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 period 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
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
¡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
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 Period
Monitoring Station |
Concentration (µg/m3) |
Action
Level, µg/m3 |
Limit
Level, µg/m3 |
|
Average |
Range |
|||
AMS1 |
77 |
29 ¡V 129 |
381 |
500 |
AMS4 |
128 |
60 ¡V 204 |
352 |
Table 3.5 Summary Table of 24-hour TSP Monitoring Results during the Reporting
Period
Monitoring Station |
Concentration (µg/m3) |
Action
Level, µg/m3 |
Limit
Level, µg/m3 |
|
Average |
Range |
|||
AMS1 |
45 |
20 ¡V 70 |
170 |
260 |
AMS4 |
51 |
30 ¡V 72 |
171 |
3.14
All 1-hour TSP monitoring was conducted as scheduled in the reporting period. No Action/Limit Level exceedance was recorded.
3.15
All 24-hour TSP monitoring was conducted as scheduled in the reporting period. No Action/Limit Level exceedance was recorded.
3.16
According to our field observations, the major dust source identified at
the designated air quality monitoring stations are as follows:
Table 3.6 Observation at Dust Monitoring Stations
Monitoring Station |
Major Dust Source |
AMS1 |
Shallow
sand beach nearby |
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. The wind data
for the reporting period is summarized in Appendix
J.
3.18
Should non-compliance of the criteria occur, action in accordance with
the Action Plan in Appendix K shall
be carried out.