SINGAPORE – While air quality in the Republic is expected to be similar as that in the past few days, there is a chance it might get worse and enter the unhealthy band. If the haze worsens, the authorities advise the public to take some precautions.

In an advisory issued early on Thursday evening (Sept 12), the National Environment Agency said that the Pollutant Standards Index (PSI) for the next 24 hours is forecast to be in the moderate range.

However, it might enter the unhealthy range if the winds become unfavourable and the haze situation in Sumatra persists.

If this happens, it would be the first time this year that the PSI has entered the unhealthy band.

The PSI ranges from 51 to 100 in the moderate range, and the 24-hour PSI has been in this range in the past few weeks.

A PSI reading of 101 to 200 would be in the unhealthy band. The 24-hour PSI has been close to entering this range in recent days. For instance, on Tuesday at 3pm, air quality in southern Singapore was 99.

The one-hour PM2.5 concentration readings over the next 24 hours are forecast to be between the normal and elevated bands.

PM2.5 is a measure of the concentration of tiny particles less than 2.5 micrometres in diameter – or about one-thirtieth the diameter of a human hair – in the air.

Based on the air quality forecast for the next 24 hours, NEA said that healthy people should reduce prolonged or strenuous outdoor physical activities.

The elderly, pregnant women and children should minimise prolonged or strenuous outdoor physical exertion, while those with chronic lung or heart disease should avoid prolonged or strenuous outdoor physical activities.

People who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical attention, advised NEA.

The agency said that it was slightly hazy on Thursday and this was due to smoke haze from hot spots in central and southern Sumatra being blown in by the prevailing winds.

The slightly hazy conditions are expected to continue, and the prevailing winds are forecast to blow from the south-east or south.

As at 7pm, the 24-hour PSI was between 75 and 87, in the moderate range, and the one-hour PM2.5 readings were between the normal and the low end of the elevated bands.


The 24-hour PSI reading as at 8.43pm on Sept 12, 2019. PHOTO: SCREENGRAB FROM HAZE.GOV.SG

For the next few days, some showers are expected in Singapore but the weather in Sumatra and Kalimantan is expected to remain generally dry.

The prevailing winds are forecast to shift to blow from the south-west or south, and this might bring more haze to Singapore, said NEA.

A total of 222 hot spots were detected in Sumatra, mostly in the provinces of Riau, Jambi and South Sumatra, the agency said on Thursday.


A map of hot spots as at 8.43pm on Sept 12, 2019. PHOTO: SCREENGRAB FROM HAZE.GOV.SG

Moderate to dense smoke haze continued to come from persistent hot spots there. Some haze was blown by the prevailing winds across the Strait of Malacca to affect Singapore and some parts of Peninsular Malaysia.

In Kalimantan, a total of 1,264 hot spots were detected on Thursday, and widespread haze continues to be seen there.