Singapore 'likely to be free of haze till year end'

NEA projection based on weather conditions and sharp drop in number of hot spots
Jeremy Au Yong Straits Times 29 Oct 10;

SINGAPORE looks set to be rid of the haze for the rest of the year.

Favourable weather conditions, and a sharp drop in the number of hot spots, bode well for clear skies ahead, said the National Environment Agency (NEA) yesterday.

The NEA, which had issued only short-term projections since the haze worsened last week, gave the assessment for the rest of the year in response to queries from The Straits Times.

The Pollutant Standards Index (PSI) readings yesterday stayed in the good range, with the 24-hour measurements hitting a high of only 39.

The PSI hit 108 last Thursday, breaching the unhealthy threshold of 100 for the first time since 2006.

Latest satellite images detected no hot spots or smoke haze in Sumatra's Riau province, which had caused the recent bout of haze, said NEA.

But the agency pointed out that it was difficult to say if all the fires had been put out as many parts of Sumatra were covered by clouds.

Still, weather conditions were turning in Singapore's favour.

The region is expected to get progressively wetter. Already, the region has experienced an increasing number of showers in recent weeks.

On Saturday, heavy showers affected many parts of Singapore in the afternoon and early evening. It rained again on Monday.

Rain also fell over Sumatra and the Strait of Malacca.

The wet weather helps to put out fires in the hot spots and wash existing smoke particles out of the air.

'The showers have helped to improve the haze situation in the region,' said NEA.

The winds are also changing direction.

With the onset of the north-east monsoon in November, winds will blow predominantly from the north-east.

Even if fires do flare up again in Sumatra, the winds would not be pushing the smoke haze this way.

'Singapore is thus unlikely to be affected by transboundary haze for the rest of the year,' said the agency.

Still, NEA said that Singapore continued to urge the Asean ministerial steering committee on transboundary haze to remain vigilant.

The impact of the smoke haze here is dependent on a confluence of factors including the proximity and extent of the fires, the strength and direction of the prevailing winds and the incidence and amount of rain.

This year's haze episode came later than usual because the start of the traditional dry season in Sumatra was delayed by the influence of La Nina conditions.

La Nina refers to cooler-than-normal sea surface temperatures in the central and eastern tropical Pacific Ocean and it brings wetter weather to the region.

The dry season - which typically runs from June to October - started only in mid-August this year. From mid-October, the Riau province experienced a period of dry weather conditions and many hot spots were detected.

Burning can occur throughout the year but it tends to be more pronounced during the dry season.