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 |
2 |
|
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 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:
· Sufficient support was provided to secure the sampler
against gusty wind.
· No
two samplers were placed less than 2 meters apart.
· The
distance between the sampler and an obstacle, such as buildings, was at least
twice the height that the obstacle protrudes above the sampler.
· A
minimum of 2 meters of separation from walls, parapets and penthouses was
required for rooftop samples.
· A
minimum of 2 meters separation from any supporting structure, measured
horizontally was required.
· No
furnaces or incineration flues were nearby.
· Airflow
around the sampler was unrestricted.
· The
samplers were more than 20 meters from the drip line.
· Any
wire fence and gate, to protect the sampler, should not cause any obstruction
during monitoring.
· Permission must be obtained to set up the
samples and to obtain access to the monitoring stations; and
· 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 – 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 °C and not
variable by more than ±3 °C; the relative humidity (RH) was < 50% and not
variable by more than ±5%. 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:
· 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.
· The
power supply was checked to ensure the sampler worked properly.
· 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.
· 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.
· 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.
· The
shelter lid was closed and secured with the aluminum strip.
· 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).
· After
sampling, the filter was removed and sent to the ETS for weighing. The
elapsed time was also recorded.
· Before
weighing, all filters were 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 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:
· 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.
· 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 |
95 |
38 - 145 |
381 |
500 |
|
AMS4 |
123 |
24 - 658 |
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 |
71 |
29 – 108 |
170 |
260 |
|
AMS4 |
65 |
29 - 99 |
171 |
|
3.14
All
1-hour TSP monitoring was conducted as scheduled in the reporting month. No Action Level and one Limit Level exceedance were recorded.
3.15
All
24-hour TSP monitoring was conducted as scheduled in the reporting month. 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 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 |
Other
construction site nearby |
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.