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Pollutant Concentrations

Readings on 24 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(3) 29(29) 46(-) 8(4) 0.5(5) 18(57)
South 19(12) 27(27) 13(-) 5(2) 0.6(6) 17(57)
East 16(10) 21(21) 32(-) 9(4) 0.6(6) 15(54)
West 12(8) 26(26) 21(-) 11(5) 0.2(2) 14(53)
Central 26(16) 26(26) 33(-) 10(4) 0.6(6) 16(55)

1-hr PM2.5 (µg/m3)b Readings on 23 May 2015

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 12 18 27 37 37 21 14 18 11 12 16 19
South 10 10 11 12 20 21 10 10 8 6 23 33
East 8 6 15 9 20 21 26 10 7 15 10 13
West 11 13 11 10 22 14 9 8 2 10 17 26
Central 8 9 10 10 17 26 14 10 11 6 6 22
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 20 14 18 17 4 5 12 15 19 23 20 16
South 24 16 22 7 19 19 23 22 31 35 19 4
East 22 6 24 8 6 18 20 23 19 19 19 12
West 36 10 12 11 12 16 17 16 16 10 10 6
Central 29 14 16 9 14 23 21 19 24 21 20 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 23 May 2015

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 45 43 50 53 57 60 59 55 46 40 44 55
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 61 60 59 53 52 52 55 58 60 61 60 56



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.