Indoor and outdoor personal exposure to benzene in Athens, Greece

OBJECTIVE: To evaluate the exposure of urban inhabitants to atmospheric benzene in Athens, Greece. METHODS: Fifty non-smoker volunteers from selected occupational groups and their homes were monitored by passive air samplers for six 5-day periods during a year. An activity diary was completed during each sampling period and relevant data were collected by a questionnaire at the beginning of the study. Additional data on urban levels on benzene were also available. RESULTS: Average benzene home and personal levels in six monitoring campaigns varied between 6.0-13.4 and 13.1-24.6 microg/m(3), respectively. Urban levels varied between 15.4 and 27.9 microg/m(3) with an annual mean of 20.4 microg/m(3). Wind speed seems to determine largely home levels and personal exposure. Proximity to busy road holds also an important influence on indoor benzene levels. Adjusted for seasonal or climate variation, other significant prognostic factors of personal exposure were home levels, total time spent outdoors and transportation mean. Time spent outdoors explains the strong relationship between occupation and personal levels of exposure. Wind had similar effect in clearing indoor and urban pollution in Athens; lessen personal exposure and home levels about 2-2.5 microg/m(3) per 1 m/s increase in speed. CONCLUSIONS: Factors related to climate (use of non-absorbent materials for wall and floor covering and frequent ventilation) might be one explanation for homes' high clearing rate. Our exposure pattern, which suggests that outdoors work give the greater contribution to benzene exposure of Athens citizens, is uncommon in northern towns of Europe. Policy makers have to take in account these differences in establishing guidelines for ambient benzene exposure.     

A case study of personal exposure to nitrogen dioxide using a new high sensitive diffusive sampler

Personal NO(2) exposure measurements were achieved during two campaigns in a large northern France city. These campaigns were following an innovating approach based on sequential exposure measurements by diffusive samplers distinguishing four categories of microenvironments ("home", "other indoor places", "transport" and "outdoors"). The objective of these campaigns was to obtain NO(2) personal exposure data in different microenvironments and to examine the determinants of personal exposure to this pollutant. Each campaign comprised two 24-h sampling periods: one during a working day and the second during the weekend. The average total NO(2) personal exposure ranged from 17 microg m(-3) for the summer weekend samplings to 38 microg m(-3) for the winter weekday samplings. The highest levels were found in transports and outdoors, the intermediate ones in other indoor places and the lowest in homes. Despite their weak levels, indoor environments contributed for more than 78% to total NO(2) personal exposure because of more time spent in these living places. A Multiple Correspondence Analysis (MCA) highlighted the determinants of NO(2) personal exposure in the "home" and "transport" microenvironments. This led to a classification of NO(2) personal exposure levels according to different means of transport: from the lowest to the highest exposure levels, train, tramway or underground, bicycle, car or motorcycle. In homes, the rise of NO(2) personal exposures is mainly due to the use of gas stoves and gas heating and the absence of automatic airing system. A classification of NO(2) personal exposure levels was set up according to the characteristics of homes. An analysis of correlations between the home NO(2) personal exposures and outdoor concentrations measured by fixed ambient air monitoring stations showed weak relations suggesting that the data of these stations are poor predictors of NO(2) personal exposures in homes.     

Health risk assessment of personal inhalation exposure to volatile organic compounds in Tianjin, China

Volatile Organic Compounds (VOCs) exposure can induce a range of adverse human health effects. To date, however, personal VOCs exposure and residential indoor and outdoor VOCs levels have not been well characterized in the mainland of China, less is known about health risk of personal exposure to VOCs. In this study, personal exposures for 12 participants as well as residential indoor/outdoor, workplace and in vehicle VOCs concentrations were measured simultaneously in Tianjin, China. All VOCs samples were collected using passive samplers for 5 days and were analyzed using Thermal Desorption GC-MS method. U.S. Environmental Protect Agency's Inhalation Unit Risks were used to calculate the inhalation cancer health risk. To assess uncertainty of health risk estimate, Monte Carlo simulation and sensitivity analysis were implemented. Personal exposures were greater than residential indoor exposures as expected with the exception of carbon tetrachloride. Exposure assessment showed modeled and measured concentrations are statistically linearly correlated for all VOCs (P < 0.01) except chloroform, confirming that estimated personal exposure using time-weighted model can provide reasonable estimate of personal inhalation exposure to VOCs. Indoor smoking and recent renovation were identified as two major factors influencing personal exposure based on the time-activity pattern and factor analysis. According to the cancer risk analysis of personal exposure, benzene, chloroform, carbon tetrachloride and 1,3-butadiene had median upper-bound lifetime cancer risks that exceeded the U.S. EPA benchmark of 1 per one million, and benzene presented the highest median risks at about 22 per one million population. The median cumulative cancer risk of personal exposure to 5 VOCs was approximately 44 per million, followed by indoor exposure (37 per million) and in vehicle exposure (36 per million). Sensitivity analysis suggested that improving the accuracy of exposure measurement in further research would advance the health risk assessment.     

Residents' particle exposures in six different communities in Taiwan

Exposure assessment studies for particulates have been conducted in several U.S. and European cities; however, exposure data remain sparse for Asian populations whose cultural practices and living styles are distinct from those in the developed world. This study assessed personal PM(10) exposure in urban residents and evaluated PM(10) indoor/outdoor levels in communities with different characteristics. Important factors of personal PM(10) exposure in Taiwan were explored. Sampling was conducted in 6 communities in Taiwan, two in each of the three major metropolitan areas. Up to nine non-smoking volunteers in each community carried personal samplers for 24 h. The geometric means (GM) of PM(10) in personal, indoor and outdoor samples were 76.3 microg/m(3) (geometric standard deviation, GSD=1.8), 73.4 microg/m(3) (GSD=1.5), and 85.8 microg/m(3) (GSD=1.7), respectively. It was found that outdoor levels rather than indoor levels contributed significantly to personal exposure. The important exposure factors include the time spent outdoors and on transportation, riding a motorcycle, passing by factories, cooking or being in the kitchen, and incense burning at home. Motorcycle riding and the proximity to factories are related to the special living and housing characteristics in Taiwan, while incense burning and Chinese cooking are culture-related. Motorcyclists experienced an average of 27.7 microg/m(3) higher PM(10) than others, while subjects passing by a factory were exposed to an average of 38.4 microg/m(3) higher PM(10) than others. Effective control and public education should be applied to reduce the contribution of these PM exposure sources.     

Determination of exposure to benzene, toluene and xylenes in Turkish primary school children by analysis of breath and by environmental passive sampling

Benzene, toluene, m/p-xylene and o-xylene (BTX) are toxic volatile organic compounds and ubiquitous air pollutants. Smoking and consumer products are indoor sources of BTX, whereas traffic and industrial activities are primary sources contributing to outdoor levels of BTX. The aim of this study was to characterize exposure of children to BTX by personal air sampling using diffusive samplers and by analysis of end-exhaled air. For this study, 101 children of 10-11 years of age were recruited from four primary schools in Southern Turkey during the warm season (May 2008). Two schools were situated in a residential area near primary and secondary iron and steel works (Payas) and two schools were located in a non-industrialized city (Iskenderun). The children and their parents were visited at home for an interview and to identify possible sources of BTX in the residence. Median concentrations of benzene determined by diffusive samplers were higher in Payas (4.1 μg/m³) than in Iskenderun (2.7 μg/m³, p < 0.001). For toluene, no differences were observed, whereas for xylene isomers air concentrations tended to be lower for children living in Payas. The median end-exhaled air concentrations were 8.2, 29, 3.8, and 5.7 pmol/L for benzene, toluene, m/p-xylene and o-xylene, respectively (Payas), and 6.9, 25, 4.9, and 6.0 pmol/L, respectively (Iskenderun). Concentrations of toluene in end-exhaled air were 50% higher in children living with household members who smoked indoors (p < 0.05) and benzene in end-exhaled air was more than 3-fold higher for those children who were exposed to tobacco smoke inside a vehicle (p < 0.001). End-exhaled concentrations of benzene were also higher in children living in a residence with an attached garage (p < 0.05). These exposure modifying factors were not identified when using the results obtained with diffusive samplers.     

Household air pollution and personal exposure to nitrated and oxygenated polycyclic aromatics (PAHs) in rural households: Influence of household cooking energies

Residential solid fuels are widely consumed in rural China, contributing to severe household air pollution for many products of incomplete combustion, such as polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives. In this study, concentrations of nitrated and oxygenated PAH derivatives (nPAHs and oPAHs) for household and personal air were measured and analyzed for influencing factors like smoking and cooking energy type. Concentrations of nPAHs and oPAHs in kitchens were higher than those in living rooms and in outdoor air. Exposure levels measured by personal samplers were lower than levels in indoor air, but higher than outdoor air levels. With increasing molecular weight, individual compounds tended to be more commonly partitioned to particulate matter (PM); moreover, higher molecular weight nPAHs and oPAHs were preferentially found in finer particles, suggesting a potential for increased health risks. Smoking behavior raised the concentrations of nPAHs and oPAHs in personal air significantly. People who cooked food also had higher personal exposures. Cooking and smoking have a significant interaction effect on personal exposure. Concentrations in kitchens and personal exposure to nPAHs and oPAHs for households using wood and peat were significantly higher than for those using electricity and liquid petroleum gas (LPG).     

Assessment through environmental and biological measurements of total daily exposure to volatile organic compounds of office workers in Milan, Italy

Personal exposure to total volatile organic compounds (TVOCs), benzene and toluene of 100 Milan office workers was assessed through personal air monitoring at home, in the office, and during commuting. Biological monitoring was performed by measuring blood benzene and toluene concentrations together with urinary trans-trans-muconic acid (t,t-MA) and cotinine at the end of the monitoring period. The geometric means of the total 24-h personal exposure were 514 micrograms/m3 for TVOCs, 21.2 micrograms/m3 for benzene and 35.2 micrograms/m3 for toluene. Daily exposure to the volatile organic compounds was almost totally determined by indoor exposure at home and in the office, with a minor contribution in the transport means. An important factor determining exposure to benzene was found to be tobacco smoke, both for active smokers and for non-smokers exposed to environmental tobacco smoke (ETS). All the mean levels of the biological indicators were significantly higher in active smokers than in non-smoking subjects non-exposed to ETS; urine cotinine and t,t-MA levels were also significantly higher in non-smokers exposed to ETS than in non-smokers non-exposed to ETS.     

Applying indoor and outdoor modeling techniques to estimate individual exposure to PM2.5 from personal GPS profiles and diaries: A pilot study

Impacts of individual behavior on personal exposure to particulate matter (PM) and the associated individual health effects are still not well understood. As outdoor PM concentrations exhibit highly temporal and spatial variations, personal PM exposure depends strongly on individual trajectories and activities. Furthermore, indoor environments deserve special attention due to the large fraction of the day people spend indoors. The indoor PM concentration in turn depends on infiltrated outdoor PM and indoor particle sources, partially caused by the activities of people indoor.We present an approach to estimate PM2.5 exposure levels for individuals based upon existing data sources and models. For this pilot study, six persons kept 24-hour diaries and GPS tracks for at least one working day and one weekend day, providing their daily activity profiles and the associated geographical locations. The survey took place in the city of Münster, Germany in the winter period between October 2006 and January 2007. Environmental PM2.5 exposure was estimated by using two different models for outdoor and indoor concentrations, respectively. For the outdoor distribution, a dispersion model was used and extended by actual ambient fixed site measurements. Indoor concentrations were modeled using a simple mass balance model with the estimated outdoor concentration fraction infiltrated and indoor activities estimated from the diaries. A limited number of three 24-hour indoor measurements series for PM were performed to test the model performance.The resulting average daily exposure of the 14 collected profiles ranged from 21 to 198 µg m^− 3 and showed a high variability over the day as affected by personal behavior. Due to the large contribution of indoor particle sources, the mean 24-hour exposure was in most cases higher than the daily means of the respective outdoor fixed site monitors.This feasibility study is a first step towards a more comprehensive modeling approach for personal exposure, and therefore restricted to limited data resources. In future, this model framework not only could be of use for epidemiological research, but also of public interest. Any individual operating a GPS capable device may become able to obtain an estimate of its personal exposure along its trajectory in time and space. This could provide individuals a new insight into the influence of personal habits on their exposure to air pollution and may result in the adaptation of personal behavior to minimize risks.     

Predictive Models Based on Personal,Indoor and Outdoor Air Pollution Exposure

Portable air pollution samplers were used to measure sulphur dioxide (SO₂), nitrogen dioxide (NO₂) and respirable suspended particulates (RSP) in a study of a group of nineteen asthmatics during two periods in the winter and summer respectively. One sampler was carried by each subject, one was placed in the home indoors, and one outdoors by the home. In addition, similar pollutants were measured at a central stationary site within a 15 km radius during the same time periods. Samplers were not placed, however, in other indoor spaces where subjects spent part(s) of the day. We used the data from all the sampling sites to develop predictive models for personal exposure. With 330 person-days of exposure data, multiple regression of these “fixed site” measures of pollution against the personal exposure measures revealed a predictive relationship whose power increased proportionally to the time the subjects spent indoors. This relationship was limited, however, since samplers were not placed at other indoor spaces, thus leaving the predictive model incomplete. A pollution index in which these indoor and outdoor pollutant measures were weighted by the time spent at home indoors and outdoors was predictive of personal exposure for NO₂ and RSP (R = 0.78,0.44 respectively); the SO₂ levels were too low to be used in the comparative analysis (R = 0.19).     

Personal Exposure in Displacement Ventilated Rooms

Personal exposure in a displacement ventilated room is examined. The stratified flow and the considerable concentration gradients necessitate an improvement of the widely used fully mixing compartmental approach. The exposure of a seated and a standing person in proportion to the stratification height is examined by means of full-scale measurements. A breathing thermal manikin is used to simulate a person. It is found that the flow in the boundary layer around a person is able to a great extent to entrain and transport air from below the breathing zone. In the case of non-passive, heated contaminant sources, this entrainment improves the indoor air quality. Measurements of exposure due to a passive contaminant source show a significant dependence on the flow field as well as on the contaminant source location. Poor system performance is found in the case of a passive contaminant released in the lower part of the room close to the occupant. A personal exposure model for displacement ventilated rooms is proposed. The model takes the influence of gradients and the human thermal boundary layer into account. Two new quantities describing the interaction between a person and the ventilation are defined.     

Indoor and outdoor BTX levels in German cities

On the basis of the ongoing study INGA (INdoor exposure and Genetics in Asthma), Germany's most detailed and standardized epidemiological study on indoor exposure to both allergens in house dust and volatile compounds in the air of the home environment has been performed. The purpose of this paper is to describe the spatial and seasonal variability of indoor and outdoor BTX (Benzene, toluene, ethyl benzene, ortho-xylene, meta- and para-xylene) concentrations for the study period from June 1995 to November 1996. Within this framework, air concentrations of volatile organic compounds (BTX) were measured in 204 households in Erfurt (Eastern Germany) and 201 households in Hamburg (Western Germany). BTX sampling was conducted over one week using OVM 3500 passive diffusion sampling devices in the indoor (living room and bedroom) and outdoor environment (outside the window of the living room). Indoor and outdoor median BTX concentrations in Erfurt were slightly, but significantly higher than those in Hamburg. This gap was most pronounced in the levels of indoor toluene (37.3 microg/m3 for Erfurt and 20.5 microg/m3 for Hamburg, P < 0.0001). In both cities, winter indoor and outdoor concentrations for the five compounds exceeded the summer values. Outdoor concentrations of ethyl benzene and ortho-xylene were very low (50% < L.D.). In general, the indoor BTX air concentrations were significantly higher than the outdoor concentra- tions, the lowest I/O ratios were found in the case of benzene. Living room and bedroom values for the five compounds were highly correlated (Spearman coefficient 0.5-0.9). Despite the better insulation of the homes in West Germany, no indication for the expected higher indoor concentrations of BTX in the West could be found. The strong and yet undiscovered indoor source for toluene in East Germany might lead to a further increase in the indoor air load in those homes in the East, which undergo renovations which will lead to improved insulation.     

Patterns and predictors of personal exposure to indoor air pollution from biomass combustion among women and children in rural China

Indoor air pollution (IAP) from domestic biomass combustion is an important health risk factor, yet direct measurements of personal IAP exposure are scarce. We measured 24-h integrated gravimetric exposure to particles < 2.5 μm in aerodynamic diameter (particulate matter, PM?.?) in 280 adult women and 240 children in rural Yunnan, China. We also measured indoor PM?.? concentrations in a random sample of 44 kitchens. The geometric mean winter PM?.? exposure among adult women was twice that of summer exposure [117 μg/m3 (95% CI: 107, 128) vs. 55 μg/m3 (95% CI: 49, 62)]. Children's geometric mean exposure in summer was 53 μg/m3 (95% CI: 46, 61). Indoor PM?.? concentrations were moderately correlated with women's personal exposure (r=0.58), but not for children. Ventilation during cooking, cookstove maintenance, and kitchen structure were significant predictors of personal PM?.? exposure among women primarily cooking with biomass. These findings can be used to develop exposure assessment models for future epidemiologic research and inform interventions and policies aimed at reducing IAP exposure. PRACTICAL IMPLICATIONS: Our results suggest that reducing overall PM pollution exposure in this population may be best achieved by reducing winter exposure. Behavioral interventions such as increasing ventilation during cooking or encouraging stove cleaning and maintenance may help achieve these reductions.     

Long-term personal exposure to traffic-related air pollution among school children, a validation study

Several recent studies suggest an association between long-term exposure to traffic-related air pollution and health. Most studies use indicators of exposure such as outdoor air pollution or traffic density on the street of residence. Little information is available about the validity of these measurements as an estimate of long-term personal exposure to traffic-related air pollution. In this pilot study, we assessed outdoor and personal exposure to traffic-related air pollution in children living in homes on streets with different degree of traffic intensity. The personal exposure of 14 children aged 9-12 years to 'soot', NO(x) (NO and NO(2)) was assessed in Amsterdam between March and June 2003. Each child's personal exposure was monitored during four repeated 48-h periods. Concurrently, in- and outdoor NO(x) measurements were carried out at the school and at the home of each participating child. Measurements were supplemented by a questionnaire on time activity patterns and possible indoor sources. Flow-controlled battery operated pumps in a made-to-fit backpack were used to sample personal exposure to 'soot', determined from the reflectance of PM(2.5) filters. Exposure to NO(x) was assessed using Ogawa passive samplers. Children living near busy roads were found to have a 35% higher personal exposure to 'soot' than children living at an urban background location, despite that all children attended the same school that was located away from busy roads. Smaller contrasts in personal exposure were found for NO (14%), NO(2) (15%) and NO(x) (14%). This finding supports the use of 'living near a busy road' as a measure of exposure in epidemiological studies on the effects of traffic-related air pollution in children.     

Nitrous acid interference with passive NO2 measurement methods and the impact on indoor NO2 data

Recent research has demonstrated that nitrous acid (HONO) is produced in indoor environments by NO2 reacting with interior surfaces, and is also emitted directly by some combustion sources. We have recently characterized the interference by HONO to NO2 measurements made by several commonly used continuous NO2 monitors. This paper reports on the effect of HONO on NO2 measurements made by passive sampling devices. The objective of this study was to evaluate this interference, and the accuracy and precision of passive samplers used for indoor NO2 measurements. We report that HONO interferes quantitatively with three of the four NO2 passive samplers tested.     

Relationship of personal exposure to volatile organic compounds to home, work and fixed site outdoor concentrations

Personal exposures of 100 adult non-smokers living in the UK, as well as home and workplace microenvironment concentrations of 15 volatile organic compounds were investigated. The strength of the association between personal exposure and indoor home and workplace concentrations as well as with central site ambient air concentrations in medium to low pollution areas was assessed. Home microenvironment concentrations were strongly associated with personal exposures indicating that the home is the driving factor determining personal exposures to VOCs, explaining between 11 and 75% of the total variability. Workplace and central site ambient concentrations were less correlated with the corresponding personal concentrations, explaining up to 11-22% of the variability only at the low exposure end of the concentration range (e.g. benzene concentrations < 2.5 μg m⁻³). One of the reasons for the discrepancies between personal exposures and central site data was that the latter does not account for exposure due to personal activities (e.g. commuting, painting). A moderate effect of season on the strength of the association between personal exposure and ambient concentrations was found. This needs to be taken into account when using fixed site measurements to infer exposures.     

Indoor aerosols: from personal exposure to risk assessment

Motivated by growing considerations of the scale, severity, and risks associated with human exposure to indoor particulate matter, this work reviewed existing literature to: (i) identify state‐of‐the‐art experimental techniques used for personal exposure assessment; (ii) compare exposure levels reported for domestic/school settings in different countries (excluding exposure to environmental tobacco smoke and particulate matter from biomass cooking in developing countries); (iii) assess the contribution of outdoor background vs indoor sources to personal exposure; and (iv) examine scientific understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident activities, source events and site specificity, and highlights the importance of indoor sources for total personal exposure. Further, it was assessed that 10–30% of the total burden of disease from particulate matter exposure was due to indoor‐generated particles, signifying that indoor environments are likely to be a dominant environmental factor affecting human health. However, due to challenges associated with conducting epidemiological assessments, the role of indoor‐generated particles has not been fully acknowledged, and improved exposure/risk assessment methods are still needed, together with a serious focus on exposure control.     

A field comparison of four samplers for enumerating fungal aerosols I. Sampling characteristics

This study compared the performance of four bioaerosol samplers, the Reuter Centrifugal Air Sampler, the Andersen N6 single stage, the Surface Air System 90, and the Air-o-Cell, in measurements for airborne fungal propagules collected in 75 public building sites without prior knowledge of water damage or mold problems in British Columbia, Canada. The samplers had differences in detection limits, reproducibility, and overall yield. However, high and significant correlations between samplers (indoor samples: Pearson r = 0.60-0.85, P < 0.001) suggest that relative performances between samplers were reasonably consistent. These results indicate that fungal airborne concentration data are dependent on the methods used for assessment, and introduce additional variability in exposure assessment studies. PRACTICAL IMPLICATIONS: In the absence of a standard protocol for sampling bioaerosols, the interpretation of aerosol data reported in indoor air quality studies is entirely dependent on an appreciation of the sampling characteristics of commonly used instrumentation. Although a number of comparative studies have been undertaken in the laboratory, only a few studies have made reported comparison data under field conditions. This study compared three culturable sampling devices, the Andersen N6, SAS 90, and RCS, and one particulate sampling device, the Air-o-Cell, in offices and public areas in a variety of buildings, under conditions of forced air or natural ventilation. The concentrations of fungal aerosols collected during simultaneous sample collection were highly correlated, yet varied by orders of magnitude. The performance of these devices must be carefully considered before a standard protocol can be promulgated.     

Polycyclic aromatic hydrocarbons inside and outside of apartments in an urban area

In the context of environmental monitoring in Berlin polycyclic aromatic hydrocarbon (PAH) concentrations in air and household dust were measured inside 123 residences (and simultaneously in a sub group in the air outside the windows). The aim of this study was to determine exposure to PAHs in the environment influencing by several factors, for instance, motor vehicle traffic in a populous urban area. Indoor air samplings were carried out in two periods (winter and spring/summer) in smokers and non-smokers apartments. Benzo(a)pyrene (BaP) median values were 0.65 ng m(-3) (winter) and 0.27 ng m(-3) (spring/summer) in smokers' apartments and 0.25 ng m(-3) (winter) and 0.09 ng m(-3) (spring/summer) in the apartments of non-smokers. The median BaP content in ambient air was 0.10 ng m(-3) (maximum: 1.1 ng/m(-3)) with an indoor-outdoor mean concentration ratio of 0.9 in non-smoker households and 5.4 in smoker apartments. In household dust we obtained median values of 0.3 mg kg(-1) (range: 0.1-1.4 mg kg(-1)). We found a significant relation between indoor and outdoor values. Approximately 75% of the variance of indoor air values was caused by the corresponding BaP concentrations in the air outside the apartment windows. Otherwise a significant correlation between indoor air and household dust values cannot be found. Therefore, according to our results, it is suggested that the indoor PAH concentration in non-smoker apartments could be attributed mainly to vehicular emissions.     

Comparison Of Tenax And Carbotrap For VOC Sampling In Indoor Air

The most important features of Tenax and Carbotrap, solid sorbents used widely for sampling organic pollutants in air, have been tested under the conditions requested for surveys in indoor spaces and for determinations of VOC emitted from indoor sources by chamber experiments. The performances of samplers, tested with 10 nonpolar and polar (mostly lipophilic) hydrocarbons, present as vapours in 0.5 to 2.0 litre air samples, include: (a) accuracy and reproducibility of the measured concentration, (b) background or “blank” of samplers, (c) stability upon storage (at ambient and below ambient temperatures) of clean samplers and of samplers loaded with VOC, and (d) performance stability after several sampling desorption cycles. The results fulfil the requirements for both adsorbents, though each presents some different drawbacks. In particular (a) Tenax samplers show a “blank” (90 percentile) of 16 ng of benzene and 5 ng of toluene, Carbotrap samplers roughly twice as much; (b) the samplers may be stored for one month either before or after use and (c) they may withstand many cycles without discernible deterioration.     

Occupational exposure and health risks of volatile organic compounds of hotel housekeepers: Field measurements of exposure and health risks

Hotel housekeepers represent a large, low-income, predominantly minority, and high-risk workforce. Little is known about their exposure to chemicals, including volatile organic compounds (VOCs). This study evaluates VOC exposures of housekeepers, sources and factors affecting VOC levels, and provides preliminary estimates of VOC-related health risks. We utilized indoor and personal sampling at two hotels, assessed ventilation, and characterized the VOC composition of cleaning agents. Personal sampling of hotel staff showed a total target VOC concentration of 57 ± 36 µg/m³ (mean ± SD), about twice that of indoor samples. VOCs of greatest health significance included chloroform and formaldehyde. Several workers had exposure to alkanes that could cause non-cancer effects. VOC levels were negatively correlated with estimated air change rates. The composition and concentrations of the tested products and air samples helped identify possible emission sources, which included building sources (for formaldehyde), disinfection by-products in the laundry room, and cleaning products. VOC levels and the derived health risks in this study were at the lower range found in the US buildings. The excess lifetime cancer risk (average of 4.1 × 10⁻⁵) still indicates a need to lower exposure by reducing or removing toxic constituents, especially formaldehyde, or by increasing ventilation rates.