SINGAPORE (The Straits Times/ANN): The air quality in Singapore is back in the good to moderate range, after 18 days of bad air.
At 3pm on Oct 22, the 24-hour Pollutant Standards Index (PSI) had improved in all regions across the island, with readings ranging from 71 to 99.
Readings in this band denote good to moderate air quality, and normal activities can be carried out.
The west was the last region to exit the unhealthy zone, dropping from 101 to 99 at 3pm.
Singapore had since Oct 5 been experiencing unhealthy air quality, denoted by 24-hour PSI readings above 101.
When air quality breaches this threshold, people should start scaling down outdoor activities. The 24-hour PSI reflects air quality in Singapore over the past day.
The PSI tracks the levels of six pollutants, although the dominant toxin during periods of transboundary haze is small particulate matter known as PM2.5.
The one-hour PM2.5 readings, which are measured in micrograms per cubic m and are a gauge of the current air quality, have remained in the “normal” range islandwide since 1am.
At 3pm, their values were between 16 and 39.
Scores from zero to 55 represent normal values; those between 56 and 150 indicate an elevated concentration of fine particles; readings between 151 and 250 are considered high; and scores above 251 are classified as very high.
However, satellite maps on the National Environment Agency’s (NEA) website showed persistent hot spots in Indonesia, indicating that the haze crisis is not yet over.
Prevailing winds have kept the smoke plumes away from Singapore for now, with denser clouds of pollution observed in areas such as Peninsular Malaysia, Kalimantan, Sumatra and the western parts of Sarawak.
Unhealthy air quality forecast for Oct 23
In an advisory on the evening of Oct 22, the National Environment Agency (NEA) said smoke haze from Kalimantan and Sumatra drifted over the region, but north-easterly and easterly winds kept most of the plume south of Singapore, said the agency.
Some smoke haze was detected at higher altitudes above the island but limited it at ground level.
Unhealthy air quality is expected on Oct 23 with PSI levels forecast to range from 101 to 150, NEA said.
While showers are forecast over Singapore and the surrounding region on Oct 23, dry conditions are expected over the southern parts of Sumatra and Kalimantan, it added.
Under prevailing south-easterly winds, smoke haze may be transported towards Singapore, NEA said.
Smoke haze from Sumatra may drift towards Singapore on Oct 24 because of south-easterly or southerly winds, but rain should bring relief before clearer conditions return on Oct 25.
Walkathon cancelled
In a Facebook post on Oct 22, the Singapore National Stroke Association said that its Stepping Out For Stroke 2026 community walkathon that was scheduled for Oct 31 will be cancelled.
This was in view of current haze conditions, it added.
“The health and safety of our participants, volunteers and the wider community remain our top priority,” it said, adding that participants who have registered will receive the revised programme and details through e-mail. -- The Straits Times/ANN
