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
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: () in 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 KER1a) for air quality monitoring.
2.5.3
According
to the approved relocation of monitoring location KER1a (EPD reference: () in
EP2/K19/A/21 pt.5), the monitoring location KER1a are proposed to be relocated
by alternative monitoring locations KER1b for air quality monitoring.
2.5.4
According
to the approved relocation of monitoring location KTD2a (EPD reference: () in
EP2/K19/A/21 pt.6), the monitoring location KTD2a are proposed to be relocated
by alternative monitoring locations KTD2b for air quality monitoring.
2.5.5
The
most updated locations 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, KTD2b 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.
2.7.2
The 24-hour TSP monitoring results at KTD1a and KER1b were below the Predicted Maximum 24-hr
TSP concentration in the approved Environmental
Impact Assessment (EIA) Report and no Action / Limit Level exceedance was
recorded in the reporting period.