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 |
|
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:
¡P Sufficient support was provided to secure the sampler against gusty wind.
¡P No two samplers were placed less than 2 meters
apart.
¡P The distance between the sampler and an
obstacle, such as buildings, was at least twice the height that the obstacle
protrudes above the sampler.
¡P A minimum of 2 meters of separation from walls,
parapets and penthouses was required for rooftop samples.
¡P A minimum of 2 meters separation from any
supporting structure, measured horizontally was required.
¡P No furnaces or incineration flues were nearby.
¡P Airflow around the sampler was unrestricted.
¡P The samplers were more than 20 meters from the
drip line.
¡P Any wire fence and gate, to protect the sampler,
should not cause any obstruction during monitoring.
¡P Permission must be
obtained to set up the samples and to obtain access to the monitoring stations;
and
¡P 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 ¡V 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 ¢XC and not variable by more than ¡Ó3 ¢XC; the relative humidity
(RH) was < 50% and not variable by more than ¡Ó5%. 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:
¡P 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.
¡P The power supply was checked to ensure the
sampler worked properly.
¡P 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.
¡P 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.
¡P 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.
¡P The shelter lid was closed and secured with the
aluminum strip.
¡P 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).
¡P After sampling, the filter was removed and sent
to the ETS for weighing. The elapsed time was also recorded.
¡P Before weighing, all filters were equilibrated
in a conditioning environment for 24 hours. The conditioning environment
temperature should be between 25¢XC and 30¢XC and not vary by more than ¡Ó3¢XC; the
relative humidity (RH) should be < 50% and not vary by more than ¡Ó5%. 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:
¡P 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.
¡P 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 |
89 |
39 ¡V 193 |
381 |
500 |
AMS4 |
74 |
22 ¡V 198 |
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 |
48 |
8 ¡V 86 |
170 |
260 |
AMS4 |
81 |
35 ¡V 163 |
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.