Anthropogenic and biogenic volatile organic compounds and ozone formation potential in ambient air of Kuala Lumpur, Malaysia

Abstract

The measurement of anthropogenic and biogenic volatile organic compounds (VOCs) in urban air is important because of their toxic effects and because they can produce secondary air pollutants (e.g. ozone, particulate matter). Benzene, toluene, ethylbenzene and xylenes (BTEX), representing anthropogenic VOCs (AVOCs), and isoprene, a biogenic VOC (BVOC), were monitored at an urban site in Kuala Lumpur (KL). Active sampling was conducted using sorbent tubes packed with Tenax® TA/1 TD for 5 days (daytime). Analysis of VOCs was performed using Thermal Desorption-Gas Chromatography Mass Spectrometry (TD-GCMS). Average daytime concentrations of VOCs were 9.42 ± 6.15 μg/m3 for benzene, 35.04 ± 12.60 μg/m3 for toluene, 11.20 ± 4.17 μg/m3 for ethylbenzene, 19.19 ± 10.76 μg/m3 for m,p-xylene, 18.40 ± 8.56 μg/m3 for o-xylene, and 6.70 ± 1.57 μg/m3 for isoprene. Weekday BTEX levels were found to be higher, especially during the morning rush hour, demonstrating the impact of traffic emissions in KL. BVOCs (isoprene) in urban KL was also higher than the reported isoprene level in Malaysian forest areas but lower than palm plantation areas. Both AVOCs and BVOCs significantly contributed to (218.6 - 733.8 μg/m3) ozone formation in the KL atmosphere.