Haze is back, and it could be hanging around for a while

As the haze edged ominously close to unhealthy levels yesterday, Singapore residents were warned to expect it to persist for the next few days.

The National Environment Agency (NEA) said the hazy conditions yesterday were due to smoke haze blown here by prevailing winds from persistent hot spots in the Indonesian island of Sumatra.

With prevailing winds forecast to blow from the south-east or south and with hot spot activities expected to persist, the haze could continue to affect Singapore for the next few days, NEA said in a statement.

On the agency's website yesterday, the 24-hour Pollutant Standards Index (PSI), a measure of air quality, showed a steady rise towards unhealthy levels.

The PSI in southern Singapore, the most affected area, was 99 at 3pm and 98 at 4pm, just below the 101 unhealthy mark.

Over the next 24 hours, the one-hour PM2.5 concentration readings are expected to range between normal and elevated, and the 24-hour PSI is forecast to be in the high end of the moderate range, NEA said.

The PM2.5 reading reflects the concentration of tiny particles less than 2.5 micrometres in diameter in the air.

When the reading hits elevated, these particles can affect the heart and lungs, particularly in people who have chronic conditions such as asthma.

NEA said: "Given the air quality forecast for the next 24 hours, healthy persons should reduce prolonged or strenuous outdoor physical exertion.

"The elderly, pregnant women and children should minimise prolonged or strenuous outdoor physical exertion, while those with chronic lung or heart disease should avoid prolonged or strenuous outdoor physical exertion."

Also of concern is the steady increase in the number of hot spots detected in Sumatra.

The 113 hot spots detected on Saturday last week had risen to 380 by Monday.

Yesterday, a total of 537 hot spots were detected, said NEA.

Malaysia has been more severely affected, with the state of Sarawak on Borneo island reaching "unhealthy" levels in air quality.

As one district hit the "very unhealthy" mark and 400 schools closed yesterday, half a million face masks were sent to Sarawak.

Several areas in peninsular Malaysia, including the capital Kuala Lumpur, were in the "unhealthy" range. Rompin, a town in Pahang state, hit "very unhealthy" levels last night.

NEA said the haze in Singapore may also hit the "unhealthy" range depending on wind conditions and the fires in Sumatra.

Mr Benjamin Tay, executive director for Singapore charity PM.Haze (People's Movement to Stop Haze), said favourable wind directions had helped Singapore avoid the worst of the haze from the Sumatra fires, which have been burning over the past two months.

But this is now changing, he told The Straits Times.

LITTLE IMPACT SO FAR

When The New Paper contacted alfresco dining and outdoor adventure venues in Singapore, most said there has been little impact from the haze.

An outdoor adventure organisation catering to children and the youth said it will be required to suspend business if the PSI reaches 170.

Its manager, who declined to be named, said: "As of now, it is slightly hazier than normal, but it will not affect us too much unless the situation worsens."

Mr Sharul Nizam, manager of Masons, a restaurant at Gillman Barracks, which has indoor and outdoor seating, said it has not been affected, but his staff are monitoring the PSI levels and will advise customers to sit indoors if conditions worsen.

NEA said it is monitoring the situation closely and will provide further updates when necessary.

READ MORE: Haze returns as hot spots flare up in Sumatra