North
South
East
West
Central

µg/m3
1-hr PM2.5 concentration
At 2am on 14 Jul 2017
PM2.5
1-hr conc.
At 2am on 14 Jul 2017
PM2.5
sub-index
Computed based on 24-hour average PM2.5 concentrations.
PM10
sub-index
Computed based on 24-hour average PM10 concentrations.
SO2
sub-index
Computed based on 24-hour average Sulphur Dioxide concentrations.
O3
sub-index
Computed based on 8-hour average Ozone concentrations.
CO 
sub-index
Computed based on 8-hour average Carbon Monoxide concentrations.
NO2
sub-index
Sub-index for nitrogen dioxide is reported only when the 1-hour concentration equals or exceeds 1130 μg/m3.
PM2.5 : Particulate matter of 2.5 microns or smaller in diameter
PM10 : Particulate matter of 10 microns or smaller in diameter
SO2 : Sulphur Dioxide
O3 : Ozone
CO  : Carbon Monoxide
NO2 : Nitrogen Dioxide