Haze in Singapore: Air quality back in the unhealthy range

SINGAPORE – The air quality across the island deteriorated overnight, with the 24-hour PSI recording unhealthy levels of air pollution early on Oct 24.

At 7am, the PSI readings were 115 in the north and south regions, 117 in the east, 142 in the west and 133 in the central region.

The PM2.5 readings – which are gauged hourly and reflect the current air quality – were also elevated across the country.

At 7am, the PM2.5 readings were 79 in the north, 78 (south), 68 (east), 107 (west) and 94 (central).

There had been a brief respite from the haze early on Oct 23, with the PSI in the good to moderate range in the morning of Oct 23, when PSI readings were in the good to moderate range and PM2.5 levels were in the normal range.

However, the air quality began worsening just before noon that day, when the PM2.5 levels began rising and they have continued fluctuating in the elevated range since, spiking at 146 at midnight, just five points shy of the “high” range.

Singapore has been experiencing unhealthy air quality, denoted by 24-hour PSI readings above 101, since Oct 5.

The 24-hour PSI, which is a rolling index of six key air pollutants, reflects air quality in Singapore over the past day.

When air quality breaches this threshold, people, especially the elderly, children and those with health issues, should start scaling down outdoor activities.

Forecast for Oct 24

In its daily advisory on the evening of Oct 23, the National Environment Agency (NEA) said moderate to unhealthy air quality is expected on Oct 24, with the PSI forecast to be in the range of 90 to 140.

Smoke haze from Sumatra was seen drifting towards Singapore and was also observed over Kalimantan on Oct 23, NEA said.

While showers are forecast over Singapore and the surrounding region on Oct 24, some smoke haze may be transported towards Singapore from Sumatra under prevailing south-southeasterly or south-southwesterly winds, it added.

Hazy conditions may improve from Oct 25.

Winds are expected to blow from the south-west or west from Oct 25, NEA said.

This may help reduce the smoke haze transported to Singapore, it said, adding that showers over Singapore and areas nearby could also help with the haze situation.