Haze update for Sept 15: PSI expected to remain in high moderate to mid-unhealthy range

Air quality in Singapore improved slightly on Tuesday (Sept 15), a day after the 24-hour Pollutant Standards Index (PSI) slipped into the unhealthy range in all five regions in Singapore.

At 6pm, the 24-hour PSI ranged between 92 and 131, placing Singapore's overall air quality in the moderate to unhealthy range.

The highest reading of 131 was recorded in central Singapore, followed by the western (114) and eastern (113) regions. 

Both northern (93) and southern (92) Singapore remained in the moderate range.

Meanwhile, the one-hour PM2.5 concentration readings ranged between 43 and 74 — with only the southern region in the normal band — while the four remaining regions recorded readings in the elevated band.

The country's 24-hour PSI forecast is again expected to be in the high moderate to mid-unhealthy range over the next 24 hours.

Explaining this in its daily haze situation update on Tuesday evening, the National Environment Agency (NEA) said that while overnight showers over some areas in the surrounding region contributed to improvements in the haze situation, prevailing winds — from the east-southeast and southeast directions — had brought smoke haze from Kalimantan and Sumatra to Singapore.

NEA added that dry conditions are expected to persist over central and southern Sumatra and southern Kalimantan in the coming days.

This means that the risk of smoke haze affecting Singapore remains.

Members of the public are advised to check one-hour PM2.5 concentration readings and the accompanying personal guide when deciding on outdoor activities in the next few hours.

For planning outdoor activities the following day, they should refer to the 24-hour PSI forecast and the corresponding health advisories.

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editor@asiaone.com