Haze in the Klang Valley of Malaysia

[摘要] Continuous measurements of dry aerosol light scattering (Bsp) were made at two sites in theKlang Valley of Malaysia between December 1998 and December 2000.In addition 24-hourPM2.5 samples were collected on a one-day-in-six cycle and the chemical composition of theaerosol was determined.Periods of excessive haze were defined as 24-hour average Bspvalues greater than 150 Mm^-1 and these occurred on a number of occasions, between May andSeptember 1999, during May 2000, and between July and September 2000. The evidence forsmoke from biomass burning being a significant contributor to aerosol during periods ofexcessive haze is discussed.For example, during periods of excessive haze, the chemicalcomposition of the aerosol showed enhanced concentrations of elemental carbon, organiccarbon and non-seasalt potassium.The diurnal cycle of Bsp and PM10 was disturbed from itsusual pattern of maxima overnight and minuma during the day with morning and afternoontraffic peaks, and instead showed a maximum peak during the middle of the day.Periods ofexcessive haze were coincident with the presence of forest fires on Sumatra during thesouthwest (SW) monsoon period, the influence of which are demonstrated by transportmodelling for one week of the SW monsoon of 2000. The study highlights that whilsttransboundary smoke is a major contributor to poor visibility in the Klang Valley, smokefrom fires on Peninsular Malaysia is also a contributor.In addition the uniform concentrationof non-seasalt sulfate in PM2.5 at both sites over the entire sampling period suggests thepresence of a domestic source of secondary aerosol production in the Klang Valley.

[学科分类] 大气科学