2.                   Air Quality Monitoring

2.1                   Monitoring Requirement

2.1.1                                 With reference to Section 2.2.25 of the EM&A manual, the baseline air quality monitoring shall be carried out for at least 14 consecutive days prior to the commissioning of the construction works. 1-hour TSP sampling shall be done at least 3 times per day at each monitoring station. During the baseline monitoring. There should not be any construction or dust generating activities in the vicinity of the monitoring stations.

2.1.2                                 As permission of access and 220V AC power supply could not be obtained from the designated dust monitoring locations, a direct reading dust meter is proposed to measure 1-hour TSP levels in accordance with Section 2.2.10 of the EM&A manual.

2.2                   Monitoring Locations

2.2.1                                 In accordance with Section 2 of the EM&A Manual, air quality monitoring should be carried out at 2 designated monitoring locations. The air quality monitoring stations summarised in Table 2.1 and shown in Figure 2.

2.3                   Monitoring Equipment

2.3.1                                 Portable Laser Particle Photometer Monitors (Sibata Model LD-3B / 5R) complete with appropriate sampling inlets are employed for 1-hour TSP measurement.

Measuring Procedures

a) Pulling up the air sampling inlet cover

b) Changing the Mode 0 to BG

c) Pressing Start/Stop switch

d) Turning the knob to SENSI.ADJ and press it

e) Pressing Start/Stop switch again

f) Returning the knob to the position MEASURE slowly

g) Pressing the timer set switch to set measuring time

h) Removing the cap and start the measurement

Equipment Calibration

1-hour dust meter should be calibrated at 1 year intervals. The calibration certificates are presented in Appendix A.

2.3.2                                 The model of the air quality monitoring equipment used is summarized in Table 2.2.

2.4                   Results and Observations

2.4.1                                 The baseline monitoring work was conducted between 1 December 2020 and 14 December 2020. The baseline monitoring schedule is provided in Appendix F.

2.4.2                                 During the baseline monitoring, at AM1, road traffic along Wang Lee Street was observed in the surroundings. At AM2, road traffic from squatter house at the west of Yuen Long STW was observed during the baseline monitoring.

2.4.3                                 The monitoring data are summarized in Table 2.3. Detailed air quality monitoring data are presented in Appendix B and wind data are presented in Appendix H.

2.5                   Action and Limit Levels for Air Quality Monitoring

2.5.1                                 The Action and Limit (A/L) Levels to be used for determining the construction dust are summarized in Table 2.4.

2.5.2                                 Following the above guidelines, the Action and Limit Levels for air quality impact monitoring have been set, as presented in Table 2.5.

2.6                   Event and Action Plan

2.6.1                                 The Event and Action Plan for Air Quality are given in Appendix E.