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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 10 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) 16(16) 12(-) 9(4) 0.4(4) 7(29)
South 6(4) 18(18) 5(-) 17(7) 0.4(4) 7(30)
East 9(6) 15(15) 8(-) 19(8) 0.3(3) 9(38)
West 7(5) 17(17) 25(-) 29(12) 0.5(5) 7(29)
Central 8(5) 15(15) 42(-) 27(11) 0.3(3) 7(30)

1-hr PM2.5 (µg/m3)b Readings on 10 Jan 2015

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 4 5 3 4 4 7 8 4 7 16 9 15
South 3 3 3 3 3 9 6 6 6 6 10 11
East 9 10 13 5 4 3 6 4 10 19 17 11
West 5 4 6 2 3 5 3 8 3 10 16 10
Central 6 6 5 2 5 4 5 7 8 6 9 5
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 6 7 7 5 7 7 6 6 5 7 5 -
South 9 14 11 21 22 4 2 2 2 4 5 -
East 12 8 8 10 14 8 5 12 7 7 8 -
West 9 14 11 8 7 9 3 2 4 14 8 -
Central 4 12 10 6 22 8 11 3 7 11 6 -

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 Jan 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 27 24 24 21 18 18 22 24 25 33 42 47
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 43 41 39 42 47 44 38 25 21 26 28 -

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.