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Pollutant Concentrations

Readings on 22 Apr 2015

View reading for:

Region 24-hr Sulphur dioxide
(µg/m3)
24-hr PM10
(µg/m3)
1-hr Nitrogen dioxide
(µg/m3)a
8-hr Ozone
(µg/m3)
8-hr Carbon monoxide
(mg/m3)
24-hr PM2.5
(µg/m3)
North 11(7) 46(46) 29(-) 14(6) 1.2(12) 31(72)
South 32(20) 35(35) 65(-) 23(10) 0.6(6) 26(67)
East 14(8) 35(35) 29(-) 29(12) 0.9(9) 29(70)
West 17(11) 56(53) 10(-) 37(15) 0.6(6) 36(78)
Central 13(8) 43(43) 77(-) 25(11) 0.7(7) 29(71)

1-hr PM2.5 (µg/m3)b Readings on 21 Apr 2015

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 36 37 49 46 20 21 32 43 58 41 38 32
South 13 9 10 20 18 18 24 34 50 37 27 36
East 25 26 31 34 32 26 32 35 50 39 38 32
West 35 52 44 45 38 50 41 57 60 53 45 30
Central 17 26 36 36 36 27 40 54 55 45 31 30
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 40 35 34 49 30 14 7 8 8 14 24 17
South 32 33 49 39 38 24 37 22 7 17 13 28
East 36 31 31 43 23 16 29 15 12 11 12 26
West 40 41 40 48 50 44 17 2 8 14 9 9
Central 31 40 39 48 17 10 18 10 12 19 15 16

Note:
a Sub-index for nitrogen dioxide is reported only when the 1-hr concentration equals or exceeds 1130 µg/m3.

b There is no sub-index for 1-hr PM2.5.

3-hr PSI Readings from 1am to 12am on 21 Apr 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 64 67 71 75 75 72 72 77 87 91 88 79
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 77 77 79 83 81 75 65 58 53 49 52 56



The real-time data is automatically published as soon as it is generated by our air monitoring stations. The data is subject to verification and correction subsequently if necessary.