Results and Observations. 2.7.1 The monitoring results for 1-hour TSP and 24-hour TSP are summarized in Table 2.4 and 2.5 respectively. Detailed impact air quality monitoring results are presented in Appendix G. Table 2.4 Summary of 1-hour TSP Monitoring Results in the Reporting Period Average (μg/m3) Range (μg/m3) Action Level (μg/m3) Limit Level (μg/m3) AMS2 83 81 – 86 374 500 AMS3A 84 81 – 88 368 500 AMS7 81 79 – 84 370 500 Table 2.5 Summary of 24-hour TSP Monitoring Results in the Reporting Period Average (μg/m3) Range (μg/m3) Action Level (μg/m3) Limit Level (μg/m3) AMS2 57 38 - 104 176 260 AMS3A 130 46 - 310 167 260 AMS7 92 40 - 188 183 260 2.7.2 The major dust source in the reporting period included construction activities from the Project, construction activities by other contacts, as well as nearby traffic emissions. 2.7.3 All 1-hour TSP results were below the Action and Limit Level at all monitoring locations in the reporting month. 2.7.4 However, two (2) 24-hour TSP results exceeded the Action Level on 13 and 29 April 13 at monitoring station AMS7 and AMS3A respectively. One (1) 24-hour TSP result exceeded the Limit Level on 08 April 2013 monitoring station AMS3A in the reporting month. 2.7.5 For the one (1) 24-hour TSP result exceeded the Limit Level on 8 April 13 at monitoring station AMS3A, according to information provided by the Contractor, land-based construction activity such as using canvas to cover sand material and stitching geotextile were being undertaken at Works Area WA2 during the monitoring period. 2.7.5.1 Functional checking on HVS at AMS3A was done. Air flow of the HVS was checked and the flow was steady during the 24-hr TSP sampling at AMS3A. The filter paper was re-weighted by the assigned HOKLAS laboratory and the result was reconfirmed. 2.7.5.2 As informed by the Contractor, construction activities like sheet piling and percussive piling, were carrying out by nearby private development project during the course of monitoring, which are close to the monitoring station AMS3A but beyond the site boundary of Works Area WA2. Traffics were observed passing exposed soil surfaces at those construction sites of nearby private development project. Please also see photo and layout map attached for reference of site conditions. 2.7.5.3 As refer to the wind data collected at wind station at Works Area WA2 during the monitoring period on 08 and 09 April 13 (as attached) East winds was prevailing during the monitoring period. Construction works carried out at construction sites of nearby private development project may contribute to the measured dust levels at the monitoring station AMS3A. 2.7.5.4 The 1-hr TSP values recorded at AMS3A on 08 April 13, which are within the monitoring period of the 24-hr TSP, were 84 g/m3, 87 g/m3 and 81g/m3 respectively. All measured values are well below the Action and Limit Levels. 2.7.5.5 The measured 24-hr TSP values recorded at AMS2 and AMS7 (which are closer to the marine-based works areas) on the same monitoring date were 104 g/m3 and 127 g/m3 respectively, which are below the Action and Limit Levels. 2.7.5.6 The following dust mitigation measures have been implemented at Works Area WA2: ⚫ Works Area WA2‟s surface was hard-paved, compacted or hydro-seeded ⚫ Vehicle washing facility was provided at vehicle exit points, ⚫ Measures for preventing fugitive dust emission are provided, e.g. tarpaulin covers. 2.7.5.7 Please see layout map attached for reference of site conditions 2.7.5.8 Please see photos attached for reference of site conditions: View of Works Area WA2 : Hard paved ground next to monitoring station AMS3A (View A) View on Site B: Beyond the site boundary of WA2 (View B) 2.7.5.9 The dust exceedance was therefore considered not to be due to the Project works. 2.7.5.10 The Contractor was recommended to continue implementing existing dust mitigation measures. 2.7.6 For the one (1) 24-hour TSP result exceeded the action Level on 13 April 13 at monitoring station AMS7, According to information provided by the Contractor, land-based construction activity such as delivering geotextile material was being undertaken at Works Area WA2 during the monitoring period. Marine-based construction activity such as stone column installation was being undertaken at portion D and portion A. 2.7.6.1 Stone column was being installed at the seabed therefore it is considered that stone column installation is unlikely to contribute to the recorded 24hr-TSP exceedance. 2.7.6.2 Functional checking on HVS at AMS7 was done. Air flow of the HVS was checked and the flow was steady during the 24-hr TSP sampling at AMS3A. The filter paper was re-weighted by the assigned HOKLAS laboratory and the result was reconfirmed. 2.7.6.3 The 1-hr TSP values recorded at AMS7 on 13 April 13, which are within the monitoring days of the 24- hr TSP, were 83 g/m3, 81 g/m3 and 80g/m3 respectively. All measured values are well below the Action and Limit Levels. 2.7.6.4 The measured 24-hr TSP values recorded at AMS2 and AMS3A on the same monitoring date were 64 g/m3 and 53 g/m3 respectively, which are below the Action and Limit Levels. 2.7.6.5 On the other hand, according to observation made at the monitoring station AMS7, there was no non- project potential cause/activity at the surrounding of monitoring station AMS7 which might potentially contribute to the dust action level exceedance. 2.7.6.6 As refer to the wind data collected at wind station at Works Area WA2 during the monitoring period on 13 and 14 April 13 (as attached) southwest winds was prevailing during the monitoring period. Construction works carried out by this Contract is unlikely to cause dust exceedance at AMS7 under southwest prevailing wind direction. 2.7.6.7 The following dust mitigation measures have been implemented at Works Area WA2: ⚫ Works Area WA2‟s surface was hard-paved, compacted or hydro-seeded ⚫ Vehicle washing facility was provided at vehicle exit points, ⚫ Measures for preventing fugitive dust emission are provided, e.g. tarpaulin covers. 2.7.6.8 The following dust mitigation measures have been implemented at throughout the construction site: ⚫ Excavators and generators were operated by ultra low sulphur diesel (ULSD) to minimize the possibility of air pollution. 2.7.6.9 Please see layout map attached for reference of site conditions 2.7.6.10 Please see photos of the conditions of the surrounding near the monitoring station AMS7: 2.7.6.11 The dust exceedance was therefore considered not to be due to the Project works. 2.7.6.12 The Contractor was recommended to continue implementing existing dust mitigation measures. 2.7.7 For the one (1) 24-hour TSP result exceeded the Limit Level on 29 April 13 at monitoring station AMS3A, according to information provided by the Contractor, land-based construction activity such as using installation of sandbags and stitching geotextile were being undertaken at Works Area WA2 during the monitoring period. 2.7.7.1 Functional checking on HVS at AMS3A was done. Air flow of the HVS was checked and the flow was steady during the 24-hr TSP sampling at AMS3A. The filter paper was re-weighted by the assigned HOKLAS laboratory and the result was reconfirmed. 2.7.7.2 As informed by the Contractor, construction activities like sheet piling and percussive piling, were carrying out by nearby private development project during the course of monitoring, which are close to the monitoring station AMS3A but beyond the site boundary of Works Area WA2. Traffics were observed passing exposed soil surfaces at those construction sites of nearby private development project. Please also see photo and layout map attached for reference of site conditions. 2.7.7.3 As refer to the wind data collected at wind station at Works Area WA2 during the monitoring period on 29 and 30 April 13 (as attached) South-southeast winds was prevailing during the monitoring period. Construction works carried out at construction sites of nearby private development project may contribute to the measured dust levels at the monitoring station AMS3A. 2.7.7.4 The 1-hr TSP values recorded at AMS3A on 29 April 13, which are within the monitoring period of the 24-hr TSP, were 82 g/m3, 82 g/m3 and 79g/m3 respectively. All measured values are well below the Action and Limit Levels. 2.7.7.5 The measured 24-hr TSP values recorded at AMS2 and AMS7 (which are closer to the marine-based works areas) on the same monitoring date were 38 g/m3 and 54 g/m3 respectively, which are below the Action and Limit Levels. 2.7.7.6 The following dust mitigation measures have been implemented at Works Area WA2: • Works Area WA2‟s surface was hard-paved, compacted or hydro-seeded • Vehicle washing facility was provided at vehicle exit points, • Measures for preventing fugitive dust emission are provided, e.g. tarpaulin covers.
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Results and Observations. 2.7.1 The monitoring results for 1-hour TSP and 24-hour TSP are summarized in Table 2.4 and 2.5 respectively. Detailed impact air quality monitoring results are presented in Appendix G. Table 2.4 Summary of 1-hour TSP Monitoring Results in the Reporting Period Average (μg/m3) Range (μg/m3) Action Level (μg/m3) Limit Level (μg/m3) AMS2 83 76 70-81 – 86 374 500 AMS3A 84 AMS3B 76 73-81 – 88 368 500 AMS7 81 79 – 84 AMS7A 78 69-83 370 500 Table 2.5 Summary of 24-hour TSP Monitoring Results in the Reporting Period Average (μg/m3) Range (μg/m3) Action Level (μg/m3) Limit Level (μg/m3) AMS2 57 38 - 104 176 260 AMS3A 130 46 - 310 167 260 AMS7 92 40 - 188 183 260)
2.7.2 The major dust source in the reporting period included construction activities from the Project, construction activities by other contacts, as well as nearby traffic emissions.
2.7.3 All 1-hour TSP results were below the Action and Limit Level at all monitoring locations in the reporting month.
2.7.4 However, two (2) 24-hour TSP results exceeded the Action Level on 13 and 29 April 13 at monitoring station AMS7 and AMS3A respectively. One (1) 24-hour TSP result exceeded the Limit Level Exceedance of 24hr-TSP with a reading of 270μg/m3 was recorded at AMS2 on 08 April 2013 monitoring station AMS3A in the reporting month10 August 2015.
2.7.5 For the one (1) 24-hour TSP result exceeded the Limit Level on 8 April 13 at monitoring station AMS3A, according 2.7.3 According to information provided by the Contractor, land-based construction activity such as using canvas to cover sand material and stitching geotextile were being undertaken at Works Area WA2 Contractor during the monitoring period, no changes of major works in the construction site of this Contract since box-culvert installation had been commenced in July 2015.
2.7.5.1 2.7.4 Functional checking on HVS at AMS3A AMS2 was done. Air flow of the HVS was checked and the flow was steady during the 24-hr TSP sampling at AMS3A. AMS2. The filter paper was re-weighted by the assigned HOKLAS laboratory and the result was reconfirmed.
2.7.5.2 As informed by the Contractor, construction activities like sheet piling and percussive piling, were carrying out by nearby private development project during the course of monitoring, which are close to the monitoring station AMS3A but beyond the site boundary of Works Area WA2. Traffics were observed passing exposed soil surfaces at those construction sites of nearby private development project. Please also see photo and layout map attached for reference of site conditions.
2.7.5.3 As refer to the wind data collected at wind station at Works Area WA2 during the monitoring period on 08 and 09 April 13 (as attached) East winds was prevailing during the monitoring period. Construction works carried out at construction sites of nearby private development project may contribute to the measured dust levels at the monitoring station AMS3A.
2.7.5.4 2.7.5 The 1-hr TSP values recorded at AMS3A AMS2 on 08 April 13, which are within the monitoring period of the 24-hr TSP10 August 15, were 84 g81μg/m3, 87 g80μg/m3 and 81g81μg/m3 respectively. All measured values are well below the Action and Limit Levels.
2.7.5.5 2.7.6 The measured 24-hr TSP values recorded at AMS2 and AMS7 AMS7A (which are is located closer to the marine-based active works areasthan AMS2) on the same monitoring date were 104 g10 August 15 was 29μg/m3 and 127 g/m3 respectivelym3, which are was below the Action and Limit Levels.
2.7.5.6 The following dust mitigation measures have been implemented 2.7.7 Site inspection for box-culvert installation at Works Area WA2: ⚫ Works Area WA2‟s surface Portion D was hard-pavedjointly conducted by ET, compacted or hydro-seeded ⚫ Vehicle washing facility was provided at vehicle exit pointsContractor and RSS on 6 August 2015, ⚫ Measures for preventing no fugitive dust emission are provided, e.g. tarpaulin coverswas observed at Portion D during the joint site inspection on 6 August 2015.
2.7.5.7 Please see layout map attached for reference of site conditions
2.7.5.8 Please see photos attached for reference of site conditions: View of Works Area WA2 : Hard paved ground next to monitoring station AMS3A (View A) View on Site B: Beyond the site boundary of WA2 (View B)
2.7.5.9 The dust exceedance was therefore considered not to be due to the Project works.
2.7.5.10 The Contractor was recommended to continue implementing existing dust mitigation measures.
2.7.6 For the one (1) 242.7.8 Box-hour TSP result exceeded the action Level on 13 April 13 at monitoring station AMS7, According to information provided by the Contractor, land-based construction activity such as delivering geotextile material was being undertaken at Works Area WA2 during the monitoring period. Marine-based construction activity such as stone column installation was being undertaken at portion D and portion A.
2.7.6.1 Stone column was culvert being installed at Portion D which is relatively far away from monitoring station AMS2 where the seabed therefore it is considered that stone column installation is unlikely to contribute to the recorded 24hr-TSP exceedance.
2.7.6.2 Functional checking on HVS at AMS7 was done. Air flow limit exceedance of the HVS was checked and the flow was steady during the 24-hr TSP sampling at AMS3A. The filter paper was re-weighted by the assigned HOKLAS laboratory and the result was reconfirmed.
2.7.6.3 The 1-hr TSP values recorded at AMS7 on 13 April 13, which are within the monitoring days of the 24- hr TSP, were 83 g/m3, 81 g/m3 and 80g/m3 respectivelyrecorded. All measured values are well below the Action and Limit Levels.
2.7.6.4 The measured 24-hr TSP values recorded at AMS2 and AMS3A on the same monitoring date were 64 g/m3 and 53 g/m3 respectively, which are below the Action and Limit Levels.
2.7.6.5 On the other hand, according to observation made at the monitoring station AMS7, there was no non- project potential cause/activity at the surrounding of monitoring station AMS7 which might potentially contribute to the dust action level exceedance.
2.7.6.6 As refer to the wind direction data collected at wind station at Works Area WA2 Chek Lap Kok by Hong Kong Observatory during the monitoring period on 13 10 and 14 April 13 11 August 2015 (as also see attached) southwest ), Southwestern winds was were prevailing during the monitoring period. Construction works carried out by this Contract is are unlikely to cause dust exceedance at AMS7 AMS2 under southwest the abovementioned prevailing wind directiondirections. (Also see below layout map for reference.)
2.7.9 In addition, no fugitive dust was expected to be generated in the process of box-culvert installation, as such, works activities from this Contract is unlikely to contribute to the recorded 24hr-TSP limit level exceedance.
2.7.6.7 2.7.10 The following dust mitigation measures have been implemented at Works Area WA2: ⚫ Works Area WA2‟s surface was hard-pavedlatest available checking record shows that plant engine is operated by ULSD.
2.7.11 With reference to the watering record, compacted or hydro-seeded ⚫ Vehicle washing facility watering was provided at vehicle exit points, ⚫ Measures for preventing fugitive dust emission are provided, e.g. tarpaulin covers8 times per day on site from 8 to 14 August 2015.
2.7.6.8 The following dust mitigation measures have been implemented at throughout 2.7.12 As such, the construction site: ⚫ Excavators and generators were operated by ultra low sulphur diesel (ULSD) to minimize the possibility of air pollution.
2.7.6.9 Please see layout map attached for reference of site conditions
2.7.6.10 Please see photos of the conditions of the surrounding near the monitoring station AMS7:
2.7.6.11 The dust exceedance was therefore considered not to be due to the Project works.works of this Contract
2.7.6.12 2.7.13 The Contractor was recommended to continue implementing existing dust mitigation measuresmeasures and the Contractor was reminded ensure to undertake watering at least 8 times per day on all exposed soil within the Project site and associated work areas throughout the construction phase.
2.7.7 For 2.7.14 The event action plan is annexed in Appendix L.
2.7.15 Meteorological information collected from the one (1) 24-hour TSP result exceeded the Limit Level on 29 April 13 at monitoring wind station AMS3A, according to information provided by the Contractor, land-based construction activity such as using installation of sandbags and stitching geotextile were being undertaken at Works Area WA2 during the monitoring period.
2.7.7.1 Functional checking periods on HVS at AMS3A was done. Air flow of the HVS was checked and the flow was steady during the 24-hr TSP sampling at AMS3A. The filter paper was re-weighted by the assigned HOKLAS laboratory and the result was reconfirmed.
2.7.7.2 As informed by the Contractor, construction activities like sheet piling and percussive piling, were carrying out by nearby private development project during the course of monitoring, which are close to the monitoring station AMS3A but beyond the site boundary of Works Area WA2. Traffics were observed passing exposed soil surfaces at those construction sites of nearby private development project. Please also see photo dates, as shown in Figure 2, including wind speed and layout map attached for reference of site conditions.
2.7.7.3 As refer to the wind data collected at wind station at Works Area WA2 during the monitoring period on 29 and 30 April 13 (as attached) South-southeast winds was prevailing during the monitoring period. Construction works carried out at construction sites of nearby private development project may contribute to the measured dust levels at the monitoring station AMS3A.
2.7.7.4 The 1-hr TSP values recorded at AMS3A on 29 April 13direction, which are within the monitoring period of the 24-hr TSP, were 82 g/m3, 82 g/m3 and 79g/m3 respectively. All measured values are well below the Action and Limit Levels.
2.7.7.5 The measured 24-hr TSP values recorded at AMS2 and AMS7 (which are closer to the marine-based works areas) on the same monitoring date were 38 g/m3 and 54 g/m3 respectively, which are below the Action and Limit Levels.
2.7.7.6 The following dust mitigation measures have been implemented at Works Area WA2: • Works Area WA2‟s surface was hard-paved, compacted or hydro-seeded • Vehicle washing facility was provided at vehicle exit points, • Measures for preventing fugitive dust emission are provided, e.g. tarpaulin covers.is annexed in Appendix H.
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