Concentration and source apportionment of volatile organic compounds (VOCs) in the ambient air of Kuala Lumpur, Malaysia

Abstract

The accumulation of volatile organic compounds (VOCs) in ambient air affects air quality through the generation of surface level ozone and secondary organic aerosol. A study of the distribution and source apportionment of VOCs was conducted at two stations to investigate the air quality status of Kuala Lumpur. Samples of ambient air were collected into Tedlar sampling bags using an air sampling pump and then pre-concentrated with solid-phase micro-extraction fibre. Gas chromatography–mass spectrometry (GC–MS) was employed to measure the VOC species. An absolute principal component score–multiple linear regression (APCS–MLR) model was then applied to identify the possible source contributions of VOCs. Seventeen VOCs were detected, and methylene chloride (243 ± 241 ppbv) was the most abundant species at both stations. Within the benzene, toluene, ethyl benzene and xylene group of VOCs, toluene was dominant with an average of 135 ± 202 ppbv, followed by p-xylene (41.3 ± 24.7 ppbv), ethyl benzene (34.0 ± 32.6 ppbv) and benzene (18.2 ± 12.9 ppbv). A strong correlation between benzene and toluene (p < 0.01, r = 0.65) indicated the influence of motor vehicle emissions during the sampling period. The APCS–MLR results indicated that the source contributors for VOCs at the sampling stations were gasoline evaporation (31 %), motor vehicle exhaust/solvent (22 %), motor vehicle emissions (21 %), petrol pump/solvent usage (15 %) and industrial emissions (10 %).