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Pollutant Concentrations

Air quality readings will be available hourly from 1am to 12am.

Readings on 20 Oct 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 9(6) 64(57) 52(-) 44(19) 0.8(8) 43(86)
South 11(7) 61(56) 35(-) 22(9) 0.6(6) 51(95)
East 15(9) 56(54) 23(-) 44(19) 0.6(6) 48(91)
West 21(13) 70(61) 17(-) 39(16) 0.6(6) 55(101)
Central 21(13) 54(53) 51(-) 42(18) 0.6(6) 41(84)

1-hr PM2.5 (µg/m3)b Readings on 19 Oct 2014

View reading for:

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
North 35 38 37 44 51 61 47 45 42 54 52 48
South 52 54 48 47 52 43 42 49 56 65 66 77
East 52 50 38 39 63 66 46 63 63 77 75 45
West 45 42 48 48 42 44 53 57 46 46 69 69
Central 38 37 27 34 37 30 43 43 56 55 53 54
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
North 59 55 55 49 47 47 38 33 28 29 29 16
South 89 85 61 72 75 37 16 18 29 35 26 23
East 53 52 48 54 56 37 21 30 30 34 29 24
West 96 99 97 88 81 58 41 32 36 37 31 27
Central 64 53 48 50 64 42 26 24 25 31 32 19

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 19 Oct 2014

Time 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm
3-hr PSI 86 87 86 85 87 90 92 93 94 99 104 106
Time 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am
3-hr PSI 110 112 113 110 109 103 89 75 70 71 72 69

Hourly updates of 3-hr PSI readings are provided from 1am to 12am. The 3-hr PSI readings are calculated based on PM2.5 concentrations only.