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Pollutant Concentrations

Air quality readings will be available hourly from 1am to 12am.

Readings on 23 Oct 2014

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 3(2) 36(36) 69(-) 23(10) 0.7(7) 22(62)
South 17(11) 32(32) 62(-) 5(2) 0.6(6) 24(64)
East 20(12) 29(29) 42(-) 12(5) 0.6(6) 23(64)
West 22(14) 39(39) 80(-) 29(12) 0.7(7) 29(70)
Central 33(20) 32(32) 72(-) 18(8) 0.8(8) 23(64)

1-hr PM2.5 (µg/m3)b Readings on 22 Oct 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 13 15 19 24 24 22 19 24 22 22 23 17
South 24 19 21 21 17 27 15 6 14 27 26 23
East 22 19 21 24 21 22 24 21 22 19 17 16
West 20 24 24 34 37 40 37 17 20 23 16 17
Central 25 15 20 21 23 20 21 21 21 18 20 14
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 18 9 7 17 22 27 31 32 30 31 24 35
South 24 20 6 24 26 34 29 34 32 27 31 39
East 32 15 13 20 19 26 21 30 32 37 39 34
West 9 14 31 26 26 38 39 48 38 40 38 36
Central 20 21 19 24 23 32 32 29 27 30 30 31

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 22 Oct 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 60 60 60 61 64 66 65 63 60 60 61 60
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 59 58 57 57 60 66 69 74 74 75 74 75

Hourly updates of 3-hr PSI readings are provided from 1am to 12am. The 3-hr PSI readings are calculated based on PM2.5 concentrations only.