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Pollutant Concentrations

Air quality readings will be available hourly from 7am to 11pm. Air quality readings from 12am to 6am will be made available at 7am on the same day.

 

Readings on 23 Dec 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 7(4) 18(18) 38(-) 7(3) 0.4(4) 8(32)
South 13(8) 19(19) 10(-) 8(3) 0.4(4) 11(46)
East 8(5) 17(17) 24(-) 6(3) 0.5(5) 11(45)
West 5(3) 15(15) 19(-) 15(6) 0.3(3) 7(30)
Central 11(7) 17(17) 38(-) 22(9) 0.3(3) 8(33)

1-hr PM2.5 (µg/m3)b Readings on 23 Dec 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 8 4 3 3 4 12 6 8 11 9 12 9
South 3 11 14 10 10 7 6 12 17 15 19 16
East 7 11 14 11 14 9 9 6 11 11 10 15
West 5 5 4 9 4 7 6 8 11 8 12 11
Central 3 10 9 10 7 8 7 6 13 9 11 8
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 6 11 17 10 13 6 6 4 5 7 5 -
South 18 16 23 21 6 10 6 2 4 9 5 -
East 16 13 15 15 8 8 6 4 7 15 8 -
West 11 11 7 9 6 7 2 4 4 9 10 -
Central 7 6 9 23 9 5 2 3 6 7 7 -

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 23 Dec 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 25 29 34 35 35 35 32 32 38 43 49 48
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 50 48 51 53 52 44 28 21 18 25 30 -

Hourly updates of 3-hr PSI readings are provided from 7am to 11pm. The 3-hr PSI readings from 12am to 6am will be made available at 7am on the same day. The 3-hr PSI readings are calculated based on PM2.5 concentrations only.