Abstract
ABSTRACT Benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene (collectively referred to as BTEX), which are prevalent in the ambient air of urban environments, potentially cause chronic health effects, particularly among outdoor workers. Aim of this study was to evaluate BTEX concentrations in the Klang Valley of Malaysia and assess the health risks to urban traffic police officers, whose duties include controlling the traffic flow and enforcing traffic laws. Air samples were collected with low-flow personal samplers during the officers’ work shifts outdoors, and the BTEX content was then analyzed via gas chromatography-mass spectrometry (GC-MS) coupled with thermal desorption (TD). A probabilistic method based on Monte Carlo simulation was applied to determine the cancer risk (CR) and hazard quotient (HQ), and a sensitivity analysis was performed to identify the greatest contributors to the estimated risks. The total BTEX concentration in the samples averaged 211.83 µg m–3, with the largest component being toluene (averaging 89.08 µg m–3 in concentration), followed by m,p-xylene (37.25 µg m–3), o-xylene (35.80 µg m–3), benzene (25.82 µg m–3), and ethylbenzene (23.89 µg m–3). The average CR value for benzene (5.31 × 10–6) as well as the 95th percentiles of the CR values for benzene and ethylbenzene (1.70 × 10–5 and 2.12 × 10–6, respectively) exceeded the acceptable level of exposure (1.0 × 10–6). The HQ values for all of the BTEX species were less than one. The sensitivity analysis revealed that the most influential parameter in increasing the estimated CR and HQ was the exposure duration, followed by the BTEX concentration. The estimated CR indicates that the prolonged exposure to benzene and ethylbenzene experienced by traffic police officers exacerbates the risk of adverse health effects. These results, which provide baseline data for determining the occupational risk to individuals who are exposed to BTEX while working on or near a road, emphasize the need for additional regulations, including the use of appropriate respiratory protective equipment.
Highlights
Volatile organic compounds (VOCs) are a prevalent group of air pollutants in urban and roadside areas
Study Location The Klang Valley is an urban agglomeration which geographically covers an area of 2832 km2 and comprises Kuala Lumpur in the center and the regional context of Selangor, namely the towns of Gombak, Klang, Petaling Jaya, Shah Alam, Kuala Selangor, Kajang, and the district of Hulu Langat (Fig. 1)
The traffic policemen were forbidden to smoke while performing their duties on the roads. These results indicated that both smoking and non-smoking traffic policemen were exposed to similar levels of BTEX during their outdoor duties
Summary
Volatile organic compounds (VOCs) are a prevalent group of air pollutants in urban and roadside areas. Toluene, ethylbenzene, and xylene, collectively known as BTEX, are mono-aromatic compounds in the VOC group. BTEX is continuously emitted from different natural and anthropogenic sources such as biogenic processes, paint application, evaporation from gasoline, industrial activities, solvent evaporation, biomass burning, and fuel combustion. Aerosol and Air Quality Research, 20: 1922–1937, 2020. Yao et al (2015) reported benzene, toluene and o-xylene (BTX) were emitted from diesel-fuelled vehicles
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