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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 15 Nov 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 7(5) 17(17) 35(-) 16(7) 0.4(4) 10(40)
South 12(7) 18(18) 28(-) 24(10) 0.5(5) 9(36)
East 4(3) 15(15) 20(-) 36(15) 0.4(4) 9(38)
West 3(2) 14(14) 7(-) 44(18) 0.6(6) 7(29)
Central 6(4) 15(15) 40(-) 46(20) 0.5(5) 8(34)

1-hr PM2.5 (µg/m3)b Readings on 14 Nov 2014

View reading for:

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

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 14 Nov 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 50 45 32 30 24 21 18 21 30 34 38 36
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 38 39 43 45 48 46 49 44 40 35 40 37

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.