Air quality to be in mid-to-high end of moderate range: NEA

Kelly Ng Today Online 23 Sep 14;

SINGAPORE — After a weekend that saw the Pollutant Standards Index (PSI) creeping into unhealthy levels, air quality is expected to be in the mid-to-high end of the moderate range today, the National Environment Agency (NEA) said last evening.

And in response to complaints by members of the public that the PSI readings on Sunday did not correspond to the visibly worsening air quality in many parts of Singapore, the agency said pollutant concentrations may be volatile from one hour to the next.

As of 8pm yesterday, the 24-hour PSI reading was 76 to 85, within the high end of the moderate range.

The total number of hot spots detected yesterday in Indonesia’s Sumatra and Kalimantan — which caused the haze experienced in Singapore — was 78 and 107 respectively, mostly in the southern parts of the islands. Smoke plumes and haze were visible in the vicinity of some hot spots in Sumatra.

Prevailing winds are forecast to blow mainly from the south-east today. While people can continue with their normal activities today, those who are not feeling well, especially the elderly, children and people with chronic heart or lung conditions should seek medical attention, the NEA said.

Earlier on Sunday evening, many TODAY readers had complained about worsening air quality in many areas of Singapore and a strong odour in the air — even though the PSI was still in the “moderate” range. The PSI reading caught up only on Sunday night, hitting a high of 129 at 9pm.

The complaints about PSI readings came despite the introduction of a new air quality reporting system in April, which is supposed to better reflect visibility levels during haze as it incorporates levels of fine particulate matter, PM2.5, into the PSI. Then, an NEA spokesperson had said the new system would pass the “window test” and “correspond more closely with what one sees”.

In response to TODAY’s queries, the NEA said yesterday: “The three-hour PSI at any time is based on PM2.5 concentration levels averaged over the previous three hours. As the hour to hour concentrations may be very volatile during a haze episode with short periods of transiently high PM2.5 levels, which can improve rapidly in the subsequent one to two hours, the three-hour PSI may not correspond to what one observes at that specific instant.”

It added that since April, the NEA has also made available one-hour PM 2.5 concentration levels on the NEA website, the haze microsite and myENV app. “Members of the public can make use of the three-hour PSI or one-hour PM2.5 concentration levels as a guide to adjust their immediate activities, like going for a jog outside,” the agency said.

A PSI reading of 101 to 200 falls within the unhealthy range, while a 51 to 100 reading is considered moderate.

Slight improvement in air quality in Singapore
Leong Wai Kit Channel NewsAsia 22 Sep 14;

SINGAPORE: The skies were less hazy on Monday (Sep 22) as compared to Sunday. The National Environment Agency (NEA) said the three-hour Pollutant Standards Index (PSI) hit the 'unhealthy' range at 8am but dropped to the 'moderate' range from late morning. The three-hour PSI reading as of 8pm was 62.

One doctor has advised residents to look out for any signs of haze sensitivity, which includes increased snoring and dryness of the throat. He added that the unpredictable hazy conditions make it difficult for some to self-medicate.

Said Dr Leong Chook Kit of Mission Medical Clinic: "They may leave the house thinking there is no haze in the morning so they do not take their medicine, or they do not even bring their mask along. But towards the evening when they have knocked off from work, the haze will come and they are stuck without their mask and without medicine."

- CNA/do

PSI to fluctuate between ‘moderate’ and ‘unhealthy’ range: NEA
Today Online 21 Sep 14;

SINGAPORE – The National Environment Agency (NEA) forecasts the island to experience slight haze as winds continue to blow from the southeast or south today (Sept 22), in their haze advisory released to members of the public yesterday.

“We may experience occasional hazy conditions during the day. The overall air quality tomorrow is expected to fluctuate between the high-end of the Moderate range and the low-end of the Unhealthy range.”

Singapore experienced a sudden deterioration in the surrounding air quality in the late afternoon yesterday, with reports coming in from certain parts of the island of a burning smell lingering in the air.

The National Environment Agency (NEA) said the swift increase in haze levels was due to a sizeable amount of smoke blowing in from Sumatra by prevailing winds.

“Singapore is experiencing deteriorating hazy conditions due to an incoming haze cloud we have detected southwest of Singapore,” said the agency in an advisory to members of the public released at 7pm yesterday.

“The total number of hotspots detected in Sumatra and Kalimantan today was 64 and 73 respectively, mostly in the southern parts of Sumatra and Kalimantan. Widespread smoke haze was visible in southern Kalimantan,” NEA added.

The three-hour Pollutant Standard Index (PSI) levels hovered around the “good” and “moderate” range for most of yesterday morning and afternoon but slowly crept up in the latter range from 1pm to 5pm. At 7pm, the reading inched closer towards the “unhealthy” range at 89 at the time when air quality can be clearly seen to be deteriorating. At 8pm, the PSI was well into the unhealthy range at 116. It registered a high of 129 before dipping slightly to 121 at 10pm. The 24-hour readings continued to hover in the “moderate” range, registering a low of 48-54 at 1pm and a high of 59-67 at 9pm.

Some members of the public complained on social media about a burning smell going around in the air, just as the island was gearing up for the Singapore Formula One race. NEA acknowledged “reports of burning smells in the central and eastern regions of Singapore” in their media advisory.

Last Thursday, Singapore also experienced PSI levels in the “unhealthy” range, registering the worst air quality readings this week when air quality hovered above 100 for most of the day.

Minister for Environment and Water Resources Dr Vivian Balakrishnan in his Facebook post assured members of the public that the environment agency will keep them informed.

“The forecast for the 24-hour PSI over the next six hours is in the high end of the moderate range or even low unhealthy level,” he added.

Earlier this week, the NEA said that Singapore is expected to experience haze for the next two weeks due to prevailing wind conditions from the south-southeast or the south-west where Sumatra lies, with periods of consecutive dry days that are typical during this South-west Monsoon season.