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Pollutant Concentrations

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

Readings on 25 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 5(3) 53(52) 44(-) 84(36) 0.6(6) 34(76)
South 17(10) 45(45) 40(-) 55(24) 0.4(4) 32(74)
East 11(7) 38(38) 34(-) 69(29) 0.6(6) 29(70)
West 25(16) 52(51) 58(-) 50(21) 0.5(5) 37(79)
Central 23(14) 40(40) 77(-) 71(30) 0.6(6) 29(70)

1-hr PM2.5 (µg/m3)b Readings on 24 Oct 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 36 50 49 46 41 35 37 40 39 24 25 34
South 40 32 20 24 25 31 32 40 34 41 34 34
East 36 34 31 31 30 35 27 26 24 33 21 18
West 40 47 48 44 30 34 35 53 43 51 33 44
Central 38 27 23 27 18 25 29 43 44 19 30 21
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 28 31 34 29 28 23 20 35 30 37 33 43
South 46 41 41 45 59 40 26 19 14 23 15 20
East 29 31 25 30 27 32 38 36 36 22 24 26
West 38 44 37 29 37 33 24 23 30 20 32 29
Central 29 31 27 26 36 34 29 31 22 26 30 25

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 24 Oct 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 79 80 79 77 74 73 72 77 78 79 75 72
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 72 75 76 75 76 76 74 71 68 68 67 68

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.