SINGAPORE: Singaporeans living in all regions of the country continued to experience an unhealthy level of pollutants in the air on Wednesday (Oct 7).
The 24-hour Pollutant Standards Index (PSI) readings in the eastern, central and western regions have stood in the unhealthy range for more than 24 hours.
However, readings for the northern and southern regions had hovered near the threshold for much of the morning, before the PSI first hit the unhealthy level of 102 in the south at 11am.
At noon, the northern region joined the rest of Singapore in the unhealthy range, with a reading of 101.
Meanwhile, the PSI stood at 133 in the central region, 124 in the west, 123 in the east and 103 in the south.
Air quality is considered unhealthy when the PSI – a 24-hour rolling average of six key air pollutants and used in planning for outdoor activities the next day – is in the range of 101 to 200.
PM2.5 readings, which are used as a gauge for immediate activities, continue to remain elevated after first crossing into the band in all regions at 11am.
At noon, the reading stood at 113 in the west, 99 in the east, 89 in the central and southern regions, and 64 in the north.
An hourly PM2.5 reading between 56 and 150 indicates an elevated concentration of fine particles.
In its daily haze advisory on Oct 6, the National Environment Agency said that with prevailing east-south-easterly to south-easterly winds, the 24-hour PSI is forecast to be in the “high moderate to mid unhealthy” range.
Dry conditions are expected to persist over Kalimantan as well as central and southern Sumatra in neighbouring Indonesia, where moderate to dense smoke plumes were observed to be drifting towards Singapore.
The PSI crossed into the unhealthy range four weeks ago, hitting 101 in central Singapore on the morning of Sept 4.
In the days that followed, readings in the central, eastern and western parts of the island occasionally crossed into the unhealthy range.
The highest reading of the year – 167 in central Singapore – was recorded on Sept 29.
The developments in September mark the first time since October 2023 that the PSI in Singapore hit unhealthy levels because of haze, with the authorities earlier warning of the risk of haze between June and October as a result of warmer and drier conditions brought on by both El Nino and the Indian Ocean Dipole.
Some experts have predicted that the haze in Singapore in 2026 could last for a longer period due to this year’s 'Godzilla' El Nino event, which could reduce rainfall and result in higher temperatures over October-November, compared with non-El Nino years.
During non-El Nino years, the dry south-west monsoon season usually tapers off by September, and the start of the rainy north-east monsoon season tends to set in around late November.
The Meteorological Service Singapore told The Straits Times that El Nino events, particularly strong ones, tend to delay the retreat of the dry season for much of the southern Asean region, and that the Met service is expecting a transition only during late October or early November for Singapore, later than in the previous two years. - The Straits Times/ANN
