Urinary biomarkers and low-level environmental benzene concentration: assessing occupational and general exposure

The categories of urban workers undergoing prolonged exposure to gasoline due to vehicle emissions, evaporation and traffic fumes are considered occupationally exposed to benzene, even if at low concentrations. The aim of this study was to evaluate the specificity of unmetabolized benzene excreted in urine (UBz) and S-phenylmercapturic acid (SPMA) as biomarkers of exposure to very low levels of benzene, and to study the impact of putative individual confounders like smoking and alcohol habits, co-exposure to other toxicants and body mass index on the exposure assessment. Environmental and biological monitoring of exposure to benzene were performed in 114 Urban Policemen. The mean value of UBz in non-smokers was significantly lower than in either groups of light to moderate smokers and heavy smokers (0.24, 1.82 and 2.82 microg L(-1), respectively). On the contrary, SPMA values did not discriminate exposure resulting from smoking habits. Moreover, the concentration of UBz in non-smokers appears to be correlated with environmental benzene concentration (BenzA) (R(2)=0.13, beta=0.37, p=0.002). On the other hand, no significant correlation was found between SPMA concentration (corrected for creatinine excretion and log transformed, LogSPMA) and LogBenzA (R(2)=0.003, beta=0.05, p=0.6). Our findings reinforce previous research on the use of unmetabolized urinary benzene as a specific and sensitive biomarker of low-level exposure to benzene and confirm that smoking habits strongly influence the excretion of UBz.     

Urban atmospheric pollution: personal exposure versus fixed monitoring station measurements

We initiated the PETER (pedestrian environmental traffic pollutant exposure research) project to investigate pedestrians' exposure to traffic related atmospheric pollutants, based on data obtained with the collaboration of selected categories of pedestrian urban workers. We investigated relations between roadside personal exposure levels of volatile aromatic hydrocarbons (including benzene) and particulate matter <10 microm (PM10) among traffic police (n = 126) and parking wardens (n = 50) working in downtown Bologna, Italy. Data were collected from workshifts throughout four 1-week periods in different seasons of 2000-2001. For benzene and PM10, comparisons were made with measurements by fixed monitoring stations, and influence of localized traffic intensity and meteorological parameters was examined. Roadside personal exposure to benzene correlated more strongly with other volatile aromatic hydrocarbons (toluene, xylenes and ethylbenzene) than with PM10. Benzene and PM10 personal exposure levels were higher than fixed monitoring station values (both p<0.0001). At multivariate analysis, benzene and PM10 data from fixed monitoring stations both correlated with meteorological variables, and were also influenced by localized traffic intensity. Plausibly because of the downtown canyon-like streets, weather conditions (during a period of drought) only marginally affected benzene personal exposure, and moderately affected PM10 personal exposure. These findings reinforce the concept that urban atmospheric pollution data from fixed air monitoring stations cannot automatically be taken as indications of roadside exposures.     

Biochemical study of retired pentachlorophenol workers with and without following dietary exposure to PCDD/Fs

Objectives

This is the first research study to compare among female, non-smoker workers: (a) the exposure to benzene, toluene and xylenes (BTXs) in urban air during work in the street (traffic policewomen, TP) vs. work in vehicles (police drivers, PD); (b) the exposure to BTXs in urban environments (in street and in car) vs. rural environments (roadwomen, RW); (c) the values of blood benzene, urinary trans, trans muconic acid (t,t-MA) and urinary S-phenylmercapturic acid (S-PMA) in urban areas (in street and in car) vs. rural areas.

Methods

Passive personal samplings and data acquired using fixed monitoring stations located in different areas of the city were used to measure environmental and occupational exposure to BTXs during the work shift in 48 TP, 21 PD and 22 RW. In the same study subjects, blood benzene, t,t-MA and S-PMA were measured at the end of each work shift.

Results

Personal exposure of urban workers to benzene seemed to be higher than the exposure measured by the fixed monitoring stations. Personal exposure to benzene and toluene was (a) similar among TP and PD and (b) higher among urban workers compared to rural workers. Personal exposure to xylenes was (a) higher in TP than in PD and (b) higher among urban workers compared to rural workers. Blood benzene, t,t-MA and S-PMA levels were similar among TP and PD, although the blood benzene level was significantly higher in urban workers compared to rural workers. In urban workers, airborne benzene and blood benzene levels were significantly correlated.

Conclusions

Benzene is a human carcinogen, and BTXs are potential reproductive toxins at low dose exposures. Biological and environmental monitoring to assess exposure to BTXs represents a preliminary and necessary tool for the implementation of preventive measures for female subjects working in outdoor environments.     

Evaluation of exposure level of N-methyl-beta-carboline-3-carboxamide (FG 7142), an anxiogenic agent in humans

beta-Carboline-3-carboxylic acid methylamide (FG 7142), an anxiogenic agent, has been detected in human urine. The urinary excretion level of FG 7142 in non-smokers was found to be 0.503 +/- 0.25 ng per day (mean +/- S.D., n=10), while that in smokers was found to be 2.418 +/- 0.384 ng per day (n=10). This suggests that humans are exposed to FG 7142 and that smokers are exposed to higher levels of FG 7142 than non-smokers. Considering the previous findings that FG 7142 is present in cigarette smoke, indoor and outdoor air and smoke condensate of tree leaves, humans may be exposed to FG 7142 via the airways and lungs, although we cannot exclude the possibility of exposure via foodstuffs. Results of animal experiments suggest that FG 7142 which enters the bloodstream is excreted into the urine via the kidneys within 24 h in an unchanged form. Therefore, monitoring the level of FG 7142 in urine may be useful for monitoring the exposure level of FG 7142.     

Benzene exposure and the effect of traffic pollution in Copenhagen,Denmark

Benzene is a carcinogenic compound, which is emitted from petrol-fuelled cars and thus is found ubiquitous in all cities. As part of the project Monitoring of Atmospheric Concentrations of Benzene in European Towns and Homes (MACBETH) six campaigns were carried out in the Municipality of Copenhagen, Denmark. The campaigns were distributed over 1 year. In each campaign, the personal exposure to benzene of 50 volunteers (non-smokers living in non-smoking families) living and working in Copenhagen was measured. Simultaneously, benzene was measured in their homes and in an urban network distributed over the municipality. The Radiello diffusive sampler was applied to sample 5 days averages of benzene and other hydrocarbons. Comparison of the results with those from a BTX-monitor showed excellent agreement. The exposure and the concentrations in homes and in the urban area were found to be close to log-normal distribution. The annual averages of the geometrical mean values were 5.22, 4.30 and 2.90 μg m⁻³ for personal exposure, home concentrations and urban concentrations, respectively. Two main parameters are controlling the general level of benzene in Copenhagen: firstly, the emission from traffic and secondly, dispersion due to wind speed. The general level of exposure to benzene and home concentrations of benzene were strongly correlated with the outdoor level of benzene, which indicated that traffic is an important source for indoor concentrations of benzene and for the exposure to benzene.     

Roadside and in-vehicle concentrations of monoaromatic hydrocarbons

Airborne concentrations of benzene, toluene and the xylenes have been measured inside passenger cars whilst driven along major roads in the city of Birmingham, UK, as well as immediately outside the car, and at the roadside. A comparison of concentrations measured in the car with those determined from immediately outside showed little difference, with a mean ratio for benzene of 1.17±0.34 and for toluene 1.11±0.16 (n=53). The ratio of in-car to roadside concentration was rather higher at 1.55±0.68 for benzene and 1.54±0.72 for toluene (n=53). The roadside concentrations were typically several-fold higher than those measured at a background suburban monitoring station within Birmingham, although much variation was seen between congested and uncongested roads, with concentrations adjacent to uncongested roads similar to those measured at the background monitoring station. Measurements of benzene and toluene in a car driven on a rural road outside the city showed very comparable in-car and out-of-car concentrations strengthening the conclusion that pollution inside the car is derived from pollutants outside entering with ventilation air. The exceptions were an older car where in-car concentrations appreciably exceeded those outside (in-to out-vehicle ratio=2.3 for benzene and 2.2 for toluene where n=5) indicating probable self-contamination, and a very new car which built up increased VOC concentrations when stationary without ventilation (in-to out-vehicle ratio=2.4 for benzene and 3.3 for toluene where n=5). A further set of measurements inside London taxi cabs showed concentrations to be influenced by the area within which the taxi was driven, the traffic density and the presence of passengers smoking cigarettes.     

Personal exposure of children and adults to airborne benzene in four French cities

Atmospheric concentrations of and personal exposure to benzene have been measured in four French metropolitan areas for 210 subjects over two seasons. Half of the volunteers were 6–13-year-old children. The adult subjects were non-smokers, not occupationally exposed and they live and work in the monitored areas. Measurements were performed using diffusive samplers followed by GC-FID analysis. The average values for ambient air concentrations (μg m⁻³) were: Rouen: 1.5; Île de France (Paris area): 1.6; Grenoble: 2.3 and Strasbourg: 2.6, showing that benzene concentrations in the ambient air of the four cities satisfy the requirements of the European Directive 2000/69EC of the European Parliament which stipulates a limit value of 5 μg m⁻³. However, the 48 h exposures measured were found to be between 2.7 and 3.5 times higher than ambient air concentrations. As a consequence, 60% of the subjects investigated, including children, were exposed to concentrations higher than the ambient air limit value. This work confirms that air monitoring data collected by fixed stations should be used with caution when assessing population exposure to benzene, especially given the influence of indoor sources and other polluted microenvironments where people spend part of their time.     

Benzene exposure in Helsinki,Finland

Personal exposures and microenvironmental concentrations of benzene were measured in the residential indoor, residential outdoor and workplace environments for 201 participants in Helsinki, Finland, as a component of the EXPOLIS-Helsinki study. Median benzene personal exposures were 2.47 (arithmetic standard deviation (ASD)=1.62) μg m⁻³ for non-smokers, 2.89 (ASD=3.26) μg m⁻³ for those exposed to environmental tobacco smoke in any microenvironment and 3.08 (ASD=10.04) μg m⁻³ for active smokers. Median residential indoor benzene concentrations were 3.14 (ASD=1.51) μg m⁻³ and 1.87 (ASD=1.93) μg m⁻³ for environments with and without tobacco smoke, respectively. Median residential outdoor benzene concentrations were 1.51 (ASD=1.11) μg m⁻³ and median workplace benzene concentrations were 3.58 (ASD=1.96) μg m⁻³ and 2.13 (ASD=1.49) μg m⁻³ for environments with and without tobacco smoke, respectively. Multiple step-wise regression identified indoor benzene concentrations as the strongest predictor for personal benzene exposures of those not exposed to tobacco smoke, followed sequentially by time spent in a car, time in the indoor environment, indoor workplace concentrations and time in the home workshop. Relationships between indoor and outdoor microenvironment concentrations and personal exposures showed considerable variation between seasons, due to differences in ventilation patterns of homes in these northern latitudes. Automobile use-related activities were significantly associated with elevated benzene levels in personal and indoor measurements when tobacco smoke was not present, which demonstrates the importance of personal measurements in the assessment of exposure to benzene.     

Assessing benzene-induced toxicity on wild type Euglena gracilis Z and its mutant strain SMZ

Benzene is a representative member of volatile organic compounds and has been widely used as an industrial solvent. Groundwater contamination of benzene may pose risks to human health and ecosystems. Detection of benzene in the groundwater using chemical analysis is expensive and time consuming. In addition, biological responses to environmental exposures are uninformative using such analysis. Therefore, the aim of this study was to employ a microorganism, Euglena gracilis (E. gracilis) as a putative model to monitor the contamination of benzene in groundwater. To this end, we examined the wild type of E. gracilis Z and its mutant form, SMZ in their growth rate, morphology, chlorophyll content, formation of reactive oxygen species (ROS) and DNA damage in response to benzene exposure. The results showed that benzene inhibited cell growth in a dose response manner up to 48 h of exposure. SMZ showed a greater sensitivity compared to Z in response to benzene exposure. The difference was more evident at lower concentrations of benzene (0.005–5 μM) where growth inhibition occurred in SMZ but not in Z cells. We found that benzene induced morphological changes, formation of lipofuscin, and decreased chlorophyll content in Z strain in a dose response manner. No significant differences were found between the two strains in ROS formation and DNA damage by benzene at concentrations affecting cell growth. Based on these results, we conclude that E. gracilis cells were sensitive to benzene-induced toxicities for certain endpoints such as cell growth rate, morphological change, depletion of chlorophyll. Therefore, it is a potentially suitable model for monitoring the contamination of benzene and its effects in the groundwater.     

Degradation characteristics of toluene,benzene, ethylbenzene,and xylene by Stenotrophomonas maltophilia T3-c

Stenotrophomonas maltophilia T3-c, isolated from a biofilter for the removal of benzene, toluene, ethylbenzene, and xylene (BTEX), could grow in a mineral salt medium containing toluene, benzene, or ethylbenzene as the sole source of carbon. The effect of environmental factors such as initial toluene mass, medium pH, and temperature on the degradation rate of toluene was investigated. The cosubstrate interactions in the BTEX mixture by the isolate were also studied. Within the range of initial toluene mass (from 23 to 70 pmol), an increased substrate concentration increased the specific degradation of toluene by S. maltophilia T3-c. The toluene degradation activity of S. maltophilia T3-c could be maintained at a broad pH range from 5 to 8. The rates at 20 and 40 degrees C were 43 and 83%, respectively, of the rate at 30 degrees C. The specific degradation rates of toluene, benzene, and ethylbenzene by strain T3-c were 2.38, 4.25, and 2.06 micromol/g-DCW/hr. While xylene could not be utilized as a growth substrate by S. maltophilia T3-c, the presence of toluene resulted in the cometabolic degradation of xylene. The specific degradation rate of toluene was increased by the presence of benzene, ethylbenzene, or xylene in binary mixtures. The presence of toluene or xylene in binary mixtures with benzene increased the specific degradation rate of benzene. The presence of ethylbenzene in binary mixtures with benzene inhibited benzene degradation. The presence of more than three kinds of substrates inhibited the specific degradation rate of benzene. All BTEX mixtures, except tri-mixtures of benzene, ethylbenzene, and xylene or mixtures of all four substrates, had little effect on the degradation of ethylbenzene by S. maltophilia T3-c. The utilization preference of the substrates by S. maltophilia T3-c was as follows: ethylbenzene was degraded fastest, followed by toluene and benzene. However, the specific degradation rates of substrates, in order, were benzene, toluene, and ethylbenzene.     

Exposure to benzene,toluene, xylenes and total hydrocarbons among snowmobile drivers in Sweden

The exposure to benzene, toluene, xylenes and total hydrocarbons among 25 individuals exposed to exhaust from a snowmobile equipped with a two-stroke engine has been evaluated. Sampling was performed by pumped and diffusive sampling in parallel. There was a relatively bad agreement between the two air-sampling methods. The bad agreement can in part be explained by back diffusion of the substances from the samplers, a high face velocity, and deposition of droplets of unburned gasoline onto or in the vicinity of the samplers.

The levels of benzene ranged from not detectable (0.01 mg m⁻³) to 2.5 mg m⁻³. For toluene, xylenes and total hydrocarbons the exposure was 0.10–12.0, 0.05–13.0 and 0.90–273 mg m⁻³ respectively. The result from two measurements on individuals travelling on an open sleigh at the rear of the vehicle indicated higher levels of benzene, 0.7–0.8 mg m⁻³. Children are often riding as a passenger on a sledge and may thus have a higher exposure than their parents. This study indicates that spare time driving a snowmobile may cause a considerable exposure to benzene. Using a four-stroke engine equipped with a catalyst could reduce the exposure. To reduce the exposure for the passenger on a sleigh an extension of the exhaust pipe may be effective.     

Analysis of anaerobic BTX biodegradation in a subarctic aquifer using isotopes and benzylsuccinates

In situ biodegradation of benzene, toluene, and xylenes in a petroleum hydrocarbon contaminated aquifer near Fairbanks, Alaska was assessed using carbon and hydrogen compound specific isotope analysis (CSIA) of benzene and toluene and analysis of signature metabolites for toluene (benzylsuccinate) and xylenes (methylbenzylsuccinates). Carbon and hydrogen isotope ratios of benzene were between -25.9 per thousand and -26.8 per thousand for delta13C and -119 per thousand and -136 per thousand for delta2H, suggesting that biodegradation of benzene is unlikely at this site. However, biodegradation of both xylenes and toluene were documented in this subarctic aquifer. Biodegradation of xylenes was indicated by the presence of methylbenzylsuccinates with concentrations of 17-50 microg/L in three wells. Anaerobic toluene biodegradation was also indicated by benzylsuccinate concentrations of 10-49 microg/L in the three wells with the highest toluene concentrations (1500-5000 microg/L toluene). Since benzylsuccinate typically accounts for a very small fraction of the toluene present in groundwater (generally <1 mol%), the signature metabolite approach works best at higher toluene concentrations when it is not constrained by detection limits. In wells with lower toluene concentrations (410-640 microg/L), carbon and hydrogen isotopic values were enriched by up to approximately 2 per thousand for delta13C and approximately 70 per thousand for delta2H. This evidence of isotopic fractionation verifies the effects of biodegradation in these low concentration wells where metabolites may already be below detection limits. The combined use of signature metabolite and CSIA data is particularly valuable given the challenge of verifying biodegradation in subarctic environments where degradation rates are typically much slower than in temperate environments.     

Penetration of Evaporative Emissions into a Home from an M85-Fueled Vehicle Parked in an Attached Garage

ABSTRACT

The use of both oxygenated fuels in carbon monoxide (CO) nonattainment areas and reformulated gasoline in ozone nonattainment areas has been mandated by the 1990 Clean Air Act Amendments. Methanol has been proposed as an alternative fuel for CO nonattainment areas. Its use will potentially increase indoor methanol inhalation exposure resulting from the evaporation of metha-nol vapor from methanol-fueled vehicles parked in residential garages. Indoor air concentrations of metha-nol, benzene, and toluene were measured in a residential home with an attached garage. The effects of vehicle emission control devices (charcoal canister hose connection); home heating, ventilation, and air conditioning (HVAC) fans; ambient air, garage, and fuel tank temperatures; and wind speed were examined.

The disconnection of the charcoal canister hose, which simulates a spent evaporative emission control device, resulted in elevated benzene, toluene, and metha-nol concentrations in the garage and attached home. Higher fuel tank temperatures resulted in higher benzene and toluene concentrations in the garage, but not methanol. The concentrations for all compounds in the garage and concentrations of benzene and toluene in the adjacent room were lower when the HVAC fan was on than when it was off, while the concentrations of all three compounds in the rest of the house were higher, although these differences were not statistically significant. Thus, the portion of the population that parks cars in garages attached to homes will experience increased methanol exposures if methanol is used as an automotive fuel.     

Fast and quantitative measurement of benzene,toluene and C2-benzenes in automotive exhaust during transient engine operation with and without catalytic exhaust gas treatment

Time-Resolved Chemical Ionization Mass Spectrometry (CIMS) has been used to investigate the emission profiles of benzene, toluene and the C₂-benzenes (xylenes and ethyl benzene) in automotive exhaust during transient engine operation. On-line emission measurements with a frequency of 1–5 Hz clearly identified the critical driving conditions that are mainly responsible for the overall aromatic hydrocarbon emissions. The passenger car, equipped with a catalytic converter showed significant BTXE-emissions only in the first part of the New European Driving Cycle (NEDC) due to sub-optimal catalyst temperature. On the same car without a catalytic converter, emissions of aromatic hydrocarbons were detected over the entire test run and the benzene–toluene mixing ratios of the exhaust gas were rather constant. With catalytic exhaust gas treatment the observed benzene–toluene mixing ratios varied to a greater extent reflecting predominantly different catalytic converter conditions. The average molar ratio of benzene over toluene rose from 0.33 to 0.53 upon exhaust gas treatment. With catalytic converter the emissions during extra urban (EUDC) driving repeatedly showed benzene–toluene mixing ratios >1 and an average molar benzene/toluene ratio of 0.74 was detected during the EUDC part of the driving cycle. Whereas the total hydrocarbon (T.HC) emissions were decreased by 83% upon exhaust gas treatment the overall reduction of the benzene emissions was only 70%.     

Penetration of evaporative emissions into a home from an M85-fueled vehicle parked in an attached garage

The use of both oxygenated fuels in carbon monoxide (CO) nonattainment areas and reformulated gasoline in ozone nonattainment areas has been mandated by the 1990 Clean Air Act Amendments. Methanol has been proposed as an alternative fuel for CO nonattainment areas. Its use will potentially increase indoor methanol inhalation exposure resulting from the evaporation of methanol vapor from methanol-fueled vehicles parked in residential garages. Indoor air concentrations of methanol, benzene, and toluene were measured in a residential home with an attached garage. The effects of vehicle emission control devices (charcoal canister hose connection); home heating, ventilation, and air conditioning (HVAC) fans; ambient air, garage, and fuel tank temperatures; and wind speed were examined. The disconnection of the charcoal canister hose, which simulates a spent evaporative emission control device, resulted in elevated benzene, toluene, and methanol concentrations in the garage and attached home. Higher fuel tank temperatures resulted in higher benzene and toluene concentrations in the garage, but not methanol. The concentrations for all compounds in the garage and concentrations of benzene and toluene in the adjacent room were lower when the HVAC fan was on than when it was off, while the concentrations of all three compounds in the rest of the house were higher, although these differences were not statistically significant. Thus, the portion of the population that parks cars in garages attached to homes will experience increased methanol exposures if methanol is used as an automotive fuel.     

Personal carbon monoxide exposure in five European cities and its determinants

Studies involving carbon monoxide (CO) exposure assessment are mainly based on measurements at outdoor fixed sites or in various indoor micro-environments. Few studies have been based on personal exposure measurements. In this paper, we report results on personal measurements of CO in five European cities and we investigate determinants which may influence this personal exposure.Within the multi-centre European EXPOLIS study, personal exposure to CO, measured every minute for 48 h, of 401 randomly selected study participants (mainly non-smokers) was monitored in Athens, Basle, Helsinki, Milan and Prague. Each participant also completed a time-microenvironment-activity diary and an extended questionnaire. In addition, for the same time period, ambient levels of CO from fixed site stations were collected.There are significant differences in both personal exposure and ambient levels within the five cities, ranging from high values in Milan and Athens to low in Helsinki. Ambient levels are a significant correlate and determinant of CO 48-h personal exposure in all cities. From the other determinants studied (time spent in street traffic, time of exposure to ETS and time of exposure to gas burning devices) none was consistently significant for all cities. Change of the ambient CO levels from the 25th to the 75th percentile of its distribution resulted in a 1.5–2 fold increase of 48-h personal exposure. Short time personal exposure was also studied in order to assess the influence of specific sources. Exposure levels were significantly higher when participants were in street traffic and in indoor locations in the presence of smokers.Personal 48-h exposure of non-smokers to CO varies among urban populations depending primarily on the ambient levels. For a CO source to be a significant determinant of the personal 48-h CO exposure, it has to affect the levels of CO in the person's proximity for an adequate length of time. Activities of individuals affect shorter term personal exposure.     

Association of exposure to benzene and smoking with oxidative damage to nucleic acids by means of biological monitoring of general population volunteers

In this study, the validation of liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) isotopic dilution method for the determination of benzene and nicotine metabolites in urine was carried out. Limit of detection are 0.026 μg/L for S-phenylmercapturic acid (SPMA), 0.55 μg/L for t,t-muconic acid (t,t-MA), and 12.41 μg/L for the cotinine, and the relative combined uncertainty was also calculated. The study involves 446 healthy volunteer residents since at least 10 years in an area of central Italy. SPMA resulted to be strongly correlated with cotinine (p?=?0.75), its concentration in smokers (93) being about ten times than in non/ex-smokers (197/156), while the t,t-MA of smokers is about twice the non/ex-smokers value. A cutoff value for the definition of smoker is set at 100 μg/g creat. Oxidative stress was studied in smokers and non- and ex-smokers by means of the determination of the biomarkers 8-Oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo), 8-Oxo-7,8-dihydroguanosine (8-oxoGuo), and 8-Oxo-7,8-dihydroguanine (8-oxoGua): no significant differences were found between smokers and non/ex-smokers, but when subjects are classified according to the cotinine cutoff value, a correlation in smokers’ urinary 8-oxodGuo is found with SPMA and cotinine (p?=?0.60 and p?=?0.57). Results were confirmed by chemometric analysis that also identified the experimental variables most contributing the discrimination as cotinine and t,t-MA.     

Characterization of Solid-Phase Microextraction and Gas Chromatography for the Analysis of Gasoline Tracers in Different Microenvironments

Abstract

Gasoline tracers were collected on solid-phase microextraction (SPME) fibers and analyzed by capillary gas chromatography with photoionization detector (GC/PID). This was part of a larger study to quantify personal exposure to motor vehicle gasoline evaporative and combustive emissions in high-end exposure microenvironments (MEs). The SPME fiber selected for this application was a 75-µm carboxen/polydimethylsiloxane. Sequential 10-min samples were collected for measurement of benzene, toluene, ethylbenzene, and ortho-, meta-, and para-xylene in different MEs in Atlanta, GA, in summer 2002 and Reno, NV, in spring 2003. Field calibrations were performed with certified gas standards in 1-L Tedlar bags for varying concentrations and exposure times. SPME detection limits were ～0.2 ppbv with a precision of 3–17% and accuracy of 30%. A dynamic system was designed for temperature and relative humidity calibrations, with corrections for the effects of these variables performed when necessary. SPME data compared satisfactorily with integrated canister samples, continuous PID, and field portable mass spectrometer data.     

Volatile organic compounds in selected micro-environments

A program of sampling for volatile organic compounds (VOCs) in ambient air was undertaken in selected locations and micro-environments in Perth, Western Australia to characterise concentrations of target VOCs and to determine the relative strength of the contributing sources to ambient air in different micro-environments in a major Australian city. Twenty-seven locations were sampled and, of the forty-one target compounds, 26 VOCs were detected in the samples collected. The highest concentrations were recorded for benzene, toluene, ethylbenzene, xylenes (BTEX), chloroform and styrene. The maximum 12-h toluene and benzene concentrations observed were from a basement carpark and were 24.7 parts per billion (ppb) and 5.6 ppb, respectively. The maximum xylenes concentration was 29.4 ppb and occurred in a nightclub where styrene was also detected. A factor analysis of the data was undertaken. Two key factors emerge that appear to be associated with petroleum and motor vehicles and environmental tobacco smoke. A third significant occurrence was a high concentration of chloroform that was observed at a sports centre complex with a swimming pool text and was uncorrelated with other compounds in the data set. This study indicates that locations associated with motor vehicles and petrol fuel, tobacco and wood smoke and chlorinated water represent the major risks for personal exposure to VOCs in Perth.     

Characterization of solid-phase microextraction and gas chromatography for the analysis of gasoline tracers in different microenvironments

Gasoline tracers were collected on solid-phase microextraction (SPME) fibers and analyzed by capillary gas chromatography with photoionization detector (GC/PID). This was part of a larger study to quantify personal exposure to motor vehicle gasoline evaporative and combustive emissions in high-end exposure microenvironments (MEs). The SPME fiber selected for this application was a 75-microm carboxen/polydimethylsiloxane. Sequential 10-min samples were collected for measurement of benzene, toluene, ethylbenzene, and ortho-, meta-, and para-xylene in different MEs in Atlanta, GA, in summer 2002 and Reno, NV, in spring 2003. Field calibrations were performed with certified gas standards in 1-L Tedlar bags for varying concentrations and exposure times. SPME detection limits were approximately 0.2 ppbv with a precision of 3-17% and accuracy of 30%. A dynamic system was designed for temperature and relative humidity calibrations, with corrections for the effects of these variables performed when necessary. SPME data compared satisfactorily with integrated canister samples, continuous PID, and field portable mass spectrometer data.