Indonesia: 1997-98 Air Pollution Episode in Southeast Asia from Vegetation Fires (IFFN No. 23)

The 1997-98 Air Pollution Episode in Southeast Asia Generated by Vegetation Fires in Indonesia

(IFFN No. 23 – December 2000, p. 68-71)


Between July and November 1997, an estimated 45,000 km2 of forest and land burnt on the islands Sumatra and Kalimantan. In the first half of 1998, another fire episode affected roughly a similar area in Kalimantan alone. The emissions of these fires caused considerable air pollution throughout the Southeast Asian region, notably in Indonesia, Singapore and Malaysia. The air pollutant that predominantly caused violations of ambient air quality standards was particulate matter. Particulate matter may cause acute and chronic respiratory diseases such as bronchitis, asthma and upper respiratory tract infections. Increased ambient particle concentrations are suspected to be linked with increased daily mortality. By scattering and absorbing light, particulates also result in reduced visibility, impairing transportation by air, land and water. Fire-related air pollution episodes are a recurrent phenomenon in Southeast Asia. Nine such incidents have been reported over the last 20 years, of which the 1997/98 smoke haze episode attracted the broadest attention.

In contrast to Singapore and Malaysia, Indonesia does not yet have an integrated air quality monitoring network which could provide real-time, region-covering air quality information. Due to the absence of such information, an assessment of the severity of the fire-related air pollution episodes is limited. As a surrogate, horizontal visibility was frequently used to report the status of ambient air pollution. However, even though sufficient information on the status of air quality was available in Singapore and Malaysia, much uncertainty existed on the impacts of such air pollution episodes and on how to response adequately to them. The governments of the affected countries recommended the public to remain indoors as much as possible, to avoid physical exertion and to wear respiratory masks outdoors. In Kuching, Borneo-Malaysia, the state of emergency was proclaimed for 10 days in 1997, leading to the closure of schools, public offices and factories. Dubious statements in the media on the impacts of the smoke haze were disseminated – such as the daily exposure would equal to 20 to 40 cigarettes; panic easily evolved.

Smoke-haze development in 1997/98

The influence of the 1997 fires in Kalimantan and Sumatra on ambient air quality was discernible by July, peaked in September/October and weakened by November, when the delayed monsoonal rain extinguished the fires and scavenged the atmosphere. During the peak episode, satellite imagery (NASA/TOMS aerosol index maps) showed a smoke haze layer which expanded over an area of more than 3 million km2, covering large parts of Sumatra and Kalimantan. Its northward extension partially reached Malaysia, Singapore, Brunei and Thailand. During this period, particulate matter concentrations frequently exceeded national ambient air quality standards. Scanty particle measurement data at hand for areas close to fires in Kalimantan and Sumatra indicate that ambient particle concentration was roughly 20 to 40 times the normal (non-haze) background concentration and exceeded levels categorised as ‘hazardous’ (or ‘significant harm level’). Monthly mean horizontal visibility at most locations in Sumatra and Kalimantan in September was below 1 km and daily maximum visibility was frequently below 100 metres.

The neighbouring region most affected by pyrogenic transmissions in 1997 was Sarawak, Borneo-Malaysia. In the city of Kuching, ambient particle concentration rose roughly 5 to 20 times above background levels, with in total 32 days in the ‘unhealthy to hazardous’ range. Visibility decreased from generally above 15 km to below 0.5 km during this period.

In Singapore and Peninsular Malaysia, a 2 to 5-fold rise in ambient particle concentration was recorded. 12 and more than 40 days, respectively, were in the ‘unhealthy’ range in Singapore and Kuala Lumpur. Visibility below 2 km predominantly prevailed at both locations during the smoke haze episode.

In contrast to the situation in 1997, the fire-related air pollution episode in the first half of 1998 was essentially restricted to Borneo. This was mainly due to the weakened southerly monsoonal flow by that time. However, again, the population in Kalimantan and Borneo-Malaysia was exposed to distinctively elevated air pollution for a period of months.

Impacts of the smoke haze episodes

In all countries affected by the smoke haze, an increase of acute health outcomes was observed. Health outcomes included emergency room visits due to respiratory symptoms such as asthma, upper respiratory infection, decreased lung function and eye and skin irritation. In Singapore, for instance, health surveillance showed a 30% increase in hospital attendance for haze-related illnesses. Generally, individuals such with pre-existing respiratory and cardiac diseases, but also elderly and children are most susceptible to adverse health outcomes from haze exposure. In addition to the acute effects, chronic diseases are likely follow. The smoke haze episodes add to the urban and industrial air pollution in Southeast Asia, which has reached alarming levels in many metropolitan areas. The synergistic effects of smoke haze and background air pollution are uncertain.

Besides health impacts, impaired visibility seriously affected the economies of Indonesia, Malaysia and Singapore. Among the economic sectors affected most were air, land and sea transportation, construction, tourism and agrobased industry. EEPSEA/WWF roughly estimated the economic value of the damages caused by the 1997 fires and haze. They estimated 1 billion US$ of haze-related damages for Indonesia only. The damages to Malaysia and Singapore are figured at 0.4 billion US$. Including the fire related damages, the total damages are estimated to amount to 4.5 billion US$. However, a variety of the damages such as decreased quality of life, losses of biodiversity and atmospheric impacts are difficult to monetarise.

Fire-related smoke haze episodes also reveal a social component: a large part of the population in Southeast Asia do not have the financial means to buy protective measures such as respiratory masks and air conditioning nor are they able to refrain from outdoor work when air pollution is high. The same applies to medical treatment costs for haze related ailments.

A regional response to the 1997/98 smoke haze episode

The 1997/98 smoke haze episode resulted in an intensification of regional measures towards cooperation in fire and smoke management which were initiated in the aftermath of the 1991 and 1994 smoke haze episodes. These measures include the establishment of ASEAN Haze Technical Task Force and the implementation of Regional and National Haze Action Plans. These plans define the ASEAN’s countries contribution to fire prevention, monitoring, fighting and other mitigation measures. Among others, it is also targeted to upgrade the national air quality and meteorological monitoring networks in order to strengthen the region’s early warning and monitoring system in respect to smoke haze.

The 1997/98 once again made evident that in addition to a sound fire management a fundamental revision of the current land conversion and fire use policies is required to prevent the reoccurrence of similar episodes. Groundbased and airborne investigations of the smoke haze 1997 indicated that fires on peat swamp vegetation made a substantial contribution to the smoke haze development, which, however, are estimated to have contributed only 30% to the total area burnt. Given this apparent particular relevance of peat swamp fires to the development of transboundary smoke haze, emission reduction and control strategies will have to focus on the prevention of fires in this type of vegetation as a matter of priority.

Thus, future land use management will also have to consider ‘air use’ management. The health impacts and economic damages of the 1997/98 demonstrated that controlling future haze events represents an influencing factor for public and economic prosperity in the Southeast Asian region.

The response of the GTZ to the smoke haze crisis

To improve the preparedness to such kind of crisis, GTZ Indonesia has appointed a Haze Emergency Coordinator (HEC) in 1997 to collect and analyse data on haze development, improve information flow and to give guidance for co-ordinated recommendations to people at risk from haze exposure. During the 1997/98 smoke haze episode, daily status reports for haze-affected project locations were prepared. Leaflets on suitable respiratory masks, air conditioning and other protective measures were distributed. Since only insufficient air quality measurement data were available, the air pollution level was estimated using visibility, satellite imagery and wind maps. Twice in 1997/98, GTZ staff and their families in smoke haze affected regions were advised to leave their project location to haze-free areas.

A key question that came up during these activities was what standards are to be applied for fire-related air pollution episodes. Are air quality standards, which are generally set for urban air pollution, suitable for haze episodes? At what pollution level should people leave to haze-free areas? But also, how should urban air pollution in Southeast Asia, which frequently exceeds levels experienced during haze episodes, be dealt with? A standardised answer can only be given with further input from science and policy. Within the GTZ, the decision on protective measures will be based upon all information available on the pollution levels, the haze development forecasts, the long and risky transport possibilities, organisational and psychological considerations and the costs involved.

The haze related activities on behalf of the Haze Emergency Coordinator supported the overall haze related activities within ASEAN. A regional air quality data base has been established that is used by various agencies attempting to assess the health impacts of the 1997/98 smoke haze. Collecting and evaluating air quality information and disseminating them to the public is essential for broadening the overall awareness towards air pollution, and in particular the connection between smoke haze and vegetation fires.

For further information, please refer to

Contact address:

Angelika Heil
Institute for Landscape Planning
Technical University Berlin
Albrecht-Thaer-Weg 2
D-14195 Berlin



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