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 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 |
108 |
50-182 |
381 |
500 |
AMS4 |
94 |
24-176 |
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 |
66 |
33-83 |
170 |
260 |
AMS4 |
57 |
26-79 |
171 |
3.14 All
1-hour TSP monitoring was conducted as scheduled in the reporting month except
1-hour TSP monitoring at AMS1 (2nd and 3rd hour) and AMS4
on 6 November 2017 which was cancelled and postponed to 7 November 2017 due to
the failure of power supply from the premises. The power supply was resumed on
7 November 2017. 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 AMS1 and AMS4 on 6 November 2017 which was cancelled
and postponed to 7 November 2017 due to the failure of power supply from the
premises. The power supply was resumed on 7 November 2017. 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.