The 24-hour Pollutant Standards Index (PSI) readings reached unhealthy levels in three regions and hourly PM2.5 levels climbed sharply late on Monday, reflecting worsening air quality.
At 11pm, hourly PM2.5 readings spiked across all five regions, ranging from 74 to 142. The central region logged a reading of 142, up from 108 earlier. The reading in the east climbed by 44 points to 134.
The south region’s reading increased to 99, while the west and north edged up to 78 and 74 respectively.
The 24-hour PSI readings ranged from 79 to 117 at 11pm, with readings for the central (117), south (111) and west (107) rising into the unhealthy range.
Readings for the north and east were at 79 and 98 respectively.
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.
Decathlon’s inaugural Kiprun race was adjusted on Sept 27 because of the poor air quality.
The 21.1km half-marathon was shortened to 10km, while distances for the other formats – the 10km, 5km and Kids Dash (670m) – were unchanged.
In its daily haze advisory on Sept 27, the National Environment Agency (NEA) said air quality in Singapore for the next 24 hours was forecast to be in the moderate to low-unhealthy range.
While some showers are forecast over Singapore and parts of the region on Sept 28, dry conditions are expected to continue over southern Sumatra, as well as southern Kalimantan.
“With the prevailing winds forecast to blow from the south-east, there remains a risk of smoke haze affecting Singapore,” NEA said.
It 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.
For periods when the air quality crosses into the unhealthy range, NEA has advised healthy people to reduce prolonged or strenuous outdoor activities, while vulnerable groups such as the elderly, children and pregnant women, as well as people with chronic lung or heart disease, should minimise or avoid such activities altogether.
The PSI first returned to the unhealthy range on Sept 4, the first time since October 2023. Readings in the central region were the highest, peaking at 154 on Sept 15.
In its fortnightly weather forecast on Sept 16, the Meteorological Service Singapore said more showers are expected in the second half of the month than in the first. THE STRAITS TIMES
