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.
Table 2.3 Summary of 24-hr TSP
Monitoring Results
|
Parameter |
Monitoring Station |
Average (µg/m3) |
Range (µg/ m3) |
Action Level (µg/ m3) |
Limit Level (µg/ m3) |
|
24-hr TSP in µg/m3 |
KTD1a |
131 |
60 – 174 |
177 |
260 |
|
KTD2a |
56 |
19 – 93 |
157 |
||
|
KER1b |
128 |
110 – 144 |
172 |
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.