Haze in Singapore: Normal PM2.5 readings and good to moderate 24-hour PSI islandwide

SINGAPORE – The air quality here has improved after the hourly PM2.5 readings remained in the normal range and the 24-hour PSI stayed in the good to moderate band across the island overnight.

At 6am on Oct 26, the one-hour PM2.5 readings in all the five regions of Singapore ranged between 20 and 29 while the 24-hour PSI stood at 71 to 78.

PM2.5 readings are gauged hourly and reflect the current air quality. Scores from zero to 55 represent normal values, and those between 56 and 150 indicate an elevated concentration of fine particles.

Air quality is considered good to moderate when the PSI – a 24-hour rolling average of six key air pollutants – is in the range of zero to 100, and unhealthy when it is in the range of 101 to 200.

When air quality breaches the “unhealthy” threshold, people, especially the elderly, children and those with health issues, should start scaling down outdoor activities.

Following weeks of bad air quality, residents in Singapore saw some respite over the weekend when the PM2.5 levels stood in the normal range for most parts of the country although the 24-hour PSI readings remained unhealthy in some areas.

Forecast for Oct 26

In its daily haze advisory on the evening of Oct 25, the National Environment Agency (NEA) said the PSI for Oct 26 is forecast to be in the range of 70 to 100.

NEA said that showers are expected over Singapore and nearby areas on Oct 26.

“With winds expected to blow from the south-west or west, the likelihood of smoke haze affecting Singapore may be reduced,” it said.

It added that this is expected to continue on Oct 27 and 28, with showers over and around Singapore expected to improve the haze situation.