3.1
In
accordance with the Updated EM&A Manual, impact 1-hour TSP and 24-hr TSP
monitoring shall be
conducted to monitor the air quality for the Works Contracts. Appendix B shows the established
Action/Limit Level for the air quality monitoring works.
3.2
Impact
1-hour TSP monitoring was conducted for at least three times every 6 days,
while the impact 24-hour TSP monitoring was conducted for at least once every 6
days at the designated air quality monitoring stations.
3.3
Impact
air quality monitoring was conducted at the monitoring stations under the Works
Contracts, as shown in Figure 1 and
Figure 2 according to Table 1.1 of Updated EM&A Manual and Baseline Air
Quality Monitoring Report (KTN & FLN NDA).
Alternative Monitoring Station for KTN-DMS4
3.4
As
KTN-DMS4 - Temporary structure near Fanling Highway
(near Pak Shek Au) is no longer as existing ASR, air
quality monitoring station should be relocated to the alternative dust
monitoring location according to the updated EM&A Manual, Section 2.6.2.
According to Figure 3.1 of Approved EIA report and site visits conducted in
June 2022, ASR at near KTN-E70 – Temporary Structure near Fanling
Highway near Pak Shek Au is considered as the most
representative alternative station KTN-DMS4(B) for air quality monitoring for KTN-DMS4 (i.e.
KTNE162).
3.5
The
alternative monitoring location KTN-DMS4(B) is agreed by EPD on 17 August 2022. The 1-hr and
24-hrs TSP monitoring commenced starting from 24 August 2022. Table 3.1 describes
the location of the air quality monitoring stations.
Table 3.1 Location for Air Quality Monitoring
Locations
|
EP No. |
Contract No. |
Monitoring Station |
Location |
|
EP-473/2013/A |
ND/2019/03 |
FLN-DMS1[2] |
Scattered Village Houses North of Proposed
Potential Ecopark |
|
ND/2019/04 |
|||
|
ND/2019/05 |
FLN-DMS3[3] |
House near Tong Hang |
|
|
ND/2019/03 |
FLN-DMS5[4]
FLN-DMS5A |
Noble Hill Good View New Village |
|
|
ND/2019/04 |
|||
|
EP-466/2013/A EP-467/2013/A EP-468/2013/A |
ND/2019/01 |
KTN-DMS4(B)[5] |
Temporary Structure near Fanling Highway (near Pak Shek
Au) |
|
EP-468/2013/A |
ND/2019/03 |
Remarks:
[1]:
Noting that construction phase air quality monitoring at the other proposed
monitoring stations (e.g. planned), where access is permitted, will be
conducted during construction
phase of relevant works contract(s).
[2]:
Since the distance between monitoring station and site boundary of ND/2019/05
under EP-473/2013/A exceeds 500m, the monitoring station is not
applicable to ND/2019/05.
[3]:
Since the distance between monitoring station and site boundary of ND/2019/03 and
ND/2019/04 under EP-473/2013/A exceeds 500m, the monitoring
station is not applicable to ND/2019/03 and ND/2019/04.
[4]:
Since the distance between monitoring station and site boundary of ND/2019/05
under EP-473/2013/A exceeds 500m, the monitoring station is not
applicable to ND/2019/05
[5]
KTN-DMS4(B) commenced starting from 24 August 2022 as
an alternative monitoring station of KTN-DMS4.
3.6
As
the power supply for High Volume Sampler (HVS) for TSP monitoring at FLN-DMS 5A,
KTN-DMS 4 and KTN-DMS 4(B) were rejected, direct reading dust meter was used to
measure both 1-hour and 24-hour TSP levels:-
Ÿ
The
proposal for alternative monitoring equipment (i.e. direct reading dust meter)
for TSP monitoring was approved by EPD according to the approved Baseline Air Quality
Monitoring Report (KTN & FLN NDA); and
Ÿ
Same measurement methodology (i.e.
direct reading dust meter) was adopted as baseline monitoring for a reliable
comparison.
3.7
The
proposed use of portable direct reading dust meters was also submitted
to IEC and agreement was obtained from the IEC in accordance with Section 2.4.5 of the Updated EM&A Manual.
3.8
HVS
for 24-hour
TSP monitoring will be adopted once secured supply of electricity become
available at FLN-DMS 5A and KTN-DMS 4(B).
3.9
Table 3.2 summarises the equipment used in the impact
air monitoring programme. Copies of calibration
certificates are attached in Appendix C.
Table 3.2 Air Quality Monitoring Equipment
|
Monitoring Station |
Equipment |
Manufacturer |
Model and Make |
Quantity |
|
FLN-DMS5 FLN-DMS5A KTN-DMS4 KTN-DMS4(B) |
Dust
Monitor (1-hour
and 24-hour TSP) |
Met One Instruments |
AEROCET-831 |
9 |
|
FLN-DMS1 FLN-DMS3 |
Dust
Monitor (1-hour
TSP) |
|||
|
HVS
Sampler (TSP) (24-hour
TSP) |
Tisch |
TISCH Model: TE-5170 |
3 |
3.10
Meteorological
information extracted from “Hong Kong Observatory - Ta Kwu
Ling Weather Station” was proposed as the alternative method to obtain
representative wind data. For Ta Kwu Ling Weather
Station, it is located nearby the Project site and situated at approximately
15m above mean sea level. The station’s wind data monitoring equipment is set
above the existing ground 10 meters in compliance with the
general setting up requirements. Furthermore, this station also
provides other meteorological information, such as humidity, rainfall, air
pressure and temperature etc.
3.11
The
general weather conditions (i.e. sunny, cloudy or rainy) were recorded by the
field staffs during the monitoring days.
3.12
Table 3.3 summarises the monitoring parameters and
frequencies of impact dust monitoring during the Works Contracts activities.
The air quality monitoring schedule for the reporting month is shown in Appendix D.
Table 3.3 Impact Dust Monitoring Parameters, Frequency and
Duration
|
Parameters |
Frequency |
|
1-hour TSP |
Three
times/ 6 days |
|
24-hour TSP |
Once /
6 days |
1-hour and 24-hour
TSP Air Quality Monitoring
Instrumentation
3.13
Direct reading
dust meter was deployed for the air quality monitoring as shown in Table 3.2.
3.14
The measuring
procedures of the dust meters were in accordance with the Manufacturer’s
Instruction Manual as follows:
(AEROCET-831)
•
Place the 1-hour
dust meter at least 1.3 meters above ground.
•
Press and hold
the Power key momentarily to power on the unit and make sure that the battery
level was not flash or in low level.
•
Allow the
instrument to stand for about 3 second to display the Sample Screen minutes.
•
Press the START
/ STOP key to run the internal vacuum pump for 1 minute and be ready to use.
•
Use the select
dial to select the PM range and press the START / STOP key to start a
measurement.
•
Finally, push
the START/STOP key to stop the measurement after 1 hour sampling.
•
Information
such as sampling date, time, value and site condition were recorded during the
monitoring period.
• All data were recorded in the data logger for
further data processing.
Maintenance/Calibration
3.15
The following
maintenance/calibration was required for the direct dust meters:
• Check and calibrate the meters 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 Air Quality
Monitoring
Instrumentation
(TISCH Model: TE-5170)
3.16
High volume Samplers
(HVS) completed with appropriate sampling inlets were employed for 24-hour TSP
monitoring. Each sampler was
composed of a motor, a filter holder, a flow controller and a sampling inlet
and its performance specification complies with that required by USEPA Standard
Title 40, Code of Federation Regulations Chapter 1 (Part 50).
HVS
Installation
3.17
The following
guidelines were adopted during the installation of HVS:
•
A horizontal
platform with appropriate support was provided 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 samplers
were more than 20 meters from the drip line.
•
Any wire fence
and gate, to protect the sampler, should not cause any obstruction during
monitoring.
•
Permission and access
to the monitoring stations have been obtained to set up the samplers.
• A secured supply of electricity was provided to
operate the samplers.
Filters
Preparation
3.18
Wellab Limited (HOKLAS
Registration No. HOKLAS083) is a HOKLAS accredited laboratory and responsible for
the preparation of 24-hour conditioned and pre-weighed filter papers for the monitoring
team.
3.19
All filters
were equilibrated in the conditioning environment for 24 hours before
weighing. The conditioning
environment temperature was around 25°C and not variable by more than ±3°C; the
relative humidity (RH) was < 50% and not variable by more than ±5%. A convenient working RH was 40%.
Operating/Analytical
Procedures
3.20
Operating/analytical
procedures for the air quality monitoring were highlighted as follows:
•
Prior to the
commencement of dust sampling, the flow rate of the HVS was properly set
(between 1.1 m3/min. and 1.4 m3/min.) in accordance with
the manufacturer's instruction to within the range recommended in USEPA
Standard Title 40, CFR Part 50;
•
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 quality monitoring station;
•
The filter
holding frame was then removed by loosening the four nuts and carefully a
weighted and conditioned filter was centered with the stamped number upwards,
on a supporting screen;
•
The filter was
aligned on the screen so that the gasket formed an airtight seal on the outer
edges of the filter. The filter
holding frame was then tightened to the filter holder with swing bolts. The applied pressure should be
sufficient to avoid air leakage at the edges;
•
The shelter lid
was closed and secured with the aluminum strip;
•
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);
•
After sampling,
the filter was removed and kept in a clean and tightly sealed plastic bag. The
filter paper was then returned to the HOKLAS accredited laboratory (Wellab Ltd.) for reconditioning in the humidity-controlled
chamber followed by accurate weighting by an electronic balance with a readout
down to 0.1mg. The elapsed time was also recorded; and
• Before weighing, all filters were equilibrated in a
conditioning environment for 24 hours. The conditioning environment temperature
should be between
Maintenance/Calibration
3.21
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 conditions; and
•
All HVS were
calibrated (five point calibration) using Calibration Kit prior to the
commencement of baseline monitoring and thereafter at bi-monthly intervals.
3.22
The monitoring
results for 1-hour TSP and 24-hour TSP are summarised
in Tables 3.4 and 3.5 respectively. Detailed monitoring results
and graphical presentations of 1-hour and 24-hour TSP monitoring results are
shown in Appendix E.
Table 3.4 Summary
Table of 1-hour TSP Monitoring Results during the
Reporting Month
|
Monitoring Station |
Concentration (µg/m3) |
Action
Level, µg/m3 |
Limit
Level, µg/m3 |
|
|
Average |
Range |
|||
|
FLN-DMS1 |
92.5 |
68.0 –
128.4 |
303 |
500 |
|
FLN-DMS3 |
94.1 |
43.5 –
164.6 |
301 |
500 |
|
FLN-DMS5 |
83.1 |
32.9 –
113.2 |
279 |
500 |
|
KTN-DMS4(B) |
88.5 |
45.7 –
136.8 |
297 |
500 |
Table 3.5 Summary
Table of 24-hour TSP Monitoring Results during the
Reporting Month
|
Monitoring Station |
Concentration (µg/m3) |
Action
Level, µg/m3 |
Limit
Level, µg/m3 |
|
|
Average |
Range |
|||
|
FLN-DMS1 |
86.5 |
55.8 –
118.8 |
150 |
260 |
|
FLN-DMS3 |
59.2 |
41.3 –
81.2 |
165 |
260 |
|
FLN-DMS5A |
95.5 |
61.5 –
119.8 |
153 |
260 |
|
KTN-DMS4(B) |
83.7 |
56.6 –
110.8 |
192 |
260 |
3.23
All 1-hour and
24-hour TSP monitoring was conducted as scheduled in the reporting month. No Action/Limit Level exceedances were
recorded.
3.24
According to
our field observations, the major dust sources identified at the designated air
quality monitoring stations in the reporting month are shown in Table 3.6:
Table 3.6 Observation
at Dust Monitoring Stations
|
Monitoring Station |
Major Dust Sources |
|
FLN
DMS1 |
Mobile crane, Excavator,
piling, road traffic |
|
FLN-DMS3 |
Excavator, piling, mobile
crane, road traffic |
|
FLN-DMS5 |
Road traffic |
|
KTN-DMS4(B) |
Excavator, piling, mobile
crane, dump truck, road traffic |
3.25
Should any non-compliance
of the criteria occur, actions in accordance with the Event/Action Plan in Appendix N shall be carried out.