3.1 Air Quality
Parameters
3.1.1 Monitoring of
the Total Suspended Particulates (TSP) levels shall be carried out by the
Environmental Specialist (ES) (see Section 1) to ensure that construction works
are not generating dust which exceeds the acceptable level. Timely action
should be taken to rectify the situation if an exceedance is detected.
3.1.2 1-hour and
24-hour TSP levels shall be measured to indicate the impacts of construction
dust on air quality. The TSP levels shall be measured by following the standard
high volume sampling method as set out in the Title 40 of the Code of Federal
Regulations, Chapter 1 (Part 50), Appendix B.
Upon approval by the Engineer’s Representative (ER) and the
Environmental Protection Department (DEP), 1-hour TSP levels may be measured by
direct reading methods for ad hoc measurements.
3.1.3 All relevant
data including temperature, pressure, weather conditions, elapsed-time meter
reading for the start and stop of the sampler, identification and weight of the
filter paper, any other special phenomena and work progress of the concerned
site shall be recorded in detail by the ES.
A sample data sheet is shown in Figure 3.1.
3.2.1 A high volume
sampler in compliance with the following specifications shall be used for
carrying out the 1-hr and 24-hr TSP monitoring:
(i)
0.6-1.7 m3/min (20-60 SCFM) 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-hr sampling
period;
(vi)
equipped with a shelter to protect the filter and sampler;
(vii)
incorporated with an electronic mass flow rate controller or other
equivalent devices;
(viii)
equipped with a flow recorder for continuous monitoring;
(ix)
provided with a peaked roof inlet;
(x)
equipped with a manometer;
(xi)
able to hold and seal the filter paper to the sampler housing in a
horizontal position;
(xii)
easy to change the filter; and
(xiii)
capable of operating continuously for 24-hr period.
3.2.2 The Contractor is responsible for provision
of the monitoring equipment and shall ensure that sufficient number of high
volume samplers with an appropriate calibration kit are available for carrying
out the baseline monitoring, impact monitoring and ad hoc monitoring. The high
volume samplers shall be equipped with an electronic mass flow controller and be
calibrated against a traceable standard at regular intervals. All the
equipment, calibration kit, filter papers, etc. shall be clearly labelled by
the ES.
3.2.3 Calibration of dust monitoring equipment
shall be conducted by the ES upon installation and thereafter at bi-monthly
intervals. The transfer standard shall
be traceable to the internationally recognised primary standard and be
calibrated annually. The calibration data shall be properly documented for future
reference by concerned parties, such as the IC(E). All the data shall be
converted into standard temperature and pressure condition.
3.2.4 The flow-rate of the sampler before and
after the sampling exercise with the filter in position shall be verified to be
constant and recorded in the data sheet as described in Section 3.1.
3.2.5 If the ES proposes to use a direct reading
dust meter to measure 1-hr TSP levels on an ad hoc basis, he shall submit
sufficient information to the IC(E) to prove that the instrument is capable of
achieving a comparable result as that the High Volume Sampler (HVS) and may be
used for the 1-hr sampling. The instrument should also be calibrated regularly
and the 1-hr sampling shall be checked periodically by the HVS to check the
validity and accuracy of the results measured by the direct reading method.
3.2.6 Wind data monitoring equipment shall also be
provided and set up at suitable locations for logging wind speed and wind
direction near to the dust monitoring locations. The equipment installation
location shall be proposed by the ES and agreed with the ER, in consultation
with the IC(E).
3.2.7 For installation and operation of wind data
monitoring equipment, the following points shall be observed:
(i) the
wind sensors should be installed on masts at an elevated level 10 m above
ground so that they are clear of obstructions or turbulence caused by the
buildings;
(ii) the
wind data should be captured by a data logger to be down-loaded for processing
at least once a month;
(iii) the wind data monitoring equipment should
be re-calibrated at least once every six months; and
(iv) wind direction should be divided into 16
sectors of 22.5 degrees each.
3.2.8 In exceptional situations, the ES may
propose alternative methods to obtain representative wind data upon approval
from the ER and agreement from the IC(E).
3.3 Laboratory Measurement/Analysis
3.3.1 A clean laboratory with constant
temperature and humidity control and equipped with necessary measuring and
conditioning instruments shall be used for sample analysis and equipment
calibration and maintenance. The laboratory shall be HOKLAS accredited.
3.3.2 If a site laboratory is set up or a
non-HOKLAS accredited laboratory is hired for carrying out the laboratory analysis,
the laboratory equipment shall be approved by the ER, in consultation with the
IC(E). Measurement performed by the laboratory shall be demonstrated to the
satisfaction of the ER and the IC(E). The IC(E) shall conduct regular audits of
the measurements performed by the laboratory to ensure the accuracy of the
results. The ES shall provide the ER and the IC(E) with one copy each of the
Title 40 of the Code of Federal Regulations, Chapter 1 (Part 50), Appendix B
for reference.
3.3.3 Filter paper of size 8"x10"
shall be labelled before sampling. It shall be a clean filter paper with no pin
holes and shall be conditioned in a humidity controlled chamber for over 24-hr
and be pre-weighed before use for the sampling.
3.3.4 After sampling, the filter paper loaded
with dust shall be kept in a clean and tightly sealed plastic bag. The filter paper shall then be returned to
the laboratory for reconditioning in the humidity controlled chamber followed
by accurate weighing by an electronic balance with a readout down to 0.1
mg. The balance shall be regularly
calibrated against a traceable standard.
3.3.5 All the collected samples shall be kept
in a good condition for 6 months before disposal.
3.4.1 The air quality sensitive receivers as
determined by the EIA are shown in Figures 3.2a-e and these will also form the
recommended dust monitoring locations.
The status and locations of dust sensitive receivers may change after
issue of this manual. If this happens,
the ES shall propose updated monitoring locations and seek approval from the ER
and agreement from IC(E).
3.4.2 When alternative monitoring locations are
proposed, the following preferred locations and factors shall be considered:
(i)
the site boundary or locations close to the major dust emission
source;
(ii)
close to the sensitive receptors; and
(iii)
the prevailing meteorological conditions.
3.4.3 The ES shall agree with the ER, in
consultation with the IC(E), the position of the high volume samplers. When positioning the samplers, the following
points shall be noted:
(i)
a horizontal platform with appropriate support to secure the
samplers against gusty wind shall be provided;
(ii)
the distance between the sampler and an obstacle, such as
buildings, shall be at least twice the height that the obstacle protrudes above
the sampler;
(iii)
a minimum of 2 metres of separation from walls, parapets and
penthouses is required for rooftop samplers;
(iv)
a minimum of 2 metres separation from any supporting structure,
measured horizontally is required;
(v)
no furnace or incinerator flue is nearby;
(vi)
airflow around the sampler is unrestricted;
(vii)
the sampler is more than 20 metres from the dripline;
(viii)
any wire fence and gate, to protect the sampler, shall not cause
any obstruction during monitoring;
(ix)
permission must be obtained to set up the samplers and to obtain
access to the monitoring stations;
(x)
a secured supply of electricity is needed to operate the samplers;
and
(xi)
no two samplers should be placed less than 2 metres apart.
3.4.4 Prior to construction, the dust
monitoring schedule shall be developed by the ES based upon the construction
schedule supplied by the Contractor.
The ES shall inform the IC(E) of the impact monitoring programme such that
he can conduct on-site audits to ensure accuracy of the impact monitoring
results. The environmental monitoring schedule shall be approved by the ER.
3.5.1 The ES shall carry out baseline
monitoring at six representative locations as follows:
¨
SR4, village
property, representative of the village houses in Ha Ling Pei, Wong Ka Wai and
Lung Tseng Tau;
¨
SR6, village
property, representative of the ASRs in the Tung Chung Valley floor;
¨
SR10, house,
representative of ASRs in Leyburn Villas;
¨
SR15, YWCA,
representative of ASRs adjacent to South Lantau Road;
¨
SR13, house,
representative of ASRs adjacent to South Lantau Road; and
¨
SR19, house,
representative of ASRs in Butterfly Crest.
3.5.2 These locations have been selected as
they represent properties which are closest to the works and/or are
particularly sensitive to impacts and are representative of the adjacent
properties. The monitoring at these
locations shall be undertaken for at least 14 consecutive days prior to the
start of the construction works to obtain daily 24-hr TSP samples. 1-hr sampling shall also be carried out at
least 3 times per day during the same period.
Monitoring shall take place within a 3 week period prior to the
commencement of construction works.
3.5.3 During the baseline monitoring, there
should not be any construction or dust generation activities in the vicinity of
the monitoring stations.
3.5.4 In case the baseline monitoring cannot be
carried out at the designated monitoring locations during the baseline monitoring
period, the ES Leader shall carry out the monitoring at alternative locations
which can effectively represent the baseline conditions at the impact
monitoring locations. The alternative baseline monitoring locations shall be
approved by the ER, IC(E) and agreed with DEP.
3.5.5 In the event that insufficient baseline
monitoring data or questionable results are obtained, the ES shall liaise with
the DEP to agree on an appropriate set of data to be used as a baseline
reference and submit this data to the ER and IC(E) for approval.
3.5.6 Ambient conditions may vary seasonally
and shall be reviewed at three monthly intervals. If the ES considers that the ambient conditions have changed and
a repeat of the baseline monitoring is required to be carried out for obtaining
updated baseline levels, the monitoring should be at times when the
Contractor's activities are not generating dust, at least in the proximity of
the monitoring stations. Should a change in ambient conditions be determined,
the baseline levels and, in turn, the air quality criteria, shall be revised.
The revised baseline levels and air quality criteria shall be agreed with the
DEP and supplied to the IC(E).
3.6.1 The ES shall carry out impact monitoring
during the course of the works. For
regular impact monitoring, the sampling frequency of at least once in every six
days shall be strictly observed at six of
the designated monitoring stations for 24-hr TSP monitoring. For 1-hr TSP monitoring,
the sampling frequency of at least three times in every six days should be
undertaken at six locations when the
highest dust impact occurs. The stations to be monitored should be selected
based on the prevailing wind direction and their proximity to the active
construction works.
3.6.2 The specific time to start and stop the
24-hr TSP monitoring shall be clearly defined for each location and be strictly
followed by the operator.
3.6.3 In case of non-compliance with the air
quality criteria, more frequent monitoring, as specified in the Action Plan in
Section 3.7, shall be conducted within 24 hours after the non-compliance is
detected. This additional monitoring shall be continued until the excessive
dust emission or the deterioration in air quality is rectified.
3.7 Event and Action Plan for Air Quality
3.7.1 The baseline monitoring results will form
the basis for determining the air quality criteria for the impact monitoring.
The ES shall compare the impact monitoring results with air quality criteria
set up for 24-hour TSP and 1-hour TSP.
Table 3.1 shows the air quality criteria, namely Action and Limit levels
to be used. Should non-compliance with
the air quality criteria occur, the ES, the IC(E) and the ER and the Contractor
shall undertake their specified actions in accordance with the Action Plan
shown in Table 3.2.
Table 3.1 Action and Limit Levels for Air Quality
Parameters |
Action |
Limit |
24 Hour TSP
Level in :g/m³ |
For baseline
level # 200 :g/m³, Action level = (Baseline *1.3+ Limit level )/2; For baseline
level >200 :g/m³, Action level = Limit
level |
260 |
1 Hour TSP Level in :g/m³ |
For baseline
level # 384 :g/m³, Action level = (Baseline *1.3+ Limit level )/2; For baseline
level >384 :g/m³, Action level = Limit
level |
500 |
3.7.2 In case of non-compliance with the air
quality criteria, more frequent monitoring exercise, shall be conducted within
24 hours after the result is obtained. This additional monitoring shall be
continued until the excessive dust emission or the deterioration in air quality
is rectified. The Event/Action Plan for air quality is given in the attached
Table 3.2.
3.7.3 The Independent Checker (Environment)
(IC(E)) shall be empowered to audit the environmental performance of
construction, all aspects of the EM&A programme, validate and confirm the
accuracy of monitoring results, monitoring equipment, monitoring locations and
procedures. If any exceedance occur,
the IC(E) shall follow the actions stated in the Event and Action Plan in Table
3.2.
3.8.1 The EIA report has recommended dust
control and mitigation measures. The Contractor shall be responsible for the
design and implementation of the following measures. The recommended
construction dust mitigation measures are summarised in the Construction Air
Environmental Mitigation Implementation Schedule provided in Appendix A.
(i)
The
Contractor shall, to the satisfaction of the Engineer, install effective dust
suppression measures and take such other measures as may be necessary to ensure
that at the Site boundary and any nearby sensitive receiver, dust levels are
kept to acceptable levels;
(ii)
The
Contractor shall not burn debris or other materials on the works areas;
(iii)
in
hot, dry or windy weather, the watering programme shall maintain all exposed
road surfaces and dust sources wet;
(iv)
where
breaking of oversize rock/concrete is required, watering shall be implemented
to control dust. Water spray shall be used during the handling of fill material
at the site and at active cuts, excavation and fill sites where dust is likely
to be created;
(v)
open
dropping heights for excavated materials shall be controlled to a maximum
height of 2m to minimise the fugitive dust arising from unloading;
(vi)
during
transportation by truck, materials shall not be loaded to a level higher than
the side and tail boards, and shall be dampened or covered before
transport. Materials having the
potential to create dust shall not be loaded to a level higher than the side
and tail boards, and shall be covered by a clean tarpaulin. The tarpaulin shall be properly secured and
shall extend at least 300mm over the edges of the side and tail boards;
(vii)
no
earth, mud, debris, dust and the like shall be deposited on public roads. Wheel washing facility shall be usable prior
to any earthworks excavation activity on the site;
(viii)
areas
of exposed soil shall be minimised to areas in which works have been completed
shall be restored as soon as is practicable; and
(ix) all stockpiles of aggregate or spoil shall be enclosed or covered and water applied in dry or windy condition.
3.8.2
If the above measures are not sufficient to restore the air
quality to acceptable levels upon the advice of the ES, the Contractor shall
liaise with the ES regarding other mitigation measures and consult the IC(E)
for their effectiveness, and then propose these measures to the ER for approval
prior to the implementation of the
measures.
Table 3.2 Event / Action Plan for Air Quality
EVENT |
ACTION |
|||
ES(1) |
IC(E)(1) |
ER(1) |
Contractor |
|
Action Level |
|
|
|
|
1. Exceedance for one sample |
1. Identify the
source. 2. Inform the
IC(E) and the ER. 3. Repeat
measurement to confirm finding. 4. Increase monitoring frequency to daily. |
1. Check
monitoring data submitted by the ES. 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 the
source. 2. Inform the
IC(E) and the ER. 3. Repeat
measurements to confirm findings. 4. Increase
monitoring frequency to daily. 5. Discuss with
the IC(E) and the Contractor on
remedial actions required. 6. If exceedance
continues, arrange meeting with the IC(E) and the ER. 7. If exceedance stops, cease additional monitoring. |
1. Check
monitoring data submitted by the ES. 2. Check the
Contractor’s working method. 3. Discuss with
the ES and the Contractor on possible
remedial measures. 4. Advise the ER
on the effectiveness of the proposed remedial measures. 5. Supervisor implementation of remedial measures. |
1. Confirm
receipt of notification of failure in writing. 2. Notify the
Contractor. 3. Ensure remedial measures properly implemented. |
1. Submit
proposals for remedial actions to IC(E) within 3 working days of notification 2. Implement the
agreed proposals 3. Amend proposal if appropriate |
EVENT |
ACTION |
|||
|
ES |
IC(E) |
ER |
Contractor |
Limit Level |
|
|
|
|
1. Exceedance for one sample |
1. Identify the
source. 2. Inform the ER
and the DEP. 3. Repeat
measurement to confirm finding. 4. Increase
monitoring frequency to daily. 5. Assess effectiveness of Contractor’s remedial actions and keep the IC(E), the DEP and the ER informed of the results. |
1. Check
monitoring data submitted by the ES. 2. Check
Contractor’s working method. 3. Discuss with
the ES and the Contractor on possible
remedial measures. 4. Advise the ER
on the effectiveness of the proposed remedial measures. 5. Supervisor implementation of remedial measures. |
1. Confirm
receipt of notification of failure in writing. 2. Notify the
Contractor. 3. Ensure remedial measures are properly implemented. |
1. Take
immediate action to avoid further exceedance 2. Submit
proposals for remedial actions to IC(E) within 3 working days of notification 3. Implement the
agreed proposals 4. Amend proposal if appropriate |
2. Exceedance for two or more consecutive samples |
1. Notify the
IC(E), the ER, the DEP and the Contractor. 2. Identify the
source. 3. Repeat
measurements to confirm findings. 4. Increase
monitoring frequency to daily. 5. Carry out
analysis of the Contractor’s working
procedures to determine possible mitigation to be implemented. 6. Arrange
meeting with the IC(E) and the ER to discuss the remedial actions to be taken. 7. Assess
effectiveness of the Contractor’s
remedial actions and keep the IC(E), the DEP and the ER informed of the
results. 8. If exceedance stops, cease additional monitoring. |
1. Discuss
amongst the ER, ES and the Contractor on the potential remedial actions. 2. Review the
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 failure in writing. 2. Notify the
Contractor. 3. In
consultation with the IC(E), agree with the Contractor on the remedial
measures to be implemented. 4. Ensure
remedial measures are properly implemented. 5. If exceedance continues, consider what activity of the work is responsible and instruct the Contractor to stop that activity of work until the exceedance is abated. |
1. Take
immediate action to avoid further exceedance. 2. Submit
proposals for remedial actions to IC(E) within 3 working days of
notification. 3. Implement the
agreed proposals. 4. Resubmit
proposals if problem still not under control. 5. Stop the relevant activity of works as determined by the ER until the exceedance is abated. |
Note: ES – Environmental Specialist, IC(E) –
Independent Checker (Environmental), ER – Engineer’s Representative
Figure 3.1 Data Sheet for TSP Monitoring
Monitoring Location: |
|
Details of Location: |
|
Sampler Identification: |
|
Date & Time of Sampling: |
|
Elapsed-time Meter Reading |
Start (min.) |
Stop (min.) |
|
Total Sampling Time (min.): |
|
Weather Conditions: |
|
Site Conditions: |
|
Initial Flow Rate, Qsi |
Pi (mmHg): |
Ti (oC): |
|
Hi (in.): |
|
Qsi (Std. m3): |
|
Final Flow Rate, Qsf |
Pf (mmHg): |
Tf (oC): |
|
Hf (in.): |
|
Qsf (Std. m3): |
|
Average Flow Rate (Std. m3): |
|
Total Volume (Std. m3): |
|
Filter Identification No.: |
|
Initial Wt. of Filter (g): |
|
Final Wt. of Filter (g): |
|
Measured TSP Level (Fg/m3): |
Name
& Designation
Signature Date
Field
Operator :
Laboratory
Staff :
Checked by :