2.1
Monitoring Requirement
In accordance with the
approved EM&A Manuals, 24-hour Total Suspended Particulates (TSP) level at
the designated air quality monitoring station is required. Impact 24-hour TSP monitoring
should be carried out at least once every 6 days. In case of complaints, 1-hour
TSP monitoring should be carried out at least 3 times per 6 days when the
highest dust impacts are likely to occur. The Action and Limit Levels of the
air quality monitoring are given in Appendix C.
2.2
Monitoring Equipment
The 24-hour TSP air
quality monitoring was performed using High Volume Air Samplers (HVS) located
at each of the designated monitoring station. Portable TSP Monitors would be
used in case of complaints for 1-hour TSP monitoring.
Table 2.1 summarizes the equipment used in air
quality monitoring.
2.3
Monitoring Methodology
2.3.1
24-hour TSP air quality monitoring
HVS
Installation
The
following guidelines were adopted during the installation of HVS:
n Sufficient support is
provided to secure the samplers against gusty wind.
n No two samplers are
placed less than 2 meters apart.
n The distance between the
sampler and an obstacle, such as buildings, is at least twice the height that
the obstacle protrudes above the sampler.
n A minimum of 2 meters
of separation from walls, parapets and penthouses is required for rooftop
samples.
n A minimum of 2 meters
separation from any supporting structure, measured horizontally is required.
n No furnaces or
incineration flues are nearby.
n Airflow around the
samplers is unrestricted.
n The samplers are more
than 20 meters from the drip line.
n Any wire fence and
gate, to protect the sampler, should not cause any obstruction during
monitoring.
Filters
Preparation
Fiberglass
filters (provided by the HOKLAS accredited laboratory) shall be used (Note:
these filters have a collection efficiency of larger than 99% for particles of
0.3 µm diameter). A HOKLAS accredited laboratory (ALS Technichem
(HK) Pty Ltd.) is responsible for the preparation of 24-hr conditioned and
pre-weighed filter papers for monitoring team.
All
filters are equilibrated in the conditioning environment for 24 hours before
weighing. The conditioning environment temperature is around 25°C and not
variable by more than ±3°C; the relative humidity (RH) is < 50% and not
variable by more than ±5%. A convenient working RH is 40%.
Operating / Analytical Procedures
Operating
/ analytical procedures for the air quality monitoring are highlighted as
follows:
n Prior to the
commencement of the dust sampling, the flow rate of the HVS are properly set
(between 0.6 m3/min and 1.7 m3/min) in accordance with
the EM&A manual. The flow rate shall be indicated on the flow rate chart.
n The power supply shall
be checked to ensure the samplers worked properly.
n On sampling, the
samplers shall be operated for 5 minutes to establish thermal equilibrium
before placing any filter media at the designated air quality monitoring
station.
n The filter holding
frame is then removed by loosening the four nuts and carefully a weighted and
conditioned filter is centered with the stamped number upwards, on a supporting
screen.
n The filter shall be
aligned on the screen so that the gasket formed an airtight seal on the outer
edges of the filter. Then the filter holding frame is tightened to the filter
holder with swing bolts. The applied pressure should be sufficient to avoid air
leakage at the edges.
n The shelter lid shall
be closed and secured with the aluminum strip.
n The timer is then
programmed. Information shall be 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).
n After sampling, the
filter shall be removed and sent to laboratory for weighing. The elapsed time
is also recorded.
n Before weighing, all
filters are 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 are returned
to MCL for further analysis of TSP concentrations collected by each filter.
2.3.2
1-hour TSP air quality monitoring
Operating / Analytical Procedures
The measuring
procedures of the 1-hr dust meter are in accordance with the Manufacturer’s
instruction Manual as follows:
§ Pull up the air sampling inlet cover
§ Change the Mode 0 to BG once
§ Push Start/Stop switch once
§ Turn the knob to SENSI.ADJ and press it
§ Push Start/Stop switch once
§ Return the knob to the position MEASURE slowly
§ Push the timer set switch to set measuring time
§ Remove the cap and make a measurement
2.4
Maintenance /
Calibration
2.4.1 24-hour TSP air quality monitoring
The
following maintenance / calibration are required for the HVS:
n The high volume motors
and their accessories are properly maintained. Appropriate maintenance such as
routine motor brushes replacement and electrical wiring checking are made to
ensure that the equipments and necessary power supply
are in good working condition.
n All HVS shall be
calibrated (five point calibration) using Calibration Kit upon installation and
thereafter in every 3 months.
n A copy of the
calibration certificates for the HVS and calibrator are provided in Appendix
D.
2.4.2 1-hour TSP air quality monitoring
The
portable TSP monitor should be calibrated at 1 year intervals
2.5.1
According
to the EM&A Manual, three air quality monitoring locations, namely KTD1,
KTD2 and KER1, are covered by this Contract within the South Apron Area of
Former Kai Tak Airport. The other two air quality
monitoring locations, which are identified in Cha Kwo
Ling area, are farther than 500m away from the site boundary and thus not
covered by this Contract. The monitoring works in Cha Kwo
Ling area are covered by other Contract(s) respectively.
2.5.2
According
to the approved alternative baseline air quality and noise monitoring locations
(EPD reference: EP2/K19/A/21 Pt.5), the original monitoring locations (KTD1,
KTD2 and KER1) are proposed to be replaced by alternative monitoring locations
(KTD1a, KTD2a and KER1b) for air quality monitoring, they are summarized in Table 2.2
and shown in Figure
2.
2.6.1 The schedule of air quality monitoring in reporting month is provided in Appendix
E.
2.6.2 No Action / Limit Level exceedance was
recorded for 24-hr TSP at KTD1a, KTD2a and KER1b in the reporting month.
2.6.3 No complaint of air quality was received. Therefore, no impact 1-hour TSP
monitoring was conducted in the reporting month.
2.6.4 During the reporting month, major dust sources including loading and
unloading of C&D wastes, vehicles movement were observed in the site.
Non-project related construction activities at the nearby construction site and
road traffic along Shing Cheong Road, Cheung Yip Street and the Kwun Tong By-pass were observed. The above factors may
affect the monitoring results.
2.6.5 The weather conditions during the monitoring are provided in Appendix K.
2.6.6 The monitoring data of 24-hr TSP are summarized in Table 2.3. Detailed monitoring data are presented
in Appendix
F.
2.6.7 The Event and Action Plan for air quality is given in Appendix H.
2.7
Comparison of 24-hr TSP Monitoring Results with EIA
Predictions
2.7.1 The monitoring data of 24-hr TSP was compared with the EIA predictions as
summarized in Table 2.4.