According to the report on air quality as monitored by Malaysian Meteorological Service (MMS) in 1995, suspended particulates in the atmosphere are mainly generated through man’s activities which include combustion of organic fuels, open burning of waste products from agriculture and forest clearing and evaporation of volatile liquids from industries.

The Klang Valley has been experiencing relatively high Total Suspended Particulate (TSP) concentration since 1989 except in 1993. Total annual TSP concentration has often exceeded the Malaysian recommended level of 90μgm-3, and sometimes reached five times the World Health Organization (W.H.O) standard of 50μgm-3.

According to the report of World Bank in 1992, even though the average mean concentration of fine suspended particulate matter in Kuala Lumpur is low in comparison to other cities in the Association of South East Asian Nations (ASEAN), it is two to three times higher than the levels of Tokyo and New York.

An early study carried out by the Malaysian Division of Environment (DOE) in 1977 revealed that the recommended TSP standard (24-hour average) of 100μgm-3 for industrial zone and 50μgm-3 for non-industrial zone has been exceeded 93% of the time in the industrial zone and 95% of the time in the residential zone.

A further study by Professor Sham Sani in 1991, concluded that the annual concentration of TSP remained high, especially in the industrial and traffic areas. The recorded annual mean concentration of TSP at Pudu, Kuala Lumpur was 186μgm-3, which was twice the Malaysian Guideline value. Undoubtedly, TSP appears to be one of the pollutants, which caused a major problem in the Klang Valley.

Furthermore, he stated that the situation is much more serious in this region not just because it is the most developed industrial area in Malaysia but also because of its topography which traps the pollutants. Rising levels of TSP caused deterioration in urban air quality in this region.

In a study on thick haze in Malaysia, Tussin observed that levels of particulates increased in 1990 with peak 24-hour values of PM10 (particulate matter with aerodynamic diameter in the range 2.5 – 10 microns) equivalent to 426μgm-3 (TSP=473.8μgm-3) in Petaling Jaya. Rindam in his study on haze phenomena in Malaysia also reported a peak of 464μgm-3 (TSP=516 μgm-3) in the Klang Valley. Tussin emphasized that these quantities were up to four times the mean levels measured during non-haze periods.

The high level of particulates was also observed in the haze episode of 1994, where Rindam reported 24-hour PM10 reading as 410μgm-3 (TSP=454.5μgm-3) on 30 September, while in Kuala Lumpur, PM10 reached 409μgm-3 on 5 October. According to Ambu, the increase in suspended particulate matter (SPM-dust, mist, fumes and smoke) has been attributed to forest fires and motor vehicle emissions.

This is the main cause of the high concentrations of particulates observed in urban centers. During the haze episode of 1997, the mean level of PM10 in the Klang Valley was 247 +/-88.7μgm-3 with a range of 83.08-421.38μgm-3. Concentrations of other particulate constituents such as sulphur, potassium, titanium, vanadium, manganese, nickel, arsenic and lead were 3-6 times higher than average during the haze period in late October, 1994.

TSP in Kuala Lumpur, as reported by meteorologists of MMS in 1991, has a high concentration of lead, calcium, nickel, iron, sodium, potassium and bromine compounds plus other elements such as barium, etc. A report of DOE in 1996 revealed that gaseous emissions in the Klang Valley are generally low. The annual concentration of SO2 has been found to be generally low although there appeared to be a tendency for a slight increase for Kuala Lumpur during the 1994-96 periods.