PSI hits 102: Haze pushes air quality in central Singapore into unhealthy range

Singapore's air quality is back in the unhealthy range at 1pm on Saturday (Sept 19), as the 24-hour Pollutant Standards Index (PSI) reading hits 102 in central Singapore.

Elsewhere, western Singapore recorded the next highest reading of 90 — in the moderate range.

Data from the National Environment Agency (NEA) shows one-hour PM2.5 concentration reading in central Singapore entering the elevated band at 10am, before climbing gradually to as high as 149 at 12pm. 

The one-hour PM2.5 concentration reading at 1pm ranges from 71 to 141, which is in the elevated band. Readings between 56 to 150 denote the elevated band, while readings between 151 to 250 are in the high-band.

What PM2.5 readings mean

The National Environment Agency (NEA) groups PM2.5 readings into four bands: normal (0-55 µg/m3), elevated (56 to 150), high (151 to 250), and very high (251 and above).

The public can check PM2.5 readings for guidelines on immediate outdoor activities.

They should note that the health impact of haze depends on their health status, as well as the duration 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.

High moderate to low-unhealthy forecast

In its daily haze situation update on Friday evening, NEA had said the country's 24-hour PSI forecast is expected to be in the high moderate to low unhealthy range.

This 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. 

[[nid:745156]]

editor@asiaone.com