Aqil Haziq Mahmud Channel NewsAsia 26 Sep 17;
SINGAPORE: Air quality levels in Singapore remain within safety limits, said the National Environment Agency (NEA) on Tuesday (Sep 26), a day after residents in many areas complained of a strong burning smell.
NEA said its checks included levels of volatile organic compounds, and industrial plants in the north-eastern parts of Singapore were found to be operating normally. The agency added that it has not received any more complaints about the smell.
"Investigations are ongoing," it said in a Facebook post. "NEA will continue to closely monitor the situation."
On Monday, residents in Sengkang, Buangkok and Hougang were among the first to notice the smell from as early as 4.30pm, describing it as "plastic burning" and "like petroleum". It spread to Bishan and Ang Mo Kio later in the afternoon.
By evening, the odour had spread to Commonwealth, Bukit Timah and Holland Village.
Authorities had also said on Monday that no toxic industrial chemicals were detected in the air and air quality levels were within safety limits.
FUMES FROM FACTORIES A POSSIBILITY
The plumes could be industrial pollution that originated in Malaysia, experts told Channel NewsAsia.
"It is likely to be exhaust from a smokestack of some kind of factory. You get a burning smell from the haze not a pungent smell," said Dr Ang Peng Hwa, who leads the Haze Elimination Action Team (HEAT).
It is possible that the smell came from the "release of chemical products or substances from a major industrial facility," said Dr Erik Velasco, a climate and meteorological research scientist at the Singapore-MIT Alliance for Research and Technology.
It came from the north "possibly beyond the channel", he added.
The weather conditions helped to spread the smell across a large part of Singapore, Dr Velasco explained.
"Slow winds coming from the north and a local meteorology that trapped the plume close to the surface concentrated the smell, and obviously, the chemical species or pollutants associated with it," he said.
Source: CNA/hm/dl
Air quality within safety limits, no further smell complaints: NEA
Lydia Lam Straits Times 26 Sep 17;
SINGAPORE - Air quality levels across Singapore, including levels of volatile organic compounds, continue to remain within safety limits, the National Environment Agency (NEA) said in a statement on Tuesday (Sept 26), a day after Singaporeans islandwide detected a chemical smell accompanied by a cloud of smoke.
NEA said in its Facebook post at 7.49pm that it has been monitoring air quality levels, including levels of volatile organic compounds (VOCs), across Singapore.
"The levels continue to remain within safety limits and we have not received further smell complaints from residents in Singapore," it said.
It added that checks conducted at industrial plants in the north-eastern parts of Singapore showed that they were operating normally.
Residents in various parts of Singapore, including Sengkang, Yishun, Seletar, Bishan, Ang Mo Kio and Clementi, had reported smelling a petrol-like chemical burning smell that irritated their eyes, noses and throats.
However, NEA and the Singapore Civil Defence Force said that there were no toxic industrial substances in the air and that air quality during the period had been "well within safety limits".
Investigations are ongoing, and NEA said it would continue to monitor the situation closely.
ST understands that the fumes are believed to have come from Johor.
NEA also said in its statement that Singapore "may experience slightly hazy conditions" on Wednesday morning due to the accumulation of particulate matter under light wind conditions.
For the next 24 hours, the 24-hr PSI is forecast to be in the Moderate range.
NEA will continue to closely monitor the situation.
Cause of chemical stench still a mystery
Air quality within safety limits, says NEA; volcanic action in Bali and haze ruled out
Samantha Boh Straits Times 27 Sep 17;
Investigations have yet to uncover the cause of the caustic chemical stench that cloaked parts of the island on Monday, but experts have so far ruled out volcanic action in Bali and the haze.
Air pollutants tracked by the authorities, such as sulphur dioxide, carbon monoxide, ozone and nitrogen dioxide, were also normal, following checks by officers from the National Environment Agency (NEA) and Singapore Civil Defence Force on Monday.
These gases are usually emitted from vehicles or factories that burn natural gas.
The NEA, which has been monitoring air quality, including volatile organic compounds (VOCs), across the island, said last night that air quality and VOC levels continue to remain within safety limits.
Some VOCs may have short-and long-term adverse effects on health.
On Monday, complaints first poured in from residents in Sengkang and Punggol about an acrid, chemical stench that was later detected by people in estates such as Ang Mo Kio, Yishun, Seletar and Bishan. Thick smoke also hung over some of the affected areas, residents said.
Some residents suggested the smell was from the town of Pasir Gudang in Johor, where a large zone of its 311 sq km is dedicated to heavy industries, and where fumes and pollutants have strayed to Singapore in past incidents.
Just last week, a fire broke out at a chemical factory there, creating thick smoke and causing thousands working and living around the area to panic.
But when contacted yesterday, people working there said there was nothing out of the ordinary on Monday afternoon.
According to the NEA, "checks conducted at industrial plants in the north-eastern parts of Singapore showed that they were operating normally".
The agency said it will continue to investigate the source of the chemical smell.
Meanwhile, experts have ruled out volcanic action in Bali and the haze.
Associate Professor Koh Tieh Yong of the Singapore University of Social Sciences said: "The winds were not coming from Bali yesterday. Bali is over 1,500km away. For a stench to travel so far and still smell so strong is highly unlikely."
The weather expert added that gases diffuse as they travel, and for it to smell so strong here, the compound had to be very concentrated at its source. There has been no report of a strong stench in Bali.
According to the NEA's daily haze update on Monday, the 24-hour Pollutant Standards Index (PSI) was in the low end of the moderate range at 6pm. The hourly concentration readings for PM2.5 - tiny pollutant particles associated with haze - was also in the normal band.
This means the air quality levels were within safety limits and, after yesterday's thunderstorm, the NEA said it received no further complaints of the stench from residents.
Ms Lelavathi Annamali, 68, who lives in Ang Mo Kio Avenue 8, said the strong kerosene smell that had stung her eyes on Monday night had largely dissipated by yesterday morning.
"Then the rain came at about 11am, and it was completely gone," said the retiree.
Slightly hazy conditions are expected in Singapore this morning and thundery showers in the afternoon, said the NEA.
The 24-hour PSI is expected to be in the moderate range, and the hourly concentration readings for PM2.5 normal.
