3.1
In accordance with the EM&A Manual,
impact 1-hour TSP and 24-hour TSP monitoring were conducted to monitor the air quality for
the Contract. 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 impact 24-hour TSP monitoring was
conducted for at least once every 6 days at 2 air quality monitoring stations.
3.3
Impact air quality monitoring was conducted
at the 2 monitoring stations under the Contract, as shown in Figure 3. Table 3.1 describes the
locations of the air quality monitoring stations.
Table 3.1 Location for Air Quality Monitoring Locations
|
Monitoring Stations |
Location |
|
AMS1 |
Sha
Lo Wan |
|
AMS4 |
San Tau |
3.4
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
|
Equipment |
Model and Make |
Quantity |
|
HVS Sampler |
TISCH
Model: TE-5170 |
2 |
|
Calibrator |
TISCH
Model: TE-5025A |
1 |
|
Wind Anemometer |
DAVIS
Model: Vantage PRO2 6152CUK |
1 |
Monitoring
Parameters, Frequency and Duration
3.5
Table
3.3 summarizes the monitoring parameters and
frequencies of impact dust monitoring during the course of the Contract
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 |
Monitoring Methodology and QA/QC Procedure
1-hour and 24-hour TSP Air Quality Monitoring
3.6
High Volume Samplers (HVS) completed with
appropriate sampling inlets were employed for air quality 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).
3.7
The following guidelines were adopted during
the installation of HVS:
· Sufficient
support was
provided to
secure the sampler 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
must be obtained to set up the samples and to obtain access to the monitoring
stations; and
· A
secured supply of electricity is needed to operate the samplers.
3.8
Filter paper of size 8” X 10” was used. A HOKLAS accredited laboratory, ETS – Testconsult Limited
(ETS), was responsible for the preparation of 24-hr conditioned and pre-weighed
filter papers for Cinotech’s monitoring team.
3.9
All filters, which were prepared by ETS, 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%.
3.10 ETS
has comprehensive quality assurance and quality control programmes.
Operating/Analytical Procedures
3.11 Operating/analytical
procedures for the air quality monitoring were highlighted as follows:
· Prior to the commencement
of the 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. 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.
· 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 sent to the ETS for weighing. The elapsed time was also recorded.
· Before weighing, all
filters were equilibrated in a conditioning environment for 24 hours. The
conditioning environment temperature should be between 25°C and 30°C and not
vary by more than ±3°C; the relative humidity (RH) should be < 50% and not
vary by more than ±5%. A convenient
working RH is 40%. Weighing results
were returned to Cinotech for further analysis of TSP
concentrations collected by each filter.
3.12 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.
· All
HVS were calibrated
(five point calibration) using Calibration Kit prior to
the commencement of the baseline monitoring and thereafter at bi-monthly
intervals.
3.13 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 Appendices E and F respectively.
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 |
|||
|
AMS1 |
28 |
4 – 63 |
381 |
500 |
|
AMS4 |
36 |
17 – 70 |
352 |
|
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 |
|||
|
AMS1 |
24 |
14 – 38 |
170 |
260 |
|
AMS4 |
58 |
23 – 142 |
171 |
|
3.14 All
1-hour TSP monitoring was conducted as scheduled in the reporting month except
1-hour TSP monitoring at AM4 on 9 May 2016 which was cancelled due to the
failure of power supply from the premises. The power supply problem was fixed
on 13 May 2016. No Action/Limit
Level exceedances were recorded.
3.15 All
24-hour TSP monitoring was conducted as scheduled in the reporting month except
24-hour TSP monitoring at AM4 on 9 May 2016 which was cancelled due to the
failure of power supply from the premises. The power supply problem was fixed
on 13 May 2016. 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 as follows:
Table 3.6 Observation at Dust Monitoring Stations
|
Monitoring
Station |
Major Dust Source |
|
AMS1 |
Exhaust
from marine traffic |
|
AMS4 |
N/A |
3.17 The
wind speed and wind direction were recorded by the installed Wind Anemometer
set at AMS4. The location is shown in Figure
3.
3.18 The
wind data for the reporting month is summarized in Appendix J.
3.19 Should
non-compliance of the criteria occur, action in accordance with the Action Plan
in Appendix K shall be carried out.