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Pollutant Concentrations

Readings on 22 Feb 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 5(3) 21(21) 32(-) 42(18) 0.3(3) 11(45)
South 4(2) 23(23) 14(-) 38(16) 0.3(3) 11(45)
East 9(6) 19(19) 5(-) 45(19) 0.6(6) 12(51)
West 3(2) 23(23) 15(-) 53(23) 0.4(4) 12(50)
Central 5(3) 22(22) 24(-) 54(23) 0.3(3) 12(48)

1-hr PM2.5 (µg/m3)b Readings on 21 Feb 2015

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 12 17 6 9 11 12 8 11 8 10 12 11
South 18 8 10 3 13 20 7 8 18 16 5 13
East 11 9 11 13 11 10 13 16 27 13 17 11
West 8 10 16 20 5 11 14 13 14 17 6 18
Central 9 19 21 16 9 6 10 14 12 15 11 7
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 14 13 12 10 10 8 8 10 7 11 12 16
South 15 12 12 19 15 5 8 9 7 9 4 6
East 11 10 11 16 12 5 15 18 9 6 9 11
West 11 9 8 23 12 6 15 13 11 7 10 13
Central 16 12 6 14 15 5 13 10 11 8 10 9

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 21 Feb 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 40 48 51 52 48 47 44 48 52 53 53 50
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 49 50 47 51 52 48 42 41 46 41 37 39



The real-time data is automatically published as soon as it is generated by our air monitoring stations. The data is subject to verification and correction subsequently if necessary.