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Pollutant Concentrations

Readings on 25 May 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 4(2) 23(23) 36(-) 13(5) 0.4(4) 13(52)
South 17(11) 21(21) 5(-) 9(4) 0.4(4) 10(43)
East 15(10) 21(21) 20(-) 23(10) 0.4(4) 15(54)
West 34(21) 28(28) 32(-) 16(7) 0.3(3) 15(54)
Central 13(8) 20(20) 21(-) 20(9) 0.4(4) 11(47)

1-hr PM2.5 (µg/m3)b Readings on 24 May 2015

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 19 13 14 7 9 18 15 22 33 29 13 14
South 8 12 6 9 15 20 24 19 18 20 24 5
East 16 14 18 34 27 29 19 15 21 17 10 11
West 6 3 9 11 13 11 18 19 25 22 25 30
Central 11 9 11 14 19 9 12 21 23 15 18 8
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 7 14 13 7 10 12 9 8 14 10 5 7
South 2 3 9 4 7 5 11 3 4 3 7 5
East 5 8 10 9 12 6 17 14 10 11 9 12
West 27 24 17 10 11 9 13 14 11 10 8 9
Central 9 12 11 9 10 5 10 6 9 8 7 7

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 24 May 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 53 47 47 51 54 56 57 58 60 61 61 57
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 53 50 47 44 41 35 41 39 42 37 35 33



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.

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