SINGAPORE, Sept 27 — Residents in Singapore woke up to unhealthy air quality again with three regions in the unhealthy range today morning.

The 24-hour Pollutant Standards Index (PSI) turned unhealthy in central Singapore at 8pm yesterday, with the western and eastern regions also entering the range at 12am and 1am respectively.

Meanwhile, one-hour PM2.5 reached as high as 131 in central Singapore at 9pm yesterday before gradually easing back to the lower-end of the elevated band.

At 9am, PSI ranged from 90 to 130 — in the moderate to unhealthy range — with central Singapore recording the highest reading of 130.

One-hour PM2.5 is the normal band for the northern, western and southern regions, while central (68) and eastern (58) Singapore have an elevated concentration reading.

PSI forecast

In its daily haze situation update yesterday evening, the National Environment Agency (NEA) had said the country’s 24-hour PSI forecast is expected to be in the moderate to low-unhealthy range.

It pointed out that moderate to dense smoke haze from fires in Kalimantan drifted towards Singapore yesterday, while smoke plumes were also observed from fires in southern Sumatra.

Along with the prevailing south-easterly or south-westerly winds, there could be a risk of smoke haze affecting Singapore, the agency explained.

It also noted that dry conditions are expected to continue over southern Sumatra and the southern and eastern parts of Kalimantan.

What to do when PM2.5 is elevated

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.

When PM2.5 readings are in the elevated band, members of the public should reduce strenuous outdoor activity for the next hour.

Vulnerable persons such as the elderly, pregnant women, children, and persons with chronic lung or heart disease should avoid strenuous outdoor activity.

However, if readings hit the high-band, all healthy persons should avoid strenuous outdoor activity for the next hour, while vulnerable persons should avoid all outdoor activity. — AsiaOne