More rain, less haze?

Recent wet weather may lead to better air quality
Victoria Vaughan Straits Times 29 Jun 10;

Pedestrians crossing Orchard Road last Friday at 10.30am after a morning downpour. The recent wet weather in the region may help to reduce haze in the months ahead. -- ST PHOTO: LIM SIN THAI

THE wet weather hitting the region in recent weeks may prove a good thing for air quality in the months ahead.

In the years when May and June have been wetter than usual, the amount of forest torched, and the intensity of the haze that subsequently engulfs Singapore, has been greatly reduced.

The head of fire and sustainability at a major pulp and paper company in Sumatra said the haze from slash-and-burn forest clearing in Indonesia is expected to be less severe due to the prolonged wet season.

Mr Brad Sanders from Asia-Pacific Resources International Ltd, or April for short, a leading developer of fibre plantations and pulp and paper, said conditions this year look less favourable for farmers who want to use fire to clear their land.

'Because it has been so wet in June, people have not been able to burn. If it does dry up a bit in August, there may be quite a few people starting fires as they have not been able to so far,' he said.

'But I don't think we'll see smoke haze having a severe impact on Singapore, as for that to happen we need a severe dry system of more than three or four weeks in length and below normal rainfall.'

April, headquartered in Singapore, has 311,000ha of plantations in Riau, Sumatra - an area about four times the size of Singapore. It has had a no-burn policy since 1994.

Mr Sanders, who has seven years of experience fighting the fires that threaten his company's crops, said the weather forecast for the region does not indicate such a long dry spell in the months ahead.

However, things could change drastically if the weather dries up, giving farmers the opportunity to start burning.

But a National University of Singapore climatologist, Associate Professor Matthias Roth, said it was too early to predict how bad this year's haze season - usually from July to September - will be.

'Once the weather becomes dry again, there is a good possibility the clearing of land will resume and we will be affected by haze from biomass burning.'

Singapore's National Environment Agency (NEA) said that from January to May this year, it recorded 772 hot spots in Sumatra and 593 in Kalimantan, but this is before the main dry season got under way this month.

As a comparison, on a single day in July last year satellite images showed 2,248 hot spots in Sumatra, compared with 1,229 in 2008, 1,218 in 2007 and 2,031 in 2006.

'One of the contributing factors to the development of hot spot activities in the region is the weather,' said the NEA spokesman. 'The traditional dry season in the region (from June to September) is normally exacerbated by the occurrence of El Nino, leading to an increase in hot spot activities.'

In 2006, when the El Nino effect was particularly bad, it led to long dry spells here and the haze situation hit a high of 150 in October - classified as unhealthy on the Pollutant Standard Index.

The highest level ever recorded was 226 in September 1997, in the very unhealthy range.

In 2007 and 2008, when the region experienced La Nina, the opposite of El Nino whose effects are often its reverse, the wetter conditions helped ease the smoke over Singapore.

During the El Nino years (2006 and 2009), the hot spot numbers in Sumatra were 12,014 and 10,297 respectively.

During La Nina in 2007 and 2008, they were 7,017 and 8,349 respectively.