Haze watch: Air quality returns to unhealthy range in central, southern Singapore

Air quality slipped back into the unhealthy range in central and southern Singapore on Monday (Sept 28) evening. At 8pm, the 24-hour Pollutant Standards Index (PSI) readings ranged from 73 to 104 — in the moderate to unhealthy range — with southern (103) and central (104) Singapore recording the highest PSI readings.Meanwhile, one-hour PM2.5 is in the elevated band in all five regions, with central Singapore seeing the highest concentration reading of 149. Readings between 56 and 150 denote the elevated band, while a reading between 151 and 250 is in the high band.In its daily haze situation update on Monday evening, the National Environment Agency (NEA) said the country’s 24-hour PSI is forecast to be in the high-moderate to mid-unhealthy range.The agency noted that moderate to dense smoke haze from fires in southern Sumatra and Kalimantan had drifted to Singapore.With prevailing winds expected to blow from the east or southeast, there remains a risk of smoke haze continuing to affect Singapore, NEA explained.