2.1
According to EM&A Manual of the Kai Tak Development EIA Study and contract requirement
under Contract No. KLN/2010/04, 1-hour
and 24-hour TSP monitoring were
conducted to monitor the air quality for KTD. For regular impact monitoring, a sampling
frequency of at least once in every six days at all of the monitoring stations
for 24-hour TSP monitoring. For 1-hour TSP monitoring, the sampling frequency
of at least three times in every six days shall be undertaken when the highest
dust impact occurs. Appendix A shows the established Action/Limit Levels for the environmental
monitoring works.
2.2
Six designated monitoring
stations were selected for air quality monitoring programme.
Impact dust monitoring was conducted at five air quality monitoring stations, namely Kai Tak Operational Base (AM1(A)), Lee Kau
Yan Memorial School (AM2), Holy Trinity Bradbury Centre (AM3(A)), EMSD Workshops (AM4(A)) and Po Leung Kuk Ngan Po Ling College (AM5(A)) in the reporting month. Table 2.1 describes the air quality
monitoring locations, which are also depicted in Figure 2.
Table 2.1 Locations for Air Quality Monitoring
|
Monitoring Stations |
Locations |
Location of
Measurement |
|
AM1(A) |
Kai Tak Operational Base |
Rooftop (about 9/F) Area |
|
AM2 |
Lee Kau Yan Memorial School |
Rooftop
(about 8/F) Area |
|
AM3(A) |
Holy Trinity Bradbury Centre |
Rooftop (about 8/F) Area |
|
AM4(A) |
EMSD Workshops |
Rooftop
(about 6/F) Area |
|
AM5(A) |
Po Leung Kuk Ngan Po Ling College |
Rooftop (about 10/F) Area |
|
#AM6 |
PA 15 |
Site
1B4 (Planned) |
Remarks: # Baseline/Impact monitoring will be
conducted when the premise is occupied or instructed by Engineer.
2.3
Table 2.2
summarizes the equipment used in the impact air monitoring programme.
Copies of calibration certificates are attached in Appendix B.
Table 2.2 Air Quality Monitoring Equipment
|
Equipment |
Model and Make |
Quantity |
|
Calibrator |
G25A |
1 |
|
1-hour TSP Dust Meter |
Laser Dust Monitor –
Model LD3B |
4 |
|
HVS Sampler |
GMWS |
5 |
|
Wind Anemometer |
Davis Weather Monitor II, Model no. 7440 |
1 |
Monitoring Parameters, Frequency and Duration
2.4
Table 2.3
summarizes the monitoring parameters and frequencies of impact dust monitoring
for the whole construction period. The air quality monitoring schedule for the
reporting month is shown in Appendix D.
Table 2.3 Impact Dust Monitoring Parameters, Frequency and Duration
|
Parameters |
Frequency |
|
1-hr TSP |
Three times / 6 days |
|
24-hr TSP |
Once / 6 days |
1-hour
TSP Monitoring
Measuring Procedures
2.5
The
measuring procedures of the 1-hour dust meters were in accordance with the
Manufacturer’s Instruction Manual as follows:
·
The 1-hour
dust meter is placed at least 1.3 meters above ground.
·
Set POWER
to “ON” and make sure that the battery level was not flash or in low level.
·
Allow the
instrument to stand for about 3 minutes and then the cap of the air sampling inlet
has been released.
·
Push the
knob at MEASURE position.
·
Set
time/mode setting to [BG] by pushing the time setting switch. Then, start the background measurement
by pushing the start/stop switch once.
It will take 6 sec. to complete the background measurement.
·
Push the
time setting switch to change the time setting display to [MANUAL] at the
bottom left of the liquid crystal display.
Finally, push the start/stop switch to stop the measuring after 1 hour
sampling.
·
Information
such as sampling date, time, count value and site
condition were recorded during the monitoring period.
Maintenance/Calibration
2.6
The
following maintenance/calibration was required for the direct dust meters:
· Check and calibrate the meter by HVS to check the validity and accuracy of the
results measured by direct reading method at 2-month intervals throughout all stages of the air quality
monitoring.
24-hour TSP Monitoring
Instrumentation
2.7
High volume
(HVS) samplers (Model GMWS-2310 Accu-Vol) completed
with appropriate sampling inlets were employed for 24-hour TSP monitoring. The sampler was composed of a motor, a filter holder, a flow controller
and a sampling inlet and its performance specification complied with that
required by USEPA Standard Title 40, Code of Federation Regulations Chapter 1
(Part 50). Moreover, the HVS also met all the requirements in section 2.5 of the updated EM&A Manual.
Operating/Analytical
Procedures
2.8
Operating/analytical
procedures for the operation of HVS were as follows:
·
A
horizontal platform was provided with appropriate support to secure the
samplers against gusty wind.
·
No two
samplers were placed less than 2 meters apart.
·
The
distance between the sampler and an obstacle, such as buildings, was at least
twice the height that the obstacle protrudes above the sampler.
·
A minimum
of 2 meters of separation from walls, parapets and penthouses was required for
rooftop samples.
·
A minimum
of 2 meters separation from any supporting structure, measured horizontally was
required.
·
No furnaces
or incineration flues were nearby.
·
Airflow
around the sampler was unrestricted.
·
The sampler
was more than 20 meters from the drip line.
·
Any wire
fence and gate, to protect the sampler, should not cause any obstruction during
monitoring.
2.9
Prior to
the commencement of the dust sampling, the flow rate of the high volume sampler
was properly set (between
2.10
For TSP
sampling, fiberglass filters have a collection efficiency of > 99% for
particles of 0.3 μm diameter were used.
2.11
The power
supply was checked to ensure the sampler worked properly. On sampling, the sampler was operated for 5 minutes to establish thermal
equilibrium before placing any filter media at the designated air monitoring
station.
2.12
The filter
holding frame was then removed by loosening the four nuts and a weighted and
conditioned filter was carefully centered with the stamped number upwards, on a
supporting screen.
2.13
The filter
was aligned on the screen so that the gasket formed an airtight seal on the
outer edges of the filter. Then the filter holding frame was tightened to
the filter holder with swing bolts. The applied pressure should be sufficient
to avoid air leakage at the edges.
2.14
The shelter
lid was closed and secured with the aluminum strip.
2.15
The timer
was then programmed. Information was recorded on the record sheet, which
included the starting time, the weather condition and the filter number (the
initial weight of the filter paper can be found out by using the filter
number).
2.16
After
sampling, the filter was removed and sent to the HOKLAS laboratory (Wellab Ltd.) for weighing. The elapsed
time was also recorded.
2.17
Before
weighing, all filters were equilibrated in a conditioning environment for 24
hours. The conditioning environment temperature should be between
Maintenance/Calibration
2.18
The
following maintenance/calibration was required for the HVS:
·
The high
volume motors and their accessories were properly maintained. Appropriate maintenance such as routine
motor brushes replacement and electrical wiring checking were made to ensure
that the equipment and necessary power supply are in good working condition.
·
High volume
samplers were calibrated at bi-monthly intervals using G25A Calibration Kit
throughout all stages of the air quality monitoring.
2.19
All 1-hour TSP monitoring was conducted as scheduled in the
reporting month. No Action/Limit
Level exceedance was recorded.
2.20
All 24-hour TSP monitoring was conducted as
scheduled in the reporting month.
No Action/Limit Level exceedance was recorded.
2.21
The air
temperature, precipitation and the
relative humidity data was obtained from Hong Kong Observatory where the
wind speed and wind direction were recorded by the installed Wind Anemometer set at rooftop (about 9/F) of Kai Tak Operational Base. The location is shown in Figure 4. These weather information for the
reporting month is summarized in Appendix
C.
2.22
The
monitoring data and graphical presentations of 1-hour and 24-hour TSP
monitoring results are shown in Appendices E and F respectively.
2.23
The summary
of exceedance record in reporting month is shown in Appendix H. No
exceedance was recorded for the air quality
monitoring.
2.24
According
to our field observations, the major dust source identified at the designated air
quality monitoring stations are as follows:
|
Station |
Major
Dust Source |
|
AM1(A) – Kai Tak Operational Base |
Road Traffic Dust Exposed site area Site vehicle
movement |
|
AM2 –
Lee Kau Yan
Memorial School |
|
|
AM3(A) - Holy Trinity Bradbury Centre |
Road Traffic Dust Site vehicle movement |
|
AM4(A) – EMSD
Workshops |
Sand Depot Concrete Batching
Plant |
|
AM5(A) – Po Leung Kuk Ngan Po Ling College |
Road Traffic Dust Loading/unloading
activities |