Singapore Air Quality Hits Unhealthy Levels in Central Region

The 24 hour Pollutant Standards Index (PSI) in the central region of Singapore entered the unhealthy range on Friday, September 4. According to the National Environment Agency (NEA), the PSI first hit 101 at 7am and rose to 105 by 10am. This marks the first time the PSI has reached unhealthy levels since October 2023. Readings in other parts of the island remained in the moderate range, with the west at 90, the east at 89, the north at 78, and the south at 75 as of 10am.

The NEA will begin issuing daily haze advisories to help the public plan activities. Health guidelines suggest that healthy individuals should reduce prolonged or strenuous outdoor physical exertion when the PSI is unhealthy. Vulnerable groups, including children, the elderly, pregnant women, and those with chronic heart or lung disease, are advised to minimize such activities or avoid them entirely. The Ministry of Manpower has also provided guidelines for employers to protect outdoor workers.

The deterioration in air quality is linked to transboundary haze from forest and land fires in Sumatra and Kalimantan, Indonesia. These fires have been fueled by dry conditions and a super El Nino weather phenomenon. Some areas in Malaysia have been severely affected, with Sarawak recording a very hazardous Air Pollutant Index of 408 in the town of Serian on September 3. The NEA expects the hotspot and smoke haze situation to remain elevated in fire prone regions due to continued dry conditions.

Air quality is monitored using two primary metrics: the 24 hour PSI and the 1 hour PM2.5 reading. The 24 hour PSI is a daily average of six pollutants used for general planning and health advisories. The 1 hour PM2.5 reading reflects immediate air quality and is used to decide on immediate outdoor activities. PM2.5 consists of fine particulate matter that can enter the bloodstream and lodge deep in the lungs.