4 Air Quality Impact

4.1 Environmental Legislation, Plans, Standards, and Guidelines

4.1.1 The relevant legislations, standards and guidelines applicable to the present study for the assessment of air quality impacts include:

Ÿ Air Pollution Control (Amendment) Ordinance 2013 (APCO) (Cap 311) - this provides the power for controlling air pollutants from a variety of stationary and mobile sources and encompasses a number of Air Quality Objectives (AQOs);

Ÿ Air Pollution Control (Construction Dust) Regulation;

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

Ÿ Environmental Impact Assessment Ordinance (EIAO) (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process (TM-EIAO), Annex 4 and Annex 12.

Air Quality Objectives

4.1.2 The prevailing AQO, as tabulated in Table 4.1 has been in forced since 1 January 2014.

Table 4.1 Hong Kong Air Quality Objectives

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

Notes:

(1) Measured at 293 K and 101.325 kPa.

(2) The number of exceedances allowed per year.

(3) Arithmetic mean.

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

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

TM-EIAO

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

4.1.4 Guidelines for conducting air quality assessment are stipulated in Annex 12 of EIAO-TM, including the determination of air sensitive receivers (ASRs), the assessment methodology, baseline study and impact prediction and assessment.

Air Pollution Control (Construction Dust) Regulation

4.1.5 With reference to the Air Pollution Control (Construction Dust) Regulation, it specifies processes that require special dust control. The contractor is required to inform EPD and adopt proper dust suppression measures while carrying out “Notifiable Works” (which requires prior notification by the regulation) and “Regulatory Works” to meet the requirements as defined under the regulation.

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

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

Environmental Guidelines

4.1.7 There are some guidelines which detail the overall air quality assessment approaches:

Ÿ Guidelines on Assessing the 'Total' Air Quality Impacts (Revised) (ver Mar 2013);

Ÿ Guidelines on Choice of Models and Model Parameters (ver Mar 2000).

Ÿ Guidelines on the Use of Alternative Computer Models in Air Quality Assessment (Revised) (ver Mar 2013); and

Ÿ Guidelines on the Estimation of PM2.5 for Air Quality Assessment in Hong Kong.

4.2 Description of the Environment and Future Trends

Existing Emission Sources

4.2.1 Within the 500m study area from the boundary of the Project site, there is no chimney identified. The major emission source within the study area is vehicular traffic on the major roads including Clear Water Bay Road and On Sau Road.

Prevailing Air Quality

4.2.2 The baseline condition of the study area is made reference to the 2010 - 2014 average monitoring data recorded at Kwun Tong Air Quality Monitoring Station (AQMS) which is the nearest station to the Project site. The monitoring results are summarized in Table 4.2.

Table 4.2 Prevailing Air Pollutant Concentrations Recorded at EPD’s Kwun Tong AQMS

Pollutant	Averaging Time	AQO^[1]	Year	Year ^[2] ^[5]					5-year mean ^[3]
				2010	2011	2012	2013	2014
Fine Suspended Particulates (PM 2.5)	24-hr	75 (9)	Max.	N/M	83	78	122	98	-
			10th Max.	N/M	64	63	87	68	-
			No. of Exceedance(s)	-	3	23	19	7	-
	Annual	35	-	N/M	31	28	33	31	-
Respirable Suspended Particulates (PM10)	24-hr	100 (9)	Max.	681^[4]	117	169	171	140	149 ^[8]
			10th Max.	97	97	95	123	110	104
			No. of Exceedance(s)	9	6	8	29	13	-
	Annual	50	-	47	49	43	52	51	48
Sulphur Dioxide (SO2) ^[6]	10-min	500 (3)	Max.	N/M	N/M	N/M	N/M	147 ^[7]	-
			4th Max.	N/M	N/M	N/M	N/M	125 ^[7]	-
	24-hr	125 (3)	Max.	34	42	53	54	65	50
			4th Max.	29	31	37	35	38	34
			No. of Exceedance(s)	-	-	-	-	-	-
Nitrogen Dioxide (NO2)	1-hr	200 (18)	Max	242	285	398	339	329	319
			19th Max.	190	241	260	226	217	227
			No. of Exceedance(s)	9	41	78	49	28	-
	Annual	40	-	59	63	59	59	54	59
Carbon Monoxide (CO)	1-hr	30,000	-	N/M	N/M	N/M	N/M	N/M	-
	8-hr	10,000	-	N/M	N/M	N/M	N/M	N/M	-
Ozone (O3)	8-hr	160 (9)	Max.	132	146	155	182	207	164
			10th Max.	100	113	120	127	133	119
			No. of Exceedance(s)	-	-	-	1	2	-
Note: [1] Values in ( ) mean the number of exceedances allowed per year.
[2] Bolded values mean exceedance of the AQOs.
[3] The 5-year mean is the arithmetic average.
[4] The value was recorded during a dust plume originated from northern part of China in March 2010 which was an abnormal event.
[5] N/M – Not Measured.
[6] Monitoring data for the AQO of 10-minute SO2 on or before Year 2013 is currently not publicly available. [7] Extracted from EPD’s Air Quality in Hong Kong 2014, Statistical Summary, http://www.aqhi.gov.hk/api_history/english/report/files/AQR2014%20summary_en.pdf [8] The mean for 2011-2014 and the exceptional high record aue to an abnormal event in 2010 is not included.

4.2.3 There was no obvious trend in the highest 1-hour, 24-hour and annual NO₂ concentrations. The highest 1-hour NO₂ concentrations ranged from 242 μg/m³ in 2010 to 398 μg/m³ in 2012. The annual NO₂ concentration remained relatively steady in the range of 54 to 63 μg/m³. Exceedances of 1-hour and annual NO₂ concentration of AQOs were recorded.

4.2.4 For RSP concentrations in Kwun Tong area, the highest 24-hour concentration of 681 μg/m³ was recorded in 2010. Nevertheless, the exceedance was due to the dust plume originated from the northern part of China in March 2010, which is an abnormal event. Excluding this year, maximum 24-hour RSP concentrations ranged from 117 μg/m³ to 171 μg/m³. Exceedances of 24-hour RSP concentrations of AQO were recorded in 2013 and 2014. For annual RSP concentration, it remained steady in the range of 43 to 52 μg/m³, and exceedance of the AQO was recorded in 2013 and 2014.

4.2.5 The high RSP and NO₂ levels were probably attributable to regional air quality problems within the Pearl River Delta Region and certain degrees of industrial/commercial and vehicular emission contribution at Kwun Tong District. In terms of SO₂, the concentrations were well below AQOs which would be due to banning of high sulphur fuel in Hong Kong.

4.2.6 In terms of FSP, EPD has recently commenced the regular monitoring since April 2011 at Kwun Tong Monitoring Station, and thus, there is in-sufficient data to establish the 5-year averaged result.

Future Background Air Quality

4.2.7 As a general reference, the future prevailing background concentrations can be made reference to the EPD’s PATH modelling results for Year 2015/2020. The PATH model is a regional air quality model developed by EPD to simulate air quality over Hong Kong against the Pearl River Delta (PRD) as background. PATH is set up on a three-dimensional grid system with horizontal nesting. As the entire 500m study area of the Project falls within the grid cell (33,29), results of the PATH Model at grid cell (33,29) at Year 2015/2020 are presented in Table 4.3 as a reference to future prevailing background concentrations of the Project.

Table 4.3 Future Air Pollutant Concentrations (at Year 2015 and 2020) from PATH Model Grid Cell (33,29)

Pollutant	Averaging Time	AQO^[1]		PATH Grid Cell ^[2] ^[3]
				(33,29)
			Year	2015	2020
Fine Suspended Particulates (PM 2.5) ^[4]	24-hr	75 (9)	Max.	89	85
			10th Max.	58	56
			No. of Exceedance(s)	1	1
	Annual	35	-	29	29
Respirable Suspended Particulates (PM10)	24-hr	100 (9)	Max.	118	114
			10th Max.	77	75
			No. of Exceedance(s)	1	1
	Annual	50	-	41	40
Sulphur Dioxide (SO2)	10-min	500 (3)	Max.	N/A	N/A
				N/A	N/A
	24-hr	125 (3)	Max.	24	24
			4th Max.	20	20
			No. of Exceedance(s)	N/A	N/A
Nitrogen Dioxide (NO2)	1-hr	200 (18)	Max	278	251
			19th Max.	153	136
			No. of Exceedance(s)	7	3
	Annual	40	-	22	18
Carbon Monoxide (CO)	1-hr	30,000	-	1,306	1,296
	8-hr	10,000	-	940	904
Ozone	8-hr	160 (9)	Max.	167	166
			10th Max.	116	119
			No. of Exceedance(s)	1	1
Note: [1] Values in ( ) mean the number of exceedances allowed per year.
[2] Bolded values mean exceedance of the AQOs. [3] N/A – Not Available.

4.3 Study Area and Air Sensitive Receivers

4.3.1 The study area for the air quality assessment is defined by a distance of 500m from the Project boundary. The study area contains a mixture of existing residential buildings, planned residential buildings, schools and commercial premises. Representative ASRs located in the vicinity of the 500m from the Project boundary are identified for assessment.

4.3.2 Planned/committed ASRs are identified by making reference to the latest Outline Zoning Plans (OZP), Layout Plans and other published plans in vicinity of the development, including:

Ÿ Ngau Tau Kok and Kowloon Bay Outline Zoning Plan (No. S/K13/28) dated April 2014;

Ÿ Kwun Tong South Outline Zoning Plan (No. S/K14S/20) dated July 2015;

Ÿ Kwun Tong North Outline Zoning Plan (No. S/K14N/14) dated June 2015;

Ÿ Tseng Lan Shue Outline Zoning Plan (No. S/SK-TLS/8) dated March 2006; and

Ÿ Tseung Kwan O Outline Zoning Plan (No. S/TKO/21) dated February 2015.

4.3.3 Based on the EIA Study Brief (EIA Study Brief No. ESB-269/2014), the sensitive receivers shall include, but not limited to, those at Siu To Yuen Village, Lung Wo Tsuen, the planned public housing development along Anderson Road and the planned residential development and educational use at the Anderson Road Quarry (ARQ) Development. Considered that only the construction dust impact will be an issue, only representative ASRs during construction phase of the Project are selected for assessment.

4.3.4 With reference to the approved Schedule 3 EIA report for Development of Anderson Road Quarry (Register No.: AEIAR-183/2014), the intake year for the nearby planned ASRs at the ARQ Development would be in 2 phases (1^st Phase at Year 2022 and 2^nd Phase Year 2026). Whereas, construction of rock cavern would be completed by 2020 in accordance with the latest engineering information, overlapping of the cavern construction before occupation of the planned ASRs would not be anticipated. As such, the planned ASRs at the ARQ Development are not included for the construction dust evaluation. The locations of the study area and representative ASRs are shown in Figure 4.1 and the description of the representative ASRs are presented in Table 4.4.

Table 4.4 Description of Representative Air Sensitive Receivers

ASR ID	Description	Land Uses [1]	Max Height Above Ground (approx.) (m)	Distance from Rock Cavern Works Boundary (approx.) (m)
ACYC-01	Village House Near Lung Wo Tsuen	R	3	200
ADET-01	Denon Terrace	R	9	440
AHKG-01	Hong Kong LPG (Holding) Ltd	C	10	420
ALEP-02	Leighton Pavillion	R	15	500
ALWT-01	Lung Wo Tsuen	R	6	320
ALWT-02	Lung Wo Tsuen	R	6	300
ALWT-03	Lung Wo Tsuen	R	3	220
AMKT-01	Man King Terrace	R	9	480
ASTY-01	Siu To Yuen Village	R	9	360
ATSV-01	Clear Water Bay Road Tan Shan Village	R	9	440
AVDT-01	Clear Water Bay Village House	R	3	400
AVDT-02	Clear Water Bay Village House	R	3	380
DARA-01	Block 1, DAR Site A	R	85.2	460
DARA-03	Block 1, DAR Site A	R	85.2	500
DARA-04	Block 1, DAR Site A	R	85.2	480
DARA-05	Block 2, DAR Site A	R	93.4	400
DARA-06	Block 2, DAR Site A	R	93.4	440
DARA-07	Planned School, DAR Site A	S	32	380
DARA-08	Planned School, DAR Site A	S	32	380
DARA-09	Planned School, DAR Site A	S	32	380
DARA-10	Planned School, DAR Site A	S	32	380
DARA-11	Planned School, DAR Site A	S	32	420
DARA-12	Planned School, DAR Site A	S	32	440
DARA-13	Planned School, DAR Site A	S	32	440
DARA-14	Planned School, DAR Site A	S	32	440
DARB-01	Block 3, DAR Site B	R	87.9	460
DARB-02	Basketball Court, DAR Site B	O	1.5	480
DARB-10	Block 9, DAR Site B	R	96.2	500
DARB-11	Block 9, DAR Site B	R	96.2	480
DARB-12	Block 9, DAR Site B	R	96.2	460
DARB-13	Block 8, DAR Site B	R	96.2	400
DARB-14	Block 8, DAR Site B	R	96.2	440
DARB-15	Block 7, DAR Site B	R	87.9	460
DARB-16	Block 7, DAR Site B	R	87.9	460
DARC-02	Block 10, DAR Site C1	R	76.9	500
DARC-09	Planned Clinic and Community Centre, DAR Site C2	H / GIC	27.6	500
DARC-10	Planned Clinic and Community Centre, DAR Site C2	H / GIC	27.6	480
DARC-11	Planned Clinic and Community Centre, DAR Site C2	H / GIC	27.6	480
DARC-12	Planned Clinic and Community Centre, DAR Site C2	H / GIC	27.6	460
DARC-13	Planned Clinic and Community Centre, DAR Site C2	H / GIC	27.6	480
DARC-14	Planned Clinic and Community Centre, DAR Site C2	H / GIC	27.6	480
DARC-15	Planned Clinic and Community Centre, DAR Site C2	H / GIC	27.6	500
Note:
[1] R: Residential; GIC: Government, Institution and Community; H: Clinic / Home for the aged / Hospital; S: School; O: Open Area/Playground; C: Commercial.

4.3.5 Several elevations are chosen for the assessment: 1.5m above local ground level (which is the average height of the human breathing zone), 5.0m and 10.0m.

4.4 Identification of Environmental Impacts (Construction Phase)

Emissions from Construction Activities

4.4.1 The construction activities for the Project would be commenced in early 2018 and completed in 2020 and the construction period would be around 24 months. The major construction activities are summarized as below:

Ÿ Mobilization and site clearance;

Ÿ Portal slopes stabilisation works;

Ÿ Cavern excavation and temporary installation;

Ÿ Permanent cavern (and adits) lining constrction; and

Ÿ Soft landscaping works

4.4.2 During this construction period, the following concurrent projects with construction works in the vicinity have been reviewed in terms of cumulative impacts and the assumptions on concurrent works are listed as follows:

Ÿ Site formation and infrastructure works of ARQ Site Development and construction of Pedestrian Connectivity – reference is made in accordance with the approved Schedule 3 EIA report, and the cumulative impact (including construction traffic) of ARQ Works under mitigated scenario in 2017 (worst case year) is taken into account in the cumulative impact assessment;

Ÿ Road improvement works (RIW) at junction of Clear Water Bay Road and On Sau Road and junction of New Clear Water Bay Road and Shun Lee Tsuen Road - The construction for the RIW will be started in end 2016 and for completion in mid 2020. It would have about 2 years overlapping works. The RIW is a Schedule 2 EIA project, and the potential impacts are assessed in a separate EIA study “Development of Anderson Road Quarry Site – Road Improvement Works”. The cumulative impact (including construction traffic) of the RIW under mitigated sceanro is taken into account in the cumulative impact assessment.

Vehicular Emission from Open Road

4.4.3 Based on 2013 Hong Kong Emission Inventory Report published by EPD, one of the major sources for Respirable Suspended Particulates (RSP) includes road transport. Thus, particulate matter generated from road traffic within 500m study area would also have cumulative air quality impact on nearby ASRs during construction phase. The associated cumulative air quality impacts (i.e. RSP and FSP) due to the vehicular emissions are also assessed.

Industrial/Portal Emission

4.4.4 There is neither portal emission nor industrial emission sources located within 500m study area, and thus cumulative impact is not expected.

4.5 Assessment Methodology (Construction Phase)

Identification of Key/Representative Air Pollutants of Emissions

4.5.1 The major construction activities as mentioned in Section 4.4.1 would induce particulates emission impact. SO₂, NO₂ and smoke emitted from diesel-powered equipment may also be the air pollutants from construction activities. However, the number of such plant required on-site (land based) will be limited and under normal operation. Moreover, with the Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation in effective from 1 June 2015, the Contractor is required to ensure the adopted equipment under the Project could meet the prescribed emission standards. Provided that the equipment will be under proper maintenance, significant dark smoke emissions and gaseous emissions are expected to be minor. Thus, the principal source of air pollution during the construction phase will be dust from the construction activities. Quantitative assessment of TSP, RSP and FSP emission impacts is conducted for assessing construction phase air quality impact.

4.5.2 Traffic emission from vehicular traffic is identified as dominant air pollution source in the study area, therefore cumulative RSP/FSP from vehicles are included in the air quality impact assessment.

Determination of Assessment Year

4.5.3 The construction period of the Project is from 2018 to 2020. Sensitivity analysis of construction dust emission burden within works boundary is conducted in order to identify the worst case assessment year (with the highest emission burden) among these three years. TSP which is the key pollutant in the construction phase is adopted for calculation based on the dust emission factors from USEPA Compilation of Air Pollution Emission Factors (AP-42), active working area and construction programme.

4.5.4 The total construction works area is about 2,500 m². The active works area and TSP emission burden for various construction years are detailed in Appendix 4.1, and summarised in the Table 4.5.

Table 4.5 Establishment of Worst-year TSP Emission Burden

Year	Max Active Works Area (m^2)	Annual TSP Emission (tonnes/year)
2018	2,500 (for 12 months)	8.3 ^[1]
2019	2,500 (for 9 months)	6.9
2020	No major physical works	0

Note:

[1] The Worst-case year is identified as the year with the maximum emision TSP emission burden.

4.5.5 Based on the initial estimation, it is identified that Year 2018 is the worst-case year for the evaluation on construction dust cumulative impacts. The cumulative sources in Year 2018 are listed in Table 4.6.

Table 4.6 Cumulative Dust Emission Sources in Year 2018

Emission	Sources
Construction Dust (FDM)	Included construction dust sources of ARQ Development on Road Improvement Works at Clear Water Bay Road / On Sau Road & New Clear Water Bay Road / Shun Lee Tsuen Road + Dust Sources from ARQ development and Pedestrian Connectivity at worst-case year (i.e Year 2017) under the approved Schedule 3 EIA report (Register No.: AEIAR-183/2014)
Open Road Emissions (CALINE4)	Open Road Emissions within 500m study area
Industrial Emissions/ Portal Emission (ISCST3)	Neither portal emission nor industrial chimneys within 500m study area

Emission Inventory

4.5.6 Predicted dust emissions are based on emission factors from USEPA Compilation of Air Pollution Emission Factors (AP-42), 5th Edition. The major dusty construction activities for the Project to be concerned and considered in the modelling assessment include:

Ÿ Site clearance

Excavation and material handlings within the construction site modelled as heavy construction activities

Wind erosion of open active site

Ÿ Portal slopes stabilisation works

Excavation and material handlings within the construction site modelled as heavy construction activities

Wind erosion of open active site

Ÿ Cavern excavation and construction

Excavation and material handlings within the construction site modelled as heavy construction activities

Wind erosion of open active site

4.5.7 Due to the size of the work sites and the need for orderly sequencing of construction activities, active construction activities will occur in different locations of the work site at different period of time. Therefore, it is not possible to pinpoint the exact locations of the individual dust emission sources over the entire work site in any short-term period. As a conservative approach, the assessment for 1-hour and 24-hour average air pollutants would be based on 100% active area.

4.5.8 In terms of the annual average prediction, the engineer has estimated that a maximum percentage of active area for each year (see Table 4.7). Given that the highest % active working area is observed to be 100% in Year 2018, it is suggested that a 100% of 1-hour/24-hour assessment emission rates are adopted for the long-term annual predictions for RSP/FSP.

Table 4.7 Percentage of Active Works Area for Annual Average Evaluation

Site	Year	Active Works Area (m2)	% Active Working Area (Annual)
Cavern (Total Working Area of 2,500m^2)	2018	2,500	100 (with the activity period of 12 months)
	2019	2,500	100 (with the activity period of 9 months)
	2020	0	0
Max % Active Working Area for Cavern Site			100%

4.5.9 RSP and FSP emission factors for heavy construction and wind erosion are estimated based on the particle size distribution stated in Section 13.2.4.3 of USEPA. According to the particle size distribution, RSP (aerodynamic diameter ≦ 10 μm) and FSP (aerodynamic diameter ≦2.5 μm) constitute 47% and 7% of the TSP (aerodynamic diameter ≦ 30 μm), respectively. Hence, conversion factors of 0.47 and 0.07 are adopted to estimate the RSP and FSP emissions from TSP emission, respectively. The particle size distribution is tabulated in Table 4.8

Table 4.8 Particle Size Distribution of Construction Dust

AQO Parameters	Particle Size (µm)	Particle Size Multiplier (k) in AP-42	Conversion Factor (Based on TSP emission)
FSP	< 2.5	0.053	= FSP / TSP = 0.053 / 0.74 = 0.07 = 7%
RSP	< 10	0.35	= RSP / TSP = 0.35 / 0.74 = 0.47 = 47%
TSP	<30	0.74	-

4.5.10 The dust emission factors of the above construction activities for the Project are summarized in Table 4.9 and detailed calculation is presented in Appendix 4.2. The dust emission factors for other concurrent projects, ARQ works and RIW works, are presented in Appendix 4.2. The locations of the dust emission sources of the Project and concurrent projects are also shown in Appendix 4.2.

Table 4.9 Emission Factors for Dusty Construction Activities (Unmitigated Scenario)

Emission Source	Activity	Pollutant	Emission Factor	Remarks
Site Clearance, Portal Slopes Stabilization Works, Cavern Excavation and Construction	Heavy Construction Activities	TSP	E=2.69 Mg/hectare/month of activity	AP-42, Section 13.2.3
		RSP	E=1.27 Mg/hectare/month of activity	Referenced to USEPA, AP-42 Compilation of Air Pollution Emission Factors (AP-42), Section 13.2.4.3, 1^st Table, Conversion Factor for RSP based on TSP emission factors is estimated to be 0.47 (refer to Table 4.8). Hence, emission factor 2.69 x 0.47 = 1.27 Mg/hectare/month of activity is adopted.
		FSP	E=0.193 Mg/hectare/month of activity	Referenced to USEPA, AP-42 Compilation of Air Pollution Emission Factors (AP-42), Section 13.2.4.3, 1^st Table, Conversion Factor for FSP based on TSP emission factors is estimated to be 0.07 (refer to Table 4.8). Hence, emission factor 2.69 x 0.07 = 0.193 Mg/hectare/month of activity is adopted.
	Wind Erosion	TSP	E=0.85 Mg/hectare/year	AP-42, Section 11.9.4
		RSP	E=0.402 Mg/hectare/year	Referenced to USEPA, AP-42 Compilation of Air Pollution Emission Factors (AP-42), Section 13.2.4.3, 1^st Table, Conversion Factor for RSP based on TSP emission factors is estimated to be 0.47 (refer to Table 4.8). Hence, emission factor 0.85 x 0.47 = 0.402 Mg/hectare/year of activity is adopted.
		FSP	E=0.0609 Mg/hectare/year	Referenced to USEPA, AP-42 Compilation of Air Pollution Emission Factors (AP-42), Section 13.2.4.3, 1^st Table, Conversion Factor for FSP based on TSP emission factors is estimated to be 0.07 (refer to Table 4.8). Hence, emission factor 0.85 x 0.07 = 0.0609 Mg/hectare/year of activity is adopted.

4.5.11 For the prediction of the 10^th highest daily average and annual average RSP and FSP concentrations, 12-hour (07:00-19:00) per normal working day is assumed for the construction period in the assessment. Since no construction activities would occur on Sundays and public holidays, only wind erosion would be assumed for these days as well as for other non-working hours (19:00 to 07:00 of the following day) on normal working days.

Dispersion Modelling & Concentration Calculation

4.5.12 The hourly meteorological data including wind speed, wind direction, and air temperature from the relevant grids from the MM5 Meteorological data (same basis for PATH model), are employed for the model run. The Pasquill stability class data are modelled separately using PC-Ramet model.

4.5.13 According to United States Environmental Protection Agency (USEPA) AP-42^[1], construction dust particles may be grouped into five particle size classes. Their size ranges are 1.25 mm, 3.75 mm, 7.5 mm, 12.5 mm, 22.5 mm, and the percentage of particles in each class was estimated to be 7%, 20%, 20%, 18% and 35%, respectively.

4.5.14 A Fugitive Dust Model (FDM) is used to assess the potential dust impact from construction activities. A height of 1.5m (the breathing level of human), 5m and 10m above ground would be adopted for the construction dust impact assessment. Air contour is prepared for the worst-hit level.

4.5.15 Vehicular emissions from the major roads in the vicinity of the study area are also assessed. EmFAC-HK v2.6 for the worst-case assessment year (i.e. Year 2018) is used to calculate the vehicular tailpipe emission in lieu of the traditional fleet average emission factors. CALINE4 developed by the California Department of Transport is used to assess vehicular emissions impact from road network within the study area.

4.5.16 PATH model is used to quantify the background air quality during the construction phase of the Project. The emission sources including those in Pearl River Delta Economic Zone, roads, marine, airport, power plants and industries within Hong Kong are all considered in the PATH model. As the assessment year is Year 2018, Year 2015 hourly data of background concentration predicted by the PATH model provided by EPD are adopted as background concentration in this study.

4.5.17 It is understood that only hourly RSP concentrations are available from PATH model. According to EPD’s Guideline on the Estimation of PM2.5 for Air Quality Assessment in Hong Kong, the conservative correction factors of 0.71 and 0.75 are applied on the annual and daily RSP concentration to generate annual and daily FSP concentration, respectively. For hourly background TSP concentration, it is considered reasonable to adopt hourly RSP concentrations from PATH as the ambient TSP background concentrations, since the particulate of sizes larger than 10 µm generated from far-field dust sources would have been largely settled before reaching the ASRs, which in turn most of the particulates from far-field sources affecting ASRs will likely be those less than or equal to 10 µm (i.e. RSP). For ease of reference, the substitution table is listed Table 4.10.

Table 4.10 Background Substitution from PATH model 2015

Parameter	Background Concentration in PATH
1-hour TSP	RSP
24-hour RSP	RSP
Annual RSP	RSP
24-hour FSP	0.75 x RSP
Annual FSP	0.71 x RSP

4.6 Prediction and Evaluation of Environmental Impacts (Construction Phase)

4.6.1 The cumulative construction dust impact within 500m study area is evaluated. The unmitigated results indicate that the predicted 1-hour average TSP, 24-hour average RSP and FSP, annual average RSP and FSP concentrations at the all representative ASRs would comply with EIAO-TM and AQOs. For 24-hour average RSP, marginal compliance to AQO would be predicted at DARC-11 (Planned Clinic and Community Centre, DAR Site C2). The detailed unmitigated results are presented in Appendices 4.3, 4.4 and 4.5.

4.6.2 In order to alleviate the dust impact, dust suppression measures are recommended to alleviate the impact by applying hourly watering with intensity of 0.152L/m² (tentatively) on the active construction work area of the Project so as to achieve a dust removal efficiency of 87.5%. Appendix 4.6 presents the calculation of the dust removal efficiency.

4.6.3 Under the mitigated scenario, the 24-hour average RSP concentrations at all ASRs would comply with the AQOs. It is noted that the contribution from the Project itself in the cumulative dust impact is less than 5% for TSP and 1% for RSP and FSP. The mitigated results for TSP, RSP and FSP are listed in Appendices 4.3, 4.4 and 4.5 respectively.

4.6.4 The contour plots of 1-hour TSP, 24-hour average and annual average RSP and FSP at the worst hit level, 1.5m above ground, are shown in Figures 4.2 – 4.11. Referring to the contour plots, there is no ASRs found within the exceedance zone.

4.7 Recommended Mitigation Measures (Construction Phase)

4.7.1 To minimize the dust impact to the surrounding ASRs, dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation should be incorporated to control dust emission from the site. Major control measures relevant to this Project are listed below, and they are recommended to be included in relevant contract documents.

Ÿ Any excavated or stockpile of dusty material should be covered entirely by impervious sheeting or sprayed with water to maintain the entire surface wet and then removed or backfilled or reinstated where practicable within 24 hours of the excavation or unloading;

Ÿ Any dusty material remaining after a stockpile is removed should be wetted with water and cleared from the surface of roads;

Ÿ A stockpile of dusty material should not extend beyond the pedestrian barriers, fencing or traffic cones;

Ÿ The load of dusty materials on a vehicles leaving a construction site should be covered entirely by impervious sheeting to ensure that the dusty materials do not leak form the vehicle;

Ÿ Where practicable, vehicles washing facilities including a high pressure water jet should be provided at every discernible or designated vehicle exit point. The area where vehicle washing takes place and the road section between the washing facilities and the exit point should be paved with concrete, bituminous materials or hardcores;

Ÿ When there are open excavation and reinstatement works, hoarding of not less than 2.4m high should be provided as far as practicable along the site boundary with provision for public crossing. Good site practice shall also be adopted by the contractor to ensure the conditions of the hoardings are properly maintained throughout the construction period;

Ÿ The portion of any road leading only to construction site that is within 30m of a vehicle entrance or exit should be kept clear of dusty materials;

Ÿ Surfaces where any pneumatic or power-driven drilling, cutting, polishing or other mechanical breaking operation takes place should be sprayed with water or a dust suppression chemical continuously;

Ÿ Any area that involves demolition activities should be sprayed with water or a dust suppression chemical immediately prior to, during and immediately after the activities so as to maintain the entire surface wet;

Ÿ Where a scaffolding is erected around the perimeter of a building under construction, effective dust screens, sheeting or netting should be provided to enclose the scaffolding from the ground floor level of the building, or a canopy should be provided from the first floor level up to the highest level of the scaffolding;

Ÿ Any skip hoist for material transport should be totally enclosed by impervious sheeting;

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

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

Ÿ Exposed earth should be properly treated by compaction, turfing, hydroseeding, vegetation planting or sealing with latex, vinyl, bitumen, shortcrete or other suitable surface stabiliser within six months after the last construction activity on the construction site or part of the construction site where the exposed earth lies.

4.8 Evaluation of Residual Environmental Impacts (Construction Phase)

4.8.1 No residual impact is anticipated.

4.9 Identification of Environmental Impacts (Operational Phase)

4.9.1 Based on the latest design information, the Project (under the EIA) covers one cavern (at +200mPD, with dimension of about 25m(W) x 11m(H) and 35m(D)) only which will be used for exhibition area/resource centre at Quarry Park. In view of the nature of exhibition area/resource centre, there would not be any combustion equipment in the proposed cavern, therefore, the proposed cavern itself is not an air emission source and no air pollutant would be emitted from the ventilation shaft(s). Based on the preliminary traffic forecast, the induced daily traffic (2-way) would be in the order of 50 vehicles/day induced on the local distributor road and the traffic is mainly attributed to the maintenance activities (wastes collection and daily necessities delivery) and work-related transport (e.g. exhibition materials transport).  Comparing to the traffic flows of nearby local distributors (i.e. Road L1 & L2 as depicted in Appendix 4.7) which have around 4000 vehicles/day (2-way) [2] per road in year 2026 (with ARQ phase 2 intake), the induced traffic volume is small and hence it would not cause adverse air quality to the surroundings.

4.9.2 In operational phase, the proposed exhibition area/resource centre in cavern is considered as an ASR. Reference has been made to the approved Schedule 3 EIA Report for Anderson Road Quarry Development (Register No.: AEIAR-183/2014) for the predicted air quality condition in the vicinity of the cavern development during the operational phase of ARQ Site. Representative air pollutants including NO₂, RSP and FSP at the assessment points on the Planned Quarry Park with the closest distance to the cavern development, namely, ARQP-34, ARQP-37 and ARQP-40, are extracted and presented in Table 4.11. Their locations are depicted in Figure 4.12. The predicted results are at the worst-case year (i.e. Year 2026) of the operational phase of ARQ Site, in which Year 2026 was the predicted year with the highest road traffic emission strength within 15 years upon full population intake of the ARQ Site, has considered all emission sources within 500m study of the ARQ Site in full development for reflecting a reasonably worst-case scenario under normal operating conditions for the proposed exhibition area/resource centre in cavern. Therefore, the predicted results at Year 2026 are considered representative and applicable in this assessment.

Table 4.11 Predicted Air Quality Condition in the Vicinity of the Cavern Development (Operational Phase)

Representative Pollutant	Ave. Time	AQO ^[1]	Cumulative Concentration (μg/m^3) ^[2]
			Assessment Point ID	ARQP-34	ARQP-37	ARQP-40
NO2	1-hour	200 (18)	Max.	255	254	255
			19^th Max.	140	139	140
			# ^[3]	4	4	4
	Annual	40	-	21	21	21
RSP	24-hour	100 (9)	Max.	114	114	114
			# ^[3]	1	1	1
	Annual	50	-	40	40	40
FSP	24-hour	75 (9)	Max.	85	85	85
			# ^[3]	1	1	1
	Annual	35	-	29	29	29

Note:

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

[2] Cumulative Concentration is extracted from the Appendix 4.14 of the approved Schedule 3 EIA Report for Anderson Road Quarry Development (Register No.: AEIAR-183/2014). The concentrations are predicted at the 1.5m above ground.

[3] # stands for number of exceendances against AQO.

4.9.3 Based on the predicted assessment results presented in Table 4.11, representative air pollutants including NO₂, RSP and FSP at these assessment points would be well complied to the AQOs. The contour plots at the worst-hit levels (i.e. 1.5m and 5m above ground) at Year 2026 from the approved Schedule 3 EIA Report for Anderson Road Quarry Development (Register No.: AEIAR-183/2014) which attached in Appendix 4.8 also demonstrate that the predicted representative air pollutants concentration including NO₂, RSP and FSP on areas nearby the cavern development would also comply with the AQOs.

4.9.4 Detailed design information for cavern, such as location of fresh air intake, is not available during the course of this EIA study. Provided that the predicted representative air pollutants concentration including NO₂, RSP and FSP on areas nearby the cavern development are well complied to the AQOs from the approved Schedule 3 EIA Report for Anderson Road Quarry Development (Register No.: AEIAR-183/2014) and the location of fresh air intake for the cavern will be properly located with sufficient buffer distance to emission sources, adverse air quality impact is not anticipated to the proposed exhibition area/resource centre in cavern.

4.10 Evaluation of Residual Environmental Impacts (Operational Phase)

4.10.1 No residual impact would be anticipated during operational phase.

4.11 EM&A Requirements

4.11.1 Given the mitigated TSP, RSP and FSP levels (with implementation of recommended mitigation measures) would comply with the relevant air quality criteria/AQOs and minimal dust impact will be anticipated from the Project works itself, environmental monitoring for the Project is considered unnecessary. Nevertheless, regular audit during construction phase is recommended to ensure the effectiveness of implementation of proposed mitigation measures. Details of the audit requirements are provided in the EM&A manual.

4.11.2 No adverse impact would be generated during the operation phase of this Project. Therefore, the EM&A works related to air quality for the operational phase is considered not necessary.

4.12 Conclusion

Construction Phase

4.12.1 Fugitive dust impact assessment for hourly TSP, daily RSP/FSP and annual RSP/FSP with the assumption of 100% active area at all times, has been conducted. With the provision of suitable dust mitigation measures, results indicate that all ASRs would comply with the 1-hour TSP TM-EIAO, 24-hour average RSP/FSP and annual average RSP/FSP criteria under AQOs.

Operational Phase

4.12.2 Based on the latest design information, the Project (under the EIA) covers one cavern (at +200mPD) only which will be used for exhibition area/resource centre at Quarry Park. Air pollutants emissions from the exhibition area/resource centre would be not anticipated. In addition, the project-induced daily traffic flow of 50 vehicle/day would not induce adverse air quality impact to the nearby ASRs.

4.12.3 Reference has been made to the approved Schedule 3 EIA Report for Anderson Road Quarry Development (Register No.: AEIAR-183/2014) for the predicted air quality condition in the vicinity of the cavern development during the operational phase of ARQ Site. The predicted representative air pollutants concentration including NO₂, RSP and FSP at the worst-case year (i.e. Year 2026) on areas nearby the cavern development are well complied to the AQOs with taken the nearby emission sources into account. Provided that the location of fresh air intake for the cavern will be properly located with sufficient buffer distance to emission sources, adverse air quality impact is not anticipated to the proposed exhibition area/resource centre in cavern.

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

[2] Reference is made to 24-hour vehicle flow number ay Year 2026 (Worst-case assessment year for ARQ Site (operational phase)) for local distributor roads with the ARQ Site nearby the Rock Cavern Appendix 4.11 of the approved Schedule 3 EIA Report for ARQ Development (Register No.: AEIAR-183/2014).