will be implemented in the CBP as required in A Guidance Note on the Technical, Management and Monitoring Requirements for Specified Process – Cement Works (Concrete Batching Plant) (BPM 3/2 (16)).

· For the mucking-out operation at TBM launching shafts, regular watering should be provided at the unloading point of spoils generated by the TBM excavation.

· For the tunnelling works by drill-and-blast, in addition to the regular watering at spoiling handing and unpaved / paved haul roads, a blast door should be installed at the opening to avoid the escape of fugitive dust from the blasting. The blast door should remain closed and ventilation stopped during blasting. Water spaying should be applied to facilitate dust settlement. A filtration system comprising watering and dust collector, etc. with overall dust removal efficiency of at least 80% should be provided at the ventilation exhaust to treat dust-laden exhaust before release to the ambient. The exhaust vents will locate at the tunnel portals at the sites of NTD, LHA and PWA.

3.8 Evaluation of Residual Impacts

3.8.1 Apart from dust suppression measures mentioned in Section 3.7, the dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation and good site practices listed below should also be carried out to further minimize construction dust impact.

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

· 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.

· Imposition of speed controls for vehicles on site haul roads.

· 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 to monitor the construction process in order to enforce controls and modify method of work if dusty conditions arise.

3.8.2 With the implementation measures specified in Air Pollution Control (Construction Dust) Regulation together with the control measures such as regular watering on the works sites and exposed surface, no adverse residual impact would be expected from the construction of the Project.

3.8.3 To minimise the exhaust emission from NRMMs during the construction phase, the following measures should be applied as far as practicable:

· Connect construction plant and equipment to main electricity supply and avoid use of diesel generators and diesel-powered equipment;

· Avoid the use of exempted NRMMs as far as practicable; and

· Deploy electrified NRMMs as far as practicable.

3.9 Environmental Monitoring and Audit

3.9.1 EM&A for potential dust impacts are recommended during the construction phase of the Project so as to check compliance with legislative requirements. Real-time RSP and FSP monitoring will also be conducted. Details of the monitoring and audit programme are presented in a stand-alone EM&A Manual.

3.10 Conclusion

3.10.1 Potential construction dust impact would arise from the construction of the Project. Cumulative dust impact from construction activities of the Project and concurrent projects were evaluated. Based on former dust monitoring data of HSR which has similar nature and scale of the Project, it would be anticipated that no significant dust impact would arise from the construction of the Project. Design control measures and dust suppression measures such as regular watering during the dusty construction activities, blasting door and regular watering during blasting operation will be implemented during the construction of the Project, no adverse construction dust impact is anticipated. A comprehensive EM&A programme would be conducted to ensure the proper implementation of measures and the compliance of AQOs during the construction of NOL.

C1603/C/NOL/ACM/M51/301	Locations of Representative Air Sensitive Receivers (Key Plan)
C1603/C/NOL/ACM/M51/302	Not Used
C1603/C/NOL/ACM/M51/303 to C1603/C/NOL/ACM/M51/317	Locations of Representative Air Sensitive Receivers