Friday, December 6

Haze – brown clouds


THE acrid smell of the air and its pungent taste invaded after the drying weeks in September and the first week of October in Kuching. (In the past couple of weeks though the storms have washed Kuching’s air clean.) These were reminders of haze earlier this year and in past years.

POOR VISIBILITY: Drivers contend with hazy conditions.

My mind drifts back to 1997 when, at Mount Kinabalu National Park, soot, a product of local forest fires, literally fell out of the sky onto my bald head.

Two days prior to this I was in Kuala Lumpur to admire the Petronas Twin Towers but, through the haze, I could only see, from ground level, the first 50 metres of the towers. Yes, I coughed owing to the air pollution. Last June, all readers of The Borneo Post had daily details of the haze that engulfed Miri, which was reported to be due to local peat fires.

What is haze? In meteorological terms it is related to visibility at ground level reduced to between 1,000 and 2,000 metres. It is the accumulation of dust and smoke particles in air of low relative humidity – dry air.

Such air is stable, descending from above and thus increasing the pressure at ground level. This situation does not allow any vertical or horizontal air movement hence windless conditions.

Haze is directly related to the growth of cities and is not new. Medieval England, with the gradual growth of London, was polluted from coal-fired limekilns there and thus subjected to a Royal Commission in 1285 to investigate the cause of the haze. Twenty-one years later the offenders were punished by torture, ransom, fines and the confiscation of their property!

On Sept 27, 2012, the visibility in Kuching was forecasted to be only 4km, the lowest in Malaysia. This should not be surprising in anticyclonic (high pressure) conditions as a growing city with pollution from vehicle exhaust emissions converted by strong sunlight into harmful substances such as ozone (O3).

Add to this open burning elsewhere, perhaps in another country, plus a change in the wind conditions and the effluent from the burning of offshore gas rigs all contribute to the local conditions. Haze can occur in rural areas but generally the average number of particulates (minute particles of soot and other chemicals in the air) are about 10 times greater in a city.

The Malaysian Meteorological Department regularly released details of the Air Pollutant Index (API), a measure of the degree of health hazards, during the haze. Also included were the number of hotspots of uncontrolled daily burning in Sabah, Sarawak, and Kalimantan, Indonesia as identified by the NOAA-18 satellite. Such technology allows all Asean countries that signed the Transboundary Haze Pollution Agreement (2002) to take action on the fires in their respective countries to reduce the potential haze particles drifting to an adjoining country. This is a positive anti-pollution pact.

The Miri and Sibu haze situations last June reveal that the extraordinarily high API indices were most probably the result of local peat fires. More subtly these were combined with a very gentle south-easterly air stream, which slowly and gradually transferred particulates, in the air, from open burning in Kalimantan.

Peat fires near Miri at Kuala Baram (covering 50ha) and at Permyjaya (10ha) were the most difficult land fires to control. They burned underground through the compressed and dry peat down to a depth of three metres. Whilst dowsing the flames with water in one area, the fire would break alight on the ground surface in another area.

In bone-dry weather, peat fires are almost impossible to control for fired peat – an embryonic form of coal – releases sulphur dioxide (SO2) into the air, which then oxidises to create sulphur trioxide (SO3). This gas creates respiration problems for asthmatics and others with sensitive respiratory conditions. Peat deposits cover one seventh of the surface landmass of Sarawak.

The API recordings for Miri were taken at the industrial training college very near to the peat fires. Air quality reports were sent at four hourly intervals to the Department of Environment.

The old adage ‘there is no smoke without fire’ can literally be read from NOAA-18 satellite photos. During those eight days, hotspots were clearly identified in Borneo and pinpointed to those who ignored their government’s advice not to practise open burning of plantation land or garden rubbish. The invisible spy in the sky can see more clearly than we can.

Haze will continue as further climatic change takes place thus causing upset to our tropical climate. The answer is never cloud seeding as a columnist has suggested, for the air is stable and not unstable when a haze occurs. Without doubt the variability of air pollution owes much to human activity but is also dependent upon local meteorological conditions.

The Fire and Rescue Department (Bomba) and People’s Volunteer Corps (Rela) personnel in Miri worked extremely hard to combat the local peat fires there and through their sustained effort eradicated the health hazards.

How did this predicament begin? We humans have much to answer for and must learn from our mistakes if the Transboundary Haze Pollution Agreement is to make a difference.