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Pollutant Concentrations

Air quality readings will be available hourly from 1am to 12am.

Readings on 29 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 8(5) 43(43) 50(-) 62(26) 0.5(5) 27(68)
South 11(7) 38(38) 41(-) 46(19) 0.4(4) 27(68)
East 4(3) 33(33) 28(-) 59(25) 0.4(4) 23(63)
West 20(13) 55(53) 61(-) 56(24) 0.5(5) 37(79)
Central 15(9) 39(39) 48(-) 20(9) 0.5(5) 28(69)

1-hr PM2.5 (µg/m3)b Readings on 29 Oct 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 39 32 28 25 28 28 24 19 19 15 17 25
South 33 25 25 22 24 38 24 27 21 30 39 44
East 28 23 29 35 24 27 24 23 25 17 21 17
West 48 45 51 38 41 37 41 41 32 44 33 34
Central 45 28 25 34 37 34 34 40 29 17 18 18
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 27 23 23 24 32 28 28 20 21 41 47 -
South 47 37 35 30 27 34 10 8 8 10 13 -
East 19 29 32 37 19 14 15 9 8 15 22 -
West 33 40 50 48 38 30 27 22 26 23 28 -
Central 19 32 33 31 27 27 24 16 16 17 18 -

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 29 Oct 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 82 79 75 72 73 73 72 72 69 67 66 67
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 69 71 74 75 74 71 66 61 57 57 61 -

Hourly updates of 3-hr PSI readings are provided from 1am to 12am. The 3-hr PSI readings are calculated based on PM2.5 concentrations only.