Haze in Singapore: PSI reading in east reaches unhealthy levels, joining west and central areas

SINGAPORE – Air quality in eastern Singapore entered the unhealthy range in the evening of Oct 5, with a 24-hour Pollutant Standards Index (PSI) reading of 101 at 6pm.

Readings in the western and central parts of the island are also in the unhealthy range, with the remaining two regions in the moderate band.

As at 6pm, the readings were:

• North: 94 (up by 1 from 5pm)

• South: 95 (up by 1)

• East: 101 (up by 1)

• West: 120 (up by 2)

• Central: 122 (unchanged)

PM2.5 readings, which are used as a gauge for immediate activities, were elevated in all five regions across Singapore:

• North: 77 (up by 2 from 5pm)

• South: 75 (up by 4)

• East: 79 (down by 1)

• West: 79 (up by 1)

• Central: 97 (down by 9)

Air quality is considered unhealthy when the 24-hour PSI is in the range of 101 to 200, while an hourly PM2.5 reading between 56 and 150 indicates an elevated concentration of fine particles.

The PSI – a 24-hour rolling average of six key air pollutants and used in planning for outdoor activities the next day – had begun an upward trajectory at midnight on Oct 5.

Dry conditions are expected to continue over Singapore and the surrounding region on Oct 5. The risk of haze affecting the Republic remains as the prevailing winds are expected to blow from the south-east or south-west.