Haze kept the central region’s 24-hour PSI in the unhealthy range for a third straight day on Wednesday, 7 October, with a reading of 129 at 5am, according to the National Environment Agency. The east and the west were also above 100, while the north and the south slipped back into the moderate band.
Central readings dipped in and out of the unhealthy range over the weekend, then stayed above 100 without a break from 1am on Monday, 5 October. Through Tuesday they held between 128 and 136.
Readings across the island
At 5am on Wednesday, the 24-hour PSI was:
- Central: 129
- East: 118
- West: 114
- North: 99
- South: 96
On Tuesday, all five regions were in the unhealthy range from noon to 7pm.
The 1-hour PM2.5 readings, which NEA uses as the guide for the next few hours, were 74 µg/m³ in the central region, 87 in the west, 63 in the east, 51 in the north and 36 in the south. Readings above 55 µg/m³ fall in Band 2, Elevated, which applied in the central, west and east regions at that hour; the north and south were in Band 1, Normal.
What NEA expects
NEA’s 24-hour PSI forecast is high moderate to unhealthy. In its update on Tuesday evening, it said moderate transboundary smoke haze covered parts of Peninsular Malaysia, Singapore, Kalimantan, Sarawak and southern and central Sumatra, with moderate to dense smoke plumes rising from hotspot clusters in large parts of Kalimantan and central and southern Sumatra.
Winds over the southern ASEAN region are forecast to blow from the southeast to the south in the coming days. Showers are expected over northern and central Sumatra, Peninsular Malaysia and northern Borneo, which may help there, but dry weather elsewhere keeps the risk of transboundary haze.
NEA’s advice, band by band
NEA uses the 24-hour PSI forecast for next-day plans. Its advice changes at each band:
- Good (0 to 50) and moderate (51 to 100): normal activities for everyone.
- Unhealthy (101 to 200): healthy people should reduce prolonged or strenuous outdoor exertion; the elderly, pregnant women and children should minimise it; people with chronic lung or heart disease should avoid it.
- Very unhealthy (201 to 300): healthy people should avoid prolonged or strenuous outdoor exertion; the elderly, pregnant women and children should minimise outdoor activity; people with chronic lung or heart disease should avoid outdoor activity.
- Hazardous (above 300): healthy people should minimise outdoor activity, and everyone else should avoid it.
For activities in the next hour, NEA points to the 1-hour PM2.5 band instead. At Band 2 (56 to 150 µg/m³), healthy people should reduce strenuous outdoor activity and vulnerable groups should avoid it. At Band 3 (151 to 250), healthy people should avoid strenuous outdoor activity and vulnerable groups should avoid all outdoor activity. At Band 4 (251 and above), everyone should minimise or avoid being outdoors.
Race nights outdoors
The Singapore Grand Prix runs on the Marina Bay Street Circuit from Friday to Sunday, 9 to 11 October, with sessions on all three days running into the evening, in the open air.
Under NEA’s guide, a spectator would check the 24-hour PSI forecast the day before and the 1-hour PM2.5 band shortly before heading out. NEA says symptoms from short-term exposure, such as throat or eye irritation, are expected to ease after leaving the haze, and anyone who feels unwell should seek medical attention.
