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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 31 Oct 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 6(4) 43(43) 84(-) 31(13) 0.5(5) 26(67)
South 12(7) 42(42) 91(-) 25(11) 0.7(7) 31(72)
East 8(5) 33(33) 61(-) 54(23) 0.5(5) 26(67)
West 5(3) 38(38) 80(-) 31(13) 0.6(6) 27(67)
Central 16(10) 36(36) 92(-) 50(21) 0.9(9) 25(65)

1-hr PM2.5 (µg/m3)b Readings on 31 Oct 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 36 38 27 24 23 30 31 31 29 27 28 27
South 32 30 25 29 26 30 32 44 44 42 41 45
East 34 33 33 27 35 31 28 34 25 26 26 14
West 27 37 33 41 28 31 32 35 32 28 27 25
Central 27 31 26 34 31 28 29 24 29 25 17 30
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 24 22 36 38 11 10 14 28 13 26 37 -
South 44 35 44 43 27 9 7 6 21 28 26 -
East 26 17 41 30 35 19 13 16 15 16 23 -
West 31 23 16 26 30 13 10 10 22 25 11 -
Central 15 33 39 42 21 6 4 16 17 20 26 -

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 31 Oct 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 71 74 73 73 71 71 71 73 73 73 71 70
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 69 68 71 74 73 64 55 50 53 58 62 -

Hourly updates of 3-hr PSI readings are provided from 7am to 11pm. The 3-hr PSI readings are calculated based on PM2.5 concentrations only.

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