Preliminary measurements of aromatic VOCs in public transportation modes in Guangzhou, China

Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
Environment International (Impact Factor: 5.56). 08/2003; 29(4):429-35. DOI: 10.1016/S0160-4120(02)00189-7
Source: PubMed


This study examined the exposure level of aromatic volatile organic compounds (VOCs) in public transportation modes in Guangzhou, China. A total of 40 VOC samples were conducted in four popular public commuting modes (subway, taxis, non-air-conditioned buses and air-conditioned buses) while traversing in urban areas of Guangzhou. Traffic-related VOCs (benzene, toluene, ethylbenzene, m/p-xylene and o-xylene) were collected on adsorbent tubes and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD) technique. The results indicate that commuter exposure to VOCs is greatly influenced by the choice of public transport. For the benzene measured, the mean exposure level in taxis (33.6 microg/m(3)) was the highest and was followed by air-conditioned buses (13.5 microg/m(3)) and non-air-conditioned buses (11.3 microg/m(3)). The exposure level in the subway (7.6 microg/m(3)) is clearly lower than that in roadway transports. The inter-microenvironment variations of other target compounds were similar to that of benzene. The target VOCs were well correlated to each other in all the measured transports. The concentration profile of the measured transport was also investigated and was found to be similar to each other. Based on the experiment results, the average B/T/E/X found in this study was about (1.0/4.3/0.7/1.4). In this study, the VOC levels measured in evening peak hours were only slightly higher than those in afternoon non-peak hours. This is due to the insignificant change of traffic volume on the measured routes between these two set times. The out-dated vehicle emission controls and slow-moving traffic conditions may be the major reasons leading elevated in-vehicle exposure level in some public commuting journeys.

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    • "Consequently, air quality is worth in vehicles than in ambient air and it causes that drivers and commuters experience high level of pollutant concentration [26]. Due to the importance of some VOC such as benzene, toluene, ethyl benzene, and xylenes (BTEX), most of the previous studies had been carried out on these cases and they reported that drivers and passengers were exposed to a wide variety of compounds [27] [28] [29] [30] [31] [32] [33] [34]. Furthermore, interactions among substances and the effects of chemical mixture like additive, synergistic, potentiating, or antagonistic should not be underestimated [17] [34]. "
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    ABSTRACT: Air pollution is currently the most serious environmental health threat worldwide. Volatile Organic Compounds (VOCs) are considered as the main effective factors in causing air pollution. Vehicles are among the major sources which emit these compounds, so it seems that automobiles' microenvironment is one of the places where people are exposed to high concentration of VOC. Evaluating the exposure amount of Total Volatile Organic Compounds (TVOC) can indeed be used as an indicator to estimate the amount of exposure to every individual VOC. This study was conducted on the concentration of TVOC inside Tehran taxies for a period of one year. For this purpose, a real time instrument equipped with photo-ionization detector (PID) was used. Consequently, the highest and the lowest measured TVOC in taxies equaled 3.33 ppm and 0.72 ppm, respectively. In addition, the arithmetic mean of TVOC concentration was 1.77±0.53 ppm inside the examined taxies. In this study, the parameters like measurement time, climate and vehicle conditions were found to have significant effect on the amount of exposure to TVOC.
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    • "The particle levels appeared to be strongly influenced by both the mode of transport and its ventilation system, while the railway transport was linked to significant lower PM burden being compared with the one produced by buses, trams, taxis, and ferries. The results coincide well with those reported by Chan et al. 2003a for volatile organic compounds (VOCs) who indicated that the passengers' exposure in China was clearly lower in the subway than in the roadway transports. On the contrary, Lau and Chan (2003) found higher VOC values in subway monitoring sites, and as they concluded, the origin of toluene , ethylbenzene, and xylenes (TEX) was the underground tunnel or the stations and not the train interior. "
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    ABSTRACT: The influence of the smokestack emissions of a ground-level train in the air quality of the passenger carriages through the ventilation system was investigated in this work. To this end, a monitoring campaign was designed and implemented at 20 different in-train sites, e.g., conductor’s cabin, carriages with passenger seats, boarding carriages, spaces for disabled people, etc., during its journey between urban and rural areas. Measurements of inorganic (NOx, SO2, CO) and organic (benzene, polyaromatic hydrocarbons, total volatile organic compounds) compounds as well as airborne particulate matter (PM) in different size ranges (ΡΜ10, ΡΜ2.5, ΡΜ1) were carried out in the interior of the carriages of a diesel engine-powered train (type KAT 2000) during fixed round trips. An exhaust dispersion cone hook was used for intervention purposes leading to the reassessment of the in-train air quality at the most contaminated sites. In order to produce reliable and comparable data, targeted measurements were conducted in a railbus which was used as reference. Based on the analysis, the air pollutants and particle levels exhibit significant variations at the same sampling point during the train journey, possibly due to the route characteristics (tunnels, uphills, turns, speed). Significant spatial fluctuations in the same train depending on the position and the proximity to the smokestack plume and the ventilation system inlet were observed as well. It is worthy to note that decreased pollutant values were observed during the intervention.
    Air Quality Atmosphere & Health 05/2015; DOI:10.1007/s11869-015-0348-1 · 1.80 Impact Factor
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    • "The car fleet in Flanders of around more than three millions in 2010 has increased with around 36 000 cars per year during the last decade. Diesel-powered cars represents a major 3 in ferry were observed (Lau and Chan, 2003). For the TEX compounds (toluene, ethylbenzene and xylene isomers) higher concentrations were found in air conditioned buses and trains and could be explained from the solvent related emissions from the interior construction materials. "
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    ABSTRACT: The increasing trend of promoting public transportation (bus tram, metro, train) and more environmental friendly and sustainable non fossil-fuel alternatives (walking, cycling etc) as substitutes for auto vehicles brings forward new questions with regard to pollutant levels to which commuters are exposed. In this study, three transportation modes (tram, auto vehicle and bicycle) are studied and concentration levels of 84 volatile organic compounds (VOCs) (hydrocarbons, aromatic hydrocarbons, oxygen containing hydrocarbons, terpenes and halogenated compounds) are measured along a route in the city of Ghent, Belgium. The concentration levels are obtained by active sampling on Tenax TA sorbent tubes followed by thermal desorption gas chromatography mass spectrometry (TD-GC-MS) using deuterated toluene as an internal standard. The median total VOC concentrations for the tram mode (33 μg/m³) is 1.7 times higher than that of the bicycle mode (20 μg/m³) and 1.5 times higher than for the car mode (22 μg/m³). It is found that aromatic hydrocarbons account for a significant proportion in the total VOCs concentration (TVOCs) being as high as 41–57%, 59–72% and 58–72% for the tram, car and bicycle respectively. In all transportation modes, there was a high (r > 0.6) degree of correlation between BTEX compounds, isopropylbenzene, n-propylbenzene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene. When comparing time weighed average concentrations along a fixed route in Ghent, it is found that commuters using the tram mode experience the highest TVOCs concentration levels. However, next to the concentration level to which commuters are exposed, the physical activity level involving the mode of transportation is important to assess the exposure to toxic VOCs. It is proven that the commuter using a bicycle (4.3 ± 1.5 μg) inhales seven and nine times more benzene compared to the commuter using the car and tram respectively, when the same route is followed.
    Atmospheric Environment 09/2014; 94:53–62. DOI:10.1016/j.atmosenv.2014.05.019 · 3.28 Impact Factor
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