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Pollutant Concentrations

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

Readings on 11 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 24(15) 36(36) 30(-) 65(27) 0.5(5) 20(60)
South 13(8) 35(35) 34(-) 42(18) 0.5(5) 20(60)
East 10(6) 29(29) 15(-) 53(23) 0.5(5) 20(60)
West 25(16) 40(40) 39(-) 44(19) 0.4(4) 24(64)
Central 19(12) 33(33) 30(-) 68(29) 0.4(4) 19(58)

1-hr PM2.5 (µg/m3)b Readings on 10 Oct 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 17 21 20 14 15 14 12 12 13 15 17 20
South 14 11 10 13 9 13 16 10 17 15 17 25
East 18 15 15 17 14 15 11 16 18 18 5 17
West 20 21 19 13 18 10 8 16 24 19 22 20
Central 17 11 18 9 13 9 10 10 11 9 8 16
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 23 22 20 23 25 25 27 28 29 28 22 24
South 26 32 31 29 32 27 18 17 15 22 27 31
East 15 14 27 24 29 21 30 24 30 35 30 32
West 32 24 32 37 38 28 24 30 28 27 32 31
Central 12 23 27 22 27 27 30 25 23 32 32 29

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 10 Oct 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 58 57 56 55 54 52 51 51 53 54 54 56
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 58 62 64 66 69 68 68 66 66 67 68 70

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.