24-hour PSI rises to 173 in central region, highest in this haze season
At 10am, the 24-hour PSI was in the unhealthy range across Singapore, and the 1-hour PM2.5 was in the elevated band in all regions.
A view of the haze seen from Bukit Gombak on Oct 9, 2026. (Photo: CNA/Mak Jia Kee)
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SINGAPORE: Air quality in Singapore worsened on Friday (Oct 9) morning, with the 24-hour Pollutant Standards Index (PSI) in the central region rising to 173 at 10am, the highest for this year's haze season.
The 24-hour PSI had been rising steadily across regions from midnight and all regions were in the unhealthy range. At 10am, the readings were 117 in the north, 166 in the west, 154 in the south and 147 in the east, putting
The 1-hour PM2.5 was in the elevated band for all regions, ranging from 87 to 142.
For those planning immediate outdoor activities, NEA advises checking the hourly PM2.5 levels.
The 24-hour PSI forecast and corresponding health advisories should be used in planning next day outdoor activities.
When 1-hour PM2.5 levels are elevated, healthy people are advised to reduce strenuous outdoor activity for the next hour, while the elderly, pregnant women, children and people with chronic heart or lung conditions should avoid such activity.
The 24-hour PSI is Singapore's indicator of daily air quality and forms the basis of NEA's daily health advisories. It is calculated using six air pollutants - PM2.5, PM10, ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide - and reflects the average air quality of the past 24 hours.
The 1-hour PM2.5 reading, on the other hand, is the hourly average of the PM2.5 pollutant levels. PM2.5 is fine particulate matter with a diameter of 2.5 micrometres or shorter, and is the dominant pollutant during haze that causes harm to health.
A 24-hour PSI reading is considered "unhealthy" when it is in the 101 to 200 range, "very unhealthy" when it is within the 201-300 range and "hazardous" when it goes over 300.
The hourly PM2.5 reading is classified in four bands: normal, elevated, high and very high. It is considered elevated when it ranges from 56 to 150. The "high" band ranges from 151 to 250, and readings above that are classified as "very high".
In its Thursday evening advisory, the National Environment Agency (NEA) said that moderate to dense smoke plumes from southern and central Sumatra and West Kalimantan were observed to drift towards Singapore.
Dry conditions are expected to persist over the southern parts of Sumatra and parts of Kalimantan.
Under prevailing southeasterly or southerly winds, smoke haze may continue to drift towards Singapore, NEA said, adding that the 24-hour PSI for Singapore is forecast to be in the high moderate to mid unhealthy range.
