BTEX pollution caused by motorcycles in the megacity of HoChiMinh
Monitoring of benzene, toluene and xylenes (BTEX) was conducted along
with traffic counts at 17 roadside sites in urban areas of
HoChiMinh. Toluene was the most abundant substance, followed
byp,m-xylenes, benzene,o-xylene and ethylbenzene. The maximum
observed hour-average benzene concentration was 254μg/m3
. Motorcycles contributed to 91% of the traffic fleet. High correlations
among BTEX species, between BTEX concentrations and the volume of
on-road motorcycles, and between inter-species ratios in
air and in gasoline indicate the motorcycle-exhaust origin of BTEX
species. Daily concentrations of benzene, toluene, ethylbenzene,
p,m-xylenes ando-xylene were 56, 121, 21, 64 and 23μg/m3
, respectively. p,m-xylenes possess the highest ozone formation
potential
among the BTEX family
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