The burning question - Haze and your health

SINGAPORE - Q: How long has the Centre for Remote Imaging, Sensing and Processing (Crisp) been monitoring the haze-causing fires?

We've been monitoring the forest fires and haze via a suite of satellites for 16 years now. Apart from 1997 - when the severe El Nino conditions saw widespread fires in Indonesia and Borneo blazing out of control - the number of hot spots and the size of the fires have remained pretty constant from year to year. The same holds true this year; it's not an El Nino year. (El Nino, a weather phenomenon which results in the warming of sea surface temperatures in the Pacific Ocean, is associated with higher than normal temperatures and diminished rainfall.)

Q: How accurate are these satellite images?

We are able to see anything 50cm or larger. On a daily basis, we use the low-resolution, wide-coverage satellites to scan the whole region for hot spots. If these are detected, our system automatically notifies us. We then search for suitable high-resolution satellite passes to capture detailed imagery over the hot spots. These high-resolution images, like a telescope, cover a much smaller area: 15km to 60km, compared with 2,300km. We need to steer the satellite to focus on the areas on fire. Crisp scientists then carry out a detailed analysis of the type, severity and location of fires and haze using the high-resolution imagery.

Q: Why is the haze so severe this time?

On the ground, the fires now are nowhere near the size and severity of those in 1997 but, this time, we have been unlucky because the winds brought the haze over to Singapore.

Then, wild fires and human burning hit Sumatra, Kalimantan, East Malaysia and Brunei. At this time, only the Riau province has large clusters of fires.

Generally, during the southwest monsoon, the winds push the pollutants from the Riau fires further up north, bypassing Singapore altogether and sparing us. The Riau fires almost never affect us. But this year, there was a sudden tropical storm off Taiwan and a = smaller storm in the South China Sea, which altered the course of the wind and directed it straight to Singapore.

At the same time, the storms are drawing the clouds and moisture away from this region, and creating the perfect hot dry conditions for burning. Without moisture in the air, rain-seeding will not work.

Q: Who is to blame?

As we can see from our images, the fires are in the forest fringes and from plantations. We can see rectangular grids, some with rows of crops on fire. There are even man-made canals in the forest, possibly used for controlling the fire.

We have the exact coordinates of all the fires, which we also send to the National Environment Agency.

This information can be matched with concession maps showing who owns the land.

Q: What can we expect next?

The storms are weakening and weather experts expect them to dissipate early in the week. When this happens, we should get some respite, as the wind will hopefully change direction and we could get some rain. Traditionally, we've always been more concerned about the hot spots in South Sumatra that come to life around July and August, as the winds then could bring some haze towards Singapore.

Right now, we are experiencing only the start of the burning season, so there could be more haze to come. Hopefully, we will get favourable wind conditions that will channel the haze away from Singapore.

Q: What's the damage on the ground in Indonesia?

What some call damage, others call development. Crisp did a study of regional deforestation recently. Using mainly satellite images, we generated a regional land cover map, one for the year 2000 and one for 2010. Our studies showed that Indonesia had lost 10 per cent of its total forests - an area more than 120 times the size of Singapore - to commercial use over the decade.

This includes close to 20 per cent of its peat swamps. A lot of the forests are cleared with fires, which results in carbon being released into the air. This is particularly so for peat swamps, which are huge carbon stores.

The effects on global warming are likely to be huge but scientists are still working hard to quantify them. Indonesia is also home to one of the world's largest forests.The destruction of forests and peat swamps is a tremendous loss to biodiversity.

Dr See Kay Choong, a consultant at the National University Hospital's (NUH) division of respiratory and critical care medicine, gives some tips on how to cope with the haze.

Q: Should I wear a mask?

Yes, you need one which can filter out microscopic particles effectively. The N95 has been scientifically proven to do so.

The N95 mask can be used again but you need to ensure that it is not soiled, wet or damaged, or distorted. Once the shape is deformed, it no longer protects the user. Keep the N95 in a clean bag if you want to reuse it.

A regular surgical mask won't help, even if you wear two of them.

Most surgical masks do not effectively filter small particles from the air and do not prevent leakage around the edge of the mask when the user inhales.

If you cannot get hold of the N95 mask or an equivalent type like the R95, try to stay indoors and keep the air-conditioner on.

Q: What about working out?

Exercising outdoors when the PSI level is above 100 will negate any beneficial effects of the workout.

The best thing you can do is to stay indoors and have minimal contact with the external environment.

If the haze persists for a week or more, consider getting an air purifier.

Q: How can the haze affect me?

For the normal man in the street, short-term exposure of a few minutes with minimal activity is unlikely to have any lasting harmful effects.

But staying in the haze for longer periods could irritate and inflame your airways, lungs and eyes.

Studies have also shown that the haze can cause inflammation of other parts of the body and worsen existing lung and heart ailments.

Q: What symptoms can I expect?

You may get a runny nose, and those prone to asthma or chronic obstructive pulmonary disease could see their condition worsening.

Your eyes could feel gritty and uncomfortable. You can alleviate the discomfort by rinsing them with water or eye-wash lotions.

Drink water to relieve throat irritation.

In the hospitals, we are prepared to see more patients with upper respiratory tract infections, rhinitis and asthma. Keep in mind that some of the symptoms may not appear immediately, but could take a few days to show up.

Q: When should I get worried?

Seek medical help immediately if you have severe breathlessness or chest discomfort, particularly if you have a pre-existing illness.

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