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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 19 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 8(5) 29(29) 27(-) 40(17) 0.3(3) 12(51)
South 9(6) 36(36) 7(-) 45(19) 0.4(4) 15(55)
East 6(4) 29(29) 9(-) 60(25) 0.4(4) 17(57)
West 2(1) 34(34) 9(-) 60(25) 0.4(4) 16(56)
Central 6(4) 32(32) 17(-) 59(25) 0.3(3) 11(47)

1-hr PM2.5 (µg/m3)b Readings on 19 Jan 2015

View reading for:

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

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 19 Jan 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 48 46 51 51 52 52 52 53 53 55 56 59
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 60 60 59 59 57 56 55 53 52 45 42 -

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.