Haze pushes Singapore air quality into unhealthy range in three regions

Singapore began Saturday with unhealthy air in three regions as haze returned to levels that prompted renewed daily warnings from the National Environment Agency.

At 9 a.m., the 24-hour Pollutant Standards Index stood at 115 in the central region. Earlier, at 6 a.m., the west and east had recorded readings of 103 and 102, respectively. Those readings later eased to 98 in the west and 96 in the east.

The north and south remained in the moderate range, with PSI readings of 83 and 87. The 24-hour index moved into the unhealthy band, defined as 101 to 200, at 7 a.m. on Friday. It was the first breach of that level since Oct. 8, 2023.

The change led the National Environment Agency to begin issuing daily haze advisories, including a 24-hour PSI forecast. In its first advisory on Friday evening, the agency said Singapore could continue to experience transboundary haze, with the forecast ranging from the higher end of the moderate category to the middle of the unhealthy range.

The 24-hour PSI averages air quality over the previous day and underpins Singapore’s health advisories. It measures six pollutants, including fine particulate matter known as PM2.5, which the agency identifies as the dominant pollutant during haze. A one-hour PM2.5 reading instead shows conditions at a single point in time. The NEA said agencies in the Haze Task Force had implemented action plans and advisories to protect public health.