Air quality unhealthy across Singapore after PM2.5 hit 'high' range in the west
The 1-hour PM2.5 reading in the west jumped into the "high" range at 4pm and dipped back into the elevated range an hour later.
Haze conditions around the Upper Cross Street area overlooking the Esplanade and Singapore Flyer on Oct 7, 2026. (Photo: CNA/Raydza Rahman)
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SINGAPORE: Air quality across all five regions of Singapore remained in the unhealthy range at 10pm on Wednesday (Oct 7), while the 1-hour PM2.5 reading remained in the elevated range islandwide, after moving into the high band earlier.
At 4pm, the 1-hour PM2.5 reading in the west jumped to 152, entering the "high" band for the first time this haze season, up from 146 at 3pm. It fell back into the elevated range an hour later.
Readings in the other regions are currently in the elevated band.
In its latest update on Wednesday morning, the National Environment Agency (NEA) said many air quality stations in Singapore, Sumatra, Kalimantan and Peninsular Malaysia were reporting unhealthy to hazardous levels.
Clusters of scattered hotspots were detected in southern parts of Sumatra and Kalimantan, while isolated hotspots were detected in Java and Sulawesi.
"Moderate to dense smoke plumes were observed in parts of Kalimantan and Sumatra, with moderate smoke haze also observed over parts of Peninsular Malaysia and Singapore," said NEA.
Significant haze was not observed in northern ASEAN, and the region's hotspot count remained low, it added.
The agency said that the hotspot and haze situation in southern ASEAN would likely remain escalated and warned of transboundary haze risks.
For northern ASEAN, isolated hotspots and localised smoke plumes could occasionally emerge in areas facing relatively drier conditions, it added.
In its evening advisory, NEA said that moderate to dense smoke plumes from southern Sumatra were observed to drift towards Singapore.
It added that moderate to dense smoke haze was also observed from hotspots detected in Kalimantan.
"Dry conditions are expected to continue over the central and southern parts of Sumatra, as well as over many parts of Kalimantan.
"Under the prevailing southeasterly to southerly winds, smoke haze from these areas may continue to drift towards Singapore," NEA said.
The agency said on Wednesday evening that the 24-hr PSI for Singapore is forecast to be in the unhealthy range.
When planning outdoor activities for the next 24 hours, the public is advised to use the 24-hour PSI forecast and health advisories.
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".
