'Hazy skies' over several parts of Singapore

Hazy skies were seen in several parts of Singapore with reports of a burning smell detected on Friday morning (Aug 26). Several people took to social media and called in to Channel NewsAsia to say that they could smell the haze from different parts of the country.

According to the National Environment Agency (NEA), the 24-hour Pollutant Standards Index (PSI) reading at 12pm was 58-80, in the Moderate range.

This was a slight climb from the 52-70 reading at 11am, which was also in the Moderate range. 

​The corresponding 3-hour PSI at 12pm was 165, up from 128 at 11am.

The 1-hr PM2.5 has been increasing during the morning across the country, but especially in the northern and western parts of Singapore. In the northern sector, it rose from below 10ug/m3 from 1am to 5am to 20ug/m3 at 7am and 172ug/m3 at 12pm. Meanwhile, 1-hr PM2.5 levels in the western sector, which were also below 10ug/m3 from 1am to 5am this morning, similarly rose to 23ug/m3 at 7am before sharply spiking in the next two hours to hit 216ug/m3 at 12pm.

The PSI incorporates six types of pollutants - sulphur dioxide, particulate matter that is 2.5 micrometres in diameter or smaller (PM2.5), particulate matter that is 10 micrometres in diameter or smaller (PM10), ozone, nitrogen dioxide and carbon monoxide. Of the six, PM2.5 is considered particularly hazardous as the small size of the particles enters the human lungs more easily. 

PSI TO REMAIN AT HIGH END OF MODERATE RANGE: NEA

In a statement at around 11.50am, NEA said the haze was likely to have been blown in by westerly winds over Singapore. A total of three hotspots were detected in central Sumatra on Thursday with localised smoke plumes were visible, the authority said, adding that the low hotspot count was due to cloudy conditions. 

The latest satellite image on Friday morning showed some hotspots in central Sumatra, NEA said.

The statutory board predicted that for the rest of Friday, the prevailing winds would fluctuate and would be expected to blow from the west or southwest. 

It also forecasted partly cloudy conditions over Singapore, with the 1-hr PM2.5 concentration levels for the day expected to remain in Elevated to High ranges.

The authority predicted that the PSI reading over the rest of the day would be in the high end of the Moderate range.

​Back in March this year, when a burning smell was detected in some parts of Singapore, the NEA said it could have been caused by some local vegetation fires.

It added that fires and some wind convergence over Singapore could have also contributed to the deterioration in the air quality in some parts of the island.

NEA said on Friday that the health impact of haze was dependent on one’s health status, the PSI level, and the length and intensity of outdoor activity.

"Given the air quality forecast for the next 12 hours, everyone can continue with normal activities. Persons who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical attention."