PM2.5 level returns to elevated range across S’pore after improvements to air quality overnight
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- Singapore’s PM2.5 rose back into the elevated range on Oct 23 after overnight air quality improved to good or moderate levels.
- The 24-hour PSI stayed good to moderate across all regions, so normal activities were still possible, but unhealthy air had affected Singapore since Oct 5.
- NEA warned air quality may worsen to PSI 101 to 150, as smoke haze from Sumatra could drift over under south-easterly winds, with rain bringing brief relief.
AI generated
SINGAPORE – The hourly PM2.5 readings across Singapore climbed back into the elevated range on the afternoon of Oct 23, after air quality remained in the good to moderate range overnight.
At 7pm, the PM2.5 readings – a gauge of the current air quality – were between 68 and 92 across Singapore.
PM2.5 readings stayed in the normal range overnight and into the early morning, before crossing into the elevated band first in the west at 10am, and later in the south, and central at 11am. Readings in the east entered the elevated band at noon.
Scores from zero to 55 represent normal values, those between 56 and 150 indicate an elevated concentration of fine particles, while readings between 151 and 250 are considered high and scores above 251 are classified as very high.
Meanwhile, the 24-hour Pollutant Standards Index (PSI) readings in the north (87), south (91) and east (91) were in the good to moderate range at 7pm. The PSI readings in the central region (105) and the west (109) were in the unhealthy band.
The PSI figure in the west first entered the unhealthy range at 4pm with a reading of 103, with the central region following suit at 6pm with a reading of 102.
Before this, air quality across Singapore had been in the good to moderate range – meaning normal activities can be carried out by everyone – for at least 24 hours. The west moved into this ideal category only at 3pm on Oct 22.
Since Oct 5, Singapore had been experiencing unhealthy air quality, denoted by 24-hour PSI readings above 101.
The 24-hour PSI, which is a rolling index of six key air pollutants, reflects air quality in Singapore over the past day.
When air quality breaches this threshold, people, especially the elderly, children and those with health issues, should start scaling down outdoor activities.
Forecast for Oct 24
In its daily advisory on the evening of Oct 23, the National Environment Agency (NEA) said moderate to unhealthy air quality is expected on Oct 24, with the PSI forecast to be in the range of 90 to 140.
Smoke haze from Sumatra was seen drifting towards Singapore and was also observed over Kalimantan on Oct 23, NEA said.
While showers are forecast over Singapore and the surrounding region on Oct 24, some smoke haze may be transported towards Singapore from Sumatra under prevailing south-southeasterly or south-southwesterly winds, it added.
Hazy conditions may improve from Oct 25.
Winds are expected to blow from the south-west or west from Oct 25, NEA said.
This may help reduce the smoke haze transported to Singapore, it said, adding that showers over Singapore and areas nearby could also help with the haze situation.
Additional reporting by Calista Wong