Traffic-related Occupational Exposures to PM2.5, CO,and VOCs in Trujillo,Peru

Abstract

A traffic-related exposure study was conducted among 58 workers (drivers, vendors, traffic police, and gas station attendants) and 10 office workers as controls in Trujillo, Peru, in July 2002. PM_2.5 was collected, carbon monoxide (CO) was measured, volatile organic compounds (VOCs) were sampled and analyzed. Newspaper vendors had the highest full-shift CO exposures (mean ± SD: 11.4 ± 8.9 ppm), while office workers had the lowest (2.0 ± 1.7 ppm). Bus drivers had the highest full-shift PM_2.5 exposures (161±8.9 pg/m³), while gas station attendants (64 ± 26.5 pg/m³) and office workers (65 ± 8.5 μg/m³) were the lowest. Full-shift benzene/toluene/ethylbenzene/xylene exposures (BTEX) among gas station attendants (111/254/43/214 μg/m³) were much higher than those among van and taxi drivers. Several of the traffic-related occupational exposures studied were elevated and are of occupational health concern.     

Blood lead survey of children, pregnant women, professional drivers, street workers, and office workers in Trujillo, Peru

In this pilot study, conducted in summer 2002, the authors measured blood lead levels (BLLs) for 118 subjects in the city of Trujillo, Peru, where leaded gasoline is in the process of being phased out. Subjects included bus drivers, combi (minivan) drivers, street vendors, newspaper vendors, traffic police, taxi drivers, gas station attendants, children living both near and distant from gas stations, pregnant women, and office workers (controls). The highest BLLs were 9.2 microg/dl and 9.3 microg/dl from a child who lived near a gas station and from a traffic policeman, respectively; however, all BLLs were below the U.S. Centers for Disease Control and Prevention's advisory level of concern (10 microg/dl). Office workers (n = 8) and pregnant women (n = 36) had significantly lower BLLs (geometric mean +/- standard deviation = 2.1 +/- 0.7 microg/dl, p < 0.022; and 2.5 +/- 1.1 microg/dl, p < 0.008, respectively) than total traffic-exposed workers (n = 48; 3.2 +/- 1.8 microg/dl). BLLs of children living near gas stations (n = 17; 3.7 +/- 2.2 microg/dl) were marginally higher (p = 0.07) than for children not living near gas stations (n = 9; 2.9 +/- 1.1 microg/dl). The study was limited by small sample size and the fact that the data were based on a convenience sample not fully representative of the cohorts studied. Nevertheless, the authors' findings suggest that leaded gasoline use in Trujillo continues to affect BLLs in traffic-exposed populations.     

Environmental exposure to volatile organic compounds among workers in Mexico City as assessed by personal monitors and blood concentrations.

Benzene, an important component in gasoline, is a widely distributed environmental contaminant that has been linked to known health effects in animals and humans, including leukemia. In Mexico City, environmental benzene levels, which may be elevated because of the heavy traffic and the poor emission control devices of older vehicles, may pose a health risk to the population. To assess the potential risk, portable passive monitors and blood concentrations were used to survey three different occupational groups in Mexico City. Passive monitors measured the personal exposure of 45 workers to benzene, ethylbenzene, toluene, o-xylene and m-/p-xylene during a work shift. Blood concentrations of the above volatile organic compounds (VOCs), methyl tert-butyl ether, and styrene were measured at the beginning and the end of a work shift. Passive monitors showed significantly higher (p > 0.0001) benzene exposure levels among service station attendants (median = 330 microg/m3; range 130-770) as compared to street vendors (median = 62 microg/m3; range 49-180) and office workers (median = 44 microg/m3, range 32-67). Baseline blood benzene levels (BBLs) for these groups were higher than those reported for similar populations from Western countries (median = 0.63 microg/L, n = 24 for service station attendants; median = 0.30 microg/L, n = 6 for street vendors; and median = 0.17 microgr;g/L, n = 7 for office workers). Nonsmoking office workers who were nonoccupationally exposed to VOCs had BBLs that were more than five times higher than those observed in a nonsmoking U.S. population. BBLs of participants did not increase during the work shift, suggesting that because the participants were chronically exposed to benzene, complex pharmacokinetic mechanisms were involved. Our results highlight the need for more complete studies to assess the potential benefits of setting environmental standards for benzene and other VOCs in Mexico.     

Exposure to particles, elemental carbon and nitrogen dioxide in workers exposed to motor exhaust

OBJECTIVES: The main aim of this study was to investigate the personal exposure to diesel and petrol exhaust fumes in occupations when exposure is prevalent and/or high. We also investigated the correlation between the five particle fractions [particles with an aerodynamic diameter <1 microm (PM(1)), particles with an aerodynamic diameter <2.5 microm (PM(2.5)), particles in size 0.1-10 microm, elemental carbon (EC) and total carbon (TC)] and nitrogen dioxide (NO(2)), in the various occupational environments. METHODS: Seventy-one workers were included in the study. They were subdivided into seven groups depending on working area, working indoors, out of doors or in vehicles and type of exposure (diesel or petrol exhaust). Personal measurements were performed during 3 days per worker. We used five indicators of the particle fraction: PM(1), PM(2.5), particle measured with a real-time monitoring instrument for particles in sizes 0.1 and 10 microm (DataRAM), EC and TC. We used NO(2) as an indicator of the gas phase. RESULTS: Tunnel construction workers showed the highest levels of exposure for all indicators, followed by diesel-exposed garage workers. For the other five groups, the levels were statistically significantly lower, and the differences between the groups were small. The full-shift geometric average of PM(1) varied between 119 microg m(-3) (tunnel construction workers) and 11 microg m(-3) (taxi drivers). For PM(2.5), the levels varied between 231 microg m(-3) (tunnel construction workers) and 16 microg m(-3) (bus and lorry drivers). For the measurements with the real-time monitoring instrument DataRAM, the levels varied between 398 microg m(-3) (tunnel construction workers) and 14 microg m(-3) (taxi drivers). For EC, the levels varied between 87 microg m(-3) (tunnel construction workers) and 4 microg m(-3) (other outdoor workers exposed to diesel exhaust), and for TC, the levels varied between 191 microg m(-3) (tunnel construction workers) and 10 microg m(-3) (taxi drivers). Finally, for NO(2), the levels varied between 350 microg m(-3) (tunnel construction workers) and 32 microg m(-3) (other outdoor workers exposed to diesel exhaust). For the indoor workers exposed to diesel exhaust fumes only, all the indicators correlated comparatively well and statistically significantly to each other (r(2) = 0.44-0.89). For the other groups, correlations were lower and showed no consistent pattern. CONCLUSIONS: The tunnel construction workers had exposure levels for all indicator substances that were considerably and significantly higher than for the other groups. The NO(2) levels were higher for indoor workers exposed to diesel exhaust than for all other groups (except tunnel construction workers). All particle fractions, as well as NO(2) correlated well in occupations with indoor exposure to diesel exhaust.     

A survey of personal exposures to benzene in Mexico City.

Benzene is a widely distributed environmental contaminant that causes leukemia. It is an important component in gasoline, it is used frequently as a solvent or chemical feedstock in industry, and it is emitted as a product of incomplete combustion. In Mexico City, investigators suspect that benzene exposure might be elevated and may pose a risk to the population; however, no published data are available to confirm or disconfirm this suspicion. We, therefore, conducted a survey in 3 occupational groups in Mexico City. Forty-five volunteers who used portable passive monitors measured their personal exposure to benzene during a workshift. None of the participants smoked during the monitoring period. Benzene exposure was significantly higher among service-station attendants (mean = 359.5 microg/m3 [standard deviation = 170.4 microg/m3]) than among the street vendors (83.7 microg/m3 and 45.0 microg/m3, respectively) and office workers (45.2 microg/m3 and 13.3 microg/m3, respectively). However, the benzene exposure levels observed among office workers were substantially higher than levels reported elsewhere for general populations. Our results highlight the need for more complete studies by investigators who should assess the potential benefits of setting environmental standards for benzene in Mexico.     

Personal exposure to particles in Banská Bystrica, Slovakia

Epidemiological studies have associated adverse health impacts with ambient concentrations of particulate matter (PM), though these studies have been limited in their characterization of personal exposure to PM. An exposure study of healthy nonsmoking adults and children was conducted in Banska Bystrica, Slovakia, to characterize the range of personal exposures to air pollutants and to determine the influence of occupation, season, residence location, and outdoor and indoor concentrations on personal exposures. Twenty-four-hour personal, at-home indoor, and ambient measurements of PM10, PM2.5, sulfate (SO4(2-)) and nicotine were obtained for 18 office workers, 16 industrial workers, and 15 high school students in winter and summer. Results showed that outdoor levels of pollutants were modest, with clear seasonal differences: outdoor PM10 summer/winter mean = 35/45 microg/m3; PM2.5 summer/winter mean = 22/32 microg/m3. SO4(2-) levels were low (4-7 microg/m3) and relatively uniform across the different sample types (personal, indoor, outdoor), areas, and occupational groups. This suggests that SO4(2-) may be a useful marker for combustion mode particles of ambient origin, although the relationship between personal exposures and ambient SO4(2-) levels was more complex than observed in North American settings. During winter especially, the central city area showed higher concentrations than the suburban location for outdoor, personal, and indoor measures of PM10, PM2.5, and to a lesser extent for SO4(2-), suggesting the importance of local sources. For PM2.5 and PM10, ratios consistent with expectations were found among exposure indices for all three subject groups (personal>indoor>outdoor), and between work type (industrial>students>office workers). The ratio of PM2.5 personal to indoor exposures ranged from 1.0 to 3.9 and of personal to outdoor exposures from 1.6 to 4.2. The ratio of PM10 personal to indoor exposures ranged from 1.1 to 2.9 and the ratio of personal to outdoor exposures from 2.1 to 4.1. For a combined group of office workers and students, personal PM10/PM2.5 levels were predicted by statistically significant multivariate models incorporating indoor (for PM2.5) or outdoor (for PM10) PM levels, and nicotine exposure (for PM10). Small but significant fractions of the overall variability, 15% for PM2.5 and 17% for PM10, were explained by these models. The results indicate that central site monitors underpredict actual human exposures to PM2.5 and PM10. Personal exposure to SO4(2-) was found to be predicted by outdoor or indoor SO4(2-) levels with 23-71% of the overall variability explained by these predictors. We conclude that personal exposure measurements and additional demographic and daily activity data are crucial for accurate evaluation of exposure to particles in this setting.     

Blood Lead Survey of Children,Pregnant Women,Professional Drivers,Street Workers,and Office Workers in Trujillo,Peru

In this pilot study, conducted in summer 2002, the authors measured blood lead levels (BLLs) for 118 subjects in the city of Trujillo, Peru, where leaded gasoline is in the process of being phased out. Subjects included bus drivers, combi (minivan) drivers, street vendors, newspaper vendors, traffic police, taxi drivers, gas station attendants, children living both near and distant from gas stations, pregnant women, and office workers (controls). The highest BLLs were 9.2 μg/dl and 9.3 μg/dl from a child who lived near a gas station and from a traffic policeman, respectively; however, all BLLs were below the U.S. Centers for Disease Control and Prevention's advisory level of concern (10 μg/dl). Office workers (n = 8) and pregnant women (n = 36) had significantly lower BLLs (geometric mean ± standard deviation = 2.1 ± 0.7 μg/dl, p < 0.022; and 2.5 ± 1.1 μg/dl, p < 0.008, respectively) than total traffic-exposed workers (n = 48; 3.2 ± 1.8 μg/dl). BLLs of children living near gas stations (n = 17; 3.7 ± 2.2 μg/dl) were marginally higher (p = 0.07) than for children not living near gas stations (n = 9; 2.9 ± 1.1 μg/dl). The study was limited by small sample size and the fact that the data were based on a convenience sample not fully representative of the cohorts studied. Nevertheless, the authors' findings suggest that leaded gasoline use in Trujillo continues to affect BLLs in traffic-exposed populations.     

A new carbon monoxide occupational dosimeter: results from a worker exposure assessment survey

The LBNL/QGI occupational carbon monoxide (CO) dosimeter (LOCD), a new, inexpensive CO passive sampler, was field-validated in an occupational exposure assessment study in the Moscone Convention Center (MCC) in San Francisco, CA in January, 1997. The LOCD measures time-weighed-average (TWA) CO exposures from 10 to 800 parts per million hours (ppm h; accuracy +/- 20%; precision 10 ppm h). This device represents a major improvement over currently available low-cost personal CO monitors. At the MCC, over 1000 workers set up and remove exhibitions. Forty propane-powered forklifts moved materials throughout the 42,000 m2 of exhibit halls. Diesel truck emissions enter the building via three internal underground loading docks. The LOCD was used to measure 154 worker exposures on 3 days. Sampler performance was compared to a standard method at 15 fixed sites. The geometric mean (GM) of all 154 exposures was 7 ppm (geometric standard deviation (GSD) = 1.6); 10% of the exposures was 10 ppm or more. Dock Walkers and Forklift Operators had the highest exposures (maximum = 34 ppm) with GM (GSD) of 9 (1.7) and 9 (1.6) ppm, respectively. Attendants and Installer/Decorators had the lowest exposures with GMs of 6 (1.6) and 7 (1.4), respectively. The Cal/OSHA personal exposure limit for CO is 25 ppm time-weighted average (TWA).     

Gasoline vapor exposures. Part I. Characterization of workplace exposures

Monitoring surveys of gasoline vapor exposures were conducted on truck drivers and terminal operators from five terminal loading facilities, on dockmen and seamen at two tanker/barge loading facilities, and on attendants at a single expressway service plaza. Results revealed wide variations in total C6+ hydrocarbon exposures for each location, with overall 8-hr time-weighted averaged (TWA) geometric means of 5.7 mg/m3 (1.4 ppm) for the terminals, and 4.0 mg/m3 (1.0 ppm) for the service plaza, respectively. The exposures ranged from 0.8 to 120.8 mg/m3 (0.2-30.1 ppm) for the terminals, and from 1.1 to 130.3 mg/m3 (0.3-32.5 ppm) for the service plaza. For the terminals, exposures were not significantly different regardless of loading method or the presence or absence of vapor recovery systems. Comprehensive chemical analyses of terminal employee exposure samples revealed that the C4 and C5 hydrocarbon components constituted 74.8 +/- 9.2% of the total exposure sample on a microgram/sample basis. The C6, C7, and C8+ components constituted 13.0 +/- 1.9, 6.2 +/- 3.0, and 5.9 +/- 7.2% of the total samples, respectively. Comprehensive analyses of the marine employee exposure samples resulted in a similar distribution of components; that is, 66.6 +/- 7.9, 17.5 +/- 4.7, 9.2 +/- 3.1, and 6.4 +/- 1.9% for the C4/C5, C6, C7, and C8+ components, respectively. The composition of the exposures, however, was weighted more toward the C5, C6 and C7 components when compared to the bulk terminal employee exposures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Five epidemiological studies on transport and asthma: objectives,design and descriptive results

A case-control study was conducted in five French metropolitan areas in order to assess the role of traffic-related air pollution in the occurrence of childhood asthma. This paper presents the study design and describes the distribution of key exposure variables. A set of 217 pairs of matched 4- to 14-year-old cases and controls were investigated (matching criteria: city, age, and gender). Current and past environmental smoke exposures, indoor allergens or air pollution sources, and personal and family atopy were assessed by standard questionnaires. When possible, direct measurements were done to check the validity of this information, on current data: skin prick tests, urine cotinine, house dust mites densities, personal exposures to, and home indoor concentrations of NO(x) and PM(2.5). Cumulative exposure to traffic-related pollutants was estimated through two indices: "traffic density" refers to a time-weighted average of the traffic density-to-road distance ratio for all home and school addresses of each child's life; "air pollution" index combines lifelong time-activity patterns and ambient air concentration estimates of NO(x), using an air dispersion model of traffic exhausts. Average current PM(2.5) personal exposure is 23.8 microg/m3 (SD=17.4), and average indoor concentrations=22.5 microg/m3 (18.2); corresponding values for NO(2) are 31.4 (13.9) and 36.1 (21.4) microg/m3. Average lifelong calculated exposures to traffic-related NO(x) emissions are 62.6 microg/m3 (43.1). The five cities show important contrasts of exposure to traffic pollutants. These data will allow comparison of lifelong exposures to indicators of traffic exhausts between cases and controls, including during early ages, while controlling for a host of known enhancers or precipitators of airway chronic inflammation and for possible confounders.     

Exposure to fuel-oil ash and welding emissions during the overhaul of an oil-fired boiler

The health effects of exposure to vanadium in fuel-oil ash are not well described at levels ranging from 10 to 500 microg/m(3). As part of a larger occupational epidemiologic study that assessed these effects during the overhaul of a large oil-fired boiler, this study was designed to quantify boilermakers' exposures to fuel-oil ash particles, metals, and welding gases, and to identify determinants of these exposures. Personal exposure measurements were conducted on 18 boilermakers and 11 utility workers (referents) before and during a 3-week overhaul. Ash particles < 10 microm in diameter (PM(10), mg/m(3)) were sampled over full work shifts using a one-stage personal size selective sampler containing a polytetrafluoroethylene filter. Filters were digested using the Parr bomb method and analyzed for the metals vanadium (V), nickel (Ni), iron (Fe), chromium (Cr), cadmium (Cd), lead (Pb), manganese (Mn), and arsenic (As) by inductively coupled plasma mass spectrometry. Nitrogen dioxide (NO(2)) was measured with an Ogawa passive badge-type sampler and ozone (O(3)) with a personal active pump sampler.Time-weighted average (TWA) exposures were significantly higher (p < 0.05) for boilermakers than for utility workers for PM(10) (geometric mean: 0.47 vs. 0.13 mg/m(3)), V (8.9 vs. 1.4 microg/m(3)), Ni (7.4 vs. 1.8 microg/m(3)) and Fe (56.2 vs. 11.2 microg/m(3)). Exposures were affected by overhaul time periods, tasks, and work locations. No significant increases were found for O(3) or NO(2) for boilermakers or utility workers regardless of overhaul period or task group. Fuel-oil ash was a major contributor to boilermakers' exposure to PM(10) and metals. Vanadium concentrations sometimes exceeded the 2003 American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value.     

Exposure to fine particulate matter (PM2.5) among highway toll station workers in taipei: direct and indirect exposure assessment

In this study, the authors assessed occupational exposure to PM2.5 among 47 highway toll station workers in Taipei, Taiwan. The subjects were monitored for 10 days to assess integrated 8-hr fine particulate matter (PM2.5) breathing zone concentration. Researchers constructed a microenvironment-time-concentration matrix and applied direct and indirect approaches to assess cumulative exposure. Mean PM2.5 concentration for workers in the truck and bus lanes was 308 microg/m3 (SD = 115.5 microg/m3), substantially higher compared with cash-payment car lanes (mean 115, SD = 41.8, p < 0.001) and ticket-payment car lanes (mean 109, SD = 48.7, p < 0.001). Concentration per vehicle in the truck and bus lanes was 6.4 and 3.7 times higher, respectively, than that of ticket- or cash-payment car lanes. Mean cumulative exposure for the 10-day period was 4,900-13,407 microg/m3.hr, with a mean of 8,019 microg/m3.hr (SD = 2,375.3). Indirect and direct concentrations were strongly correlated (r2 = .61, F(1,125); p = 0.000). The results of this study show that personal exposure to PM2.5 can be reliably estimated using indirect approaches.     

Manganese exposures in Toronto during use of the gasoline additive, methylcyclopentadienyl manganese tricarbonyl

A year-long population-weighted study of personal exposures to particulate matter (PM2.5) was conducted in Toronto while the manganese-containing additive, methylcyclopentadienyl manganese tricarbonyl (MMT), was present in gasoline at an average level of 11.9 mg Mn/l, which was higher than the maximum of 8.3 mg Mn/l allowed in the U.S. In this study, 925 three-day personal samples of PM2.5 (air concentration of aerosol with an aerodynamic diameter of less than 2.5 microm) were collected, along with a record of participants' occupations, personal habits, surroundings, and activities during sampling. Stationary samples of PM2.5 were collected indoors and outdoors at a subset of participants' homes over the same 3-day periods. Three-day samples of PM2.5 were also collected at fixed locations. Personal exposures to PM2.5 were highly influenced by exposure to tobacco smoke, and were poorly correlated with outdoor levels (Kendall's tau=0.13). The mean concentration of PM2.5 in homes (21 microg/m3) was significantly higher than the mean outdoor level (15 microg/m3). By contrast, the mean PM2.5 Mn concentration (air concentration of Mn in PM2.5) was higher outdoors (9.7 ng/m3) than indoors (5.5 ng/m3). Other than from tobacco smoke, there were no indications of significant indoor sources of PM2.5 Mn in homes. The most important predictor of exposure to PM2.5 was time spent in the subway, and a high level (428 ng/m3) of PM2.5 Mn was measured in the subway. The source of this Mn was hypothesized to be friction erosion of subway rails. Small, but statistically significant correlations were present between personal exposures to PM2.5 Mn and several traffic-related variables (time spent in transit, in a motor vehicle, near a roadway with traffic, and in a parking garage). However, in a stepwise regression that adjusted for weather and personal activities, time in a motor vehicle was the only traffic-related variable significantly associated with PM2.5 Mn, and it was only the 10th most important personal activity variable in the final model. Concentrations of PM2.5 Mn were higher at two fixed locations than outside of participants' homes, which were likely further from high traffic areas than the fixed sites. Likewise, outdoor and fixed site samples collected during periods that included weekend days contained lower air concentrations of Mn than samples collected during weekdays when traffic was heavier. On the other hand, the monthly average concentration of Mn in gasoline was negatively correlated with both outdoor and personal PM2.5 Mn, which suggests that traffic-related sources of Mn other than MMT may be present. After omitting participants with exposure to Mn from certain identifiable non-MMT sources (subway riders, metal workers and persons exposed to tobacco smoke), the average (median) personal exposure of the remaining 325 participants to PM2.5 Mn was reduced from 14 ng/m3 (8.5 ng/m3 ) to 8.3 ng/m3 (7.0 ng/m3). Potential sources of this residual Mn exposure include, in addition to MMT, naturally occurring Mn in the earth's crust, other occupational exposure, airborne release of Mn from industrial operations, and friction erosion of Mn from steel-containing products. Taken together, these facts (elimination of participants with Mn exposure from known non-MMT sources reduced average exposures by 40%, the existence of multiple non-MMT sources of the remaining Mn exposure, and the negative correlation between MMT usage and PM2.5 Mn) suggest that the preponderance of personal Mn exposure was from non-MMT sources.     

Indoor air pollution and acute lower respiratory infections in the first two years of life

The relationship between outdoor air pollution and acute respiratory infections (ARI) was previously documented. There are recent indications for connection between indoor air pollution and ARI in infants and young children. The aim of this study was to identify the relationship of indoor air pollutants to acute lower respiratory infection (ALRI) in children (< 2 years). The indoor air pollutants concentrations were measured in the homes of the sample. The sample consisted of 115 children (< 2 years) representing the control group (24), ALRI but no pneumonia (24), pneumonia (30), severe pneumonia or very severe disease (37). Air sampling was performed to measure the concentration of total suspended particulates (TSP), SO2 and CO. These pollutants were found in higher concentrations in cases' homes (52.46 +/- 19.68 microg/m3, 298.15 +/- 669.37 microg/m3, and 1.92 +/- 3.60 ppm) than in controls' homes (31.92 +/- 8.76 microg/m3, not detected, and 0.33 +/- 1.63 ppm respectively). Whereas SO2 was detected only in houses using kerosene, TSP and CO were detected with the different types of cooking fuels. Their mean concentrations were highest for biomass (88.86 +/- 13.30 microg/m3 and 9.29 +/- 2.50 ppm) and lowest for gas (40.78 +/- 15.25 microg/m3 and 0.76 +/- 2.19 ppm). Measures to improve indoor air quality are highly required.     

Hydrocarbon exposures at petroleum bulk terminals and agencies.

Occupational exposures to the 55 hydrocarbon components of gasoline and petroleum products were measured at the bulk terminals and agencies of six Ontario petroleum companies during the summer of 1986. A total of 82 long-term (full-shift) and 111 short-term personal samples were taken over 3 months. The data, expressed as concentrations in milligrams per cubic meter, were highly variable and appeared to fit the lognormal distribution well. Full-shift exposures of bulk terminal drivers, agency drivers, and plantmen to total hydrocarbons (THC), computed as an n-hexane equivalent, and other hydrocarbon components for which exposure limits exist can be expected to exceed their respective 1986-1987 threshold limit value-time-weighted average (TLV-TWA) no greater than 1% of the time on the basis of the lognormal model. The short-term THC exposures of agency truck drivers can be expected to exceed the 1986-1987 TLV-short-term exposure limits about 7% of the time while top-loading and more than 17% while off-loading. For benzene, the short-term exceedance percentages are 1% and 4% for top- and off-loading operations, respectively. For long-term benzene exposures, up to 69% of the assessments can be expected to exceed the 1990-1991 proposed TLV-TWA of 0.3 mg/m3 (0.1 ppm). The full-shift hydrocarbon exposures of agency drivers were significantly higher than those for bulk terminal drivers. At the bulk terminals, the short-term hydrocarbon exposures during top-loading were significantly higher than during bottom-loading.     

Participants' exposure to PM2.5 and gaseous/particulate polycyclic aromatic hydrocarbons during the Ma-tsu Goddess parade

The Ma-tsu Goddess parade is a very special religious tradition in Taiwan attracting thousands of believers every year. This parade is an 8-day-and-7-night event and the entire walking distance is about 280 km. This study assesses participants' exposure to PM(2.5), and gaseous and particulate PAHs. The contribution of various exposure factors was also evaluated. Sampling was conducted during the entire parade period in 2001. Exposures of participants who were riding motorcycles or driving cars were assessed. Personal environmental monitors mounted with Teflon filters and polyurethane foams were used for particulate and gaseous sampling. PAHs were analyzed with GC-FID. Stepwise regression analysis was used to evaluate the contribution of various factors, including the number of temples visited each day, the duration of temple visits, the number of temple co-visitors, visitors riding motorcycles or driving cars, etc. During the Ma-tsu Goddess parade, the mean PM(2.5), particulate and gaseous PAH exposures were around 119 +/- 60.8, 0.36 +/- 0.23 and 0.86 +/- 0.48 microg/m(3), respectively. Participants' PM(2.5) and particulate PAH exposures were about two to three times the exposure during daily routines. The profiles of 16 PAH species in the particulate and gaseous phases for participants' and normal daily exposures were also different. Incense smoke and vehicle exhaust were two important sources. Worshippers would be exposed to 0.096 microg/m(3) more PM(2.5) for every incremental minute in temples. In addition, motorcyclists were exposed to 0.21 microg/m(3) higher particulate PAHs than the car drivers.     

Airborne particulate metals in the New York City subway: A pilot study to assess the potential for health impacts

A prior study in New York City observed that airborne concentrations of three metals found in steel - iron, manganese, and chromium - are more than 100 times higher in the subway system than in aboveground air. To investigate the potential for health effects of exposure at these levels, we conducted a pilot study of subway workers comparing personal exposures to steel dust with biomarkers of metal exposure, oxidative stress, and DNA damage in blood and urine samples. Workers wore a personal air sampler operating at 4 L/m for one to three work shifts with blood and urine samples collected at the end of the final shift. We found that PM_2.5 exposures varied among subway workers on the basis of job title and job activity. The subway workers’ mean time-weighted PM_2.5 exposure was 52 μg/m³, with a median of 27 μg/m³, and a range of 6-469 μg/m³. The observed concentrations of PM_2.5, iron, manganese, and chromium fell well below occupational standards. Biomarker concentrations among the 39 subway workers were compared with a group of 11 bus drivers, and a group of 25 suburban office workers. Concentrations of DNA-protein crosslinks and chromium in plasma were significantly higher in subway workers than in bus drivers, but no significant difference was observed for these biomarkers between subway workers and office workers. Urinary isoprostane concentrations were significantly correlated with the number of years working in the subway system, and were detected at higher, though not significantly higher, concentrations in subway workers than in bus drivers or office workers. At the group level, there was no consistent pattern of biomarker concentrations among subway workers significantly exceeding those of the bus drivers and office workers. At the individual level, steel dust exposure was not correlated with any of the biomarkers measured.     

Biological monitoring of smoke exposure among wildland firefighters: a pilot study comparing urinary methoxyphenols with personal exposures to carbon monoxide, particular matter, and levoglucosan

Urinary methoxyphenols (MPs) have been proposed as biomarkers of woodsmoke exposure. However, few field studies have been undertaken to evaluate the relationship between woodsmoke exposure and urinary MP concentrations. We conducted a pilot study at the US Forest Service-Savannah River Site, in which carbon monoxide (CO), levoglucosan (LG), and particulate matter (PM(2.5)) exposures were measured in wildland firefighters on prescribed burn days. Pre- and post-shift urine samples were collected from each subject, and cross-shift changes in creatinine-corrected urinary MP concentrations were calculated. Correlations between exposure measures and creatine-adjusted urinary MP concentrations were explored, and regression models were developed relating changes in urinary MP concentrations to measured exposure levels. Full-shift measurements were made on 13 firefighters over 20 work shifts in winter 2004 at the US Forest Service Savannah River site, a National Environmental Research Park. The average workshift length across the 20 measured shifts was 701+/-95 min. LG and CO exposures were significantly correlated for samples where the filter measurement captured at least 60% of the work shift (16 samples), as well as for the smaller set of full-shift exposure samples (n=9). PM(2.5) and CO exposures were not significantly correlated, and LG and PM(2.5) exposures were only significantly correlated for samples representing at least 60% of the work shift. Creatinine-corrected urinary concentrations for 20 of the 22 MPs showed cross-shift increases, with 14 of these changes showing statistical significance. Individual and summed creatinine-adjusted guaiacol urinary MPs were highly associated with CO (and, to a lesser degree, LG) exposure levels, and random-effects regression models including CO and LG exposure levels explained up to 80% of the variance in cross-shift changes in summed creatinine-adjusted guaiacol urinary MP concentrations. Although limited by the small sample size, this pilot study demonstrates that urinary MP concentrations may be effective biomarkers of occupational exposure to wood smoke among wildland firefighters.     

Carbon monoxide exposure assessment among toll operators in Klang Valley, Kuala Lumpur, Malaysia

A comparative cross-sectional study was conducted to determine tollbooth carbon monoxide (CO) levels and carboxyhaemoglobin (COHb) levels among the tollbooth operators and office workers in the Klang Valley, Kuala Lumpur. All tollbooths were equipped with well functioning air-conditioning. The total number of respondents was 180: 90 toll operators and 90 office workers aged between 19 and 52 years. The highest peak of CO level recorded was 61 ppm. The highest average peak CO level within a shift was 30 ppm. The CO level was higher during peak traffic at 6.00 - 8.00 a.m. There was no significant correlation between average peak CO level with vehicle load (r = -0.007, p = 0.474). The toll operators' median COHb level (1.0%, IQR = 0.8%) was significantly higher (p = 0.008) compared to office workers (0.7%, IQR = 0.8). There was a weak and significant correlation between COHb levels with average peak CO levels (r = 0.228, p = 0.031). In conclusion, tollbooth operators were chronically exposed to CO leading to higher COHb levels compared to office workers.     

Gasoline vapor exposures at a high volume service station

Gasoline vapor concentrations were measured at a high volume service station for one week in May, 1983, for service station attendants, self-service customers and for various area locations. To facilitate the retention of highly volatile, low-molecular weight gasoline vapor components, 100/50 mg charcoal adsorption tubes were used with flow rates of 100 cc/min for long-term exposure samples and 900 cc/min for short-term exposures. Methylene chloride was selected as the desorption solvent. Desorbed hydrocarbons were analyzed and quantitated by capillary column gas chromatography using a flame ionization detector and a 0-100 degrees C temperature program. The data proved that the predominant ambient air hydrocarbons are those of C4 and C5 compounds. Monitoring results showed that the total gasoline vapor TWA exposures for service station attendants ranged from 0.6 to 4.8 ppm with a geometric mean of 1.5 ppm. Short-term personal samples collected while refueling ranged from not detectable to 38.8 ppm with a geometric mean of 5.8 ppm.