Cloud cover hinders hotspot detection, but winds could still bring haze from persistent fires: NEA

SINGAPORE: Dense cloud cover obstructed satellite views north of Singapore on Tuesday (Jan 27) and prevented the detection of hotspots, but weather conditions could transport smoke haze from "persistent fires" towards the country, said the National Environment Agency (NEA).

In an update on Facebook, the agency cited the dry weather ahead and prevailing winds from the north and northeast as factors for possible hazy conditions.

On Tuesday, the 24-hour Pollutant Standards Index (PSI) readings were in the good to moderate range. As of 6pm, it ranged from 39 to 61, remaining within the good to moderate range.

The 24-hour PSI is computed based on six air pollutants - PM2.5, PM10, ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide. 

It serves as an indicator of Singapore's daily air quality and is the reading that NEA's daily health advisories are based on.

Over the past few days, many have taken to social media to complain of a burnt smell, with some saying it has irritated their noses and throats. 

On Saturday, NEA said PM2.5 levels in the eastern part of Singapore were "slightly elevated", referring to fine inhalable particles in the air measuring up to 2.5 micrometres in diameter.  

It noted complaints from some residents of a faint burnt smell, adding that it was likely due to a detected hotspot and smoke plume in Johor near Singapore.

On Monday, NEA said that it continued to observe hotspots to the north of Singapore due to vegetation fires, and that some smoke haze could be transported over due to the prevailing winds blowing from the north or northeast.

The 24-hour PSI ranged from 43 to 56, in the good-to-moderate range, at the time of its Facebook post.

"While a burning smell may be noticeable, it does not always result in a significant change to air quality reading," added NEA.