Haze: 24-hour PSI may enter high end of unhealthy range in the next 24 hours

Haze as seen in Yishun at 8:30am, 21 Oct 2015.
Haze as seen in Yishun at 8:30am, 21 Oct 2015.ST PHOTO: JAMIE KOH

SINGAPORE - Hazy conditions are expected to persist with the 24-hour Pollutant Standards Index (PSI) forecast to be in the low to mid sections of the unhealthy range for the next 24 hours, said the National Environment Agency (NEA) in its latest advisory.

However, if denser haze is blown in, it may even enter the high end of the unhealthy range, the agency added on Wednesday (Oct 21).

Hazy conditions continued on Wednesday with a slight deterioration in the haze and visibility conditions in the afternoon. This was due to haze from the surrounding region being blown in by the prevailing south-easterly winds, added the agency.

At 9pm on Wednesday, the 24-hr PSI was 112-126, in the Unhealthy range, and the 1-hour PM2.5 was 38-68 micrograms per cubic m. The three-hour PSI - not tied to a health advisory - stood at 102.

There were a total of 166 hot spots detected in Sumatra on Wednesday. The agency noted that, with parts of central and southern Sumatra affected by moderate to dense haze, some of the haze has spread to the sea areas south of Singapore.

Some haze from Kalimantan is also observed to have spread to the sea areas east-southeast of Singapore, said the NEA.