Carbonaceous
aerosols play a key role in climate modification and
exert a deleterious effect on human health. Thus, this study aimed
to determine the thermally derived carbonaceous fraction in particulate
matter (PM)2.5 from the Southern Malay Peninsula, a tropical
area in Malaysia, during January 2019 to March 2019. PM2.5 was captured on quartz filters using a high-volume sampler on a
24 h basis. Eight of the carbon fractions were measured using the
thermal optical reflectance method. Carbonaceous aerosol was thoroughly
characterized by estimating elemental carbon (EC), organic carbon
(OC), total carbon, secondary OC, soot-EC, and char-EC to determine
the mechanism of emission from fossil fuel combustion, biomass, and
secondary origins. The effect of local meteorological factors and
air mass transport on the change in the light-absorbing aerosol fraction
was also examined. Secondary organic sources and primary sources emitted
46 and 54% of OC, respectively. The estimated char-EC in this study
was 10-fold higher than soot-EC, indicating that biomass burning and
coal combustion were the predominant routes of EC emission, whereas
petrol or diesel engines were the less predominant generators of soot-EC.
Trajectory modeling showed that biomass fires in the Indochina region
were the potential origin of carbonaceous aerosols transported from
the northeasterly direction.