Central S'pore's air quality remains in unhealthy range overnight, 24-hour PSI reaches 106

The 24-hour Pollutant Standards Index (PSI) in central Singapore crossed into the unhealthy range at 11pm last night (Sep. 9) and has climbed steadily since.

According to the National Environment Agency's (NEA) website, the 24-hour Pollutant Standards Index (PSI) for central Singapore hit 106 as of 9am on Sep. 10.

Overnight readings

The 24-hour PSI readings in other parts of Singapore, including the north (75), south (78), east (83) and west (86), remained in the moderate range as of 9am on Sep. 10.

As such, the overall PSI in Singapore was in the moderate to unhealthy range, from 75 to 106 at 9am.

The 24-hour PSI reflects air quality over the preceding 24 hours. NEA advises the public to use it for planning next day outdoor activities.

For immediate outdoor activities, check the 1-hr PM2.5 concentration readings.

As of 9am on Sep. 10, the 1-hr PM2.5 remains in the normal range.

NEA advisory

NEA said in a Sep. 9 advisory that the the 24-hr PSI is forecast to be in the "high moderate" to "low unhealthy" range.

Moderate to dense smoke plumes continue to be detected from fires in southern and central Sumatra and Kalimantan, with smoke haze observed to drift towards Singapore, the agency said.

It added that while some showers are forecast over central and northern Sumatra in the coming days, dry conditions are expected to persist over Kalimantan and southern Sumatra.

"With prevailing winds blowing from the southeast or south, there remains a risk of smoke haze affecting Singapore should the fires persist."