From May 1, Singapore will see more days with the air quality being classified as in the “moderate” range, as concentrations of smaller polluting particles of PM2.5 will be included in the Pollutant Standards Index (PSI) readings.
“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,” the National Environment Agency (NEA) said in a statement on Tuesday.
NEA added that people can carry on normal activity if air quality is in the “good” or “moderate” range and there will be no change to normal routines on the ground.
PM2.5 are tiny particles that can travel deep into the respiratory tract, and get embedded in lung tissue.
It is currently reported separately from the PSI.
Minister for Environment and Water Resources Vivian Balakrishnan on Tuesday told Parliament that Singapore will move to an integrated air quality reporting index, where PM2.5 will be incorporated into the current PSI as its sixth pollutant parameter.
In explaining the change, Dr Balakrishnan said as far as public health is concerned, PM2.5 concentrations are more often a cause for concern.
He said the move would also simplify the air quality reporting system.
Going forward, he said PM2.5 levels are expected to determine the PSI “almost all the time”.
Since August 24, 2012, NEA has been reporting 24-hour PM2.5 concentrations alongside the PSI, which 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 PSI.
From May 1, the PSI will 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.
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.
NEA said air quality information will be reported every hour from 7am to 11pm during non-haze periods, and around the clock during haze periods.
The information will be made available on the NEA website, the haze microsite, NEA Facebook, NEA Twitter and smart phone app, MyENV.
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.
Dr Balakrishnan also announced the setting up of an International Advisory Panel on transboundary pollution, which will be co-chaired by Professor S Jayakumar and Professor Tommy Koh.