3. AiR Quality

3.1 Introduction

3.1.1 This section presents an assessment of potential air quality impacts associated with construction and operation of the extension of Mui Wo Lai Chi Yuen Cemetery. The assessment was conducted in accordance with the requirements in Annexes 4 and 12 of the Technical Memorandum on Environmental Impact Assessment Ordinance (EIAO-TM) and the requirements in Section 3.4.3 of the EIA Study Brief.

3.2 Environmental Legislation, Standards and Guidelines

3.2.1 The relevant legislation, standards and guidelines applicable to the present study for the assessment of air quality impacts are:

· 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);

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

· Air Pollution Control (Construction Dust) Regulation (Cap 311R); and

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

Air Pollution Control Ordinance (APCO)

3.2.2 The prevailing AQO, as tabulated in Table 3.1 below has been in forced since 1 January 2014.

Table 3.1 Hong Kong Air Quality Objectives

Pollutant	Averaging Time	Concentration Limit, µg/m^3 (1)	No. of Exceedances Allowed per Year
Fine Suspended Particulates (PM2.5 / FSP)^(3)	24-hour	75	9
	Annual^(2)	35	Not applicable
Respirable Suspended Particulates (PM10 / RSP)^(4)	24-hour	100	9
	Annual^(2)	50	Not applicable
Sulphur Dioxide (SO2)	10-minute	500	3
	24-hour	125	3
Nitrogen Dioxide (NO2)	1-hour	200	18
	Annual^(2)	40	Not applicable
Photochemical Oxidants (as Ozone)	8-hour	160	9
Carbon Monoxide (CO)	1-hour	30,000	0
	8-hour	10,000	0
Lead (Pb)	Annual^(2)	0.5	Not applicable

Notes:

(1) Measured at 293 K and 101.325 kPa.

(2) Arithmetic mean.

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

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

EIAO-TM

3.2.3 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.

Air Pollution Control (Construction Dust) Regulation

3.2.4 With reference to the Air Pollution Control (Construction Dust) Regulation, it specifies processes that require special dust control. The Contractors are required to inform the 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

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

3.3 Description of the Environment

Baseline Conditions

3.3.1 The Project site is located in rural area at a slope next to the entrance staircase of the existing Lai Chi Yuen Cemetery in Mui Wo, Lantau Island and is within the Lantau South Country Park. No major air emission source is identified in the area. The EPD air quality monitoring station closest to the Project site is Tung Chung Station. The latest available five-year air quality data measured at Tung Chung Station are summarised in Table 3.2.

Table 3.2 Summary of the Latest Available Five-Year Air Quality Data at Tung Chung Station (2011 to 2015)

Air Pollutant	Averaging Time		Concentration, μg/m^3					AQO
			Year 2011	Year 2012	Year 2013	Year 2014	Year 2015
PM2.5	24-hour	10^th Highest	78	74	76	65	65	75
	Annual		32	28	26	24	22	35
PM10	24-hour	10^th Highest	109	106	108	101	93	100
	Annual		47	45	42	39	36	50
SO2	10-minute	4^th Highest	-^(1)	-^(1)	-^(1)	86	88	500
	24-hour	4^th Highest	38	33	39	35	22	125
NO2	1-hour	19^th Highest	184	166	177	198	162	200
	Annual		51	43	49	45	40	40
O3	8-hour	10^th Highest	189	197	171	175	176	160
CO	1-hour	1^stHighest	2290	2660	1810	2230	1780	30,000
	8-hour	1^stHighest	2188	2461	1640	1692	1416	10,000

Notes:

(1) No monitoring data is available for 10-minute SO₂ from 2011 to 2013.

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

(3) All data was calculated from the hourly data provided in EPD’s website (http://epic.epd.gov.hk/EPICDI/air/station/?lang=en) and extracted from EPD’s Air Quality Reports – Annual Air Quality Monitoring Results (http://www.aqhi.gov.hk/en/download/air-quality-reportse469.html?showall=&start=1).

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

3.3.2 As shown in Table 3.2, the 10^th highest daily PM_2.5 and PM₁₀, and annual average NO₂ exceeded the AQO criteria in some years during 2011 to 2014, while the concentrations of these pollutants were in a decreasing trend and complied with the AQO criteria in 2015. For O₃, exceedances of the AQO criterion were observed from 2011 to 2015, but its concentration was decreased from 189 μg/m³ in 2011 to 176 μg/m³ in 2015. It is considered that the high O₃ level is a regional air quality problem within the Pearl River Delta Region.

3.3.3 For other pollutants such as SO₂ and CO, the measured concentrations at Tung Chung Station during 2011 to 2015 were well below the AQO criteria.

3.3.4 The construction of the Project will commence in February 2018 and complete in September 2019 while the operation of the proposed Lai Chi Yuen Cemetery extension will commence in late 2019. Hence, the air pollutant concentrations in 2018 and 2019 at the Project area have been adopted as the background concentration for the construction and operation of the Project. Future background air quality concentrations can be predicted from the Pollutants in the Atmosphere and the Transport over Hong Kong-2016 (PATH-2016) model. PATH-2016 model with Years 2018 and 2019 emission inventory was released by EPD. Air pollutants concentrations for 2018 and 2019 predicted from PATH-2016 in the Project area have been extracted, and are presented in Table 3.3.

Table 3.3 Air Pollutants Concentrations in 2018 and 2019 Predicted from PATH-2016 Model

Air Pollutant	Averaging Time		Future Background Concentration, μg/m^3
			Year 2018	Year 2019
PM2.5	24-hour	10^th Highest	57	57
	Annual		24	24
PM10	24-hour	10^th Highest	76	75
	Annual		33	33
SO2	24-hour	4^th Highest	28	28
NO2	1-hour	19^th Highest	92	89
	Annual		17	17
O3	8-hour	10^th Highest	164	165
CO	1-hour	1^st Highest	993	992
	8-hour	1^st Highest	816	814

Notes:

(1) Extracted from PATH grid (22, 26) in which the Project site is located.

(2) Predicted concentrations exceeding AQOs are shown as bold and underlined characters.

(3) With reference to the EPD’s Guidelines on Choice of Models and Model Parameters, PATH-2016’s output of RSP concentration are adjusted as follows:

- 10^th highest daily RSP concentration: add 26.5 µg/m³

- Annual RSP concentration: add 15.6 µg/m³

(4) With reference to the EPD’s Guidelines on the Estimation of PM2.5 for Air Quality Assessment in Hong Kong, the following conservative formulae are adopted to calculate background FSP concentration from the RSP concentration extracted from the PATH model:

- Annual (µg/m³): PM2.5 = 0.71 × PM10

- Daily (µg/m³): PM2.5 = 0.75 × PM10

(5) Predicted concentration exceeding AQOs are shown as bold and underlined characters.

3.3.5 As shown in Table 3.3, the predicted background concentrations of all concerned air pollutants except ozone (O₃) would be well within their respective AQOs upon the commencement of the construction and operation of the proposed new niches. The high O₃ level is a regional air quality problem within the Pearl River Delta Region.

Air Sensitive Receivers

3.3.6 The Study Area for the air quality assessment is defined by a distance of 500m from the boundary of the Project and the works of the Project within the Study Area as shown in Figure 3.1. Four representative air sensitive receivers (ASRs) located at the north and northwest of the Project site were identified based on the relevant Outline Zoning Plans, Development Permission Area Plans, Outline Development Plans and Layout Plans and other relevant published land use plans. The identified representative ASRs within the Study Area of the Project are described in Table 3.4 and their locations are shown in Figure 3.1.

Table 3.4 Representative Air Sensitive Receivers

ASR	Description	Land Use	Approximate Distance from the Nearest Site Boundary (m)	No. of Storey
A1	Scattered Village Houses	Residential	209	1
A2	Lai Chi Yuen Tsuen	Residential	274	2 - 3
A3	Scattered Village Houses	Residential	82	1
A4	Ngau Koo Wan Hill Court	Recreational	307	1

3.4 Identification and Evaluation of Environmental Impacts

Construction Phase

3.4.1 Potential sources of air quality impacts during construction of the Project would be related to dust emission from site formation, erection of retaining walls and construction of proposed new niches and the ancillary facilities including a joss paper burner and planters.

3.4.2 As described in Section 2, the proposed extension works will involve construction of an elevated platform of around 225m² supported by structural columns within the existing Lai Chi Yuen Cemetery and a site access of around 7.5m² just outside the cemetery connecting to the existing Lantau Trail for pedestrian access only. The elevated platform will be constructed by in-situ concrete casting. The proposed site access will be constructed by simple open cut followed by in-situ casting of reinforced concrete retaining wall/slab and the required depth of excavation for the site access construction would be less than 1.5m. With these construction methods, only minor excavation and backfilling works for the platform and site access construction would be expected. Since only small amount of construction and demolition materials (approximately 500m³) would be generated from the Project, potential impacts associated with the transportation of dusty materials would be negligible. In view of the minor and small scale of the construction works, dust emission from the construction of the Project would be insignificant. With the implementation of dust suppression measure stipulated under the Air Pollution (Construction Dust) Regulation and good site practice, no adverse air quality impact would be anticipated.

3.4.3 Since there is no other construction activity identified within 500m of the Project at the time of this EIA preparation, cumulative air quality impact from other construction activity is not expected during construction phase.

Operational Phase

3.4.4 South Lantau Road and the local access road to/from the Lai Chi Yuen Cemetery are the major roads to the Project site. South Lantau Road is a closed road which requires valid Lantau Closed Road Permit for vehicles to access, such that the number of other vehicles induced by the Project would be limited. The single track local access road leading to Lai Chi Yuen would be prohibited for entry of any vehicles except emergency vehicles such as police car and ambulance during Ching Ming and Chung Yeung Festivals. It is estimated that only 28 additional bus trips per hour (2-way) would be induced by the proposed cemetery extension, giving rise to a total of 373 vehicles per hour travelling on South Lantau Road during the Ching Ming Festival and Chung Yeung Festival. In view of the limited increase in traffic flow due to the Project and the low background pollutants concentrations of the study area based on EPD’s PATH data as shown in Table 3.3, adverse air quality impact arising from road traffic within the study area is not anticipated. No mitigation measure is therefore deemed necessary.

3.4.5 There is no joss paper burner in the existing Lai Chi Yuen Cemetery, while grave sweepers are allowed to use iron buckets or containers for burning joss paper or incense in the existing cemetery. Under this Project, a joss paper burner will be installed near the new niches as shown in Figure 2.2. There will be emissions from the joss paper burner during the operation of the Project. According to the latest design of the Project, the proposed joss paper burner would adopt the Best Available Technology (BAT), including a water scrubber, an electrostatic precipitator and an exhaust fan connected in series to effectively remove the air pollutants in the emissions. Adequate air flow would be supplied to the furnace chamber in order to allow sufficient oxygen for complete combustion and avoid production of carbon monoxide (CO) and soot. Upon the multi-stage air treatment, the smokeless clean air would be discharged via an extraction fan to the atmosphere. Moreover, the good operational practices and administrative measures as stipulated in EPD’s Guideline on Air Pollution Control for Joss Paper Burning at Chinese Temples, Crematoria and Similar Places would also be adopted.

3.4.6 According to the information provided by FEHD, the operation hours of the proposed joss paper burner would be 8:30am to 5:30pm. Based on the experience of the operator of Lai Chi Yuen Cemetery, iron buckets are infrequently used, except during Ching Ming Festival and Chung Yeung Festival periods. With reference to the approved Environmental Impact Assessment Reports for Provision of Cremators at Wo Hop Shek Crematorium (Register No.: AEIAR-119/2008) and Phased Reprovisioning of Cape Collinson Crematorium (Register No.: AEIAR-137/2009), the duration of a typical joss burning memorial ceremony is 10 minutes and the joss paper offerings are assumed to be 0.5 kg per ceremony. Within the operation period of the joss paper burner, maximum 54 sessions of typical 10-minute joss burning memorial ceremonies could be conducted in one day. Thus, 27 kg of joss paper offerings are estimated to be combusted in the joss paper burner in one day. This estimation could be considered as the worst-case scenario, since, based on experience of the operator of Lai Chi Yuen Cemetery, most grave sweepers use the iron buckets between 10am and 3pm. The iron buckets are very seldom in use outside 10am to 3pm. The pattern of activities at the proposed joss paper burner of the Project is estimated to be similar to that at the existing Lai Chi Yuen Cemetery. Thus, it is predicted that far less than 54 sessions of joss burning memorial ceremonies would be conducted each day.

3.4.7 Considering the amount of offerings that would be burnt each day would be small (less than 27 kg), the infrequent use of the joss paper burner and with the flue gas treatment system incorporated and the implementation of the good operational practices and administrative measures, adverse air quality impact arising from the joss paper burning would not be anticipated.

3.4.8 With the provision of the joss paper burner (with control device) under this Project, FEHD would direct the users of the existing Lai Chi Yuen Cemetery to adopt the proposed burner for joss paper burning. As such, with the installation of the proposed burner, potential emissions from joss paper burning activities in the existing Lai Chi Yuen Cemetery would be minimized.

3.4.9 Since there was no major industrial emission identified within 500m of the Project at the time of this EIA preparation, no cumulative air quality impact from industrial emission would therefore be expected.

3.5 Recommended Mitigation Measures

Construction Phase

3.5.1 Sufficient dust suppression measures as stipulated under the Air Pollution Control (Construction Dust) Regulation and good site practices should be properly implemented in order to minimize the construction dust generated.

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

b) Use of frequent watering of particular dusty construction areas close to ASRs;

c) 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;

d) Open temporary stockpiles should be avoided or covered. Prevent placing dusty material storage plies near ASRs;

e) Tarpaulin covering of all dusty vehicle loads transported to, from and between site locations;

f) Establishment and use of vehicle wheel and body washing facilities at the exit point of the site;

g) Imposition of speed control for vehicles on unpaved site roads. 8 km/hr is the recommended limit;

h) Routing of vehicles and positioning of construction plant should be at the maximum possible distance from ASRs.

Operational Phase

3.5.2 Apart from the adoption of BAT to the proposed joss paper burner, the following good operational practices and administrative measures as well as good maintenance practices as stipulated in EPD’s Guideline on Air Pollution Control for Joss Paper Burning at Chinese Temples, Crematoria and Similar Places should be strictly followed in order to ensure proper operation of the joss paper burner:

Good Operational Practices and Administrative Measures

(i) Before burning joss paper, the operator should make sure that the air pollution control equipment has been turned on and running normally. Joss paper burning should never be carried out without operation of the air pollution control equipment.

(ii) The operator should ensure only offerings made with paper materials are burnt in the furnace. Other wrapping materials, in particular plastic materials, should be removed.

(iii) It is essential to employ trained operators to control the feeding rate of joss paper to the furnaces. In case visible emissions are observed at the flue gas discharge, the feeding rate should be reduced as appropriate, and if visible emissions persist, the operator should immediately stop the burning activities and call for maintenance of the air pollution control equipment if necessary.

(iv) Whenever there is a sign of deterioration in performance of the electrostatic precipitator, the operator should arrange cleaning of the electrostatic precipitator. For those electrostatic precipitators with automatic self-cleaning function, the operator should ensure self-cleanings are carried out at frequencies recommended by manufacturers.

(v) The operator should regularly clean the burning chamber and clear away ash remains inside the burning chamber, preferably at least once a day. To prevent emissions during ash clearing process, the ash should be wetted sufficiently by water spraying.

Good Maintenance Practices

(i) Maintenance and repair of air pollution control equipment should only be carried out by competent personnel with sufficient training and relevant skills in accordance with manufacturer’s recommendations.

(ii) Air pollution control equipment should be maintained regularly to ensure optimum performance. All components should also be inspected, cleaned and serviced regularly.

(iii) Any defective parts of the air pollution control equipment should be replaced as soon as possible. To facilitate immediate replacement, sufficient stick of spare parts should be kept on-site.

(iv) Operators should keep a copy of the operation and maintenance manual and should maintain a proper log of maintenance records on-site to facilitate maintenance of the equipment.

3.6 Evaluation of Residual Impacts

Construction Phase

3.6.1 With the implementation of dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, no adverse residual dust impact would be anticipated during construction phase.

Operational Phase

3.6.2 With the incorporation of flue gas treatment system and the implementation of the good operational practices and administrative measures for the proposed joss paper burner, no adverse residual impact would be anticipated.

3.7 Environmental Monitoring and Audit Requirements

Construction Phase

3.7.1 Since no adverse dust impact would be anticipated at the ASRs with the implementation of sufficient dust suppression measures as stipulated under the Air Pollution Control (Construction Dust) Regulation and good site practices, no air quality monitoring is considered necessary. Regular site environmental audit during the construction phase of the Project should be conducted to ensure the recommended dust suppression measures are properly implemented.

Operational Phase

3.7.2 By incorporating flue gas treatment system in the proposed joss paper burner and limiting joss paper burning activities through administration procedures, adverse air quality impact arising from joss paper burning would not be anticipated. Therefore, no EM&A requirement for air quality during operation of the Project is deemed necessary. Nonetheless, it should be noted that trained operators should be employed to control the feeding rate of joss paper to the furnaces, regularly clean the burning chamber, observe flue gas discharge, and ensure normal operation of the joss paper burner to avoid abnormal air pollutant emissions.

3.8 Conclusion

The potential air quality impacts arising from the construction and operation of the Project were assessed. Adverse construction phase air quality impact would not be anticipated with the implementation of dust suppression measures as stipulated in the Air Pollution Control (Construction Dust) Regulation and good site practices. With the incorporation of flue gas treatment system and the implementation of the good operational practices and administrative measures as well as good maintenance practices for the proposed joss paper burner, no adverse air quality impact would be expected during operation of the Project.