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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 16 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) 26(26) 15(-) 37(16) 0.5(5) 13(52)
South 7(4) 26(26) 7(-) 35(15) 0.5(5) 11(45)
East 8(5) 26(26) 12(-) 63(27) 0.5(5) 16(55)
West 2(1) 26(26) 9(-) 58(25) 0.4(4) 12(49)
Central 6(4) 23(23) 28(-) 47(20) 0.3(3) 10(42)

1-hr PM2.5 (µg/m3)b Readings on 16 Jan 2015

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 16 11 12 19 18 18 17 16 12 16 16 12
South 2 3 4 10 7 11 11 16 14 14 22 20
East 12 18 18 18 23 20 22 16 11 21 24 13
West 6 11 11 9 12 10 8 15 14 18 21 21
Central 2 8 8 8 11 16 11 14 11 9 14 10
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 10 13 8 10 9 12 8 11 15 11 13 -
South 14 14 12 13 11 19 7 9 8 10 8 -
East 16 9 9 9 12 13 19 16 17 13 16 -
West 13 13 13 11 8 7 13 6 14 10 11 -
Central 12 8 8 9 10 16 8 16 13 12 5 -

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 16 Jan 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 36 37 40 47 51 53 54 54 53 54 55 56
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 55 52 48 44 42 47 48 50 50 51 49 -

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.