Plans are in place here to more accurately monitor levels of PM2.5, the air pollutant associated with vehicle emissions and the seasonal haze that has blanketed Singapore in the past.
The National Environment Agency (NEA) revealed yesterday that it will expand the country's air pollution monitoring network to give "a better picture" of PM2.5 levels across a wider area.
The aim is to develop better policies to bring down its levels.
PM2.5 is a fine particulate matter less than 2.5 microns in size. Over-exposure to it increases the risk of heart and lung illnesses and can reduce an individual's lifespan.
"Once you have the data, you will have a better sense of the seriousness of the issue," NEA deputy director of pollution control Rohaya Saharom told reporters, on the sidelines of a green transport forum at Traders Hotel.
Documents obtained by The Straits Times reveal that the NEA will add nine more monitoring stations nationwide to the existing 15 by early next year.
The stations monitor round- the-clock PM2.5, on top of the Pollutant Standards Index (PSI), which measures sulphur dioxide, nitrogen dioxide, ozone, carbon monoxide and PM10.
Singapore uses the PSI and not the Air Quality Index used by countries like the United States. The latter specifies PM2.5 concentrations.
The NEA used to publish the annual average PM2.5 readings, but has been reporting it hourly since June, when Singapore was hit by the worst haze in its history.
Ms Saharom said the plan to expand the network was already "in the pipeline" before June.
The agency also wants to study the levels of air pollutants like PM2.5 contributed by sectors such as transport and power generation, said Ms Saharom. Doing so would help the Government formulate "more defined" policies to cut pollution.
The NEA did not reveal a timeline for its plan.
Singapore's annual mean PM2.5 level has hovered between 16 and 19 micrograms per cubic metre (µg/m3) over the past six years, which does not meet the World Health Organisation standard of 10 µg/m3. The NEA aims to cut this to 12 µg/m3 by 2020.
PM2.5 is "clearly the most serious" air pollution concern, said vehicle pollution control expert Michael Walsh. A recent US study found that globally, about 2.1 million deaths annually are caused by over-exposure to it.
Reducing vehicle numbers or improving their emission standards would be the most effective way to reduce PM2.5 levels, especially in urban areas, he added.