· to identify the extent of construction dust impact on sensitive receivers;
· to determine the effectiveness of mitigation measures to control fugitive dust emission from activities during the construction phase;
· to audit the compliance of the Contractor with regard to dust control, contract conditions and the relevant dust impact criteria;
· to recommend further mitigation measures if found to be necessary; and
· to comply with Action and Limit (A/L) Levels for air quality as defined in this Manual.
· The Hong Kong Air Quality Objectives (AQOs) for TSP, 24-hour TSP levels of 260 mg m-3; and
·
The statutory 1-hour
TSP limit of 500 mg m-3.; and
·5 odour units based on averaging time of 5 seconds
or equivalent H2S
concentration of 2.5 ppb.
· 0.6 - 1.7 m3 per minute (20 - 60 standard cubic feet per minute) adjustable flow range;
· equipped with a timing / control device with ± 5 minutes accuracy for 24 hours operation;
· installed with elapsed-time meter with ± 2 minutes accuracy for 24 hours operation;
· capable of providing a minimum exposed area of 406 cm2 ;
· flow control accuracy: ± 2.5% deviation over 24-hour sampling period;
· equipped with a shelter to protect the filter and sampler;
· incorporated with an electronic mass flow rate controller or other equivalent devices;
· equipped with a flow recorder for continuous monitoring;
· provided with a peaked roof inlet;
· incorporated with a manometer;
· able to hold and seal the filter paper to the sampler housing at horizontal position;
· easy to change the filter;
·
capable of operating continuously for
24-hour period.
(i)
The
wind sensors shall be installed 10m above ground so that they are clear of
obstructions or turbulence caused by the buildings;
(ii)
The
wind data shall be captured by a data logger.
The data shall be downloaded for analysis at least once a month;
(iii)
The
wind data monitoring equipment shall be re-calibrated at least once every six
months;
(iv)
Wind
direction should be divided into 16 sectors of 22.5 degrees each.
Table 2.1 Proposed
Air Quality Monitoring Stations
Station |
Location |
AM1 |
KMS Housing Development at
the South of WCR |
AM2 |
Residential Development near Eastern Harbour Crossing |
AM3 |
|
AM4 |
Area 67 – Planned School Area |
AM5 |
Area 78 – Planned
Residential Area (R3) and Education Area (Site 78E) |
AM6 |
Area 86 – MTRC Area 86 Development |
(i)
at
the site boundary or such locations close to the major dust emission source;
(ii)
close
to the air sensitive receivers;
(iii)
proper
position/sitting and orientation of the monitoring equipment; and
(iv)
take
into account the prevailing meteorological conditions.
(i)
a
horizontal platform with appropriate support to secure the samplers against
gusty wind shall be provided;
(ii)
no
two samplers shall be placed less than 2 meter apart;
(iii)
the
distance between the sampler and an obstacle, such as buildings, must be at
least twice the height that the obstacle protrudes above the sampler;
(iv)
a
minimum of 2 metres of separation from walls, parapets and penthouses is
required for rooftop samplers;
(v)
a
minimum of 2 metres of separation from any supporting structure, measured
horizontally is required;
(vi)
no
furnace or incinerator flue is nearby;
(vii)
airflow
around the sampler is unrestricted;
(viii)
the
sampler is more than 20 metres from the dripline;
(ix)
any
wire fence and gate, to protect the sampler, shall not cause any obstruction
during monitoring;
(x)
permission
must be obtained to set up the samplers and to obtain access to the monitoring
stations; and
(xi)
a
secured supply of electricity is needed to operate the samplers.
Table 2.2 Action
and Limit Levels for Air Quality
(Dust)
Parameter |
Action Level (1) |
Limit Level |
TSP (24 hour average) |
BL £ 200 mg m-3, AL = (BL * 1.3 +
LL)/2 BL > 200 mg m-3, AL = LL |
260 mg m-3 |
TSP (1 hour average) |
BL £ 384 mg m-3, AL = (BL * 1.3 +
LL)/2 BL > 384 mg m-3, AL = LL |
500 mg m-3 |
Note: (1)
BL = Baseline level, AL = Action level, LL = Limit level.
Table 2.3 Event and Action Plan for Air
Quality (Dust)
EVENT |
ACTION |
|||
ET |
IC(E) |
ER |
CONTRACTOR |
|
Action
level being exceeded by one sampling |
1.
Identify source, investigate the causes of complaint and propose remedial
measures; 2.
Inform IC(E) and ER; 3.
Repeat measurement to confirm finding; 4.
Increase monitoring frequency to daily. |
1.
Check monitoring data submitted by ET; 2.
Check Contractor’s working method. |
1.
Notify Contractor. |
1.
Rectify any unacceptable practice; 2.
Amend working methods if appropriate. |
Action
level being exceeded by two or more
consecutive sampling |
1.
Identify source; 2.
Inform IC(E) and ER; 3.
Advise the ER on the effectiveness of the proposed remedial measures; 4.
Repeat measurements to confirm findings; 5.
Increase monitoring frequency to daily; 6.
Discuss with IC(E) and Contractor on remedial actions required; 7.
If exceedance continues, arrange meeting with IC(E) and ER; 8.
If exceedance stops, cease additional monitoring. |
1.
Check monitoring data submitted by ET; 2.
Check Contractor’s working method; 3.
Discuss with ET and Contractor on possible remedial measures; 4.
Advise the ET on the effectiveness of the proposed remedial measures; 5.
Supervise Implementation of remedial measures. |
1.
Confirm receipt of notification of exceedance in writing; 2.
Notify Contractor; 3.
Ensure remedial measures properly implemented. |
1.
Submit proposals for remedial actions to IC(E) within three working
days of notification; 2.
Implement the agreed proposals; 3.
Amend proposal if appropriate. |
Limit level being exceeded by one sampling |
1. Identify source, investigate the causes of exceedance and
propose remedial measures; 2. Inform Contractor ,IC(E), ER, and EPD; 3. Repeat measurement to confirm finding; 4. Increase monitoring frequency to daily; 5. Assess effectiveness of Contractor’s remedial actions and keep
IC(E), EPD and ER informed of the results. |
1.
Check monitoring data submitted by ET; 2.
Check Contractor’s working method; 3.
Discuss with ET and Contractor on possible remedial measures; 4.
Advise the ER on the effectiveness of the proposed remedial measures; 5.
Supervise implementation of remedial measures. |
1.
Confirm receipt of notification of exceedance in writing; 2.
Notify Contractor; 3.
Ensure remedial measures properly implemented. |
1.
Take immediate action to avoid further exceedance; 2.
Submit proposals for remedial actions to IC(E) within three working
days of notification; 3.
Implement the agreed proposals; 4.
Amend proposal if appropriate. |
Limit level being exceeded by two or more consecutive sampling |
1.
Notify IC(E), ER, Contractor and EPD; 2.
Identify source; 3.
Repeat measurement to confirm findings; 4.
Increase monitoring frequency to daily; 5.
Carry out analysis of Contractor’s working procedures to determine
possible mitigation to be implemented; 6.
Arrange meeting with IC(E) and ER to discuss the remedial actions to
be taken; 7.
Assess effectiveness of Contractor’s remedial actions and keep IC(E),
EPD and ER informed of the results; 8.
If exceedance stops, cease additional monitoring. |
1.
Discuss amongst ER, ET, and Contractor on the potential remedial
actions; 2.
Review Contractor’s remedial actions whenever necessary to assure
their effectiveness and advise the ER accordingly; 3.
Supervise the implementation of remedial measures. |
1.
Confirm receipt of notification of exceedance in writing; 2.
Notify Contractor; 3.
In consolidation with the IC(E), agree with the Contractor on the
remedial measures to be implemented; 4.
Ensure remedial measures properly implemented; 5.
If exceedance continues, consider what portion of the work is
responsible and instruct the Contractor to stop that portion of work until
the exceedance is abated. |
1. Take immediate action to avoid further exceedance; 2. Submit proposals for remedial actions to IC(E) within three
working days of notification; 3. Implement the agreed proposals; 4. Resubmit proposals if problem still not under control; 5. Stop the relevant portion of works as determined by the ER until
the exceedance is abated. |
Construction Phase
· Use of regular watering, with complete coverage, to reduce dust emissions from exposed site surfaces and unpaved roads, particularly during dry weather.
· Use of frequent watering for particularly dusty construction areas and areas close to ASRs.
·
Side enclosure and covering of any aggregate or
dusty material storage piles to reduce emissions. Where this is not practicable owing to frequent usage, watering
shall be applied to aggregate fines.
·
Open stockpiles shall be avoided or covered. Where possible, prevent placing dusty
material storage piles near ASRs.
· Tarpaulin covering of all dusty vehicle loads transported to, from and between site locations.
·
Establishment and use of vehicle wheel
and body washing facilities at the exit points of the site. and
·
Routing of vehicles and
positioning of construction plant should be at the maximum possible distance
from ASRsProvision of wind shield and dust extraction units
or similar dust mitigation measures at the loading points, and use of water
sprinklers at the loading area where dust generation is likely during the
loading process of loose material, particularly in dry seasons/ periods.
·
Imposition of speed controls for vehicles on unpaved site
roads. Ten kilometers per hour is the
recommended limit.
·
Where possible, routing of vehicles and positioning
of construction plant should be at the maximum possible distance from ASRs.
· Instigation of an environmental monitoring and auditing program to monitor the construction process in order to enforce controls and modify method of work if dusty conditions arise.
PSK
site formation and Construction of WCR
·
Strictly limit the truck speed
on site not more than 10 km per hour and Wwatering
the haul roads at least 4 times a day to reduce the dust generation by 75%,.
in accordance with Control Techniques for Particulate Emissions from
Stationary Sources, Volume 2, US Environmental Protection Agency 1982.
WCR reclamation work phase 2 & 3
·
Strictly
limit the truck speed on site not more than 10 km per hour and water spraying
to keep the haul roads in wet condition.
This will reduce the dust generation by about 90%, in accordance with Control
Techniques for Particulate Emissions from Stationary Sources, Volume 2, US
Environmental Protection Agency 1982.
Operational Phase
·
Provision of a
ventilation building at the eastern portal of WCR (Eastern Portal Ventilation
Building) and it should be designed to extract 70% of the tunnel emission from
the eastbound carriageway of the WCR tunnel.
Then 30% of the tunnel emission from eastbound carriageway would be
discharged through the WCR portal at the TKO area. The exhaust vent shaft of the ventilation building are proposed
to be designed to exhaust in upward direction and the exhaust height should be
at least 25m above ground level to prevent adverse air quality impact on the
nearby ASRs. The exit velocity would be 8 m/s.
·
10%
vehicle emission from the westbound WCR tunnel should be allowed to emit from the Kowloon side
portal, 90% of the westbound
WCR tunnel emissions would be extracted and discharged at the Mid-Ventilation
Building. The Mid-ventilation building
should be relocated from Tiu Keng Leng to the proposed reclamation area near
CBL/WCR/Road P2 Interchange. The
mid-ventilation building on the reclamation area should be at least 350 m to
south of Ocean Shores. There would be two exhaust vent
pipes discharge the in-tunnel air to the exhaust vent shaft. The exhaust vent shaft of the ventilation
building would be upward direction with the exit velocity of 16 m/s, and
release height would be 6 m above ground.
·
The preliminary
design of the ventilation buildings (including exit height, exhaust directions,
exit velocity, design airflow rate and the exhaust diameter of the ventilation
building) is summarized in Table 2.4.
Table 2.4 Design
of WCR Ventilation Building at the Eastern Portal and Mid- Ventilation Building
|
Design Airflow
Rate (m3/s) |
Exit Velocity
(m/s) |
Exit Height (m) |
Exhaust Diameter
(m) |
Exhaust Direction |
|
Ventilation Building at eastern portal |
321 |
16 |
25 |
5.1 |
Upward |
|
Mid-Ventilation Building |
Vent 1 |
228 |
16 |
6 |
4.3 |
Upward |
Vent 2 |
210 |
16 |
6 |
4.1 |
Upward |
·The exhaust vent shaft of the ventilation building should be upward
direction with the exit velocity of 8 m/s, and release height should be 10 m above
ground.