3
AIR QUALITY MONITORING
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(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 |
2 |
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.
Monitoring
Parameters, Frequency and Duration
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 |
Monitoring
Methodology and QA/QC Procedure
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 25°C and
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 |
89.8 |
54.4 – 125.2 |
303 |
500 |
|
FLN-DMS3 |
89.9 |
56.2 – 114.1 |
301 |
500 |
|
FLN-DMS5 |
85.8 |
42.1 – 125.6 |
279 |
500 |
|
KTN-DMS4(B) |
86.2 |
47.0 – 162.5 |
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 |
93.0 |
54.8 – 129.3 |
150 |
260 |
|
FLN-DMS3 |
73.9 |
43.0 – 95.5 |
165 |
260 |
|
FLN-DMS5A |
89.1 |
70.5 – 113.9 |
153 |
260 |
|
KTN-DMS4(B) |
77.2 |
46.1 – 104.1 |
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.