Air quality in central region enters unhealthy range again with 24-hour PSI readings of 102-103
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Hazy conditions as seen from Chancery Lane at 10.30am on Sept 17.
ST PHOTO: KUA CHEE SIONG
SINGAPORE – Air quality in Singapore worsened on Sept 17, with the 24-hour Pollutant Standards Index (PSI) reading in the central region crossing into the unhealthy range again.
The 24-hour PSI reading for that area hit 102 at 9pm, before inching up to 103 at 10pm, after a reprieve a day earlier, when readings across Singapore fell into the moderate range from 11am onwards.
The PSI for the central region later fell back to 102 at 11pm.
From 9pm to midnight, readings in the north, south, east and west remained in the moderate range.
Hourly PM2.5 readings, which indicate the current concentrations of fine particulate matter, were in the normal band for the north (55) and south (40), and east (51), and in the elevated band in the west (64) and central (93) regions as at 9pm.
As at 10pm, the hourly PM2.5 readings in the north stood at 58, crossing into the elevated band.
However, the readings for all regions returned to within the normal band by midnight.
The National Environment Agency (NEA) has advised the public to refer to the hourly PM2.5 readings for immediate activities and 24-hour PSI ones to plan for the day ahead.
Air quality is considered unhealthy when the 24-hour PSI is in the range of 101 to 200, while an hourly PM2.5 reading between 56 and 150 indicates an elevated concentration of fine particles.
NEA has advised that during such periods, those who are healthy should reduce prolonged or strenuous outdoor activities, while vulnerable groups like the elderly, children and pregnant women, as well as people with chronic lung or heart disease, should minimise or avoid such outdoor activities altogether
The PSI first returned to the unhealthy mark two weeks ago, on Sept 4, the first time since October 2023. Readings in the central region were the highest, peaking at 154 on Sept 15.
With dry conditions persisting over parts of Indonesian hot spots Sumatra and Kalimantan, coupled with prevailing winds blowing from the south or south-east, Singapore remains at continued risk of haze, said NEA in a haze advisory on Sept 16.
But air quality could improve in the next two weeks, with the Meteorological Service Singapore forecasting on Sept 16 more showers here for the rest of September, compared with the first half of the month.
