3 Air Quality Impact

3.1 Introduction

3.1.1 This section presents the assessment on potential air quality impacts arising from construction and operation of the Project, which has been conducted in accordance with the criteria and guidelines as stated in section 1 of Annex 4 and Annex 12 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) as well as the requirements given in Clause 3.4.4 of the EIA Study Brief (ESB-291/2015).

3.1.2 An application for an Environmental Permit (EP) would be submitted for the following Schedule 2 Designated Projects (DPs) (refer to Figure 1.3) and these DPs during construction and operational phases are included in this air quality impact assessment:

· Construction of new primary distributor road (Road P1) (DP1)

· Construction of eight new distributor roads (Road D1 to D8) (DP2)

· Construction of slip roads: between Road D8 Junction and existing Castle Peak Road; Junction of D8/P1 and Junction of D7/P1; and Kong Sham Western Highway (KSWH) connection to Road D3 (DP5)

· Construction of partly depressed and partly decked-over roads located at Road D2, Road D4 and Road D6 (DP6)

· Construction of four new SPSs at Sites 2-34, 3-41, 3-48 and 4-35, respectively (DP9).

· Construction of Road P1 and slip-road from KSWH to Road D3 located within the “Conservation Area” of Yuen Tau Shan (DP12)

3.1.3 The following DPs would apply the EP through separated EIA studies but their potential impacts during construction phase and/or operational phase are also included in this air quality impact assessment. The locations of these DPs are shown in Figure 1.2 and the details of the DP refer to Section 1.5.

· Construction of new West Rail Hung Shui Kiu (HSK) Station (Site 4-34) (DP3)

· Potential Construction of Environmentally Friendly Transport Services (EFTS) (DP4) – subject to further review

· Potential Construction of a new container back-up and storage area (Sites 3-1, 3-4, 3-5, 3-13 and 3-14) (DP7) – subject to further review

· Construction of New HSK sewage treatment works (STW) (Site 3-26 and part of existing San Wai STW) (DP8)

· Construction of flushing water service reservoirs for reuse of reclaimed water at Tan Kwai Tsuen and Fung Kong Tsuen (Sites 3-3 and 5-40) (DP10)

· Construction of one refuse transfer station (RTS) (Site 3-12) (DP11)

3.2 Environmental Legislation, Policies, Plans, Standards and Criteria

3.2.1 The criteria and guidelines for air quality assessment are laid down in Annex 4 and Annex 12 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM).

3.2.2 The Air Pollution Control Ordinance (APCO) provides the statutory authority for controlling air pollutants from a variety of sources. The Hong Kong Air Quality Objectives (AQOs), which stipulate the maximum allowable concentrations over specific periods for typical pollutants, should be met. The relevant AQOs are listed in Table 3.1 which would be adopted in the air quality impact assessment.

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

3.2.4 In accordance with the EIAO-TM, odour level at an air sensitive receiver should meet 5 odour units based on an averaging time of 5 seconds for odour prediction assessment.

Table 3.1 Hong Kong Air Quality Objectives

Pollutant	Averaging Time	Maximum Average Concentration (µg/m³) ⁽¹⁾	No. of Exceedances Allowed
Fine Suspended Particulates (FSP) (PM 2.5) ⁽³⁾	24-hr	75	9
Fine Suspended Particulates (FSP) (PM 2.5) ⁽³⁾	Annual ⁽²⁾	35	NA
Respirable Suspended Particulates (RSP) (PM10) ⁽⁴⁾	24-hr	100	9
Respirable Suspended Particulates (RSP) (PM10) ⁽⁴⁾	Annual	50	NA
Sulphur Dioxide (SO₂)	10-min	500	3
Sulphur Dioxide (SO₂)	24-hr	125	3
Nitrogen Dioxide (NO₂)	1-hr	200	18
Nitrogen Dioxide (NO₂)	Annual	40	NA
Carbon Monoxide (CO)	1-hr	30,000	0
Carbon Monoxide (CO)	8-hr	10,000	0
Photochemical Oxidants (as ozone)	8-hr	160	9

Note:

(1) Gaseous air pollutants are measured at 293 K and 101.325 kPa.

(2) Arithmetic mean.

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

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

Air Pollution Control (Construction Dust) Regulation

3.2.5 Notifiable and regulatory works are under the control of Air Pollution Control (Construction Dust) Regulation. Notifiable works include site formation, reclamation, demolition, foundation and superstructure construction for buildings and road construction. Regulatory works include building renovation, road opening and resurfacing, slope stabilisation, and other activities including stockpiling, dusty material handling, excavation, concrete production, etc. This Project is expected to include notifiable works (site formation, demolition, foundation and superstructure construction for buildings as well as road construction) and regulatory works (road resurfacing, temporary stockpile, dusty material handling, and excavation). Contractors and site agents are required to inform EPD and adopt dust reduction measures to minimise dust emissions, while carrying out construction works, to the acceptable level.

Air Pollution Control Ordinance – Control of Emission from Specified Processes

3.2.6 A licence is required for the operation of specified processes (SPs), such as Cement Work (Concrete Batching Plant), under Part IV of APCO. The list of specified processes which required licence for operation is stated in Annex I of APCO. Application for a licence should be made to EPD. EPD may either grant or refuse or grant a licence subject to whether the applicant can fulfill the environmental standards to avoid causing air pollution. If EPD decides to grant the licence, a set of conditions would be imposed to prevent adverse impacts from the discharge of air pollutant emissions.

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

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

3.3 Baseline Conditions

Local Air Quality and Environ

3.3.1 The proposed Project is predominantly rural with low population density and located next to the existing Tin Shui Wai and Tuen Mun New Towns. The local air quality is dominated by vehicular exhaust emissions from the Yuen Long Highway, KSWH and Castle Peak Road as well as the scattered industrial emissions within the area.

3.3.2 As the proposed Project is within the vicinity of Shenzhen as well as Guangdong Province, the existing air quality in the assessment area is seasonally affected by the industrial emissions from the Guangdong Province as well.

3.3.3 In accordance with the Revised RODP, it is proposed that the current chicken farm at the Fung Kong Tsuen shall be stayed and some new sites for “Port Backup, Storage and Workshop Uses” (“PBU+SWU”) would be built in the vicinity of the chicken farm.

3.3.4 There is no EPD air quality data available for the assessment area. The nearest EPD air quality monitoring station in the vicinity of the assessment area is Yuen Long air quality monitoring station (AQMS). The annual average monitoring data recorded at this station has shown the trend of pollutants’ concentration in the past five years. The recent five years (Year 2011 to 2015) annual average concentrations are summarised in Table 3.2.

Table 3.2 Air Pollutant Concentrations (Year 2011 – 2015) measured at EPD’s Yuen Long AQMS

Pollutant	Averaging Time	AQO^[1]	Data Summary	Year ^[2][7]
Pollutant	Averaging Time	AQO^[1]	Data Summary	2011	2012	2013	2014	2015
Fine Suspended Particulates (PM _2.5)	24-hr	75 (9)	Maximum	109	87	140	119	127
			10th Highest	76	65	106	86	78
			No. of Exceedance(s)	13	1	35	18	11
	Annual	35	-	36	29	37	35	30
Respirable Suspended Particulates (PM₁₀)	24-hr	100 (9)	Maximum	173	165	184	156	176
			10th Highest	111	100	142	124	102
			No. of Exceedance(s)	25	10	47	21	12
	Annual	50	-	54	44	56	50	44
Total Suspended Particulates (TSP)	Daily^[6]	500	Maximum	196	161	218	N/A	N/A
Sulphur Dioxide (SO₂)	10-min^[5][6]	500 (3)	Maximum	N/A	N/A	N/A	112	67
			4th Highest	N/A	N/A	N/A	92	51
			No. of Exceedance(s)	N/A	N/A	N/A	0	0
	24-hr	125 (3)	Maximum	36	42	53	34	20
			4th Highest	33	29	33	27	17
			No. of Exceedance(s)	0	0	0	0	0
Nitrogen Dioxide (NO₂)	1-hr	200 (18)	Maximum	257	180	230	227	339
			19th Highest	188	147	183	165	162
			No. of Exceedance(s)	8	0	7	4	5
	Annual	40	-	54	49	54	52	45
Carbon Monoxide (CO)	1-hr	30,000	-	3210	2200	2690	2560	2460
Carbon Monoxide (CO)	8-hr	10,000	-	2360	1829	1911	2319	2143
Ozone (O₃)	8-hr	160 (9)	Maximum	195	217	159	304	261
			10^th Highest	138	163	130	177	161
			No. of Exceedance(s)	3	14	0	13	10

Note: [1] Values in ( ) mean the number of exceedances allowed per year. TSP is not a criteria pollutant in the AQOs.
[2] Bolded and underlined values mean exceedance of relevant AQOs.
[3] Reference conditions of gaseous pollutants concentration data: 298 K and 101.325 kPa (before 2014) and 293K and 101.325 kPa (since 2014).
[4] N/M – Not Measured. N/A – Not Available (Relevant report is not available yet or data is not made available by EPD).
[5] Monitoring data for the AQO of 10-minute SO₂ on or before Year 2013 is currently not publicly available.
[6] Extracted from EPD’s Air Quality in Hong Kong of relevant years.
[7] The hourly data of SO₂, NO₂, RSP, FSP, O₃ and CO are provided in EPD’s website (http://epic.epd.gov.hk/EPICDI/air/station/?lang=en) and its 8-hour, daily and annual average concentrations are calculated based on the hourly data.

3.3.5 Table 3.2 indicates that the annual average concentration of NO₂ and RSP/FSP at some years fail the AQO criteria. The 8-hour average O₃ concentrations in Year 2011 to 2015 also fail the criterion. Except the daily FSP level recorded in Year 2012, the 10^th highest daily RSP/FSP concentrations fail the criterion in Year 2011 to 2015. The high RSP/FSP level at the Yuen Long Station was probably due to regional air quality problems within the Pearl River Delta Region. In particular, the industrial activities both at Yuen Long Industrial Estate and the Fu Tin Industrial Area in Shenzhen remain active. Heavy traffic in the area (major highways) also contributes to the regional particulates concentrations because NO₂ and RSP are typical pollutants of road emissions.

3.3.6 Apart from EPD’s monitoring stations, there are also monitoring stations set up by the CLP Power Hong Kong Ltd. (CLP) in Yuen Long Areas. The latest monitoring results for NO₂ and SO₂ (from Year 2011 to 2015) are listed in Table 3.3.

Table 3.3 Air Pollutant Concentrations Measured at CLP’s Tin Shui Wai and Lau Fau Shan AQMS [1]

Year	2011	2012 ⁽³⁾	2013	2014	2015
Pollutant/ Locations ^{(5, 6)}	Annual Average NO₂Concentration (μg/m³) ⁽⁴⁾
Tin Shui Wai	39	32	45	35	37
Lau Fau Shan	36	30	30	32	24
	Hourly Average NO₂Concentration (μg/m³), 19^th Highest ⁽⁴⁾
Tin Shui Wai	153	127	179	151	149
Lau Fau Shan	174	138	158	147	159
	Daily Average SO₂Concentration, 4^th Highest (μg/m³) ⁽⁴⁾
Tin Shui Wai	24	30	33	35	18
Lau Fau Shan	34	35	22	22	21

Note:

(1) Not use.

(2) Monitoring results exceeded AQOs are shown as bold and underlined characters.

(3) “N/A“ means data is not available

(4) Reference conditions of gaseous pollutants concentration data: 298 K and 101.325 kPa.

(5) Annual data are extracted from “Air Quality in Hong Kong” published by EPD.

(6) Hourly and daily data are calculated from the hourly data provided in CLP’s website (https://www.clpgroup.com/poweru/eng/air_quality/airQuality_monitoring_detail.aspx).

3.3.7 It is observed that the monitoring results of hourly average NO₂ and daily average SO₂ concentration recorded in Tin Shui Wai and Lau Fau Shan in Year 2011 - 2015 comply with the AQOs. Similar to the EPD’s data, the annual average NO₂ concentrations fail the AQO criteria at some years.

Future Background Air Quality

3.3.8 As a general reference, the future prevailing background concentrations can be made reference to the EPD’s PATH modelling results for Year 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. Details of the PATH results are presented in Table 3.4.

Table 3.4 Future Air Pollutant Concentrations at Year 2020 from PATH-2016 Model

	Pollutant	Averaging Time	AQO^[1]	Data Summary	PATH Grid Cell ^[2] ^[3]
	Pollutant	Averaging Time	AQO^[1]	Data Summary	(20, 47)	(20, 48)	(20, 49)	(21, 44)	(21, 45)	(21, 46)
	Fine Suspended Particulates (PM_2.5) ^[4][5]	24-hr	75 (9)	Max.	111.9	110.6	108.7	106.2	104.4	106.3
				10th Max.	72.3	71.3	69.6	69.6	69.5	70.3
				No. of Exceedance(s)	6	5	5	5	5	5
		Annual	35	-	30.1	29.9	29.3	29.9	29.6	29.7
	Respirable Suspended Particulates (PM₁₀)^[5]	24-hr	100 (9)	Max.	149.2	147.5	144.9	141.6	139.2	141.8
				10th Max.	96.4	95.1	92.9	92.8	92.7	93.7
				No. of Exceedance(s)	6	5	5	5	5	5
		Annual	50	-	42.4	42.1	41.3	42.0	41.7	41.9
	Sulphur Dioxide (SO₂)	24-hr	125 (3)	Max.	36.8	37.9	44.7	36.6	36.5	36.4
				4th Max.	32.7	32.2	35.8	26.3	28.3	29.5
				No. of Exceedance(s)	0	0	0	0	0	0
	Nitrogen Dioxide (NO₂)	1-hr	200 (18)	Max	131.2	131.9	130.0	118.5	120.0	125.2
				19th Max.	94.6	95.8	99.7	100.0	99.2	97.6
				No. of Exceedance(s)	0	0	0	0	0	0
		Annual	40	-	19.6	19.3	19.2	22.6	22.6	21.0
	Carbon Monoxide (CO)	1-hr	30,000	-	996.0	1005.6	1064.4	993.4	989.1	995.6
	Carbon Monoxide (CO)	8-hr	10,000	-	837.6	851.2	873.2	846.7	835.5	838.1
	Photochemical Oxidants (as ozone)	8-hr	160 (9)	Max.	221.2	218.6	224.0	222.2	221.7	218.0
				10th Max.	156.3	158.3	151.2	160.0	159.4	156.6
				No. of Exceedance(s)	8	7	8	10	9	9
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] Since PM_2.5 is not available from PATH model outputs, 24-hour average PM_2.5 and annual average PM_2.5 are estimated by 0.75 x PM₁₀ and 0.71 x PM₁₀ respectively with reference to Guidelines on the Estimation of PM 2.5 for Air Quality Assessment in Hong Kong.
[5] 10th highest daily and annual RSP concentration is adjusted by adding 37.6 µg/m³ and 21.9 µg/m³ respectively with reference to Guidelines on Choice of Models and Model Parameters. Same adjustment is applied to estimation of PM_2.5 as well.

Table 3.4 Future Air Pollutant Concentrations at Year 2020 from PATH-2016 Model (Cont’d)

Pollutant	Averaging Time	AQO^[1]	Data Summary	PATH Grid Cell ^[2] ^[3]
Pollutant	Averaging Time	AQO^[1]	Data Summary	(21, 47)	(21, 48)	(21, 49)	(21, 50)	(22, 44)	(22, 45)
Fine Suspended Particulates (PM_2.5) ^[4][5]	24-hr	75 (9)	Max.	107.0	108.4	106.7	105.0	113.0	110.4
			10th Max.	70.3	70.5	68.7	69.5	71.9	69.5
			No. of Exceedance(s)	5	5	5	5	7	5
	Annual	35	-	29.3	29.5	28.9	29.1	30.8	29.8
Respirable Suspended Particulates (PM₁₀)^[5]	24-hr	100 (9)	Max.	142.7	144.6	142.3	140.0	150.7	147.2
			10th Max.	93.8	94.0	91.6	92.6	95.9	92.7
			No. of Exceedance(s)	5	5	5	5	7	5
	Annual	50	-	41.3	41.5	40.7	40.9	43.4	42.0
Sulphur Dioxide (SO₂)	24-hr	125 (3)	Max.	36.6	36.8	36.8	38.8	36.4	36.5
			4th Max.	30.0	30.2	30.0	33.0	25.8	26.1
			No. of Exceedance(s)	0	0	0	0	0	0
Nitrogen Dioxide (NO₂)	1-hr	200 (18)	Max	126.3	126.1	115.6	124.8	118.7	121.6
			19th Max.	95.2	93.3	92.4	96.6	93.0	99.7
			No. of Exceedance(s)	0	0	0	0	0