SINGAPORE: Air quality across the island remained poor on Oct 18, with the 24-hour Pollutant Standards Index (PSI) in the west hitting a seasonal high of 230 at 10am before dipping slightly to 227 at noon.
At noon, PSI readings for the rest of the island remained in the “unhealthy” range, ranging from 127 to 180, making the west the only region in the “very unhealthy” band.
Air quality is considered “unhealthy” when the PSI, a 24-hour rolling average of six key air pollutants, is in the range of 101 to 200, and “very unhealthy” when it is in the range of 201 to 300.
The one-hour PM2.5 readings, measured in micrograms per cubic metre, hovered between the “elevated” and “normal” bands.
Most regions recorded “elevated” readings at noon: west (136), central (65), south (61) and east (58). Only the north fell in the “normal” band, with a reading of 52.
PM2.5 scores from zero to 55 represent normal values, while those between 56 and 150 indicate an elevated concentration of fine particles. Readings between 151 and 250 are considered high, while scores above 251 are classified as very high.
The highest PM2.5 reading so far in 2026 was recorded at 3pm on Oct 14 in the western part of the island, at 288.
Singapore is experiencing its 14th consecutive day of unhealthy air since Oct 5, the longest continuous stretch of poor air quality the country has endured since the 2015 haze crisis. That year, poor air quality lasted 14 days, from Sept 23 to Oct 7.
In its daily haze advisory on the evening of Oct 17, the National Environment Agency forecast that the PSI could range between 150 and 220, placing it in the “unhealthy” to “very unhealthy” categories.
Showers are expected over Singapore and the surrounding region on Oct 18.
“Winds are forecast to shift to blow from the south-south-east or south, which may reduce the transport of smoke haze from Kalimantan to Singapore. However, some smoke haze from Sumatra may drift towards Singapore,” the agency said.
More showers are also forecast over Singapore and parts of Kalimantan on Oct 19 and 20, it added.
The agency said the winds are expected to gradually weaken and blow from the south-east or south, which could further reduce the movement of smoke haze from Kalimantan to Singapore. - Straits Times/ANN
