3a.1.1.1 This section presents the assessment of the potential air quality impacts associated with the construction and operation phases of the IWMF located in Tsang Tsui Ash Lagoon (TTAL) site. A key environmental issue would be the cumulative aerial emission impacts in the vicinity of the IWMF. Other potential air quality impacts arising from construction dust emissions and odour emissions are also assessed.
3a.2 Environmental Legislation, Policies, Plans, Standards and Criteria
3a.2.1 Introduction
3a.2.1.1
The criteria for evaluating air
quality impacts and the guidelines for air quality assessment are laid down in
Annex 4 and Annex 12 of the Technical
3a.2.2 Air Quality Objectives and EIAO-TM
3a.2.2.1 The Air Pollution Control Ordinance (APCO) provides a statutory framework for establishing the Air Quality Objectives (AQOs) and stipulating the anti-pollution requirements for air pollution sources. The AQOs, which must be satisfied, stipulate the maximum allowable concentrations over specific period for a number of criteria pollutants. The relevant AQOs are listed in Table 3a.1.
Table 3a.1
|
Pollutant |
Maximum Concentration (mg/m3)(1) |
|||
|
Averaging Time |
||||
|
1 hour(2) |
8 hour(3) |
24 hour(3) |
Annual(4) |
|
|
Total Suspended
Particulates (TSP) |
- |
- |
260 |
80 |
|
Respirable
Suspended Particulates (RSP) (5) |
- |
- |
180 |
55 |
|
|
800 |
- |
350 |
80 |
|
Nitrogen Dioxide
(NO2) |
300 |
- |
150 |
80 |
|
Carbon Monoxide
(CO) |
30,000 |
10,000 |
- |
- |
|
Photochemical
Oxidants (as Ozone, O3)
(6) |
240 |
- |
- |
- |
Notes:
(1)
Measured at 298 K and 101.325 kPa.
(2)
Not to be exceeded more than three times per year.
(3)
Not to be exceeded more than once per year.
(4)
Arithmetic mean.
(5)
Suspended particulates in air with a nominal
aerodynamic diameter of
(6)
Photochemical oxidants are determined by measurement
of ozone only.
3a.2.2.2
The EIAO-TM stipulates that the
hourly TSP level should not exceed
3a.2.2.3 In accordance with the EIAO-TM, odour at an air sensitive receiver should not exceed 5 odour units based on an averaging time of 5 seconds for odour prediction assessment.
3a.2.3 Air Pollution Control (Construction Dust) Regulation
3a.2.3.1 Notifiable and regulatory works are under the control of Air Pollution Control (Construction Dust) Regulation. Notifiable works are site formation, reclamation, demolition, foundation and superstructure construction for buildings and road construction. Regulatory works are building renovation, road opening and resurfacing slope stabilisation, and other activities including stockpiling, dusty material handling, excavation, concrete works etc. This Project is expected to include both notifiable works and regulatory works. Contractors and site agents are required to inform the Environmental Protection Department (EPD) on carrying out construction works and to adopt dust reduction measures to reduce dust emission to the acceptable level.
3a.3 Description of the Environment
3a.3.1.1
The TTAL site is located at the existing ash lagoons in Nim Wan, Tuen
Mun, overlooking the
3a.3.1.2
There is currently no
EPD-operated air quality monitoring station located in the TTAL site study
area. Historical air quality monitoring
data from the nearest station, namely the rooftop Yuen Long station operated by
EPD is taken to examine the historical trend of the air quality condition in the
vicinity of the TTAL study area. Table
Table 3a.2 Annual Average Concentrations of Pollutants from Year 2005 to Year 2009 at EPD’s Air Quality Monitoring Station (Yuen Long)
|
Pollutant |
Annual Average Concentration (mg/m3) |
||||
|
Year 2005 |
Year 2006 |
Year 2007 |
Year 2008 |
Year 2009 |
|
|
RSP |
62 |
62 |
64 |
60 |
51 |
|
SO2 |
28 |
28 |
24 |
21 |
14 |
|
NO2 |
58 |
58 |
55 |
56 |
52 |
|
CO |
1038 |
841 |
969 |
726 |
711 |
|
O3 |
32 |
32 |
36 |
35 |
41 |
3a.4.1.1 In accordance with the criteria stipulated in the EIAO-TM, air sensitive receivers (ASRs) have been identified for this assessment. Domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public workshop, library, court of law, sports stadium or performing arts centre are classified as ASRs. Existing ASRs within the area of concern have been confirmed through site visits and review of the survey maps.
3a.4.1.2 Any other premises or place with which, in terms of duration or number of people affected, has a similar sensitivity to air pollutants as the aforelisted premises and places are also considered to be a sensitive receiver.
3a.4.1.3 Planned/committed ASRs within the area of concern have been reviewed with reference to relevant Outline Zoning Plans, Outline Development Plans, Layout Plans and other published plans.
3a.4.2 ASRs for Gaseous Pollutants Impact Assessment
3a.4.2.1
Representative ASRs are
identified within the potential hot spot areas for the gaseous pollutants
impact assessment based on the findings of the PATH (Pollutants in the
Atmosphere and the Transport over
3a.4.3 ASRs for Odour Impact Assessment
3a.4.3.1
For odour impact assessment,
three ASRs are identified within
Table 3a.3 Identified Air Sensitive Receiver for the TTAL Site (Odour Impacts)
|
ASR |
Description |
Nature of ASR (1) |
Building
Height, m |
Ground level,
mPD |
Distance to
Project Boundary, m |
|
TT4 |
|
G/IC |
3 |
4.7 |
88 |
Note:
(1) G/IC –Government / Institution / Community
3a.5 Identification of Pollution Sources
3a.5.1.1 The major construction works of the Project would be site formation, construction of facilities, and construction of the access road. The major potential air quality impact during construction phase of the Project would be dust arising from:
· Excavation and materials handling;
· Filling activities;
· Haul roads; and
· Wind erosion of open sites and stockpiling areas.
3a.5.1.2 As part of this Project, apart from some localized cut and fill operations at the ash lagoon, the majority of the ash stored at the ash lagoon would be left in-situ. The construction dust generating activities would be those associated with site formation and building construction. Extensive excavation and transportation of the ash would not be required as part of this Project. Based on the preliminary design, the construction works would generate about 29,903m3 construction and demolition materials in total, out of which, 7,668m3 would be required to be disposed offsite. Therefore, extensive excavation and transportation of dusty material would not be required as part of this Project.
3a.5.1.3 With the implementation of practicable dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation, adverse construction dust impact at the ASR is not expected during construction of the Project.
3a.5.1.4 With reference to the approved STF and WENT Landfill Extensions EIA Reports, the construction period of these two projects would not overlap with the construction activities of the IWMF. Therefore, cumulative dust impact from these projects are not expected.
3a.5.2 Operation Phase – Gaseous Pollutants
3a.5.2.1
Aerial emissions from the IWMF
chimney would be controlled to within the target emission levels, which is
presented in Section
3a.5.2.2 Cumulative air quality impacts at the identified ASRs due to the nearby pollutant emission sources would also be expected. Major nearby emission sources include:
·
· Black Point Power Station;
· Industrial uses in Tuen Mun;
· Planned Black Point Gas Supply Project;
· Planned STF;
· WENT Landfill & Extensions;
· Traffic Emissions; and
· Emissions from marine vessels travelling and berthing near the Project site.
3a.5.3 Operation Phase – Odour Impacts
3a.5.3.1 Apart from the incineration emission, odour nuisance from the proposed on-site wastewater treatment plant, the waste reception halls, the waste storage area, the mechanical treatment processes of the sorting and recycling plant within the Project site would also be expected during the operation phase of the Project. There are other potential odour emission sources in the nearby area including the existing and the planned WENT Landfill & Extension and the STF.
3a.6.1.1 Under the APCO, dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation should be implemented. With effective implementation of these mitigation measures, adverse construction dust impacts are not expected at the ASRs. Quantitative assessment is therefore considered not necessary.
3a.6.1.2 Audit and monitoring program during the construction phase of this Project has been formulated and is presented in the Environmental Monitoring and Audit Manual prepared under this study.
3a.6.2 Operation Phase - Gaseous Pollutants
Major emissions in close proximity to ASRs
3a.6.2.1
An inventory of major emissions
in close proximity of less than
3a.6.2.2 The emission inventory is presented in the second half of this sub-section together with the detailed modelling approach.
Chimney Emissions from the IWMF
3a.6.2.3 The target emission levels proposed for the incineration plant of the IWMF are listed in Table 3a.4 and are equivalent to the concentration limits stipulated in “A Guidance Note on the Best Practicable Means for Incinerator (Municipal Waste Incineration) BPM 12/1(08)” published by the EPD except nitrogen oxides. For nitrogen oxides, the target emission levels for the IWMF would be set as half of respective concentration limits stipulated in BPM 12/1 (08), that is, daily average value of 100 mg/m3 and half-hourly average value of 200 mg/m3 (expressed as nitrogen dioxide). A table comparing the proposed target emission levels and other relevant overseas standards is shown in Appendix 3.1. The target emission limits of the IWMF will meet the stringent emission limits stipulated by the European Commission for waste incineration. The location of the emission is shown in Figure 3a.2.
Table 3a.4 Target Emission Levels
|
Air Pollutant |
Target Emission Levels (mg/m3) (a) |
|
|
Daily |
Half - Hourly |
|
|
Particulates (b) |
10 |
30 |
|
Gaseous and vaporous organic substances, expressed as total organic
carbon |
10 |
20 |
|
Hydrogen Chloride (HCl) |
10 |
60 |
|
Hydrogen Fluoride (HF) |
1 |
4 |
|
|
50 |
200 |
|
Carbon Monoxide (CO) |
50 |
100 |
|
Nitrogen Oxides (NOX) as Nitrogen Dioxide (NO2) |
100 |
200 |
|
Mercury |
0.05 (e) |
- |
|
Total Cadmium & Thallium |
0.05 (e) |
- |
|
Total Heavy Metals (c) |
0.5 (e) |
- |
|
Dioxins & Furans (in mg I-TEQ m-3) |
1x10-7(d) |
- |
Notes:
(a) Emission limits are reference to 0oC and 101.325 kPa,
dry and 11% oxygen content conditions.
(b) The particulate emission limit is assumed to be RSP.
(c) Including Sb, As, Pb, Co, Cr, Cu, Mn, V and Ni.
(d) The averaging time is 6 to 8 hours.
(e) Average values over a sampling period of minimum of 30 minutes
and maximum of 8 hours.
3a.6.2.4 The incineration plant consists of six incineration process units, each with a design capacity of 600 tonnes of MSW per day. During normal operation, only five incineration process units would be in operation while one incineration process unit would be shut down for regular maintenance. The total treatment capacity will be maintained at 3,000 tpd. The 6 flues connecting to the 6 incineration units are grouped as 2 chimneys (each consists of 3 flues) within one concrete windshield. The 2 chimneys are situated adjacent to each other at about 6m apart. Given the short separation of the 2 chimneys, the plumes emitted from the 2 chimneys would inevitably become a combined plume shortly after discharge. Therefore, for the purpose of the air quality modelling, all the IWMF chimney emissions were modelled as a single point of emission. The stack discharge parameter from the incineration plant is summarized in Table 3a.5 and the details of the emission data are presented in Appendix 3.2.
Table 3a.5 Operation Parameters of the Incineration Plant
|
Oxygen concentration
of flue gas |
6.1% |
|
% moisture in flue
gas |
20.4% |
|
Temperature of the
flue gas |
413K |
|
Flow rate of flue gas |
694,200Nm3/hr |
|
Exit velocity |
|
|
Total stack
cross-sectional area |
|
|
Stack height |
150m above ground |
Vehicular Emissions associated with the IWMF
3a.6.2.5
During operation phase of the
IWMF, extra traffic associated with trucks delivering maintenance equipment and
coach for employee and visitors to the IWMF are anticipated. Vehicle emissions from
Marine Emissions associated with the IWMF
3a.6.2.6 Currently, the MSW collected at Island East Transfer Station (IETS), Island West Transfer Station (IWTS), Outlying Islands Transfer Station (OITS), West Kowloon Transfer Station (WKTS) and North Lantau Transfer Station (NLTS) is delivered to the WENT Landfill by marine transport. The marine transport routes from the refuse transfer stations to the berth area of the WENT Landfill will remain the same if the IWMF is located at the TTAL site. Therefore, the marine vessels operation mode and schedule stated in the approved WENT Landfill Extensions EIA Report are still valid and have been adopted in the cumulative assessment. A summary of the inventory for marine emissions is summarised in Appendix 3.4.
General
3a.6.2.7 The assessment has been carried out in three stages as follows:
· Stage 1 – Terrain and building wake effects test for the selected stack height of the IWMF using wind tunnel model;
· Stage 2 – Identification of potential hot spot areas using PATH model; and
· Stage 3 – Cumulative air quality assessment for identified potential hot spot areas using PATH and Gaussian models (i.e. CALINE4 and ISCST3).
Stage 1 – Terrain and building wake effects test for the selected stack height of the IWMF using wind tunnel model
3a.6.2.8 The purpose of the Stage 1 assessment is to determine and to verify that the selected stack height for the IWMF would not result in adverse terrain and building wake effects at the TTAL site. Visualization of plume behaviour for various wind directions and speeds has been conducted to provide a qualitative understanding of the effect of the structures on the dispersion. This is to verify that the plume from the IWMF stack will not hit critical ASRs.
3a.6.2.9 Wind tunnel tests have been conducted for various wind directions and wind speeds. These tests will define the wind directions where building and terrain wake effects are the most significant. Further wind tunnel tests were then conducted at the critical wind direction to determine the maximum concentration for the selected stack height at critical ASRs to verify that the selected stack height for the IWMF would not result in exceptionally high concentration at critical ASRs due to adverse terrain and building wake effects.
3a.6.2.10 The detailed technical aspects on conducting the wind tunnel tests are presented in S3a.6.2.14 to S3a.6.2.17.
Stage 2 – Identification of the potential hot spot area by using PATH model
3a.6.2.11
The
purpose of the Stage 2 assessment is to examine the cumulative air quality
impacts at a territory-wide scale by using PATH model. Based on the predictions of the PATH model,
potential hot spot areas and critical air pollutants of concern are identified
for the detailed assessment by using both the PATH and the Gaussian models in
Stage 3. The detailed modelling approach
for PATH model is presented in S3a.6.2.18 to S3a.6.2.42.
Stage 3 – Cumulative air quality assessment for identified potential hot spot areas using PATH and Gaussian models (i.e. CALINE4 and ISCST3)
3a.6.2.12
The
purpose of the Stage 3 assessment is to examine the cumulative air quality
impacts at the hot spot areas identified in the Stage 2 assessment. ISCST3 model and PATH model will be used to
assess the chimney emission impact from the IWMF on the ASRs. CALINE4 model were
used to simulate line sources including open road emissions within
3a.6.2.13
The
future background concentrations for air pollutants are predicted by the PATH
model. The PATH model output is added to
the sum of the CALINE4 and ISCST3 model results sequentially on an hour-to-hour
basis to derive the short-term and long-term cumulative impacts at the
ASRs. The highest pollutant
concentration predicted at an ASR amongst the 8760 hours (a year) is taken as
the worst predicted hourly pollutant concentration for that ASR. The maximum 24-hour average pollutant
concentration at an ASR is the highest predicted daily average concentration
amongst the 365 days. The annual average
pollutant concentration at an ASR is the average of 8760 hourly concentrations. The detailed modelling approach for CALINE4,
ISCST3 and PATH models are presented in S3a.6.2.43 to S3a.6.2.48. A summary
of the industry chimneys and vehicular emissions for CALINE4 and ISCST3
model are summarized in Appendices 3.4 and 3.8,
respectively.
Physical Model - Wind Tunnel (for Stage 1 assessment)
3a.6.2.14
Wind tunnel simulations have
been conducted such that concentration estimates under neutral, stable, and
unstable conditions can be obtained for the IWMF site for the wind directions
and wind speeds important to air pollution encountered in
3a.6.2.15 First, the concentration as a function of wind speed and wind direction is defined in the wind tunnel at all receptor locations of interest. Next this functional relation is used to estimate the hourly concentration levels at all receptors by applying a theoretical correction factor to the wind-tunnel predictions to account for plume buoyancy effects. Since the wind tunnel simulations are conducted under neutral stratification, a theoretical correction factor([1]) to the wind-tunnel predictions have been applied to account for plume buoyancy and atmospheric stability effects under stable and unstable conditions.
3a.6.2.16
A scale model of the test site
and surrounding to obtain concentration measurements out to
Numerical Model – PATH (for Stage 2 & 3 assessment)
3a.6.2.18
PATH model was used to quantify
the background air quality during operation phase of the Project. The commissioning time of the IWMF will be
around Year 2016/17 with maximum capacity build up in the commencement year. The emission sources including those in Pearl
River Delta Economic Zone, roads, airport, power plants and industries within
(a)
Emissions within
3a.6.2.19
The Study of Air Quality in the
Pearl River Delta Region conducted in Year 2000 had recommended various
mitigation strategies to control and improve the regional air quality
problems. In December 2003, the
governments of Hong Kong Special Administrative Region (HKSAR) and
3a.6.2.20 A Mid-term Review Study on Pearl River Delta Regional Air Quality Management Plan was commissioned by EPD of HKSAR Government and the Guangdong Environmental Protection Bureau (GPEPB) in November 2006 to update the regional pollutant emission for 2003 and 2010 Control Scenario, as well as to review the effect of control measures committed by the governments.
3a.6.2.21
In addition, the
3a.6.2.22 In accordance with the Final Report for Review of Air Quality Objectives and Development of a Long Term Air Quality Strategy for Hong Kong Feasibility Study (AQO Review Report), Year 2015, 2020 and post-2020 emission inventories are developed based on the above emission data. Year 2015 inventory, which is estimated based on the interpolation from the emission inventory for Year 2010 from the Mid-Term Review and the Year 2020 inventory compiled from 珠江三角洲環境保護規劃, is the highest emission inventory among three scenarios. As stated above, the operation of the IWMF is expected to build up to the maximum capacity in the commencement Year. Therefore, Year 2015 emission inventory as presented in the AQO Review Report is considered a reasonable assumption for the PATH model.
(b)
Emissions from
3a.6.2.23
The emissions from the
operation activities at the
3a.6.2.24
In accordance with the
(c) Emissions from Power Stations within HKSAR
3a.6.2.25 In accordance with the Administration’s response to the follow-up actions arising from the “Subcommittee on Second Technical Memorandum for Allocation of Emission Allowances in Respect of Specified Licences” (Ref: CB(1)410/10-11(02)), the emission allowances for Year 2015 to be allocated to the respective power stations listed in Table 3a.6 are used in PATH model for this study.
Table 3a.6 Allocated Emission Allowances for Year 2015
|
Power Stations |
Allocated Emission Allowances ( in Tonnes) |
||
|
SO2 |
NOx |
RSP |
|
|
Lamma Power Station and Lamma Power Station
Extension |
6,780 |
10,020 |
300 |
|
Black Point Power Station |
1,440 |
4,140 |
110 |
|
|
4,260 |
13,390 |
420 |
|
Penny’s Bay Gas
Turbine Power Station |
2 |
2 |
1 |
(d) Industrial Sources / Biogenic Sources within HKSAR
3a.6.2.26
According to the prediction in
the Study of Air Quality in the Pearl River Delta Region, there will be no
significant increase in the biogenic emission in
3a.6.2.27
The emissions from other
industrial sources have also been considered in the PATH model. As the IWMF is expected to be operated in
full capacity in Year 2015, estimation has been made by projecting from the
emission level for
3a.6.2.28 Other specific emission sources have been updated based on their respective best available information. The specific industrial emission sources within HKSAR including Ecopark, Sludge Treatment Facilities, Green Island Cement Facilities, Existing WENT Landfill and its Extensions, Shiu Wing Steel Mill and Black Point Gas Supply Project are also considered in the PATH model and their emissions are based on the full capacity of their operation. Their emissions inventories are make reference to the respective approved EIA reports and their Specified Process Licence.
(e) Marine Emissions within HKSAR
3a.6.2.29 The emissions from marine vessels within HKSAR have also been considered by making reference to the AQO Review Report. With reference to the AQO Review Report, the marine traffic in Year 2030 should be higher than Year 2015. The adoption of the emission at Year 2030 is considered as conservative approach. The projected marine emission at Year 2030 is shown in Appendix 3.6.
3a.6.2.30
With regards to the potential
emissions from the container terminals in the Kwai Tsing area, it is understood
from the container terminal operators’ press releases and other public
documents that the operators have converted or planned to convert most of their
diesel rubber-tyre gantry cranes (RTGC) to either electric or hybrid RTGC by
2010. With reference to the press
releases from Modern Terminals Limited, it is expected to reduce the fuel
consumption per each converted RTGC by nearly 40% after 2009. For the Hongkong International Terminals
(HIT), they have a plan to convert 70% of RTGC to electric RTGC by 2010. In addition, the emissions of the proposed
CT10, making reference to the Study on
(f) Vehicular Emissions within HKSAR
3a.6.2.31 EMFAC-HK model is adopted to estimate the vehicle emission rates and inventories of exhaust oxides of nitrogen and particulate matter. EMFAC-HK model have been conducted for 3 assessment years (Year 2015, 2020 & 2030) for each of the 18 HKSAR districts covered in the PATH model. The assessment years selected for the Project are in-line with the implementation years of different phases of air pollution control measures as presented in the AQO Review Study.
3a.6.2.32 The required traffic data for Years 2015, 2020 & 2030 was predicted by the 2006-based Base District Traffic Model (BDTM) traffic model. The 2006-based BDTM traffic model is recently developed by the Transport Department (TD) with the latest planning data and transport network. The traffic data produced by the traffic model is in the form of 24-hour traffic flow with VMT, speed fraction and number of trips in 16 types of vehicle for 3 assessment years. The methodology to produce the abovementioned data has been agreed by the TD. For each district, the results of relevant core traffic counting station(s) reported in TD’s Traffic Census were used to represent the general traffic pattern and vehicular grouping within the whole district. This methodology would have some limitations in representing the detailed traffic composition and traffic pattern on individual roads, yet given that the total traffic volume within the district would still be maintained, the small spatial variations of the total vehicle emissions are considered minimal and acceptable for this territory-wide study.
3a.6.2.33 For the purpose of PATH modelling, the estimated total vehicle emission for each district would be distributed over the road network surrogate in the respective district. For each district, EMFAC-HK model have been conducted for all roads covered by the traffic model as a whole. There are no separate EMFAC-HK model runs for different road types as different road types are currently not represented in the PATH model.
3a.6.2.34 However, for those districts identified with hot spot areas for the Project (namely Kwai Tsing District, Tuen Mun District and Islands District), separate EMFAC-HK model runs for different road types (classified by post speed) as shown in the Table 3a.7 below have been conducted to produce vehicle emission factors for different road types to be examined in the hot spots assessment. This is useful in representing the variation of vehicle emissions for different road types with different vehicle travel speeds in a local context.
Table 3a.7 Different road types for the hot spot areas
|
District |
Road Types Exist |
|
Kwai
Tsing |
1.
Local
Road (post speed 50kph) 2.
Trunk
Road (post speed 70-80kph) ·
3.
Expressway
(post speed >100kph) ·
|
|
Tuen
Mun |
1.
Local
Road (post speed 50kph) 2.
Trunk
Road (post speed 70-80kph) ·
|
|
Islands
(i.e Lantau) |
1.
Local
Road (post speed 50kph) 2.
Trunk
Road (post speed 70-80kph) ·
3.
Expressway
(post speed >100kph) ·
·
|
3a.6.2.35
The
vehicle population data (at the end Year 2008) published by EPD have been used
for future assessment years in the EMFAC-HK model and TD has no objection on
the use of published vehicle population data for EMFAC-HK model. For the hourly temperature and relative
humidity profile, given the small variations of temperature and relative
humidity profile between each district, the information provided by the Hong
Kong Observatory (HKO) as recorded at the Hong Kong Observatory meteorological
station (at Tsim Sha Tsui) have been adopted for all the EMFAC-HK model input. The key assumptions (including vehicle
population, technology fractions, hourly temperature and relative humidity) for
the EMFAC-HK model are shown in Appendix 3.7.
3a.6.2.36
The
EMFAC-HK model cannot estimate the SO2 emission and its emission
factors for different vehicle types.
With reference to the Guideline on Modelling Vehicle Emissions published
by EPD, the calculation of the SO2 emission and its emission factors
is conducted in accordance with USEPA PART 5 programme. The equation is shown below:
ESO2[g/km] = 1.96 x (Sf/100) x (Df x 1000) x (Ef /100)
Where
1.96 = factor to account for fraction emitted (0.98) (based on the assumption that 98% of the sulphur in fuel is emitted as SO2 in accordance with USEPA PART5 program) and weight ratio of SO2 to S (2.0)
Sf = fuel sulphur content (weight percent) = 0.005%
Df = density of fuel (0.745kg/L for gasoline and 0.832kg/L for diesel fuel)
Ef = vehicle fuel efficiency (L / 100km)
3a.6.2.37 The Efs for different types of vehicle are extracted from the Electrical and Mechanical Services Department (EMSD) Primary Indicator Values and listed in Table 3a.8. The calculated emission rate for SO2 for different types of vehicles are summarized in Table 3a.9.
Table 3a.8 Fuel Efficiency
|
Vehicle
Type |
Gross
Vehicle Weight (tonnes) |
Fuel
Efficiency (L per 100km) |
|
Heavy Goods Vehicles |
24.01 – 38 |
61.1 |
|
Light Goods Vehicles (Diesel) |
<2.5 |
10.2 |
|
Light Goods Vehicles (Diesel) |
2.51-4 |
12.2 |
|
Light Goods Vehicles (Diesel) |
4.01-5.5 |
18.6 |
|
Light Goods Vehicles (Petrol) |
-- |
14.8 |
|
Private Car |
Assume all engine size >3000cc |
17.9 |
Note:
Fuel efficiency are extracted from EMSD’s websites:
http://www.emsd.gov.hk/emsd/eng/pee/classc.shtml
http://www.emsd.gov.hk/emsd/eng/pee/classd.shtml
http://www.emsd.gov.hk/emsd/eng/pee/classhgv.shtml
Table 3a.9 Emission rate for SO2 for different types of vehicles
|
Vehicle Types |
Sf |
Df |
Ef |
ESO2
(g/km) |
|
Petrol PC &LGV (Petrol) |
0.005 |
0.745 |
17.9 |
0.0131 |
|
Diesel PC&LGV <2.5t |
0.005 |
0.832 |
17.9 |
0.0146 |
|
Diesel LGV 2.5-3.5t |
0.005 |
0.832 |
12.2 |
0.0099 |
|
Public Light Buses |
0.005 |
0.832 |
18.6 |
0.0152 |
|
Diesel LGV >3.5t |
0.005 |
0.832 |
18.6 |
0.0152 |
|
HGV<15t |
0.005 |
0.832 |
61.1 |
0.0498 |
|
HGV>15t |
0.005 |
0.832 |
61.1 |
0.0498 |
|
Double Deck Franchised Buses |
0.005 |
0.832 |
61.1 |
0.0498 |
|
Motor Cycles (Petrol) |
0.005 |
0.745 |
17.9 |
0.0131 |
|
Taxi |
0.005 |
0.745 |
17.9 |
0.0131 |
|
Private Light Buses <3.5t |
0.005 |
0.832 |
12.2 |
0.0099 |
|
Private Light Buses >3.5t |
0.005 |
0.832 |
18.6 |
0.0152 |
|
Non-franchised Buses <6.4t |
0.005 |
0.832 |
61.1 |
0.0498 |
|
Non-franchised Buses 6.4-15t |
0.005 |
0.832 |
61.1 |
0.0498 |
|
Non-franchised Buses >15t |
0.005 |
0.832 |
61.1 |
0.0498 |
|
Single Deck Franchised Buses |
0.005 |
0.832 |
61.1 |
0.0498 |
3a.6.2.38
The
worst emission year for vehicle emission have been taken as the year among the
3 assessment years with the highest total vehicle emissions from all 18
districts within HKSAR. The vehicle
emission for this worst emission year (i.e. Year 2015) of major pollutants of
NOx and PM10 has been adopted in the PATH model. The calculated vehicle emissions for the
entire
Table 3a.10 Total vehicle emission for different assessment years for the entire territory
|
Assessment
Year |
Tonnes per Year |
||
|
SO2 |
NOx |
PM10 |
|
|
Year 2015 |
217 |
8,511 |
595 |
|
Year 2020 |
241 |
7,191 |
411 |
|
Year 2030 |
247 |
5,519 |
309 |
Note:
The tentative commencement date of the TMWB
Project would be at Year 2016. For
conservative analysis, the emission burden (emission data was extracted from
TMCLKL EIA Report) from TMWB was considered in the assessment.
3a.6.2.39 The emissions from other emission sources (e.g. non-road mobile sources, VOC containing sources etc) within HKSAR have also been considered by making reference to 2030 emission inventory (without implementation measure) as mentioned in the AQO Review Report. Year 2030 emission inventory is expected to be higher than in Year 2015 as there is a positive growth factor in the forecast data.
(h) Non-criteria Pollutants
3a.6.2.40 Apart from the criteria air pollutants listed under AQO, there are some other toxic air pollutants that would be generated from the combustion process of the IWMF. These potential non-criteria air pollutants are listed as follows:
· Gaseous and vaporous organic substances, expressed as total organic carbon
· Hydrogen Chloride (HCl)
· Hydrogen Fluoride (HF)
· Mercury
· Cadmium
· Thallium
· Other heavy metals
· Dioxins & Furans
3a.6.2.41 These toxic air pollutants (except total organic carbon) have been simulated as unreactive particulates (PM2.5 or finer) under PATH. A unit of a particular (Tracer A) species of unreactive particulate was set to be emitted from the IWMF stack.
Numerical Model – CALINE4 (for Stage 3 assessment)
3a.6.2.44
The
worst emission year (Year 2015) for vehicle emission have been taken as the
year among the 3 assessment years with the highest total vehicle emissions from
the district where the hot spot locate.
The vehicle emission for this worst emission year has been adopted in
the local dispersion model(s) for that particular hot spot in the cumulative
impact assessment.
3a.6.2.45 The calculated vehicle emissions for each hot spot area for different assessment years are summarized in Table 3a.11.
Table 3a.11 Total vehicle emission for different assessment years for each hot spot area
|
Hot
Spot Areas |
Parameter |
Tonnes per Year |
||
|
2015 |
2020 |
2030 |
||
|
Kwai Tsing |
NOx |
528.1 |
403.5 |
294.5 |
|
RSP |
43.3 |
26.2 |
18.5 |
|
|
Tuen Mun |
NOx |
223.7 |
168.2 |
117.3 |
|
RSP |
16.6 |
9.2 |
5.6 |
|
|
Nim Wan & Lung Kwu Sheung Tan |
NOx |
63.6 |
63.0 |
41.2 |
|
RSP |
4.9 |
3.7 |
2.0 |
|
|
|
NOx |
828.1(1) |
562.4 |
426.3 |
|
RSP |
47.5(1) |
23.9 |
18.3 |
|
Note:
The tentative commencement date of the
HZMB-BCF & TMCLKL Projects would be at Year 2016. For conservative analysis, the traffic flow
at Year 2016 for the abovementioned project was considered in the assessment.
3a.6.2.46
The
dispersion modelling has been conducted based on the meteorological data
extracted from the PATH model. Ozone
Limiting Method (OLM) was adopted for conversion of NOx to NO2
based on the predicted O3 level from PATH. A tailpipe emission NO2/NOx
ratio of 7.5% based on the EPD’s “Guidelines on Choice of Models and Model
Parameters” has been assumed. The NO2/NOX
conversion was calculated as follows:
[NO2]pred
= 0.075 ´
[NOX]pred + MIN {0.925 ´ [NOX]pred,
or (46/48) ´
[O3]bkgd}
where
[NO2]pred is the predicted NO2
concentration
[NOX]pred is the predicted NOX
concentration
MIN means
the minimum of the two values within the brackets
[O3]bkgd is the representative O3 background
concentration
(46/48) is the molecular weight of NO2
divided by the molecular weight of O3
Numerical Model – ISCST3 (for Stage 3 assessment)
3a.6.2.47
The
ISCST3 model assesses both criteria and non-criteria air pollutants
concentrations at the ASRs. The impacts
due to the IWMF and associated marine emission, STF and WENT Landfill &
Extension, planned Black Point Gas Supply Project, other industrial chimneys
and portal emissions within
[NO2]pred
= 0.1 ´
[NOX]pred + MIN {0.9 ´ [NOX]pred,
or (46/48) ´
[O3]bkgd}
where
[NO2]pred is the predicted NO2
concentration
[NOX]pred is the predicted NOX
concentration
MIN means
the minimum of the two values within the brackets
[O3]bkgd is the representative O3 background
concentration
(46/48) is the molecular weight of NO2
divided by the molecular weight of O3
3a.6.3 Operation Phase – Odour Impacts
3a.6.3.1 Odour nuisance may arise from the operation of the on-site wastewater treatment plant, the waste reception halls, the waste storage area and the mechanical treatment plant of the Project. The wastewater treatment plant, the waste reception halls and the waste storage areas would be fully enclosed and the odorous air in this facility would be extracted and used for combustion air of incineration to remove the odorous compounds. For the mechanical plant, they would be equipped with deodorizing units or odour filtration system. The odour removal efficiency of the deodorizing units would be 95%. Besides, the wastewater treatment plant, waste reception halls, waste storage area and the mechanical treatment plant would also be operated under a negative pressure to prevent odour leaking to the outdoor environment, adverse odour impact on nearby ASRs would not be expected.
3a.6.3.2 As the odour characteristics from the IWMF are similar to the MSW disposed at the tipping face at the landfill. The odour emission rate of the MSW was made reference to the approved EIA Report for North East New Territories (NENT) Landfill Extension for this assessment. The detailed emission rate and stack parameters adopted in the assessment are shown in Appendix 3.9.
3a.6.3.3 Air quality impacts of odour, mainly those residual odour emissions from the deodorizing units, on ASRs have been modelled with the ISCST3 model. MM5 hourly meteorological data were employed for the model run.
3a.6.3.4 The modelled hourly odour concentrations at the ASRs was converted to 5-second average odour concentration by the methodology proposed by Duffee et al.([2]) and Keddie([3]). In addition, Turner([4]) has identified that the Pasquill-Gifford vertical dispersion parameter used in the ISCST3 model is around 3 to 10 minutes. As a conservative assumption, the hourly average estimated by ISCST3 model is assumed as 15 minutes average, and the conversion factors for the predicted 1-hour averaged concentration of odour at the receivers would be adjusted to 5-second averaging time by the values shown in Table 3a.12.
Table 3a.12 Conversion Factors to 5 second Average Concentration
|
Pasquill
Stability Class |
Conversion
Factor |
||
|
15 min
to 3 min |
3 min to
5 sec |
Overall |
|
|
A |
2.23 |
10 |
22.3 |
|
B |
2.23 |
10 |
22.3 |
|
C |
1.7 |
5 |
8.5 |
|
D |
1.38 |
5 |
6.9 |
|
E |
1.31 |
5 |
6.55 |
|
F |
1.31 |
5 |
6.55 |
3a.6.3.5 With the installation of the proper deodorization units, the odour emissions from the IWMF would be limited and hence the potential odour impacts would likely be confined to the immediate vicinity of the IWMF site and the contribution of the IWMF odour emission on the cumulative odour impact to nearby ASRs would likely be minimal.
3a.7 Prediction and Evaluation of Environmental Impacts
3a.7.1.1 Construction activities at the IWMF will involve site formation works, superstructure works and installation of associated utilities facilities. Extensive excavation works is not expected. All the above activities are not expected to generate significant amount of construction dust.
3a.7.1.2 Control measures stipulated in the Air Pollution Control (Construction Dust) Regulation of Air Pollution Control Ordinance (APCO) should be implemented to ensure that construction impacts are controlled within the relevant standards described above. An environmental audit programme for construction phase has been devised to verify the effectiveness of the control measures so as to ensure proper construction dust control. With proper implementation of dust control measures, significant construction dust impacts at ASRs during the construction phase of the Project is not anticipated.
3a.7.2
Operation Phase - Gaseous Pollutants
Stage 1 – Terrain and building wake effects test for the selected stack height of the IWMF using wind tunnel model
3a.7.2.1 Wind tunnel test has been conducted for the selected stack height of the IWMF. The results confirmed that the proposed stack height would not result in exceptionally high concentration at critical ASRs due to adverse terrain or building wake effects. The physical model test report is shown in Appendix 3.10.
Stage 2 – Identification of the potential hot spot area by using PATH model
3a.7.2.2
The
purpose of the Stage 2 assessment is to examine the cumulative air quality impacts
at a territory-wide scale by using PATH model. Plots of the predicated cumulative air
pollutant concentrations of NO2, SO2, RSP and CO in
3a.7.2.3
Besides,
in order to examine the air quality impacts associated with the stack emissions
of the IWMF alone, the differences between the PATH modelling results for two
scenarios namely with and without IWMF stack emission were calculated on a hour
by hour basis for one of the key air pollutant namely NO2. The worst-case hourly, worst-case daily, and
the annual contribution of the IWMF stack emission on the cumulative NO2
concentrations over the
3a.7.2.4
Based
on the predictions from the PATH model, higher IWMF contributions are
identified at Nim Wan, Lung Kwu Sheung Tan and Tuen Mun areas whereas localised
high cumulative concentrations of NO2 and RSP are predicted at Nim
Wan,
3a.7.2.5
As
shown in Appendix 3.11,
localised high RSP annual average concentrations are predicted near the border
with Shenzhen. The high concentrations are
largely due to the trans-boundary pollution sources rather than associated with
this Project. Therefore, this area is
not considered as hot spot area for further examination under the Stage 3 assessment.
3a.7.2.6
For
SO2, the predicted 1-hr average, daily average and annual average SO2
concentration at territory-wide scale are all less than 63% of the respective
AQO. In view of the relatively low predicted
concentrations and the adoption of low-sulphur and ultra-low-sulphur fuel under
the existing government policy, SO2 would not
be a critical air
pollutant of concern. For CO, the
predicted 1-hr average and 8-hr average concentration at territory-wide scale
are relatively small (about 20% of the respective AQO) in
quantity compared with the respective AQO. Therefore,
only NO2 and RSP are covered under the Stage 3 assessment.
3a.7.2.7
The
representative ASRs within the hot spot areas listed in Section 3a.7.2.4 above are identified and tabulated in Table 3a.13. The
locations of the ASRs are shown in Figure 3a.1.
Table 3a.13 Identified Air Sensitive Receivers for the TTAL Site (Gaseous Pollutants)
|
ASR |
Description |
Nature of ASR (1) |
Building Height, m |
Ground level, mPD |
Distance to Project Boundary, m |
|
TT1 |
Ha Pak Nai |
R |
9 |
3.4 |
1989 |
|
TT2 |
Sludge Treatment
Facilities Site Office |
I |
- |
5.0 |
205 |
|
TT3 |
EPD WENT
Landfill Site Office |
I |
6 |
5.7 |
625 |
|
TT4 |
|
G/IC |
3 |
4.7 |
88 |
|
TT5 |
Black Point
Power Station (Office) |
I |
9 |
5.6 |
1130 |
|
TT6 |
Lung Kwu Sheung
Tan |
R |
6 |
3.4 |
1871 |
|
TM1 |
Block F, |
G/IC |
66 |
5.8 |
5627 |
|
TM2 |
|
R |
104 |
4.5 |
6149 |
|
TM3 |
|
R |
89 |
5.8 |
5961 |
|
TM4 |
|
R |
96 |
5.0 |
5770 |
|
TM5 |
Block 4, |
R |
102 |
16.0 |
5245 |
|
TM6 |
Leung King Estate |
R |
102 |
10.0 |
4261 |
|
TC1 |
|
CDA |
141 |
7.5 |
14291 |
|
TC2 |
|
CDA |
153 |
6.8 |
14508 |
|
TC3 |
Ling Liang
Church Sau Tak primary School |
G/IC |
21 |
6.4 |
14590 |
|
TC4 |
|
R |
108 |
9.3 |
14954 |
|
TC5 |
|
R |
129 |
11.1 |
14664 |
|
TC6 |
Yat Tung Estate
- Hong Yat House |
R |
105 |
9.7 |
15523 |
|
AP1 |
Chek Lap Kok
Fire Station |
C |
9 |
7.5 |
13317 |
|
AP2 |
Gate Gourmet
Catering Building |
C |
30 |
6.7 |
12890 |
|
AP3 |
DHL |
C |
30 |
5.4 |
13636 |
|
AP4 |
Regal Airport
Hotel |
C |
90 |
5.3 |
11253 |
|
AP5 |
SkyCity Nine
Eagles Golf Course |
C |
- |
6.2 |
11496 |
|
AP6 |
SkyCity Nine
Eagles Golf Course |
C |
- |
6.2 |
11700 |
|
AP7 |
Hong Kong
SKyCity Marriott Hotel |
C |
45 |
6.2 |
11414 |
|
AP8 |
Terminal 2 |
G/IC |
25 |
6.4 |
11573 |
|
SLW1 |
Sha Lo Wan House
No.1 |
R |
9 |
5.0 |
14195 |
|
SLW2 |
|
R |
9 |
4.9 |
14556 |
|
SLW3 |
Tin Sum |
R |
9 |
5.7 |
14362 |
|
KT1 |
Block 6, Lai
King Estate |
R |
42 |
40.1 |
22380 |
|
KT2 |
Block 7, Lai
King Estate |
R |
66 |
40.1 |
22507 |
|
KT3 |
Lai King Home |
R |
12 |
40 |
22631 |
|
KT4 |
|
G/IC |
6 |
38.5 |
22867 |
|
KT5 |
Lai Hong House, |
R |
135 |
25 |
23526 |
|
KT6 |
|
G/IC |
30 |
38.9 |
23523 |
|
KT7 |
|
G/IC |
- |
7.6 |
24502 |
|
KT8 |
Hoi Yin House, Hoi Lai Estate |
R |
108 |
5.9 |
24842 |
Notes:
R – Residential; C – Commercial; I –
Industrial; G/IC –Government / Institution / Community; CDA - Comprehensive
Development Area
Stage 3 – Cumulative air quality assessment for identified potential hot spot areas using PATH and Gaussian models (i.e. CALINE4 and ISCST3)
3a.7.2.8
The predicted cumulative NO2
and RSP concentrations at the representative ASRs within the identified hot
spot areas using PATH and Gaussian models are summarized in Appendix 3.12. The hourly and/or daily and annual average contour
plots for NO2 and RSP at 1.5m above ground are presented in Figures 3a.3 to 3a.7. From the contour
plots, exceedances of the hourly NO2 of 300µg/m3 are predicted
in Nim Wan & Lung Kwu Sheung Tan and
3a.7.2.9
The other potential air
pollutants (individual chemicals) covered in Annex 1 of EPD’s “A Guidance Note
on the Best Practicable Means for Incinerator (Municipal Waste Incineration)
BPM 12/1(08)” are identified as non-criteria air pollutants. The predicted short-term and long-term
concentrations of these non-criteria air pollutants and their health impacts
are assessed in Section
3a.7.3
Operation Phase – Odour Impacts
3a.7.3.1 Odour level at the nearest representative ASR for odour impact, namely Tin Hau temple, is predicted and the assessment result is shown in Table 3a.14.
Table 3a.14 Predicted Odour Levels at the ASR
|
ASR |
Description |
Odour Level (5 seconds average) (OU) at |
|
TT4 |
|
0.02 |
3a.7.3.2 The modelling results indicated that the predicted odour impact at the nearest ASR for odour impact would be well below EIAO-TM’s odour criteria of 5 OU based on an averaging time of 5 seconds. The predicted odour level of 0.02 OU at the nearest ASR due to IWMF emissions is well below 1 OU, i.e. not detectable by most of the population. Cumulative odour impacts with other potential odour sources further away from IWMF including the STF, WENT Landfill and its Extension is therefore not expected.
3a.8.1.1
To ensure compliance with the guideline level and
AQO at the ASRs, the Air Pollution Control (Construction Dust) Regulation
should be implemented and good site practices should be incorporated in the
contract clauses to minimize construction dust impact. A number of practicable measures are listed
below:-
· Use of regular watering, with complete coverage, to reduce dust emissions from exposed site surfaces and unpaved roads, particularly during dry weather.
· Use of frequent watering for particularly dusty construction areas and areas close to ASRs.
· 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.
· Open stockpiles should be avoided or covered. Where possible, prevent placing dusty material storage piles near ASRs.
· Tarpaulin covering of all dusty vehicle loads transported to, from and between site locations.
· Establishment and use of vehicle wheel and body washing facilities at the exit points of the site.
· Provision of wind shield and dust extraction units or similar dust mitigation measures at the loading points, and use of water sprinklers at the loading area where dust generation is likely during the loading process of loose material, particularly in dry seasons/ periods.
· Imposition of speed controls for vehicles on unpaved site roads. Ten kilometres per hour is the recommended limit.
· Where possible, routing of vehicles and positioning of construction plant should be at the maximum possible distance from ASRs.
· Instigation of an environmental auditing program to monitor the construction process in order to enforce controls and modify method of work if dusty conditions arise.
3a.8.2.1
Air pollution control and stack monitoring system
will be installed for the IWMF to ensure that the emissions from the IWMF
stacks will meet the proposed target emission limits that is more stringent
than those stipulated in
3a.8.2.2
To ensure the compliance of odour criteria at the sensitive
receptors in the vicinity of the IWMF, all the potential odour emissions
associated with the operation of the IWMF namely those from wastewater treatment plant, the waste reception halls, the waste
storage area, the mechanical treatment plant should be collected
and destroyed by the incineration process or ventilated to deodorizer before
discharge to the atmosphere.
3a.9 Residual Environmental Impact
3a.9.1.1
With the implementation of the mitigation measures
as stipulated in the Air Pollution Control (Construction Dust) Regulation, and
with the adoption of good site practices and audit, no adverse residual dust
impact is expected.
3a.9.2.1
With the implementation of practicable air
pollution control and stack monitoring system for the IWMF, emissions from the IWMF
stacks will meet the proposed target emission limits that is more stringent
than those stipulated in
3a.9.2.2
With the implementation of recommended odour mitigation
measures, no adverse residual odour impact would be expected at the nearby
ASRs.
3a.10 Environmental Monitoring and Audit Requirements
3a.10.1.1
With the implementation of practicable dust
suppression measures stipulated in the Air Pollution Control (Construction
Dust) Regulation, adverse construction dust impact is not expected during
construction of the Project. Yet,
regular site environmental audits during the construction phase of the Project
as specified in the EM&A Manual should be conducted to ensure that the
recommended dust suppression measures are implemented properly.
3a.10.2.1
During the operation of the IWMF, the potential
sources of air quality impacts would be the air emissions from the stacks of
incineration process and the odour nuisance from the the
waste reception halls, the waste storage area, the mechanical treatment plant. Air pollution control and stack monitoring
system will be installed for the IWMF to ensure that the emissions from the
IWMF stack will meet the stringent target emission limits and all the potential
odour emissions associated with the operation of the IWMF will be collected and
destroyed by the incineration process or ventilated to deodorizer before
discharge to the atmosphere. Monitoring
of air quality parameters of concern due to stack emissions has to be conducted
in accordance with the requirements similar to those stipulated in the “A
Guidance Note on the Best Practicable Means for Incinerator (Municipal Waste
Incineration) BPM 12/1(08)”. Besides,
odour monitoring should be carried out by odour patrol to demonstrate the
effectiveness of the proposed odour mitigation measures and to ensure the odour
impact can be minimized to meet the air pollution control requirements.
3a.11.1.1
Air quality impacts from the construction works for
the Project would mainly be related to construction dust from excavation,
materials handling, filling activities and wind erosion. With the implementation of mitigation
measures specified in the Air Pollution Control (Construction Dust) Regulation,
dust impact on air sensitive receivers would be minimal.
3a.11.2.1
During the operation of the IWMF, the potential
sources of air quality impacts would be the air emissions from the stacks of
incineration process and the odour nuisance from the
waste reception halls, the waste storage area and the mechanical treatment plant.
3a.11.2.2
Air pollution control and stack monitoring system
will be installed for the IWMF to ensure that the emissions from the IWMF
stacks will meet the proposed target emission limits that is more stringent than
those stipulated in
3a.11.2.3
With the implementation of practicable air
pollution control, the cumulative air quality impact assessment results shows
that all the air sensitive receivers in the vicinity of the Project site would
comply with the Air Quality Objectives (AQOs).