Singapore haze: Air quality improves but PM2.5 readings rise again in three regions
The hourly PM2.5 readings fell into the normal band across all five regions by noon, although readings subsequently returned to the elevated range in three.
A view of the clear skies in central Bishan on Oct 19, 2026. (Photo: CNA/Marcus Mark Ramos)
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SINGAPORE: Air quality improved across Singapore on Monday morning (Oct 19), with 24-hour Pollutant Standards Index (PSI) readings falling into the moderate range in three of the country's five regions for the first time in more than a week.
However, 1-hour PM2.5 readings subsequently rose into the elevated range in three regions, signalling a slight deterioration in air quality later in the day.
At 6pm, the 24-hour PSI ranged from 89 in the north, where air quality was moderate, to 114 in the west, where it remained unhealthy.
The north was the first region to see its PSI reading fall into the moderate band at 1am, marking the first time any part of Singapore had recorded moderate air quality since Oct 9.
The south followed at 8am and the east at 10am.
One-hour PM2.5 readings had also improved, falling into the normal band across all five regions by noon. However, readings in the west, central and north subsequently climbed back into the elevated range.
At 6pm, readings in these three regions ranged from 61 to 79, while those in the south and east remained in the normal band, at 55 and 51, respectively.
At 9pm, PM2.5 readings in the east entered the elevated band with a reading of 56, before droppping to 46 at 10pm.
The National Environment Agency (NEA) in its advisory on Monday evening said that the PSI forecast for Tuesday would be between moderate to unhealthy - ranging from 90 to 160.
The earlier improvement came after air quality remained unhealthy across most of Singapore on Sunday.
The west was particularly badly affected, with its 24-hour PSI staying in the very unhealthy range from 8pm on Saturday until 5pm on Sunday, when it fell into the unhealthy band.
At 10am on Sunday, the region's 24-hour PSI reached 230 – the highest reading recorded during this year's haze season.
NEA said that the improvement in air quality over Singapore was due to the turning of winds to blow from the south-southeast and showers in the vicinity.
Despite the improvement, smoke haze from Kalimantan and Sumatra was observed in the vicinity of Singapore.
POTENTIALLY REDUCED HAZE ON TUESDAY
Haze might be reduced in the country on Tuesday since showers are forecast over Singapore and the surrounding region, NEA said. However, haze from Sumatra may still drift towards Singapore.
From Tuesday night till Thursday, the winds are likely to turn east-southeasterly with dry conditions forecast over the surrounding region, including parts of Kalimantan.
This may bring smoke haze from fires in Kalimantan towards Singapore, NEA said.
And despite the improvement in Singapore's air quality, the risk of severe transboundary haze remains as dry conditions persist in parts of the southern ASEAN region.
In an update on Monday morning, NEA said scattered to widespread hotspots had been detected in Kalimantan and southern Sumatra, with moderate to dense smoke haze observed over parts of Singapore, Peninsular Malaysia, Kalimantan, Sumatra and western Sarawak.
Air quality monitoring stations in Singapore and Peninsular Malaysia recorded unhealthy levels, while those in Borneo and Sumatra reported readings ranging from unhealthy to hazardous.
NEA said the full extent of the hotspots in Kalimantan and Sumatra could not be determined because of thick smoke haze and cloud cover.
While rain could help ease the hotspot and haze situation in some areas, conditions are expected to remain elevated in fire-prone regions experiencing prolonged dry weather.
There is therefore a continued risk of severe transboundary haze, NEA said.
ADVICE FOR VULNERABLE GROUPS
When the 24-hour PSI is in the unhealthy range, NEA advises the elderly, pregnant women and children to minimise prolonged or strenuous outdoor physical exertion.
People with chronic diseases, including heart or lung conditions, should avoid such activities.
For decisions on mask use and immediate outdoor activities, the public should refer to the one-hour PM2.5 readings instead.
When the 1-hour PM2.5 readings are in the high band, vulnerable individuals, including the elderly, pregnant women and those with chronic heart or lung conditions, should avoid outdoor activities, according to the Ministry of Health (MOH).
Those who need to go outdoors for immediate activities may wear a well-fitting N95 mask or equivalent to reduce their exposure to haze particles.
When 1-hour PM2.5 readings reach the very high band of 251 and above, healthy individuals should also minimise all outdoor activities. Those who need to venture outdoors may similarly use an N95 mask for protection.
The ministry has also advised the elderly, pregnant women and those with severe heart or lung conditions who experience breathing difficulties to consult their doctor before using an N95 mask.
Those who experience discomfort while wearing one should take a break from using it.
Besides N95 masks, KN95, FFP2 and KF94 masks are also effective in reducing exposure to haze particles, according to MOH.
Members of the public can visit the HazeMaskGoWhere website for more information on collection locations and live updates on mask availability at the vending machines.
On Tuesday night, MOH also advised the public on the use of masks to protect against haze.
It said surgical masks can help reduce discomfort and the risk of infections by providing a barrier against larger irritant particles.
However, if PM2.5 readings are above 250 and people need to be outdoors for several hours, MOH recommends wearing an N95 or equivalent mask.
Cloth masks are generally ineffective at filtering fine particles, although they can help reduce discomfort by providing a barrier against larger irritant particles in the air.
