SINGAPORE – There could be more respite from the haze on Friday (Sept 27), as air quality is expected to be in the good range in some parts of the Republic for the first time since it hit unhealthy levels two weeks ago.

This is even as Minister for the Environment and Water Resources Masagos Zulkifli called for stronger action to prevent what he referred to as the “perennial scourge for South-east Asia” from recurring.

The National Environment Agency (NEA) said on Thursday evening that for the next 24 hours, the 24-hour Pollutant Standards Index (PSI) is forecast to be in the good to moderate range.

Air quality took a sharp turn for the worse here on Sept 14 when the 24-hour PSI reading crossed the unhealthy level for the first time since 2016. It has remained in the moderate to unhealthy range since then.

The one-hour PM2.5 concentration reading, which NEA has said is a better indicator of current air quality, is expected to be in the normal band, although it may occasionally enter the elevated band.

NEA said that the likelihood of haze affecting Singapore is low, noting that thundery showers are forecast over Singapore and in parts of Sumatra for the next few days.

Still, there could be slight haze here in the next few days if winds shift to blow smoke haze from Sumatra.

A PSI reading of zero to 50 indicates good air quality, while a reading of 51 to 100 is in the moderate range. A reading of 101 to 200 is considered unhealthy, very unhealthy from 201 to 300, and hazardous when the reading is more than 300.

There are four bands on the PM2.5 concentration scale: 0 to 55 for normal, 56 to 150 for elevated, 151 to 250 for high, and very high for any higher readings.

At 9pm on Thursday, the 24-hour PSI reading was 64-74, in the moderate range. The PM2.5 reading was 22-37, in the normal band.

In a Facebook post on Thursday, Mr Masagos said he was glad that the rain has brought some relief to the haze.

He said stronger action is needed to prevent the haze in the region and that Singapore conveyed its concerns over the rise in hot spots, as well as offered its assistance, to the Indonesian government last week.

Noting that the Indonesian government is reportedly “investigating several companies, including Singapore-based ones”, Mr Masagos said NEA has already written to its Indonesian counterpart to request for more information, so that the Republic can investigate on its end.

“We will not hesitate to enforce the Transboundary Haze Pollution Act if Indonesia is able to provide Singapore with evidence of wrongdoing by any company that has contributed to haze in Singapore,” he wrote.

“Singapore will not tolerate the actions of errant companies that jeopardise the health and lives of people here and in other countries, and which set back our efforts to fight climate change.”