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 |
16 |
7 – 37 |
381 |
500 |
AMS4 |
37 |
8 – 148 |
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 |
20 |
6 – 49 |
170 |
260 |
AMS4 |
26 |
20 – 33 |
171 |
3.14 All 1-hour TSP
monitoring was conducted as scheduled in the reporting. No Action/Limit Level exceedances
were recorded.
3.15 All 24-hour TSP
monitoring was conducted as scheduled in the reporting. 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.