3.1
In
accordance with the Updated EM&A Manual, impact 1-hour TSP and 24-hr TSP
monitoring were conducted to monitor the air quality for the Works Contracts. Appendix B shows the established
Action/Limit Levels 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 one air quality monitoring station.
3.3
Impact
air quality monitoring was conducted at the monitoring stations under the Works
Contracts, as shown in Figure 1 according
to Table 1.1 of Updated EM&A Manual. Table
3.1 describes the location of the air quality monitoring station.
Table 3.1 Location
for Air Quality Monitoring Locations
|
EP No. |
Contract No. |
Monitoring
Station |
Location |
|
EP-468/2013/A |
ND/2019/01 ND/2019/03 |
KTN-DMS4 |
Temporary
Structure near Fanling Highway (near Pak Shek Au) |
Noting that
construction phase air quality monitoring at the other proposed monitoring stations
(e.g. planned), where access is permitted, will be conducted during the
relevant works contract(s).
3.4
As
the power supply for High Volume Sample (HVS) for TSP monitoring at KTN-DMS 4
was rejected, direct reading dust meter was used to measure both 1-hour and
24-hour average TSP levels:-
Ÿ
The
proposal for alternative monitoring equipment (i.e. direct reading dust meter)
for TSP monitoring was approved by EPD according to approved Baseline Air
Quality Monitoring Report (KTN & FLN NDA); and
Ÿ
Adopt
same measurement methodology (i.e. direct reading dust meter) as baseline monitoring
for reliable comparison.
3.5
The
proposed use of portable direct reading dust meters was submitted to IEC and
obtained agreement from the IEC as stated in Section 2.4.5 of the Updated
EM&A Manual.
3.6
HVS
for 24-hr TSP monitoring will be adopted once secured supply of electricity
become available at KTN-DMS 4.
3.7
Table 3.2 summarizes 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 |
Model and Make |
Quantity |
|
KTN-DMS4 |
Dust
Monitor |
AEROCET-831 |
1 |
3.8
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 ten meters in compliance with the general setting up
requirement. Furthermore, this station also provides other meteorological
information, such as the humidity, rainfall, air pressure and temperature etc.
3.9
The
general weather conditions (i.e. sunny, cloudy or rainy) were recorded by the
field staffs during the monitoring day.
3.10
Table 3.3 summarizes 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-hr
TSP |
Three
times/ 6 days |
|
24-hr
TSP |
Once /
6 days |
1-hour
and 24-hour TSP Air Quality Monitoring
Instrumentation
3.11
Direct reading
dust meter was deployed for the air quality monitoring as shown in Table 3.2.
3.12
The measuring
procedures of the dust meter are in accordance with the Manufacturer’s
Instruction Manual as follows:
(AEROCET-831)
•
The dust meter
is placed at least 1.3 meters above ground.
•
Remove the red
rubber cap from the AEROCET-831 inlet nozzle.
•
Turn on the
power switch that is located on the right side of the AEROCET-831.
•
On power up the
product intro screen is displayed for 3 seconds. The intro screen displays the
product name and firmware version.
•
Then the main
counter screen will be displayed.
•
Press the START
button. Internal vacuum pump start running. After 1 minute the pump will stop
and the 0.5µm and 5µm channels will show the cumulative counts of particles
larger than 0.5µm and 5µm per cubic foot.
•
The AEROCET-831
is now checked out and ready for use.
•
To switch off
the AEROCET-831 power to stop the measuring after sampling.
•
Information
such as sampling date, time, and display value and site condition were recorded
during the monitoring period.
Maintenance/Calibration
3.13
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.
3.14
The monitoring
results for 1-hour TSP and 24-hour TSP are summarized in Table 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 |
|||
|
KTN-DMS4 |
68.4 |
18.4 –
196.7 |
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 |
|||
|
KTN-DMS4 |
76.9 |
47.2 –
104.7 |
192 |
260 |
3.15
All 1-hour and
24-hour TSP monitoring was conducted as scheduled in the reporting month. No
Action/Limit Level exceedances were recorded.
3.16
According to
our field observations, the major dust source 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 Source |
|
KTN-DMS4 |
Excavation works, Road
traffic |
3.17
Should
project-related non-compliance of the criteria occur, action in accordance with
the Action Plan in Appendix J shall
be carried out.