Haze pushed Singapore’s air into the unhealthy range in four of five regions early on Tuesday, 6 October, with the 24-hour PSI at 129 in the central region at 7am. The National Environment Agency expects the 24-hour PSI to stay between high moderate and mid unhealthy, in the week of the Singapore Grand Prix.
Readings across the island
At 7am on Tuesday (6 October), the 24-hour PSI was:
- Central: 129 (unhealthy)
- West: 116 (unhealthy)
- East: 112 (unhealthy)
- North: 107 (unhealthy)
- South: 95 (moderate)
The PSI’s unhealthy band runs from 101 to 200, so only the south was still in the moderate range.
The 1-hour PM2.5 readings, which NEA uses as the guide for what to do in the next hour, were 57 µg/m³ in the central region, 44 in the west, 54 in the east, 47 in the north and 36 in the south. Readings above 55 µg/m³ fall in Band 2, Elevated, which applied in the central region at that hour; the west, east, north and south were in Band 1, Normal.
Why the haze has come back
On Monday evening, moderate to dense smoke plumes from southern Sumatra were drifting towards Singapore, with smoke haze also coming from fires in Kalimantan. At 7pm on Monday the 1-hour PM2.5 readings had reached 72 to 109 µg/m³, in Band 2, and the 24-hour PSI was 97 to 124.
Dry weather is expected to continue over southern Sumatra and Kalimantan. With winds forecast to blow from the southeast or east-southeast, smoke haze could keep drifting this way.
What NEA advises at these levels
When the 24-hour PSI is in the unhealthy range:
- Healthy people should reduce prolonged or strenuous outdoor physical exertion.
- The elderly, pregnant women and children should minimise it.
- People with chronic lung or heart disease should avoid it.
The 1-hour PM2.5 bands work over a shorter window. At Band 2 (56 to 150 µg/m³), healthy people should reduce strenuous outdoor activity for the next hour, and the elderly, pregnant women, children and people with chronic lung or heart disease should avoid it. At Band 1 (0 to 55), normal activities can carry on.
NEA’s rule of thumb is to use the 1-hour PM2.5 reading for anything happening now, and the 24-hour PSI forecast for plans the next day.
Race week outdoors
Several of this week’s Grand Prix events are in the open air. Ray-Ban’s Beyond the Track pop-up is at Fountain Square in Clarke Quay until 14 October, and the Orchard Paddock runs at Ngee Ann City Civic Plaza from Thursday to Saturday, 8 to 10 October.
The race itself runs on the Marina Bay Street Circuit around Marina Centre and the Padang from Friday to Sunday, 9 to 11 October, with road closures in the area from 12.01am on Wednesday.
