The air quality index peaked at 167 in the central region at 12pm on September 29, marking a new high since the PSI first returned to the unhealthy range on September 4. This marks the first instance of such severe haze conditions in Singapore since October 2023. As at 6am on September 30, one-hour PM2.5 readings, which serve as a gauge for immediate activity, remained in the elevated range in the central (64), eastern (67), and western (67) regions. In contrast, the northern and southern regions saw readings drop to 53 and 52 respectively, returning to the normal range.
The National Environment Agency (NEA) attributes the persistent haze to moderate to dense smoke drifting from fires in Kalimantan and southern Sumatra. Dry conditions are expected to persist over these source regions, while prevailing winds from the east or southeast continue to push smoke toward Singapore. Although showers are forecast for September 30, the NEA warns that smoke haze may still affect the island, with the 24-hour PSI forecast to remain in the high moderate to mid-unhealthy range.
Health Advisories and Guidelines
Health impacts from haze depend on an individual’s health status, the PSI level, and the duration and intensity of outdoor activity. The NEA advises healthy individuals to reduce prolonged or strenuous outdoor physical exertion when the 24-hour PSI is in the unhealthy range (101–200). For vulnerable groups, including the elderly, children, pregnant women, and those with chronic lung or heart disease, the agency recommends minimizing or avoiding such activities altogether.
For immediate planning, the public is directed to monitor one-hour PM2.5 concentration readings. An hourly PM2.5 reading between 56 and 150 µg/m³ indicates an elevated concentration of fine particles. During these periods, strenuous outdoor activity should be avoided for the next hour. The 24-hour PSI forecast remains the primary tool for planning activities for the following day.
The deterioration in air quality began on September 27, when the central region’s PSI entered the unhealthy range at 110. By September 28, the 24-hour PSI ranged from 68 to 94 across the island, with one-hour PM2.5 readings hitting 138 µg/m³ in central Singapore. The situation worsened on September 29, with the central region peaking at 167. Extensive cloud cover has limited the ability to fully determine the extent of hotspots in the region, but satellite imagery confirms smoke haze originating from the aforementioned areas.
Residents are advised to check the NEA’s haze microsite, the myENV mobile application, or the NEA website for real-time updates. The Meteorological Service Singapore noted in a September 16 forecast that more showers are expected in the second half of the month, which may eventually help clear the haze, though current conditions remain unfavorable for rapid dispersion.
