Haze in Singapore: air quality worsens with unhealthy PSI levels

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 has been shortened to 10km, while distances for the other formats – the 10km, 5km, and Kids Dash (670m) – remain unchanged.

NEA Advisory

In its daily haze advisory at about 6pm on Sept 26, the National Environment Agency (NEA) said air quality in Singapore for the next 24 hours was forecast to be in the moderate range to low-unhealthy range.

While some showers are forecast over Singapore and parts of the region overnight and on Sept 27, dry conditions are expected to continue over southern Sumatra, as well as southern and eastern Kalimantan.

Winds forecast to blow from the south-east or south-west could bring smoke haze to 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 like 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.