Hard to identify cause of smoky smell in air: NEA

KENNETH CHENG Today Online 30 Mar 16;

SINGAPORE — The smoky smell that has been lingering in the air across the island in recent days may have been brought on by transboundary haze in the region, or fires in Singapore or other sources of localised burning, the National Environment Agency (NEA) said on Tuesday (March 29).

On a regional haze map put up by the ASEAN Specialised Meteorological Centre at 7.30pm, there were scattered hotspots detected over Vietnam, Laos and Cambodia. Localised, thin smoke plumes were also observed in the vicinity of some of the hotspots.

The centre, which runs a regional collaboration programme among the national meteorological services of ASEAN member countries, reported that “wet weather condition continue to subdue hotspot activities with only isolated hotspots detected in Brunei” in the southern ASEAN region.

Since Sunday, there have been multiple reports from the public, regarding an acrid smell in the air and reduced visibility in some parts of the island, with some making calls to Mediacorp newsrooms to register their observations. From late Tuesday afternoon, there have been reports from various parts of the country, including the Central Business District and Sentosa, of palpable smoky smells in the air and visibly hazy conditions.

The three-hour PSI reading on Tuesday crept up from 69 at noon to 83 at 10pm. And the 24-hour PSI stayed within the Moderate range (51-100) in all parts of the island, registering between 61 and 69 at noon to between 65 and 80 at 10pm.

The NEA spokesperson said that “transboundary smoke haze from forest and peat fires in the region” may be a possible cause, but added that it was difficult to identify the cause or source of such smells because of their “transient nature”.

Such smells, the spokesperson said, are usually — but may not always be — accompanied by higher Pollutant Standards Index (PSI) or PM2.5 readings which measure fine particulate matter in the air. This means there is no strong correlation between PSI or PM2.5 readings and burning smells in the air.

Between last September and October, Singapore experienced a prolonged bout of haze which, at one point, forced the closure of primary and secondary schools for a day.

Singaporeans report 'haze' smell
The 3-hour Pollution Standards Index reading hit 87 at 8pm on Tuesday (Mar 29), the highest level this year.
Channel NewsAsia 29 Mar 16;

SINGAPORE: The 3-hour Pollutant Standards Index (PSI) crept up from Tuesday afternoon (Mar 29) before peaking at 87 at 8pm, the highest level this year. It went down to 83 by 10pm.

However readings of the 24-hour PSI at 8pm was 65-78, still within the Moderate range. When the 24-hour PSI goes beyond 100, it is considered unhealthy.

In response to media queries, the National Environment Agency (NEA) said there are a few possible causes for a burning smell in the air. It could be due to "transboundary smoke haze from forest and peat fires in the region, the occurrence of local fires or other localised sources of burning". It added that smells may not always be accompanied by higher PSI or PM2.5 readings.

The PSI is an index of daily air quality levels and computed on the concentration of fine particulate matter (PM2.5), the dominant pollutant during haze episodes, along with other pollutants.

"Due to the transient nature of such smells, it is difficult to identify the cause or source of the smells," NEA said, adding that there is no correlation between PSI/PM2.5 readings and burning smells in the air.

According to the Meteorological Service Singapore (MSS), scattered hotspots were detected over Vietnam, Laos and Cambodia on Tuesday.

"Localised, thin smoke plumes were observed in the vicinity of some of the hotspots," MSS said on its website, adding that in southern ASEAN, wet weather continued to subdue hotspot activities, with isolated hotspots detected in Brunei.

Last year saw Singapore badly hit by transboundary haze from neighbouring Indonesia for a prolonged period, with the 24-hour PSI hitting the 'Hazardous' and 'Very Unhealthy' range for several days.

- CNA/dl