Singapore Central Region PSI Remains Unhealthy Due to Haze
Air quality across central Singapore remained locked in the unhealthy range late on Sept 27. Relief arrived elsewhere. Twenty-four-hour Pollutant Standards Index readings across the east and west dropped back into the moderate band. The deteriorating conditions still forced sudden adjustments to major weekend sporting events, including Decathlon’s inaugural Kiprun race.
Central Singapore Lingers in Unhealthy Haze
At 9 pm on Sept 27, the eastern region’s 24-hour PSI fell to 99, slipping below the 101 threshold that defines the unhealthy band. That drop aligned the east with the northern, southern, and western sectors. Those areas registered moderate readings of 78, 85, and 90, respectively. Central Singapore remained an outlier at 110.
Tracking the 24-Hour PSI and PM2.5 Fluctuations
Earlier in the day, the western region dipped into the moderate range at 4 pm with a reading of 100. That followed an extended stretch in the unhealthy category that began in the morning. At 7 am, readings stood at 128 in the central zone, 115 in the east, and 106 in the west. Northern and southern zones held at 89 and 95.
The haze episode first pushed the central region into the unhealthy category at 8 pm on Sept 26 at 104. Readings climbed overnight, peaking at 127 at 3 am. The east entered the unhealthy band at midnight at 103, followed by the west at 1 am at 102. Hourly PM2.5 concentrations, which measure fine particulate matter, ranged from 29 to 60 at 7 am before easing to between 17 and 31 by 4 pm.
Decathlon Kiprun Race Altered as Smoke Blows In
Organizers altered Decathlon’s inaugural Kiprun race on Sept 27 in response to the regional air quality. The 21.1 km half-marathon was shortened to 10 km. Formats for the 10 km, 5 km, and 670 m Kids Dash remained unchanged.
In its daily advisory issued around 6 pm on Sept 26, the National Environment Agency forecast air quality for the subsequent 24 hours to range from moderate to low-unhealthy. While overnight showers were expected across parts of Singapore and the region, dry conditions persisted over southern Sumatra and parts of southern and eastern Kalimantan. Prevailing winds blowing from the south-east or south-west continued to carry smoke haze toward the island.
Health Advisories and Public Guidelines
The agency advised the public to consult hourly PM2.5 readings for immediate outdoor activities and use 24-hour PSI metrics for daily planning. Under unhealthy conditions, healthy individuals are advised to reduce prolonged or strenuous outdoor exertion. Vulnerable populations—including the elderly, children, pregnant women, and individuals with chronic heart or lung disease—were urged to minimize or avoid outdoor activities entirely.
The 24-hour PSI first breached the unhealthy threshold on Sept 4, marking the first such occurrence since October 2023. Central Singapore recorded the highest concentrations during the period, peaking at 154 on Sept 15. The Meteorological Service Singapore indicated in its mid-September forecast that increased shower activity is anticipated through the remainder of the month.