Singapore air quality deteriorated on Oct 3 as the 24-hour Pollutant Standards Index reached an unhealthy reading of 102 in the central region, straitstimes.com reported. The National Environment Agency attributed the worsening conditions to moderate to dense smoke plumes drifting from southern Sumatra and Kalimantan in Indonesia.
PSI readings climb across the island-state
The 24-hour Pollutant Standards Index readings climbed across all areas of the island-state. Early morning readings at 6am ranged from 73 to 88 in the north, south, east, and west before rising to between 76 and 94 by 11am, according to straitstimes.com. Immediate fine particulate matter gauges showed elevated concentrations in three regions, with PM2.5 readings hitting 66 in the east, 57 in the west, and 63 in the central region.
Channel NewsAsia reported that as of 6pm, the 24-hour PSI ranged from 64 to 81 within the moderate range, while 1-hour PM2.5 readings spanned 44 to 73 micrograms per cubic metre across normal and elevated bands. Air quality is classified as unhealthy when the 24-hour PSI reaches 101 to 200, whereas hourly PM2.5 readings between 56 and 150 indicate elevated fine particle concentrations, channelnewsasia.com noted.
Transboundary Smoke from Indonesian Wildfires
The National Environment Agency stated in its evening haze advisory that prevailing southeasterly or southerly winds transported smoke from fires in Sumatra and Kalimantan toward Singapore. Swiss monitor IQAir placed Kuala Lumpur as the world’s most polluted major city with an Air Quality Index of 166 on Wednesday, while Singapore ranked third globally at 155 due to the regional wildfire smoke, the South China Morning Post reported.
September marked the first time since October 2023 that Singapore’s PSI hit unhealthy levels due to haze. The 24-hour index last crossed into the unhealthy range on Sept 30, peaking at 134 in central Singapore, following a yearly high of 167 recorded on Sept 29, straitstimes.com reported.
El Nino delays the rainy monsoon transition
The Meteorological Service Singapore informed straitstimes.com that strong El Nino conditions and the Indian Ocean Dipole contributed to warmer and drier conditions, delaying the retreat of the southern ASEAN dry season. While non-El Nino dry south-west monsoons typically taper off by September, forecasters expect the rainy north-east monsoon transition to occur later than in previous years, arriving only in late October or early November.
Some experts predict that the 2026 haze could persist longer due to a “Godzilla” El Nino event reducing rainfall and elevating temperatures through October and November, straitstimes.com reported.
NEA advises reducing strenuous outdoor physical exertion
The National Environment Agency advised healthy individuals to reduce prolonged or strenuous outdoor physical exertion if the 24-hour PSI enters the unhealthy range. Elderly residents, pregnant women, and children should minimize strenuous outdoor activities, while individuals with chronic heart or lung disease must avoid them entirely, channelnewsasia.com reported.
Residents turned to social media platforms including Facebook and Reddit to share photographs of landmarks like Marina Bay Sands and the Singapore Flyer obscured by the dense milky haze, with users noting throat itchiness and smoke odors indoors, The Independent Singapore reported.
What is the difference between PSI and PM2.5?
- What is the difference between the 24-hour PSI and the 1-hour PM2.5 reading?
- Channel NewsAsia reported that the 24-hour PSI is a rolling average of six key air pollutants used for planning next-day activities, whereas the 1-hour PM2.5 reading measures immediate fine particulate concentrations for real-time outdoor decisions.
- How high did the air pollution index reach during the September haze peak?
- straitstimes.com reported that the highest 24-hour PSI reading for the year reached 167 in the central region on Sept 29.
- Which specific Indonesian regions are generating the smoke plumes?
- The National Environment Agency reported that moderate to dense smoke plumes originated from fires in southern Sumatra and Kalimantan.
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