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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 26 Nov 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 2(1) 20(20) 57(-) 6(3) 0.4(4) 10(43)
South 9(5) 22(22) 15(-) 7(3) 0.5(5) 14(53)
East 17(11) 23(23) 16(-) 14(6) 0.5(5) 16(56)
West 7(4) 19(19) 32(-) 12(5) 0.5(5) 9(38)
Central 13(8) 19(19) 45(-) 15(6) 0.6(6) 11(47)

1-hr PM2.5 (µg/m3)b Readings on 25 Nov 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 4 3 6 10 13 10 12 8 14 9 15 12
South 11 17 9 2 3 5 3 9 15 13 31 48
East 4 12 16 16 16 15 14 18 26 24 15 20
West 5 5 8 9 9 7 6 7 13 8 11 15
Central 12 9 9 4 7 3 5 6 9 9 12 15
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 19 17 19 7 9 17 4 4 5 10 13 9
South 36 25 26 20 5 12 18 3 2 8 7 12
East 11 18 39 34 23 30 15 5 4 6 6 7
West 23 14 7 14 8 16 9 2 5 3 6 11
Central 21 19 30 28 8 22 11 4 2 6 10 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 25 Nov 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 24 29 36 38 38 36 36 36 46 51 54 57
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 60 61 62 61 58 56 53 48 26 19 25 35

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.