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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 12 Jan 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 10(6) 21(21) 14(-) 23(10) 0.4(4) 10(43)
South 7(4) 23(23) 5(-) 22(10) 0.4(4) 11(44)
East 5(3) 21(21) 6(-) 38(16) 0.2(2) 12(51)
West 5(3) 24(24) 19(-) 37(16) 0.4(4) 11(44)
Central 8(5) 20(20) 49(-) 39(16) 0.3(3) 8(35)

1-hr PM2.5 (µg/m3)b Readings on 12 Jan 2015

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 11 8 7 11 14 9 7 7 13 17 13 13
South 7 5 10 5 4 6 8 7 8 13 20 23
East 7 10 10 11 9 11 10 11 12 14 19 14
West 10 6 7 11 9 8 7 9 10 14 16 15
Central 7 8 6 8 5 3 7 6 9 12 11 16
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 11 13 8 10 9 11 4 7 7 13 11 -
South 23 19 17 18 9 13 4 9 8 6 3 -
East 12 11 16 13 10 19 8 18 11 12 10 -
West 20 13 10 13 8 7 6 6 7 15 18 -
Central 10 10 10 10 9 11 4 14 10 10 3 -

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 12 Jan 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 38 36 32 33 35 34 33 32 37 46 53 55
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 55 54 53 52 47 47 37 39 34 42 39 -

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.