Singapore Air Quality Returns to Moderate Range After Unhealthy Haze Levels

Air quality across all five regions of Singapore returned to the moderate range on September 5, following a period where several areas recorded unhealthy Pollutant Standards Index (PSI) readings. The central region saw a peak PSI of 123 before dropping to between 96 and 98 by the evening. The east and west regions also entered the unhealthy range earlier in the day, with readings of 102 and 103 respectively at 6am, before returning to moderate levels. The north and south regions remained in the moderate range throughout the day.

This event marked the first time since October 2023 that the PSI exceeded 100. In response, the National Environment Agency (NEA) began issuing daily haze advisories on September 4, which include 24-hour PSI forecasts to help the public plan activities. The NEA stated that Singapore could continue to experience transboundary haze due to active fires in Kalimantan and the southern and central parts of Sumatra. Smoke plumes from these areas continue to drift toward Singapore, and dry conditions are expected to persist in the coming days.

The 24-hour PSI is calculated using six air pollutants, including PM2.5, which is the dominant pollutant during haze episodes. Air quality is classified as unhealthy when the PSI falls between 101 and 200. The Haze Task Force has implemented action plans and advisories to protect public health during this period.