Singapore Air Quality Worsens as Haze From Indonesia Hits All Five Regions
TEMPO.CO, Jakarta - Singapore's air quality deteriorated into the unhealthy range across all five regions on Monday morning, September 15, as smoke haze from forest fires in Indonesia continued to affect the city-state.
At 6 a.m., the 24-hour Pollutant Standards Index (PSI) readings were 104 in the north, 111 in the south, 128 in the east, 128 in the west, and 154 in the central region, according to The Straits Times.
The readings eased slightly by 9 a.m. but remained in the unhealthy range, with PSI levels at 103 in the north, 106 in the south, 122 in the east, 124 in the west, and 148 in the central region.
Singapore's National Environment Agency (NEA) classifies a 24-hour PSI reading of 101 to 200 as unhealthy and advises the public to reduce outdoor activities when air quality reaches that level.
Air quality across Singapore had already worsened on September 14, when PSI readings in all regions except the north entered the unhealthy range after several days of moderate conditions. The north crossed the 101 threshold at around 1 a.m. on September 15, rising to 102 from 99 at midnight.
A PSI reading of 51 to 100 is considered moderate, while levels between zero and 50 are classified as good.
One-hour PM2.5 readings across most of Singapore fell to normal levels by 6 a.m. on September 15, ranging from 32 to 44 micrograms per cubic meter.
However, the central and western regions recorded elevated readings of 66 and 59 micrograms per cubic meter, respectively. Singapore classifies PM2.5 concentrations of up to 55 micrograms per cubic meter as normal, 56 to 150 as elevated, and 151 to 250 as high.
In an advisory issued on September 14, the NEA forecast that Singapore's air quality over the following 24 hours would range from high-moderate to mid-unhealthy levels.
The latest deterioration follows the PSI entering the unhealthy range on September 4, when central Singapore recorded a reading of 101. Since then, central, eastern and western areas have periodically recorded unhealthy levels.
The current episode marks the first time since October 2023 that haze has pushed Singapore's PSI into the unhealthy range. Authorities had previously warned of an increased risk of haze between June and October due to warmer and drier conditions associated with El Nino and the Indian Ocean Dipole.
The NEA said moderate to dense smoke plumes from forest fires in Kalimantan continued to be observed, with some drifting toward Singapore. Smoke plumes were also detected over southern Sumatra.
Dry conditions are expected to persist across Singapore and the surrounding region in the coming days. With winds forecast to continue blowing from the southeast to east-southeast, the NEA warned that Singapore is likely to remain affected by smoke haze.

