9.1
This section presents the requirements, methodology,
equipment, monitoring locations, criteria and protocols for the monitoring and
audit of air quality impacts during the construction phase of the Project.
9.2
The objectives of the air quality monitoring shall be:
(i) To identify the
extent of construction dust impacts on sensitive receivers;
(ii) To determine the
effectiveness of mitigation measures to control fugitive dust emission from
activities during construction phase;
(iii) To audit the compliance
of the Contractor with regard to dust control, contract conditions and the
relevant dust impact criteria;
(iv) To recommend further
mitigation measures if found to be necessary; and
(v) To comply with
Action and Limit (A/L) Levels for air quality as defined in this Manual.
9.3
The criteria against which ambient air quality monitoring
shall be assessed are:
(i) The Hong Kong Air
Quality Objectives (AQOs) for TSP, 24-hour TSP levels of 260 mg m-3; and
(ii) The statutory
1-hour TSP limit of 500 mg m-3.
9.4
These levels are not to be exceeded at Air Sensitive
Receivers (ASRs).
9.5
The TSP levels shall be measured by following the standard
method as set out in High Volume Method for Total Suspended Particulates, Part
50 Chapter 1 Appendix B, Title 40 of the Code of Federal Regulations of the
USEPA.
9.6
Dust laden with air shall be drawn through a high volume
sampler (HVS) fitted with a conditioned, pre-weighed filter paper, at a
controlled rate. After sampling for
24-hours, the filter paper with retained particles is collected and returned to
the laboratory for drying in a desiccator followed by accurate weighing. 24-hour average TSP levels are
calculated from the ratio of the mass of particulates retained on the filter
paper to the total volume of air sampled.
9.7
All relevant data including temperature, pressure, weather
conditions, elapsed-time meter reading for the start and stop of sampler,
identification and weight of the filter paper, and other special phenomena and
work progress of the concerned site, etc, shall be recorded down in
detail. A sample data sheet is
shown in Appendix C.
9.8
HVS in compliance with the following specifications shall be
used for carrying out the 1-hour and 24-hour monitoring:
(i)
0.6 - 1.7 m3 per minute (20 -
60 standard cubic feet per minute) adjustable flow range;
(ii)
equipped with a timing / control device
with ± 5 minutes accuracy for 24 hours operation;
(iii)
installed with elapsed-time meter with ±
2 minutes accuracy for 24 hours operation;
(iv)
capable of providing a minimum exposed
area of 406 cm2 (63 in2);
(v)
flow control accuracy: ± 2.5% deviation over 24-hour sampling
period;
(vi)
incorporated with an electronic mass flow
rate controller or other equivalent devices;
(vii)
equipped with a flow recorder for
continuous monitoring;
(viii) provided
with a peaked roof inlet;
(ix)
incorporated with a manometer;
(x)
able to hold and seal the filter paper to
the sampler housing at horizontal position;
(xi)
easy to change the filter;
(xii)
capable of operating continuously for
24-hour period.
9.9
The ET shall be responsible for the provision of the monitoring
equipment. He shall ensure that sufficient number of HVSs with appropriate
calibration kit is available for carrying out the baseline, regular impacts
monitoring and ad-hoc monitoring.
The HVSs shall be equipped with an electronic mass flow controller and
be calibrated against a traceable standard at regular intervals, in accordance
with requirements stated in the manufacturers operating manual and as described
below. All the equipment,
calibration kit, filter papers, etc, shall be clearly labelled.
9.10
The flow rate of each HVS with mass flow controller shall be
calibrated using an orifice calibrator.
Calibration shall be carried out every six months.
9.11
The flow-rate of the sampler before and after the sampling
exercise with the filter in position shall be verified to be constant and be
recorded down on the data sheet as mentioned in Appendix C.
9.12
The worst affected locations in the vicinity of construction
sites have been identified for TSP dust monitoring as shown in Table 9.1 and illustrated in Figure 9.1 – 9.3.
Table 9.1 Air Monitoring Stations during Construction Phase
Construction Work Site |
Identification No. |
Air Monitoring Location |
|
AM1 |
ASR
K5 - |
AM2 |
ASR K15 - Victoria
Public Mortuary |
|
AM3 |
ASR K17 - |
|
AM4 |
ASR K19 - School at |
|
University
Station |
AM5 |
ASR U11- New Fortune
House, Block A |
AM6 |
ASR U3 - |
|
AM7 |
ASR U5 - Jadeview Court |
|
Sai Ying
Pun Station |
AM8 |
ASR S1 - Bon-Point |
AM9 |
ASR S2 - No. 18-20
Eastern St |
|
AM10 |
ASR S3 - |
9.13
When alternative monitoring locations are proposed, the
monitoring locations shall be chosen based on the following criteria:
(i)
Monitoring at sensitive receivers close to
the major site activities which are likely to have air quality impacts;
(ii)
Monitoring at the air sensitive receivers
as defined in the Technical Memorandum;
(iii)
Assurance of minimal disturbance to the
occupants during monitoring.
9.14
When positioning the HVSs, the following points shall be
noted:
(i)
A horizontal platform with appropriate
support to secure the samplers against gusty wind shall be provided;
(ii)
no two samplers shall be placed less than
2 m apart;
(iii)
the distance between the sampler and an
obstacle, such as buildings, must be at least twice the height that the
obstacle protrudes above the sampler;
(iv)
a minimum of 2 m separation from walls,
parapets and penthouses is required for rooftops samplers;
(v)
a minimum of 2 m separation from any
supporting structure, measures horizontally is required;
(vi)
no furnace or incinerator flue is nearby;
(vii)
airflow around the sampler is
unrestricted;
(viii) the
sampler is more than 20 m from the dripline;
(ix)
any wire fence and gate to protect the
sampler, shall not cause any obstruction during monitoring;
(x)
permission must be obtained to set up the
samplers and to obtain access to the monitoring stations; and
(xi)
a secured supply of electricity is needed
to operate the samplers.
9.15
Baseline monitoring shall be carried out to determine the
ambient 1-hour and 24‑hour TSP levels at the monitoring locations prior to the
commencement of the Project works.
During the baseline monitoring, there shall not be any construction or
dust generating activities in the vicinity of the monitoring stations.
9.16
TSP baseline monitoring shall be carried out for a
continuous period of at least two weeks under typical weather conditions with
the 24-hour and three 1-hour ambient measurements taken daily at each
monitoring location. General
meteorological conditions (wind speed, direction and precipitation) and notes
regarding any significant adjacent dust producing sources shall also be
recorded throughout the baseline monitoring period.
9.17
The baseline monitoring will provide data for the
determination of the appropriate Action levels with the Limit levels set
against statutory or otherwise agreed limits.
9.18
Baseline checking of ambient TSP levels shall be carried out
every six months at each monitoring location, when no dusty works activities
are in operation. If the ET
considers that significant changes in the ambient conditions have arisen, a
repeat of the baseline monitoring may be carried out to update the baseline
levels and air quality criteria, after consultation and agreement with the ER,
the IEC and the EPD.
9.19
The monthly schedule of the compliance and impact monitoring
programme shall be drawn up by the ET one month prior to the commencement of
the scheduled construction period.
For regular impact monitoring, a sampling frequency of at least once in
every six days shall be strictly observed at all of the monitoring stations for
24-hour TSP monitoring. In case of
complaints, 1-hour TSP monitoring shall be conducted at least three times in
every six days when the highest dust impacts are likely to occur. The impact monitoring programme is
summarised in Table 9.2.
Table 9.2 Dust Impact Monitoring Programme
Sampling duration |
Frequency |
1
hour |
·
3 times every 6 days (as required
in case of complaints) |
24
hours |
·
Once every 6 days |
9.20
Before commencing the monitoring, the ET shall inform the IEC
of the impact monitoring programme such that the IEC can conduct an on-site
audit to ensure the accuracy of the impact monitoring results.
9.21
Action and Limit levels that provide an appropriate
framework for the interpretation of monitoring results have to be agreed
between ET, IEC, EPD and the Engineer before commencement of the air
monitoring. The air quality
monitoring data shall be checked against the agreed A/L levels. Recommended A/L levels are listed in Table 9.3.
Table 9.3 Proposed Action and Limit Levels for Impact Monitoring
Parameter |
Action Level (1) |
Limit Level |
TSP (24
hour average) |
·
BL £
200μg m-3, AL = (BL
* 1.3 + LL)/2 ·
BL > 200μg m-3, |
260 μg m-3 |
TSP (1
hour average) |
·
BL £
384μg m-3, AL = (BL
* 1.3 + LL)/2 ·
BL
> 384μg m-3, AL = LL |
500μg m-3 |
(1) BL =
Baseline level,
9.22
The principle upon which the EAP is based on the
prescription of procedures and actions associated with the measurement of
certain defined levels of air pollution recorded by the environmental
monitoring process and the agreed A/L levels. In cases where exceedance of these A/L
levels occurs, the ET, the IEC, the Engineer and the Contractor shall strictly
observe the relevant actions of the respective EAP listed in Table 9.4.
Table 9.4 Event and Action Plan for Ambient Air Quality Monitoring (Construction)
ACTION |
||||
ET |
IEC |
ER |
CONTRACTOR |
|
ACTION LEVEL |
||||
1. Exceedance for one sample |
1.
Identify
source, investigate the causes of complaint and propose remedial measures; 2.
Inform IEC
and ER; 3.
Repeat
measurement to confirm finding; 4.
Increase
monitoring frequency to daily. |
1.
Check
monitoring data submitted by ET; 2.
Check
Contractor’s working method. |
1. Notify Contractor. |
1. Rectify
any unacceptable practice; 2. Amend working methods if
appropriate. |
2. Exceedance for two or more
consecutive samples |
1.
Identify
source; 2.
Inform IEC
and ER; 3.
Advise
the ER on the effectiveness of the proposed remedial measures; 4.
Repeat
measurements to confirm findings; 5.
Increase
monitoring frequency to daily; 6. Discuss with IEC and ER (together with the Contractor) on
remedial actions required; 7.
If
exceedance continues, arrange meeting with IEC and ER; 8. If exceedance stops, cease additional monitoring. |
1.
Check
monitoring data submitted by ET; 2.
Check
Contractor’s working method; 3.
Discuss
with ET and ER (together with the Contractor) on possible remedial measures; 4.
Advise
the ET/ER on the effectiveness of the proposed remedial measures; 5.
Supervise
Implementation of remedial measures. |
1. Confirm
receipt of notification of exceedance in writing; 2.
Notify
Contractor; 3.
Ensure
remedial measures properly implemented. |
1. Submit
proposals for remedial to ER within three working days of notification; 2. Implement
the agreed proposals; 3. Amend proposal if
appropriate. |
LIMIT LEVEL |
||||
1. Exceedance for one sample |
1. Identify
source, investigate the causes of exceedance and propose remedial measures; 2. Inform
IEC, ER, Contractor and EPD; 3. Repeat
measurement to confirm finding; 4. Increase
monitoring frequency to daily; 5. Assess
effectiveness of Contractor’s remedial actions and keep IEC, EPD and ER
informed of the results. |
1.
Check monitoring
data submitted by ET; 2.
Check
Contractor’s working method; 3.
Discuss
with ET and ER (together with the Contractor) on possible remedial measures; 4.
Advise
the ER on the effectiveness of the proposed remedial measures; 5.
Supervise
implementation of remedial measures. |
1.
Confirm
receipt of notification of exceedance in writing; 2.
Notify
Contractor; 3.
Ensure
remedial measures properly implemented. |
1.
Take
immediate action to avoid further exceedance; 2.
Submit
proposals for remedial actions to ER with a copy to IEC within three working
days of notification; 3.
Implement
the agreed proposals; 4. Amend proposal if
appropriate. |
2. Exceedance for two or more
consecutive samples |
1.
Notify IEC,
ER, Contractor and EPD; 2.
Identify
source; 3.
Repeat
measurement to confirm findings; 4.
Increase
monitoring frequency to daily; 5.
Carry
out analysis of Contractor’s working procedures to determine possible
mitigation to be implemented; 6.
Arrange
meeting with IEC and ER to discuss the remedial actions to be taken; 7.
Assess
effectiveness of Contractor’s remedial actions and keep IEC, EPD and ER
informed of the results; 8.
If
exceedance stops, cease additional monitoring. |
1.
Discuss
amongst ER, ET, and Contractor on the potential remedial actions; 2.
Review
Contractor’s remedial actions whenever necessary to assure their
effectiveness and advise the ER accordingly; 3.
Supervise
the implementation of remedial measures. |
1.
Confirm
receipt of notification of exceedance in writing; 2.
Notify
Contractor; 3.
In consultation
with the IEC, agree with the Contractor on the remedial measures to be
implemented; 4.
Ensure
remedial measures properly implemented; 5.
If
exceedance continues, consider what portion of the work is responsible and
instruct the Contractor to stop that portion of work until the exceedance is
abated. |
1. Take
immediate action to avoid further exceedance; 2. Submit
proposals for remedial actions to ER with a copy to IEC within three working
days of notification; 3. Implement
the agreed proposals; 4. Revise
and resubmit proposals if problem still not under control; 5. Stop
the relevant portion of works as determined by the ER until the exceedance is
abated. |
9.23
The EIA Report recommended air quality control and
mitigation measures during the construction phase of the Project. The mitigation measures are summarised
below.
9.24
Dust mitigation measures stipulated in the Air Pollution
Control (Construction Dust) Regulation should be incorporated to control dust
emission from all construction work sites.
For the proposed two rock crushing plants at Kennedy Town Abattoir Site
and
9.25
According to the preliminary engineering information, the
following design control measures have been incorporated into the design of the
crushing plants, barging facilities and stockpile areas, as presented in Table 9.5, 9.6 and 9.7.
Table 9.5 Rock Crushing Plants – Dust Emission Design Control Measures
Process |
Description |
Dust Emission
Design Control Measures |
Unloading of raw materials |
Unloading
of stone/rock at the receiving hopper |
The unloading process would be
undertaken within enclosed rock crushing facility. Water spraying would be provided
at the unloading point. |
Crushing of raw materials |
Crushing the stone/rock with
rock crusher. |
The crushing process is the
secondary crushing. The rock crushing
plant is enclosed and water spraying system would be installed. Dust extraction and collection system
(80% dust removal efficiency) would be provided. |
Screening process |
Screening the crushed stone/rock |
The crushed stone/rock would be
screened by the screening and sorting facility before transporting to the
temporary stockpile via enclosed conveyor. Water spraying system would be
installed. Dust extraction and collection system
(80% dust removal efficiency) would be provided. |
Table 9.6 Temporary
Stockpiles – Dust Emission Design Control Measures
Process |
Description |
Dust Emission Design Control Measures |
|
||
Loading point |
Loading of crushed materials
from rock crushing facility onto stockpile |
The transportation would be via an enclosed conveyor belt system and water spraying and flexible dust curtains would be provided at the loading point to suppress the dust impact. |
Storage of materials |
Active area for loading &
unloading materials |
The active area would be minimized to 20% of the total area of the stock piles. The 80% inactive area would be well covered with impervious sheeting. Water spraying system would be applied on the active area and watering with complete coverage of active area four times a day would be required. |
Trucks |
Transportation of materials to
Barging Point 1 |
Wheel wash facilities provided at the site exit. The vehicles would be washed before leaving the stockpiles. The spoils would also be well covered before leaving the site in order to minimise generation of dusty materials. The haul roads within the site would be all paved and water
spraying would be provided to keep the wet condition. |
|
||
Loading point |
Loading of crushed materials
from rock crushing facility onto stockpile |
The transportation would be via an enclosed conveyor belt system and water spraying and flexible dust curtains would be provided at the loading point to suppress the dust impact. |
Storage of materials |
Active area for loading &
unloading materials |
Water spraying system would be
applied on the active area and watering with complete coverage of active area
four times a day would be required. |
Trucks |
Transportation of materials to
Barging Point 2 |
The vehicles would be washed before leaving the stockpiles. The spoils would also be well covered before leaving the site in order to minimise generation of dusty materials. The haul road would all be paved
and water spraying would be provided to keep the wet
condition. |
Table 9.7 Barging Facilities – Dust Emission Design Control Measures
Process |
Description |
Dust Emission Design Control Measures |
|
||
Haul road within barging
facilities |
Transportation of spoils to
Barging Point 1 |
All road surfaces within the barging facilities would be paved and
water spraying would be provided to keep the wet condition. |
unloading of materials |
unloading of spoil materials |
The unloading process would be undertaken within enclosed tipping hall. Flexible dust curtains and water spraying would be provided at the discharge point for dust suppression. |
Trucks |
Vehicles leaving the barging
facility |
Vehicle wheel washing facilities provided at site exit. |
|
||
Haul road within barging
facilities |
Transportation of spoils to
Barging Point 2 |
All road surfaces within the barging facilities would be paved and
water spraying would be provided to keep the wet condition.
|
Unloading of materials |
Unloading of spoil materials
from trucks to Barging Point 2 |
The unloading process would be undertaken within the enclosed tipping hall. Flexible dust curtains and water spraying would be provided at the discharge point for dust suppression. |
Unloading of spoil materials
from enclosed tipping hall to Barging Point 3 |
The tipping hall would be enclosed structure. The conveyor from tipping hall to the Barging Point 3 would be enclosed. Water spraying and flexible dust curtains would be provided at the receiving point of the tipping hall. Flexible dust curtains and water spraying would be provided at the discharge point of barging facilities for dust suppression. |
|
Trucks |
Vehicles leaving the barging
facility |
Vehicle wheel washing facilities provided at site exit. |
9.26
The crushing and screening facilities of Rock Crushing
Plants at Kennedy Town Abattoir Site and
9.27
For the heavy construction works areas of KET Station
construction site, 50% of active area and watering with complete coverage of
active construction area four times a day are required. Regarding the works areas of temporary
magazine site, 50% of active area and watering with complete coverage of active
construction area two times a day are required.
9.28
For both rock crushing plants, the requirements and
mitigation measures stipulated in the Guidance
Note on the Best Practicable Means for Mineral Works (Stone Crushing Plants)
BPM 11/1 should be followed and implemented. The following good site practices should
be carried out to further minimize construction dust impact.
(i)
Use of regular watering, with complete
coverage, to reduce dust emissions from exposed site surfaces and unpaved
roads, particularly during dry weather;
(ii)
Use of frequent watering for particularly
dusty construction areas and areas close to ASRs;
(iii)
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 shall be applied to aggregate fines;
(iv)
Open stockpiles shall be avoided or
covered. Where possible, prevent
placing dusty material storage piles near ASRs;
(v)
Tarpaulin covering of all dusty vehicle
loads transported to, from and between site locations;
(vi)
Establishment and use of vehicle wheel
and body washing facilities at the exit points of the site;
(vii)
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;
(viii) Imposition
of speed controls for vehicles on unpaved site roads. Ten kilometers per hour is the
recommended limit;
(ix)
Where possible, routing of vehicles and
positioning of construction plant should be at the maximum possible distance
from ASRs;
(x)
Every stock of more than 20 bags of
cement or dry pulverised fuel ash (PFA) should be covered entirely by
impervious sheeting or placed in an area sheltered on the top and the 3 sides;
(xi)
Cement or dry PFA delivered in bulk
should be stored in a closed silo fitted with an audible high level alarm which
is interlocked with the material filling line and no overfilling is allowed;
(xii)
Loading, unloading, transfer, handling or
storage of bulk cement or dry PFA should be carried out in a totally enclosed
system or facility, and any vent or exhaust should be fitted with an effective
fabric filter or equivalent air pollution control system;
9.29
The implementation for the recommended mitigation measures
is presented in Appendix A.