New air quality reporting system from May 1

SINGAPORE - From May 1, 2014, Singapore will move to an integrated air quality reporting index, where PM2.5 will be incorporated into the current Pollutant Standards Index (PSI) as its sixth pollutant parameter.

Since Aug 24, 2012, the National Environment Agency (NEA) has been reporting 24-hour PM2.5 concentrations alongside the PSI. This was done as the first step in the transition to the new air quality reporting system.

NEA will now complete the transition by incorporating the 24-hour PM2.5 concentrations into the Index. The PSI will therefore reflect a total of six pollutants - sulphur dioxide (SO2), particulate matter (PM10) and fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3).

The 3 hour PSI will also take into account PM2.5 concentrations. In addition,NEA will also publish the 1-hour PM2.5 concentrations every hour.

Previously, health advisories issued by the Government were based on 24-hour PSI and 24-hour PM2.5, whichever was worse. Under the new air quality reporting system, the health advisory will be based on the new 24-hour PSI as it now directly takes into account PM2.5.

Air quality information will be reported every hour from 7am to 11pm during non-haze periods, and around the clock during haze periods. These will be made available on the NEA website (, the haze microsite (, NEA Facebook (, NEA Twitter (@NEAsg) and smart phone app, MyENV. You can also check AsiaOne's weather page (

As a result of PM2.5 being incorporated into the PSI, more days will be classified as 'Moderate' compared to before, even though the actual concentration of pollutants has not changed. This is purely due to the integration of the PM2.5 concentrations into the PSI scale. There will be no change to normal routines on the ground as people can carry on normal activity if air quality is in the 'Good' or 'Moderate' range.

NEA will continue to regularly review Singapore's air quality reporting index to ensure that it remains a relevant and useful guide for the public to help plan their daily activities.

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