3. AIR
QUALITY IMPACT ASSESSMENT
3.2 Statutory
Requirements and Evaluation Criteria
3.4 Identification of
Air Sensitive Receivers
3.5 Baseline
Condition and Background Air Quality
3.7 Evaluation of
Impacts during Construction Phase
3.8 Evaluation of
Impacts during Operation Phase
3.10 Potential for
Cumulative Impacts
3.12 Monitoring and
Audit Requirements
|
Air Sensitive Receivers |
|
|
|
|
|
Tables |
|
|
Table 3.1 |
Hong Kong Air Quality Objectives |
|
Table 3.2 |
Identified Representative Air Sensitive Receivers |
|
Table 3.3 |
5-year Averaged Annual Background Concentration of Air Pollutants recorded at Tai Po Station by EPD for the Period of 2016-2020 |
|
Table 3.4 |
Background Air Pollutants at Year 2025 by PATH v2.1 Model (μg/m3) |
3.1.1 This Section presents an assessment of the potential
air quality impact that could arise from the construction and operation of the
Project. It covers the scope outlined Clause 3.4.10 of the EIA Study Brief (ESB-322/2019) and is
based on the criteria and guidelines for evaluation and assessment of air
quality impacts stated in Annexes 4 and 12 of the EIAO-TM.
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 EIAO-TM.
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 |
Concentration Limit (μg/m3)[i] |
Number of Exceedances Allowed per Year |
|
Sulphur
dioxide, SO2 |
10-minute |
500 |
3 |
|
24-hour |
50 |
3 |
|
|
Respirable
suspended Particulates, RSP (PM10) [ii] |
24-hour |
100 |
9 |
|
Annual |
50 |
Not applicable |
|
|
Fine
suspended Particulates,
FSP (PM2.5) [iii] |
24-hour |
50 |
35 (18)[iv] |
|
Annual |
25 |
Not applicable |
|
|
Nitrogen
dioxide, NO2 |
1-hour |
200 |
18 |
|
Annual |
40 |
Not applicable |
|
|
Ozone,
O3 |
8-hour |
160 |
9 |
|
Carbon
monoxide, CO |
1-hour |
30,000 |
0 |
|
8-hour |
10,000 |
0 |
|
|
Lead |
Annual |
0.5 |
Not applicable |
|
Notes: [i] All measurements of the concentration of gaseous air
pollutants, i.e. sulphur dioxide, nitrogen dioxide, ozone and carbon monoxide, are adjusted to a
reference temperature of 293K and a reference pressure of 101.325 kPa. [ii Suspended
particles in air with a nominal aerodynamic diameter of 10 μm or less. [iii] Suspended
particles in air with a nominal aerodynamic diameter of 2.5 μm or less. [iv] The
blanket value refers to the number of allowable exceedances for 24-hour PM2.5
for new Government Projects (i.e. 18). |
|||
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 EIAO-TM 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.
Air
Pollution Control (Construction Dust) Regulation
3.2.3 The
measures stipulated in the Air Pollution Control (Construction Dust) Regulation
should be followed whenever possible to ensure that any dust impacts are
reduced. The measure specifies processes that require special dust control, and require the Contractor to inform EPD and
implement proper dust suppression measures while carrying out “Notifiable
Works” and “Regulatory Works”.
Air
Pollution Control (Non-road Mobile Machinery) (Emission) Regulation
3.2.4 The Air
Pollution Control (Non-road Mobile Machinery) (Emission) Regulation
stipulates that non-road mobile machinery (NRMM), except those exempted, are
required to comply with the prescribed emission standards. The Contractor is
required to ensure the adopted machines or non-road vehicle under the Project
could meet the prescribed emission standards and requirement.
Air
Pollution Control (Fuel Restriction) Regulation
3.2.5 The Air
Pollution Control (Fuel Restriction) Regulation was
enacted in 1990 and amended in 2008. The regulation imposes legal control
on the type of fuels allowed for use and their sulphur contents in commercial
and industrial processes. Gaseous fuel, conventional solid fuel with a sulphur
content not exceeding 1% by weight or liquid fuel with a sulphur content not
exceeding 0.005% by weight and a viscosity not more than 6 centistokes at
40°C, such as
Ultra Low Sulphur Diesel (ULSD) are permitted to be used in commercial and
industrial processes.
Recommended Pollution Control
Clauses for Construction Contracts
3.2.6 The
Recommended Pollution Control Clauses (RPCC) are generally good engineering
practice to minimize inconvenience and environmental nuisance to nearby
residents and other sensitive receivers. Some modifications may be necessary to
suit specific site conditions.
DEVB’s TC no. 13/2020, Timely
Application of Temporary Electricity and Water Supply for Public Works
Contracts and Wider Use of Electric Vehicles in Public Works Contracts
3.2.7 In
response to the carbon emission reduction target as specific in the “Hong Kong
Climate Action Plan 2030+”, timely provision of electricity could help reduce
carbon emission arising from operation of diesel generators at the beginning of
the construction works. At the detailed design stage, project team should
timely apply for the temporary electricity with a target that the necessary
cables laying works could be completed before the commencement of the works
contract. In addition, timely provision of electricity to construction
sites can facilitate the use of Electric Vehicles (EVs) in public works contracts.
The Project team should specify the use of EV(s) as well as the installation of
designated medium-speed charger for each EV as a standard provision at the site
accommodation in each public works contract.
DEVB's TC No.1/2015, Emissions
Control of NRMM in Capital Works Contracts of Public Works
3.2.8
This Circular promulgates the requirements for the use
of non-road mobile machinery (“NRMM”) approved under the Air Pollution Control
(Non-road Mobile Machinery) (Emission) Regulation (“the Regulation”) in new
capital works contracts of public works including design and build contracts,
in addition to the statutory requirements of the Regulation.
3.3.1 Clause 3.4.10.2 of the EIA Study Brief (ESB-322/2019) prescribes the Study Area which is generally
defined by a distance of 500m from boundary of the
Project, or to include other project locations as identified in the EIA. Figure 3.1 shows the
Study Area within the 500m envelope of the Project (including the works areas)
and the identified representative ASRs which have been described in the next
section in details. This Study Area is the same for both the construction and
operation phases.
3.4.1 Representative existing, planned and committed ASRs within the Study
Area have been identified based on the topographic maps supplemented by site
surveys, Outline Zoning Plans (OZPs), other published plans in the vicinity of
the Project Site. Reference has been made to the approved Outline Zoning Plan
(OZP) for Ping Che and Ta Kwu Ling (No.S/NE-TKL/14)
and Ta Kwu Ling North (No.S/NE-TKLN/2)
in identifying appropriate ASRs. In addition, site visits have been conducted
to verify the ASRs and its assessment point.
3.4.2 Existing
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 Figure 3.1. No planned or committed ASRs have been identified within
the Study Area.
Table 3.2 Identified Representative Air
Sensitive Receivers
|
ASR |
Description |
Nature of Use |
No. of storeys |
Height of ASR (m above ground) |
Separation Distance from the Nearest Site Boundary
(m) |
Phases
Affected |
|
|
Construction Phase |
Operation Phase |
||||||
|
ASR1 |
307 Ping Yeung |
Residential |
3 |
1.5,
4.5, 7.5 |
5 |
P |
x |
|
ASR2 |
17 Ping Yeung |
Residential |
1 |
1.5 |
4 |
P |
x |
|
ASR3 |
362 Ping Yeung |
Residential |
3 |
1.5,
4.5, 7.5 |
5 |
P |
x |
|
ASR4 |
331 Ping Yeung |
Residential |
3 |
1.5,
4.5, 7.5 |
4 |
P |
x |
|
ASR5 |
156B Ping Yeung |
Residential |
2 |
1.5,
4.5 |
7 |
P |
x |
|
ASR6 |
Temporary
Shelter near TKL04 |
Residential |
1 |
1.5 |
3 |
P |
x |
|
ASR7 |
Sing Ping
Village |
Residential |
2 |
1.5,
4.5 |
36 |
P |
x |
|
ASR8 |
Caritas Fung
Wong Fung Ting Home |
Home for the
Elderly |
2 |
1.5,
4.5 |
6 |
P |
x |
|
ASR9 |
5 Tong Fong |
Residential |
3 |
1.5,
4.5, 7.5 |
67 |
P |
x |
|
ASR10 |
55 Lei Uk |
Residential |
3 |
1.5,
4.5, 7.5 |
33 |
P |
x |
|
ASR11 |
Wun Chuen Sin Kwoon |
Temple |
2 |
1.5,
4.5 |
35 |
P |
x |
|
ASR12 |
200 Tai Po Tin |
Residential |
3 |
1.5,
4.5, 7.5 |
42 |
P |
x |
|
ASR13 |
323 Tai Po Tin |
Residential |
3 |
1.5,
4.5, 7.5 |
32 |
P |
x |
|
ASR14 |
118 Tai Po Tin |
Residential |
3 |
1.5,
4.5, 7.5 |
36 |
P |
x |
|
ASR15 |
103 Ping Che |
Residential |
2 |
1.5,
4.5 |
87 |
P |
x |
|
ASR16 |
Temporary
Shelter near TKL05 |
Residential |
1 |
1.5 |
2 |
P |
x |
|
ASR17(1) |
New Territories
North New Development Area |
New Town Development |
NA |
NA |
NA |
P |
x |
Notes: (1) The Detail of New Territories North New Development
Area has yet to be available.
3.5.1 The
Project Site is located in a rural
area in Ta Kwu Ling with predominately village and
agricultural uses around. Several
villages are identified on either side of the Project Site. The local air quality is influenced mainly by
general background conditions. The nearest EPD’s Air Quality Monitoring Station
(AQMS) is located in Tai Po urban area (roof of the
Tai Po Government Offices Building, 1 Ting Kok Road).
The latest 5 years annual averaged concentrations (2016 – 2020) of air
pollutants are presented in Table 3.3.
Table 3.3 5-year Averaged Annual
Background Concentration of Air Pollutants recorded at Tai Po Station by EPD
for the Period of 2016-2020
|
Air Pollutant |
Averaging Time |
AQO (a) |
Data Description |
Unit |
Year (b) (c) |
5-year mean |
||||
|
2016 |
2017 |
2018 |
2019 |
2020 |
||||||
|
Fine Suspended Particulates (FSP) (PM 2.5) |
24-hour |
50 (18) |
19th Max. |
μg m-3 |
43 |
46 |
38 |
41 |
33 |
40 |
|
No. of
Exceedance(s) |
- |
13 |
13 |
5 |
7 |
2 |
0 |
|||
|
Annual |
25 |
- |
μg m-3 |
20 |
22 |
19 |
20 |
15 |
19 |
|
|
Respirable
Suspended Particulates (RSP)
(PM10) |
24-hour |
100 (9) |
10th Max. |
μg m-3 |
74 |
82 |
69 |
65 |
58 |
70 |
|
No. of
Exceedance(s) |
- |
1 |
1 |
0 |
2 |
0 |
1 |
|||
|
Annual |
50 |
- |
μg m-3 |
29 |
32 |
31 |
31 |
24 |
29 |
|
|
Sulphur
Dioxide (SO2) |
10-minute |
500 (3) |
4th Max. |
μg m-3 |
37 |
39 |
24 |
20 |
19 |
28 |
|
24-hour |
50 (3) |
4th Max. |
μg m-3 |
10 |
9 |
8 |
10 |
7 |
9 |
|
|
Nitrogen
Dioxide (NO2) |
1-hour |
200 (18) |
19th Max. |
μg m-3 |
112 |
127 |
125 |
142 |
106 |
122 |
|
No. of
Exceedance(s) |
- |
0 |
0 |
0 |
0 |
0 |
0 |
|||
|
Annual |
40 |
- |
μg m-3 |
33 |
39 |
36 |
36 |
30 |
35 |
|
|
Carbon Monoxide (CO) |
1-hour |
30,000 |
Max. |
μg m-3 |
N/M |
N/M |
N/M |
N/M |
N/M |
N/M |
|
8-hour |
10,000 |
Max. |
μg m-3 |
N/M |
N/M |
N/M |
N/M |
N/M |
N/M |
|
|
Ozone (O3) |
8-hour |
160 (9) |
10th Max. |
μg m-3 |
147 |
181 |
167 |
197 |
165 |
170 |
|
No. of
Exceedance(s) |
- |
5 |
17 |
13 |
27 |
14 |
15 |
|||
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)
(c) Bolded values represent exceedances of the AQOs.
(d) N/M – not measured
3.5.2
The 5-year average for all parameters complied
with the respective AQO requirements except ozone (O3). Ozone is a
product of photochemical reactions of NOx and volatile organic compounds (VOCs)
instead of being emitted directly from human activities. In the presence of NOx (a
common roadside pollutant), ozone will be broken down into oxygen. Since NOx concentration
in rural areas is low, ozone scavenging effect is small and results in
generally high level.
3.5.3
All measured 19th highest 1-hour NO2 levels
from 2016 to 2020 complied with the AQO of 200 μg/m3.
All measured annual mean levels were within the AQO of 40 μg/m3. The 10th highest daily
RSP levels from 2016 to 2020 complied with the AQO of 100μg/m3.
The annual RSP levels were all within the AQO of 50μg/m3. The 19th
highest daily FSP levels had decreased from 43 μg/m3 in
2016 to 33 μg/m3 in 2020, as
compared with the AQO of 50 μg/m3.
The annual FSP levels were all within the AQO of 25μg/m3. All the measured 4th highest
10-minute and 4th highest 24-hour SO2 levels were well
within their respective AQOs of 500 μg/m3 and 50 μg/m3. The highest 8-hour O3 levels
were ranged from 197 to 147μg/m3. Exceedances were found from
Year 2017 to Year 2020. The highest 1-hour and 8-hour CO levels were not
measured at Tai Po Station.
PATH v2.1 Model Year 2025
Prediction
3.5.4
The Project is located on PATH Grid Cells (38,56), (38,57),
(39,56) and (39,57) of PATH v2.1. The annual average of concerned air
pollutants at Year 2025 modeled by PATH v2.1 model
are summarized in Table 3.4 below.
Table 3.4 Background
Air Pollutants at Year 2025 by PATH v2.1 Model (μg/m3)
|
Air
Pollutant |
Averaging
Time |
AQO |
Data
Description |
PATH Grids |
|||
|
(38,56) |
(38,57) |
(39,56) |
(39,57) |
||||
|
Fine
Suspended Particulates (FSP) (PM2.5) |
24-hour |
50 (18) |
19th
Max. |
41 |
40 |
38 |
39 |
|
Annual |
25 |
- |
17 |
17 |
16 |
16 |
|
|
Respirable Suspended Particulates (RSP) (PM10) |
24-hour |
100 (9) |
10th
Max. |
69 |
70 |
67 |
69 |
|
Annual |
50 |
- |
29 |
29 |
28 |
28 |
|
|
Sulphur Dioxide (SO2) |
10-minute |
500 (3) |
4th
Max. |
80 |
86 |
74 |
84 |
|
24-hour |
50 (3) |
4th
Max. |
13 |
13 |
12 |
12 |
|
|
Nitrogen Dioxide (NO2) |
1-hour |
200 (18) |
19th
Max. |
107 |
106 |
94 |
91 |
|
Annual |
40 |
- |
13 |
13 |
11 |
12 |
|
|
Carbon Monoxide (CO) |
1-hour |
30,000 |
Max. |
908 |
911 |
880 |
894 |
|
8-hour |
10,000 |
Max. |
835 |
837 |
817 |
826 |
|
|
Ozone (O3) |
8-hour |
160 (9) |
10th
Max. |
203 |
204 |
202 |
201 |
Notes:
[1] For
24-hr average PM10, the concentration is adjusted by adding 11.0 μg/m3, extracted from EPD’s Guidelines on Choice of Models
and Model Parameters.
[2] For
annual average PM10 and PM2.5 the concentration is
adjusted by adding 10.3 μg/m3 and 3.5
μg/m3, extracted from EPD’s
Guidelines on Choice of Models and Model Parameters.
[3] Bolded values
represent exceedances of the AQOs.
[4] Blanketed
refers to the number of exceedances allowed per year.
3.6.1 An air quality
impact assessment has been undertaken in accordance with the criteria and
guidelines as stated in Annexes 4 and 12 of the Technical Memorandum on
Environmental Impact Assessment Process (TM-EIAO). The improvement works will
be divided in sections. Each section is divided into segments of about 50m, at
most 3 work fronts will be conducted at the same time and only 1 excavator will
be operated in each work front. Therefore, significant dust impact is not
anticipated. Thus, a quantitative assessment is not proposed. The relevant
justifications and assessment results are presented in below sections.
3.6.2 For
operational phase, no air pollution source from the Project is identified.
Thus, adverse air quality impact is not anticipated. No mitigation measures are
required.
Identification of Air Pollution Sources
3.7.1 The
following sources of air pollution are expected during the construction phase
of the Project:
·
Fugitive dust caused by earth works including site clearance,
excavation of the proposed drainage channel, materials handling, loading and
unloading etc. for the construction of the TKL04 and TKL05;
·
Fugitive
dust caused by earth works including site clearance, excavation and backfilling
activities for the construction of the u-channel and drainage pipelines;
·
Fugitive
dust caused by formwork and
reinforcement works;
·
Wind erosion of open sites and stockpiling areas.
·
Gaseous
emissions from diesel-powered construction equipment; and
·
Odour
from the excavated stream bed materials.
3.7.2 Other
superstructure works involving the re-provisioning of the pedestrian and
vehicular river crossings should unlikely be a major dust generating source,
given the relatively small-scale construction works involved.
3.7.3 Potential
impacts associated with the construction of the Project mainly include
vehicular emissions (i.e. NO2, PM10 and PM2.5) from on-site
vehicles/PMEs and the fugitive dust (i.e. TSP, PM10 and PM2.5) emissions
from the excavation, formwork and reinforcement, storage and handling of
materials and the movements of on-site vehicles on haul roads.The
proposed drainage improvement works at each active works area (each
approximately 50m) which is programmed to take only about 2- 4 weeks to
complete
Evaluation of Impacts
Fugitive
Dust
3.7.4 The
construction of TKL04 and TKL05 will be constructed in sections of maximum 50m
in length and hence the exposed area will be reduced. The construction activities will not be
undertaken at the same time at adjoining sections such that the potential air
quality impacts due to fugitive dust generation can be reduced.
3.7.5 Based on
the engineering design, it is estimated that about 28,500m3 of
construction and demolition (C&D) materials and river bed material will be excavated from the Project
during the peak construction year in 2025.
About 4,560m3 of the excavated materials will be reused
on-site and the rest (about 23,940m3) of excavated materials will be
temporarily stored in stockpiling areas for subsequent disposal 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.
3.7.6 For site clearance and demolition works, the proposed drainage improvement works at each active works area (each approximately 50m) which is programmed to take only about 2- 4 weeks to complete. It is estimated that a total of 6 truck trips per days (about 4 truck trips per day for surplus inert C&D materials and 2 truck trips per day for construction waste) will be required to dispose the C&D materials/construction waste off-site. For the surplus inert C&D materials and construction waste generated from the excavation works, a total of 12 truck trips per days (about 11 truck trips per day for surplus inert C&D material and 1 truck trip per day for construction waste) will be required to dispose the materials/waste off-site. The disposal sites will be proposed by Contractor in the Environmental Management Plan (EMP) and Waste Management Plan (WMP) for the Engineer’s approval before implementation. Nevertheless, all vehicles will be cleansed by wheel washing facility before leaving the construction sites, and soil brought away from construction sites is thus not anticipated. Vehicle containing dusty material will also be covered by sheet to avoid any potential nuisance. Any dusty discharge on road is a violation of the Public Health & Municipal Ordinance. Therefore adverse off site dust impact is not anticipated. With proper implementation of good site practices, potential dust impacts associated with on-site handling and transportation of the public fill and construction waste to disposal sites are not expected to occur.
3.7.7 Excavation,
U-channel/piping construction and backfilling are the major construction
activities during the construction of the associated drainage facilities at
Ping Che Road and Ping Yeung Village.
Traditional open cut method will be adopted. However, some of the works will be carried
out in the narrow village alleys, accesses and open space of the villages (i.e.
Ping Yeung Village), therefore, only hand-held tools or small-scale
construction plant will be used for excavation, pipe laying and backfilling. It
is understood that the construction of drainage system would be carried out
section by section. Since the drainage
system would be constructed in small sections, with each section about 50 m long
at maximum, thus the excavation area for each construction event would be
limited. 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. Precast material will be used as far as
possible to minimise the potential dust impact from on-site construction works,
e.g. concreting. 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.
3.7.8 In view of
the relatively small scale of the construction works, the quantity of excavated
materials generated and no concrete batching on-site, the potential fugitive
dust nuisance during the construction phase should be limited with the
implementation of typical dust suppression measures and good site practices
recommended in Section 3.9.1. No adverse air quality impacts on the
identified representative ASRs are anticipated during the construction phase.
Gaseous
Emissions from Diesel-powered Construction Equipment
3.7.9 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 such plant are expected to operate. 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. EPD has also
introduced the Air Pollution Control (Non-road Mobile Machinery) (Emission)
Regulation, which came in operation on 1 June 2015, to regulate emissions
from machines and non-road vehicles.
Starting from 1 December 2015, only approved or exempted non-road mobile
machinery are allowed to be used in construction
sites. Hence, with the implementation of
the said Regulation, the gaseous emissions such from construction equipment are
considered relatively small and will not cause adverse air quality impact to
the surrounding ASRs. Therefore, no adverse air quality impacts are expected
from gaseous emissions.
Odour
3.7.10 Excavation
of river bed material will be required for the
construction of the proposed Drainage Channel TKL04 and TKL05. Depending on the quality of the river bed material, the excavation and handling of river bed
material may cause odour impacts during construction. Hydrogen sulphide (H2S) is the key
odour constituent of the excavated material.
With the implementation of good site practice recommended in Section 3.9.2, odour nuisance is not
anticipated.
3.8.1 Maintenance
would be necessary for the proposed channels 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. Virtually little or no maintenance
will be necessary. During the operation phase, the Project will unlikely
cause any adverse air quality impacts in terms of dust, gaseous emission and odour.
Construction
Phase
3.9.1 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:
Excavation
Material and Stockpiling Areas
·
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.
·
Erection of hoarding along the site boundary, where
appropriate.
·
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.
·
Regular maintenance of construction equipment deployed
on-site should be conducted to prevent black smoke emission.
·
Adopt at least 2.4m and higher hoarding height close
to the ASRs with short separation distance (2m – 7m).
·
Avoid dusty works and stockpiling near the ASRs with
short separation distance (2m – 7m).
Transport
and Removal of Materials
·
Locate the haul road away from those concerned ASRs;
·
Minimization of unpaved, exposed earth by immediate
covering/ permanent paving as soon as the works have been completed.
·
The travelling speed of vehicles within the site
should be controlled to reduce the traffic induced dust dispersion and
re-suspension.
·
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.
·
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.
Construction Works
within Work Areas
·
Where possible, routing of vehicles and positioning of
construction plant should be at the maximum possible distance from ASRs.
·
All demolished materials that may generate dust should
be covered entirely by impervious sheeting or placed in a covered area with the
top and three sides enclosed within a day of demolition.
·
At construction works areas where demolition takes
place, water or dust suppression chemicals should be sprayed prior to, during
and immediately after the demolition activities to ensure that the top surface
remains wet.
·
Excavated river bed materials
that are placed on trucks for disposal should be properly covered during
transportation to minimise the release of any potential odour. Odorous river bed
material excavated during construction phase should be removed off-site as soon
as practicable within 24 hours to avoid any odour nuisance.
·
Regular maintenance of construction equipment
deployed on-site should be conducted to prevent black smoke emission.
·
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.
Site Cleanliness and
Tidiness
·
The requirements stipulated in the Works Branch
Development Bureau Technical Circular No. 08/2010 Enhanced Specification for
Site Cleanliness and Tidiness should be followed as far as practicable to
enhance the cleanliness and tidiness of construction sites.
Control on NRMMs
·
NRMMs
should be approved or exempted with a label issued by EPD. The label should be
displayed at a conspicuous position of the machine or vehicle. Non-road
vehicles are required to meet the emission standards and smoke requirements as
stipulated under the Air Pollution Control (Non-road Mobile Machinery)(Emission) Regulation.
Operation Phase
3.9.2 No mitigation measures are considered necessary during the operation of
the Project. In the event that excavated materials are
found to be odorous during regular maintenance, the following measures should
be implemented by DSD.
·
Temporarily stockpile odorous excavated material as
far away from ASRs as possible; and
·
Temporary stockpiles of odorous excavated material
should be properly covered with tarpaulin and should be removed off-site as
soon as practically possible within 24 hours to avoid any odour nuisance
arising.
3.10.1 The
potential for cumulative air quality impact during the construction phase has
been checked against the following known committed/existing projects at the
time the EIA is prepared:
·
Implementation
of Water Intelligent Network (WIN), Remaining District Metering Areas and
Pressure Management Areas in Yuen Long and Sheung Shui & Fanling Major Supply Zones;
·
Widening
of the Western Section and Eastern Section of Lin Ma Hang Road (Ping Yuen River
to Ping Che Road / Tsung Yuen Ha to Lin Ma Hang).
3.10.2 Implementation of WIN will fall within the Study Area while the works
will be confined into localised works area with little potential to generate
fugitive dust. In addition, the
upgrading works of the section of connecting road to Liantang
/ Heung Yuen Wai Boundary Control Point (LT/HYW BCP) within the Study Area is
not substantial and is at about 400m from the nearest ASRs (at Tong Fong) of
this Project. Therefore, the potential
of causing unacceptable cumulative fugitive dust impacts from these projects is
considered low.
3.10.3
In
addition to the above projects, there are also three planning studies with
study areas within and in the vicinity of the Project Site, which included the
following:
·
Preliminary Feasibility
Study on Developing the New Territories North (NTN);
·
Drainage Improvement
Works in Hang Tau, Kong Ha and Sha Tau Kok Town, and Lower Ping
Yuen River; and
·
North East New
Territories Sewerage System Upgrade.
3.10.4
The cumulative impacts with the above concurrent projects are
mostly related to the air quality impacts such as dust, caused by excavation
works during the construction phase. It
is expected that the cumulative impacts from the construction and operation of
the proposed Drainage Channel TKL04 and TKL05 and other concurrent projects
will not lead to exceedance of any relevant air quality criteria, provided that
the recommended mitigation measures as stated in the referenced EIA studies are
implemented properly. As such, no adverse
cumulative environmental impacts are envisaged during both construction and
operation of the Project.
3.11.1 No adverse
residual impact is anticipated from the construction and operation of the
Project with the implementation of the recommended mitigation measures and good
construction site practice.
3.12.1 Dust
impacts during the construction phase can be readily mitigated through
implementation of standard mitigation measures and good housekeeping practices.
3.12.2 No
specific air quality monitoring is necessary during construction phase. Monthly
site inspections and audits will be conducted to ensure that the recommended
mitigation measures are properly implemented during the construction stage to
reduce the air quality impacts from the Project.
3.13.1 Construction
works of the Project will inevitably generate some fugitive dust, especially
during the excavation of the proposed channel.
With the section-by-section construction approach, the areas of
excavation works should be limited in scale.
Regular site wetting will also help to control wind-blown nuisances.
3.13.2 Excavation
and handling of river bed material may cause odour
impacts during construction and operation.
With the implementation of good site practice, odour nuisance is not
anticipated.
3.13.3 Through
proper implementation of dust control measures required under the Air Pollution Control (Construction Dust)
Regulation and the Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation,
construction fugitive dust should be controlled at source to satisfactory
levels.
3.13.4 Maintenance works for the Project
will be small-scale in nature. During
the operation phase, the Project will unlikely cause any adverse air
quality impacts in terms of dust and odour.
3.13.5 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, monthly site inspections and audits will be conducted as part of the
EM&A Programme of the Project.