3.2 Statutory Requirements and Evaluation Criteria 3-2

3.3 Study Area 3-3

3.4 Identification of Air Sensitive Receivers 3-3

3.5 Existing Air Quality 3-4

3.6 Evaluation of Impacts during Construction Phase 3-7

3.7 Evaluation of Impacts during Operation Phase 3-10

3.8 Mitigation Measures 3-10

3.9 Potential for Cumulative Impacts 3-11

3.10 Residual Impacts 3-12

3.11 Monitoring and Audit Requirements 3-12

3.12 Conclusion 3-13

3. Air Quality Impact Assessment

3.1 Introduction

3.1.1 This Section presents a qualitative assessment of the potential air quality impacts that could arise from the construction and operation of the Project. Representative Air Sensitive Receivers (ASRs) have been identified and an assessment of air quality impacts has been conducted. Mitigation measures and Environmental Monitoring and Audit (EM&A) programme have been proposed if deemed necessary.

3.2 Statutory Requirements and Evaluation Criteria

3.2.1 The criteria for evaluating air quality impacts and the guidelines for air quality assessment are laid out in Annex 4 and Annex 12 of the TM-EIAO. The principal legislation for the management of air quality in Hong Kong is the Air Pollution Control Ordinance (APCO) (Cap. 311). The Air Quality Objectives (AQOs) stipulating statutory ambient limits for air pollutants and the maximum allowable number of exceedances over specific averaging periods are presented in Table 3.1.

Table 3. 1 – Hong Kong Air Quality Objectives

Air Pollutant	Averaging Time		No. of Exceedances Allowed per Year
Sulphur Dioxide (SO₂)	10 minutes	500	3
	24-hours	125	3
Respirable Suspended Particulates (RSP) ^(b)	24-hours	100	9
Respirable Suspended Particulates (RSP) ^(b)	Annual	50	-
Fine Suspended Particulates (FSP) ^(c)	24-hours	75	9
Fine Suspended Particulates (FSP) ^(c)	Annual	35	-
Nitrogen Dioxide (NO₂)	1-hour	200	18
	Annual	40	-
Ozone (O₃)	8-hours	160	9
Carbon Monoxide (CO)	1-hour	30,000	-
	8-hours	10,000	-
Lead	Annual	0.5	-
Notes: (a) Measured at 298K and 101.325 kPa. (b) Suspended particles in air with a nominal aerodynamic diameter of 10 μm or less (c) Suspended particles in air with a nominal aerodynamic diameter of 2.5 μm or less

3.2.2 A maximum hourly TSP level of 500 mg m^-3 at Air Sensitive Receivers (ASRs) is also stipulated in Section 1, Annex 4 of the EIAO-TM to assess potential construction dust impacts. The measures stipulated in the Air Pollution Control (Construction Dust) Regulation should also be followed whenever possible to ensure that any dust impacts are reduced.

3.2.3 Annex 4 of the EIAO-TM has also stipulated that the odour level at a sensitive receiver should not exceed 5 odour units based on an averaging time of 5 seconds for odour prediction assessment.

3.3 Study Area

3.3.1 Clause 3.4.4.2 of the EIA Study Brief prescribes the Study Area which is generally defined by a distance of 500 m from boundary of the Project, or to include other project locations as identified in the EIA. Figures 3.1 – 3.6 shows the Study Area within the 500 m envelope of the Project (including the works areas) and the identified representative ASRs which have been described in the next section in details. The Study Area is the same for both the construction and operation phases.

3.4 Identification of Air Sensitive Receivers

3.4.1 Air Sensitive Receivers (ASRs) have been identified in accordance with Annex 12 of EIAO-TM and are summarised in Table 3.2 and shown in Figures 3.2 – 3.6.

Table 3. 2 – Identified Representative Air Sensitive Receivers

ASR	Description	Minimum Distance away from the Project (m)	Type of Use
FPCL1	Fortune Pharmacal Co. Ltd.	77	Industrial
HKSM1	Hong Kong School of Motoring – Yuen Long School Driving Test Centre	118	Office
TSSP1	Temporary Shelter at Shan Pui	273	Residential
SPCH1	Shan Pui Chung Hau Tsuen	11	Residential
TTWS1	Tung Tau Wai San Tsuen	39	Residential
SPCH2	Shan Pui Chung Hau Tsuen	15	Residential
WCTT1	Wang Chau Tung Tau Wai	89	Residential
TNRG1	Twin Regency	30	Residential
WCLU1	Wang Chau Lam Uk Tsuen	65	Residential
YYGD1	Yuk Yat Garden	50	Residential
WFCT1	Wang Fu Court	16	Residential
YUST1	Yeung Uk San Tseun	58	Residential
YLLP1	Yuen Long Long Ping Estate Wai Chow School	66	Educational
LSTS1	A.D. & F.D.P.O.H. Ltd. Leung Shing Tak School	70	Educational
TSPE1	The Spectra	21	Residential
HPHO1	Hor Ping House, Long Ping Estate	92	Residential
VHTK1	Village house at Tai Kui	13	Residential
PFBD1	Po Fai Building	6	Residential
MYBD1	Man Yip Building	6	Residential
FYBD1	Fuk Yip Building	6	Residential
FOHE1	Fook On House	13	Residential
YFHE1	Yuen Fat House	6	Residential
KSBD1	Kin Shing Building	6	Residential
HLBD1	Healey Building	8	Residential
WCMS1	Wah Cheung Mansion	6	Residential
WSMS1	Wah Shing Mansion	6	Residential
YLBD1	Yuen Long Building	6	Residential
TPTG1	Tai Pei Tau Rest Garden	28	Residential
CSPP1	Chung Sing Path Playground	30	Recreational
YTHE1	Yuen Tong House	6	Residential
FYBD2	Fung Yue Building	6	Residential
SFBD1	Siu Fung Building	6	Residential
HPHE1	Happy House	6	Residential
KHHE1	Kam Hei House	6	Residential
CKHE1	Chi King House	19	Residential
YCHE1	Yuen Cheung House	19	Residential
HWBD1	Ho Wang Building	10	Residential
WKBD1	Wah Kin Building	11	Residential
CCHS1	Caritas Yuen Long Chan Chun Ha Secondary School	10	Educational
YFGD1	Yee Fung Garden	39	Residential
YLVA1	Yuen Long Villa	20	Residential
SFCT1	Sun Fai Court	10	Residential
MTTN1	Ma Tin Tsuen	11	Residential
MTTN2	Ma Tin Tsuen	11	Residential
LTTN1	Lung Tin Tsuen	11	Residential
LAGR1	La Grove	30	Residential
MTPK1	Ma Tin Pok Village House	30	Residential
MTPK2	Ma Tin Pok Village House	90	Residential
PKSN1	Park Signature	172	Residential
TLTN1	Tin Liu Tsuen	11	Residential
TLTN2	Tin Liu Tsuen	18	Residential
TLTN3	Tin Liu Tsuen	7	Residential
SCTN1	Sham Chung Tsuen	16	Residential
PYVA1	Park Yoho Venezia	121	Residential
CCST1	Cheung Chun San Tsuen	258	Residential
RIVA1	Riva	51	Residential
KPTN1	Ko Po Tsuen	13	Residential
KHWA1	Kam Hing Wai	141	Residential

3.5 Existing Air Quality

3.5.1 Data collected by EPD air quality monitoring programme during the period of 2015 to 2019 were examined with the average period value presented in Table 3.3. It is noted that the 5-year averaged annual and 1-hour concentrations of NO₂, 24-hour concentrations of FSP and RSP and 8-hour concentration of O₃ exceeded the relevant AQO. The concentrations of SO₂ and CO were in relatively low level and well within the AQOs during 2015-2019.

3.5.2 The traffic emissions from Castle Peak Road, Long Yip Road,Yuen Long Highway and other local roads, as well as emissions from the Yuen Long Industrial Estate (YLIE) and Tung Tau Industrial Area (TTIA), are considered likely to be the key local sources affecting the ambient air quality within the Study Area.

Table 3. 3 – 5-year Averaged Annual Background Concentration of Air Pollutants recorded at Yuen Long Station by EPD for the Period of 2015-2019

Air Pollutant	Averaging Time	AQO^(a)	Data Description	Unit	Year ^{(b) (c)}					5-year mean
Air Pollutant	Averaging Time	AQO^(a)	Data Description	Unit	2015	2016	2017	2018	2019	5-year mean
Fine Suspended Particulates (FSP) (PM 2.5)	24-hour	75 (9)	Max.	μg m^-3	127	76	77	80	81	88
			10th Max.	μg m^-3	78	63	52	46	45	57
			No. of Exceedance(s)	-	12	1	2	1	2	4
	Annual	35	-	μg m^-3	30	23	22	20	20	23
Respirable Suspended Particulates (RSP) (PM10)	24-hour	100 (9)	Max.	μg m^-3	176	128	111	121	125	132
			10th Max.	μg m^-3	102	86	87	75	83	87
			No. of Exceedance(s)	-	12	4	2	4	1	5
	Annual	50	-	μg m^-3	44	37	40	37	37	39
Sulphur Dioxide (SO₂)	10-minute	500 (3)	Max.	μg m^-3	67	77	105	70	53	74
	10-minute	500 (3)	4th Max.	μg m^-3	51	58	80	52	42	57
	24-hour	125 (3)	Max.	μg m^-3	20	18	24	20	12	19
	24-hour	125 (3)	4th Max.	μg m^-3	17	17	20	17	11	16
Nitrogen Dioxide (NO₂)	1-hour	200 (18)	Max	μg m^-3	339	202	214	231	193	236
			19th Max.	μg m^-3	162	149	156	150	161	156
			No. of Exceedance(s)	-	5	1	2	3	0	2
	Annual	40	-	μg m^-3	45	46	41	43	44	44
Carbon Monoxide (CO)	1-hour	30,000	Max.	μg m^-3	2460	2080	1450	1720	2150	1972
Carbon Monoxide (CO)	8-hour	10,000	Max.	μg m^-3	2143	1474	1324	1574	1903	1684
Ozone (O₃)	8-hour	160 (9)	Max.	μg m^-3	261	269	272	249	310	272
			10th Max.	μg m^-3	164	143	175	162	200	169
			No. of Exceedance(s)	-	11	5	13	10	25	13

Notes: (a) Values in ( ) indicate the number of exceedances allowed per year

(b) Data extracted from EPD Website (http://www.aqhi.gov.hk/en/download/air-quality-reportse469.html?showall=&start=1)

3.5.3 The future year background concentrations are made reference to the EPD’s PATH-2016 modelling results. The dust (RSP and FSP) concentrations of the assessment year extracted from Year 2020 PATH results are presented in Table 3.4.

Table 3. 4 – Background Concentrations extracted from PATH-2016 Model

Grid	Respirable Suspended Particulates (RSP) (PM10)		Fine Suspended Particulates (FSP) (PM 2.5)		Sulphur Dioxide (SO₂)		Nitrogen Dioxide (NO₂)
Grid	24-hour average 10th Max.	Annual average	24-hour average 10th Max.	Annual average	10-minute average 4th Max.	24-hour average 4th Max.	1-hour average 10th Max.	Annual average
24,45	83.9	35.6	62.9	25.3	109.8	25.7	94.6	19.6
24,46	82.3	35.1	61.7	24.9	113.9	26.0	101.1	23.5
24,49	81.2	34.4	60.9	24.4	109.2	26.2	100.0	18.6
25,45	81.6	35.2	61.2	25.0	111.3	25.6	99.6	19.5
25,46	81.7	35.2	61.3	25.0	111.5	26.0	111.5	26.1
25,47	82.2	35.4	61.6	25.2	111.5	26.1	114.3	27.7
25,48	82.3	35.2	61.7	25.0	111.3	26.2	114.4	25.6
26,45	81.4	34.9	61.1	24.8	112.1	25.3	103.3	16.6
26,46	81.2	34.9	60.9	24.8	111.3	25.5	100.9	19.2
26,47	81.7	34.9	61.3	24.8	111.6	25.8	103.8	19.8
26,48	82.8	35.2	62.1	25.0	110.7	25.9	101.2	19.3
26,49	82.0	35.0	61.5	24.8	110.2	26.0	95.5	16.9
27,47	81.6	34.7	61.2	24.6	111.6	25.7	95.1	16.7
27,48	82.3	35.4	61.8	25.1	110.6	25.8	96.6	17.4
28,46	81.9	35.1	61.4	24.9	112.4	25.2	84.0	14.2
28,47	81.0	34.4	60.8	24.4	111.7	25.5	88.6	14.6
28,48	81.0	34.8	60.7	24.7	111.3	25.8	87.2	14.9
29,46	80.7	33.9	60.5	24.1	112.7	25.1	79.6	13.0
29,47	81.7	34.3	61.3	24.4	111.2	25.2	78.1	12.4

Notes:

[1] For 24-hr average PM₁₀, the concentration is adjusted by adding 26.5 μg/m³, extracted from EPD’s Guidelines on Choice of Models and Model Parameters.

[2] For annual average PM₁₀, the concentration is adjusted by adding 15.6 μg/m³, extracted from EPD’s Guidelines on Choice of Models and Model Parameters.

[3] For 24-hr average PM_2.5, as there is no information from the PATH-2016 model, a conversion factor of 0.75 is multiplied to the 24-hr average PM₁₀, extracted from EPD’s Guidelines on the Estimation of PM2.5 for Air Quality Assessment in Hong Kong.

[4] For annual average PM_2.5, as there is no information from the PATH-2016 model, a conversion factor of 0.71 is multiplied to the annual average PM₁₀, extracted from EPD’s Guidelines on the Estimation of PM2.5 for Air Quality Assessment in Hong Kong.

[5] For 10-min average SO₂, as there is no information from the PATH-2016 model, the most conservative conversion factor 2.45 (Stability Class A) was applied to the 1-hour SO2 concentration to estimate the 10-minute SO₂concentrations, extracted from EPD’s Guidelines on the Estimation of 10-minute Average SO₂ Concentration for Air Quality Assessment in Hong Kong.

3.6 Evaluation of Impacts during Construction Phase

Identification of Air Pollution Sources

3.6.1 The following sources of air pollution are expected during the construction phase of the Project:

· Fugitive dust during construction of the Barrage Scheme including site clearance, site formation, excavation, foundation and piling, building works, etc;

· Fugitive dust caused by earthworks at YLN during revitalisation works including surface breaking, excavation, materials handling, loading, unloading and backfilling, etc;

· Fugitive dust from construction and modification of parapet walls;

· Gaseous emissions from diesel-powered construction equipment and vehicle associated with construction of the Project; and

· Odour from the excavated channel bed materials.

Evaluation of Impacts

Fugitive Dust

(a) Barrage Scheme

3.6.2 Site clearance, site formation, excavation, backfilling, construction of substructure and superstructure are the major construction activities for the Barrage Scheme. Construction of the Barrage Scheme would last for about 54 months. Site clearance, site formation, excavation and backfilling works would take about 30 months within the 54 months period.

3.6.3 Vegetation if appropriate and debris will be removed during site clearance and fugitive dust emission is considered to be limited. Excavation and backfilling works may have the potential to generate fugitive dust. About 60,803 m³ of excavated materials will be generated in association with the construction of the Barrage Scheme. On-site storage of excavated materials will be minimised as far as practicable and surplus excavated materials will be transported off-site for disposal so that potential dust emissions can be minimised. It is estimated that a maximum of 8 trucks per day will be required to dispose of the C&D materials/construction waste off-site. The size of the works area for the Barrage Scheme is about 7,300 m², in which about 900 m² is the E&M Control Centre, about 3,400 m² for the two pumping stations, about 500 m²for the tidal barriers, about 1,150 m² for the link bridge and some of the works areas are for storage use and occupied by the construction plant or equipment. Active works area in which excavation and filling will be undertaken is smaller than the works area. With proper implementation of good site practices and mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation, potential unacceptable dust impacts associated with on-site handling and transportation of the public fill and construction waste to disposal sites are not expected to occur. Also the nearest ASR FPCL1 is located at more than 77m from the works area of the Barrage Scheme. As the dust impact is localized and with implementation of the dust suppression works, no unacceptable dust impact on this ASR and those beyond is anticipated during site formation and excavation works.

3.6.4 Negligible fugitive dust emission is expected from construction of substructure and superstructure as they will involve mainly concreting and steel-reinforcement works and these works are not dust generating.

(b) Revitalisation concepts for YLN

3.6.5 The construction duration for the revitalisation works is expected to last for about 2 years within the tentative construction programme. The most affected air sensitive receivers will be those along the two sides of the YLN. Only minor impacts will be expected due to construction works because the scale of demolition of the existing nullah and excavation is expected to be relatively small.

3.6.6 As the construction works will be constructed section by section, construction dust nuisance is not expected to cause any significant dust impacts to the nearby sensitive receivers. The quantity of C&D materials from site clearance and excavation is unlikely to be large enough to cause a significant dust nuisance. It is anticipated that excavated material will only be stockpiled on each local works area and the duration of the stockpiling will be as short as possible.

3.6.7 Based on the engineering design, it is estimated that about 77,438 m³ of construction and demolition (C&D) materials and channel bed material will be excavated from the Project for the whole construction period. About 7,744 m³ of the excavated materials will be reused on-site and the rest (about 69,694 m³) will be temporarily stored in stockpiling areas for subsequent disposal off-site. Since the construction works will be conducted section by section, It is estimated that a maximum of 2 trucks per day from a single work site will be required to dispose of the C&D materials/construction waste off-site. Dust generated from construction vehicle movements to and from the stockpiling areas and works areas will generally be limited within the work areas. The feasibility of reusing some of the excavated materials as backfilling materials will be rigorously examined during the detailed design stage. As some materials may be used back in the construction processes, the quantity of material need to be disposed of or imported can be reduced. Hence construction dust nuisance at nearby representative sensitive receivers will expect to be insignificant.

3.6.8 In addition, the construction dust nuisance can be alleviated by implementation of proper construction dust mitigation measures as required by the Air Pollution Control (Construction Dust) Regulation. Moreover, as the proposed channels are close to existing roads, purpose-built haul road is not expected for the transportation of excavated material and filling material.

(c) Construction and modification of parapet walls along YLN, Sham Chung River (SCR) and Kam Tin River (KTR), with the provision of flap valves and other necessary backwater control mechanisms

3.6.9 Limited excavation and backfilling works are required during the construction of parapet walls, flap valves and the associated drainage works. It is understood that the construction of the parapet walls would be carried out section by section, with each section about 20m long a maximum, thus construction dust nuisance is not expected to cause any significant dust impacts to the nearby sensitive receivers. Any dust emissions during excavation activities is expected to be localized and dust impact to nearby ASRs is not anticipated with implementation of dust mitigation measures. For backfilling works, fugitive dust emissions will be reduced by compacting the filled area immediately after backfilling and covered by impervious sheet when it is not in use.

3.6.10 In view of the relatively small scale of the construction works, the quantity of excavated materials generated, the potential fugitive dust nuisance during the construction phase should be limited. With the implementation of dust suppression measures and good site practices stipulated in the Air Pollution Control (Construction Dust) Regulation, no unacceptable adverse air quality impacts on the identified representative ASRs are anticipated during the construction phase.

Gaseous Emissions from Diesel-powered Construction Equipment and Vehicles

3.6.11 The potential air quality impacts associated with the gaseous emissions from diesel-powered construction equipment are expected to be relatively low as only a small number of generators and vehicles are expected to be deployed on site. Requirements as stipulated in the Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation will be followed to control potential emissions from non-road mobile machinery. In addition, all construction plant is required to use ultra-low-sulphur diesel (ULSD) (defined as diesel fuel containing not more than 0.005% sulphur by weight) as stipulated in Environment, Transport and Works Bureau Technical Circular (ETWB-TC(W)) No. 19/2005 on Environmental Management on Construction Sites. With reference to DEVB TC(W) No. 13/2020, public works contracts will be required to observe the requirements of timely application of temporary electricity to minimize the use of diesel generators. Therefore, no adverse air quality impacts are expected from gaseous emissions.

Odour from Excavated Channel Bed Materials

3.6.12 Excavation of the nullah bed material will be required for the construction of the Project. Depending on the quality of the nullah bed material, the excavation and handling of nullah bed material may cause odour impacts during construction. Hydrogen sulphide (H₂S) is the key odour constituent of the excavated material. Excavation works should be conducted in the shortest time span possible. Programming of the works should be carried out to ensure that the time for such works can be minimised. If necessary, the contractors should also liaise with local resident to inform them of the duration of potential odour nuisance, and that efforts are made to minimise and mitigate such nuisance. Odorous excavated material should be placed as far away from ASRs as possible. Temporary stockpiles of odorous excavated material should be removed off-site as soon as practically possible within 24 hours to avoid odour nuisance arising. With the implementation of good site practice recommended in Section 3.8, unacceptable odour nuisance is not anticipated.

3.7 Evaluation of Impacts during Operation Phase

3.7.1 Potential odour may arise from the screened debris/materials collected as a result of the screening operation conducted at the inlet chamber of the pumping facilities. The screened debris/materials will be removed on demand basis to maintain the function of the pumping station as well as to preclude any potential odour impact during operation. Considered the separation of inlet screens and nearest ASR is over 80m, potential odour impact from screening operation during operation phase is not anticipated.

3.7.2 Maintenance would be necessary for the revitalised YLN to remove excessive silts, vegetation, debris and obstructions in order to maintain its hydraulic performance and structural integrity. Moderate siltation will generally be allowed to accumulate, and removal of excess silt would be carried out at locations where it would impede water flow. Such small-scale maintenance would require only light mechanical equipment such as a small loader and/or a small crane truck. Hand-held equipment will be used for vegetation removal. Therefore, unacceptable impacts from dust and gaseous emission are not expected to occur.

3.8 Mitigation Measures

Construction Phase

3.8.1 Relevant dust control measures stipulated in the Air Pollution Control (Construction Dust) Regulation, and good site practices will be incorporated as the Contract Specifications for implementation throughout the construction period. These include:

· The works area for site clearance and excavation should be sprayed with water before, during and after the operation so as to maintain the entire surface wet.

· Restricting heights from which materials are to be dropped, as far as practicable to reduce the fugitive dust arising from unloading/ loading.

· Immediately before leaving a construction site, all vehicles should be washed to remove any dusty materials from the bodies and wheels. However, all spraying of materials and surfaces should avoid excessive water usage.

· Where a vehicle leaving a construction site is carrying a load of dusty materials, the load should be covered entirely by clean impervious sheeting to ensure that the dusty materials will not leak from the vehicle.

· Erection of hoarding along the site boundary, where appropriate.

· Any stockpile of dusty materials should be covered entirely by impervious sheeting; and/or placed in an area sheltered on the top and three sides.

· All dusty materials should be sprayed with water immediately prior to any loading, unloading or transfer operation so as to maintain the dusty materials wet.

· Reduce the traffic induced dust dispersion and re-suspension, the travelling speed of vehicles within the site should be controlled.

· Regular maintenance of construction equipment deployed on-site should be conducted to prevent black smoke emission.

· At locations when ASR is located within short distance from the site boundary (about 5m), solid screen or barriers should be erected around dusty activities to minimise potential dust impact

· Connect construction plant and equipment to mains electricity supply and avoid use of diesel generators and diesel-powered equipment as far as practicable to minimize the emission impact from these machineries on nearby residents

3.8.2 Excavated nullah bed materials that are placed on trucks for disposal should be properly covered with tarpaulin sheets during transportation to minimise the release of any potential odour. The odorous excavated material should be placed as far away from the sensitive receivers as possible. Odorous channel bed material excavated during construction phase should be removed off-site as soon as practicable within 24 hours to avoid any odour nuisance.

Operation Phase

3.8.3 During operation phase, mitigation measures are considered necessary when materials generated from the maintenance works are found to be odorous, and the following measures should be implemented by DSD.

· Odorous materials should be placed in covered containers or properly covered with tarpaulin as far as possible;

· Temporarily store odorous material as far away from ASRs as possible;

· Odorous materials should be removed off-site as soon as practically possible within 24 hours to avoid any odour nuisance arising; and

· Regular inspection at inlet chamber of existing pumping facilities to prevent accumulation of debris/materials at the inlet screens causing odour nuisance.

3.9 Potential for Cumulative Impacts

3.9.1 The potential for cumulative air quality impact during the construction and operation phase of the Project has been checked against the following concurrent projects identified in Section 2:

· Yuen Long Town Nullah (YLTN) Improvement Works;

· Elevated Pedestrian Corridor (EPC) in Yuen Long Town Connecting with Long Ping Station;

· Housing Sites in Yuen Long South;

3.9.2 For YLTN improvement works, the construction period will overlap with that of the Project (Barrage Scheme) during 2022 to 2026. For the revitalisation works, no overlap of construction works is expected as the DWFI for the YLTN improvement works will need to be completed before revitalisation works can commence. According to its EIA report, dust impact is anticipated during construction but it would be minimal if dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation is implemented.

3.9.3 For EPC in Yuen Long Town Connecting with Long Ping Station, the construction period will overlap with that of the Project during 2022 to 2026. The EPC works is over 1 km from the Barrage Scheme, cumulative impact is not envisaged. Only the revitalisation works of YLN may overlap with the EPC project. According to its EIA report, no adverse dust, gaseous emissions and odour impacts are anticipated during construction with proper implementation of mitigation measures.

3.9.4 For Housing Sites in Yuen Long South, the Project (Barrage Scheme) is located well over 2 km from the project. Cumulative impact is not expected. Only the proposed revitalisation of YLN and modification of parapet wall at SCR may potentially overlap with that of this housing development project. According to its EIA report, dust impact would arise from the construction activities such as soil excavation, site formation and wind erosion. No adverse residual air quality impact is anticipated with implementation of mitigation measures during construction.

3.9.5 In consideration of both the Project and concurrent projects will not generate significant dust and odour impact, unacceptable adverse cumulative dust and odour impact is not anticipated.

3.9.6 Operation of the Project will only involve limited scope of maintenance works to remove excessive silts, vegetation, debris and obstructions. As such, unacceptable cumulative impact to air quality is not anticipated during concurrent operation with other projects.

3.10 Residual Impacts

3.10.1 No unacceptable residual impact is anticipated from the construction and operation of the Project with the implementation of the recommended mitigation measures and good site practices.

3.11 Monitoring and Audit Requirements

3.11.1 Weekly site inspections during construction stage will be carried out in order to confirm that the mitigation and control measures are properly implemented and are working effectively to ensure construction dust, gaseous/odour emissions will be reduced/controlled to acceptable level.

3.11.2 No adverse impact would be generated during the operation phase of this Project. Therefore, no monitoring is required during operational phase.

3.12 Conclusion

3.12.1 The potential sources of air quality impacts associated with the construction and operation of the Project have been identified and the potential impacts were evaluated.

3.12.2 Potential impacts of dust, gaseous and odour emissions from construction activities have been considered. With implementation of standard construction practices and mitigation measures, no unacceptable impact on ASRs is anticipated. As such no unacceptable residual air quality impacts are envisaged from the construction and operation of the Project.

3.12.3 Cumulative air quality impacts associated with concurrent projects within the Study Area have been considered, no unacceptable impacts are anticipated.

3.12.4 In order to ensure and demonstrate that mitigation measures are properly implemented during the construction stage for reducing the air quality impacts from the Project, weekly site inspections and audits will be conducted as part of the EM&A Programme of the Project.