Singapore’s 24-hour Pollutant Standards Index (PSI) entered the unhealthy range in the west and central regions by 6 a.m. ET Friday, while the other three stayed moderate, Channel NewsAsia reported.
CNA said the west had already reached 103 by 4 a.m. ET (08:00 UTC). Two hours later, the 24-hour PSI stood at 108 there and 102 in the central region; the north, south and east were between 85 and 89. At 7 p.m. ET Thursday (23:00 UTC), readings across the five regions ranged from 67 to 90, while one-hour PM2.5 concentrations were 20 to 52 micrograms per cubic meter. By 6 a.m. ET Friday (10:00 UTC), those hourly readings had risen to 70 to 98, CNA reported.
The National Environment Agency (NEA) classifies PSI readings from 101 to 200 as unhealthy and readings from zero to 100 as good to moderate. In an Oct. 22 advisory, it forecast a 24-hour PSI of 101 to 150 for Friday. The deterioration followed a Thursday afternoon improvement described by CNA; EconoTimes covered the earlier improvement in Singapore’s air quality.
In an update posted at 5:28 a.m. ET Friday (09:28 UTC), NEA reported scattered hotspots in southern Kalimantan and Sumatra. It described moderate to dense haze over parts of Singapore and nearby areas, with unhealthy readings at some monitoring stations. Cloud cover limited the agency’s assessment of the extent of the haze and hotspots.
NEA said showers might improve conditions in some places, while haze could stay elevated in areas experiencing prolonged dry conditions. It recommends using one-hour PM2.5 readings to make immediate decisions about outdoor activity. When the 24-hour PSI is unhealthy, the agency advises elderly people, pregnant women and children to minimize prolonged or strenuous outdoor physical exertion. For those with chronic heart or lung conditions, NEA recommends avoiding prolonged or strenuous exertion outdoors.
