Haze update Sept 18: Singapore air quality moderate; 24-hour PSI forecast in high-moderate to low-unhealthy range

Singapore's air quality remained in the moderate range on Friday (Sept 18).

The 24-hour Pollutant Standards Index (PSI) turned unhealthy in central Singapore at 9pm on Thursday night, remaining in that range for about four hours. 

As at 5pm on Friday, the 24-hour PSI ranged from 64 to 86 — in the moderate range — with central Singapore recording the highest PSI of 86. This was followed by western Singapore, with a PSI reading of 79.

Meanwhile, one-hour PM2.5 concentration readings ranged between 31 to 61, in the normal to elevated bands.

Central Singapore was the only region in the elevated band, while the other four regions remained in the normal band as at 5pm.

The one-hour PM2.5 reading reflects current air quality and should be used when deciding whether to carry out outdoor activities in the next few hours.

In its daily haze update on Friday evening, the National Environment Agency (NEA) said the country's 24-hour PSI forecast is expected to remain in the high moderate to low unhealthy range.

This, it said, is due to smoke plumes from fires in Kalimantan drifting towards Singapore. Some smoke plumes were also observed over southern Sumatra, the agency added.

Given that prevailing winds are expected to blow from the east-southeast or southeast, NEA said the risk of smoke haze affecting Singapore remains. 

Members of the public should note that the health impact of haze is dependent on one's health status, the PSI level, and the length and intensity of outdoor activity. 

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editor@asiaone.com