Chemical characterisation of the haze in Brunei Darussalam during the 1998 episode

Coinciding with the El-Nino Southern Oscillation (ENSO) of 1997–1998, SE Asia experienced a severe air pollution episode locally referred to as haze. The monitoring and response efforts in the region mainly centred around criteria pollutants, though it was obvious that the pollution episode is fundamentally different from classical urban air pollution. This paper reports the results of the first-ever study of the detailed chemical composition of the haze in SE Asia. Although numerous studies of forest fire plumes have been conducted in other parts of the world, ours is the first study to be carried out with the specific aim of identifying and quantifying chemical components which are likely to have long-term human health implications. Volatile organic compounds (VOCs) including BTEX (benzene, toluene, ethylbenzene, and xylene), aldehydes, cresol, phenol, acetic acid, polynuclear aromatic hydrocarbons (PAHs), suspended particles <10 μm in diameter (PM10), alkali metals, alkaline earth metals, heavy metals, S, Cl, C, H, N, NO2 and O3 were determined in Brunei Darussalam in April 1998 during a particularly severe haze episode caused mainly by local fires. Some of the substances identified in the haze are known or suspected carcinogens, mutagens, and teratogens (e.g. benzene, toluene, xylene, PAHs), and they have the potential to cause serious long-term effects.