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Diesel exhaust (DE) contains a variety of toxic air pollutants, including diesel particulate matter (DPM) and gaseous contaminants (e.g., carbon monoxide (CO)). DPM is dominated by fine (PM2.5) and ultrafine particles (UFP), and can be representatively determined by its thermal-optical refractory as elemental carbon (EC) or light-absorbing characteristics as black carbon (BC). The currently accepted reference method for sampling and analysis of occupational exposure to DPM is the National Institute for Occupational Safety and Health (NIOSH) Method 5040. However, this method cannot provide in-situ short-term measurements of DPM. Thus, real-time monitors are gaining attention to better examine DE exposures in occupational settings. However, real-time monitors are subject to changing environmental conditions. Field measurements have reported interferences in optical sensors and subsequent real-time readings, under conditions of high humidity and abrupt temperature changes. To begin dealing with these issues, we completed a controlled study to evaluate five real-time monitors: Airtec real-time DPM/EC Monitor, TSI SidePak Personal Aerosol Monitor AM510 (PM2.5), TSI Condensation Particle Counter 3007, microAeth AE51 BC Aethalometer, and Langan T15n CO Measurer. Tests were conducted under different temperatures (55, 70, and 80°F), relative humidity (10, 40, and 80%), and DPM concentrations (50 and 200 μg/m(3)) in a controlled exposure facility. The 2-hr averaged EC measurements from the Airtec instrument showed relatively good agreement with NIOSH Method 5040 (R(2) = 0.84; slope = 1.17±0.06; N = 27) and reported ∼17% higher EC concentrations than the NIOSH reference method. Temperature, relative humidity, and DPM levels did not significantly affect relative differences in 2-hr averaged EC concentrations obtained by the Airtec instrument vs. the NIOSH method (p < 0.05). Multiple linear regression analyses, based on 1-min averaged data, suggested combined effects of up to 5% from relative humidity and temperature on real-time measurements. The overall deviations of these real-time monitors from the NIOSH method results were ≤20%. However, simultaneous monitoring of temperature and relative humidity is recommended in field investigations to understand and correct for environmental impacts on real-time monitoring data.

A new, passive particle deposition air sampler, called the Einstein-Lioy Deposition Sampler (ELDS), has been developed to fill a gap in passive sampling for near-field particle emissions. The sampler can be configured in several ways: with a protective hood for outdoor sampling, without a protective hood, and as a dust plate. In addition, there is an XRF-ready option that allows for direct sampling onto a filter-mounted XRF cartridge which can be used in conjunction with all configurations. A wind tunnel was designed and constructed to test the performance of different sampler configurations using a test dust with a known particle size distribution. The sampler configurations were also tested versus each other to evaluate whether or not the protective hood would affect the collected particle size distribution. A field study was conducted to test the sampler under actual environmental conditions and to evaluate its ability to collect samples for chemical analysis. Individual experiments for each configuration demonstrated precision of the sampler. The field experiment demonstrated the ability of the sampler to both collect mass and allow for the measurement of an environmental contaminant i.e. Cr(6+). The ELDS was demonstrated to be statistically not different for Hooded and Non-Hooded models, compared to each other and the test dust; thus, it can be used indoors and outdoors in a variety of configurations to suit the user's needs.

Background: Air pollution has been a topic of intense concern and study for hundreds of years. During the second half of the 20th century, the United States implemented regulations and controls to reduce the levels of criteria air pollutants and achieve the National Ambient Air Quality Standards (NAAQS) for the protection of human health, while concurrently reducing the levels of toxic air pollutants., Objective: In this commentary we trace the changes in air pollution in New Jersey as a case study, demonstrating the impact of local, state, and federal strategies to control emissions of pollutants and pollutant precursors from the 1950s until today., Discussion: The original NAAQS (1970-1995) have been achieved, and significant progress has been made to achieve revised standards for ozone and particulate matter (PM) < 2.5 µm in aerodynamic diameter (PM2.5) in New Jersey, which in the past was considered a highly polluted industrial state., Conclusions: Assuming no reversals on current regulations because of some major event or energy infrastructure disruption, outdoor air pollution reductions will continue to address health risks among specific segments of the general population affected by ozone/PM and pollution caused by neighborhood, local, and regional point and mobile sources.

The strategies for protecting our deployed U.S. Forces are outlined in National Research Council documents published in 1999-2000. This article summarizes experiences and information gathered and interpreted regarding population and rescue workers' exposures in the aftermath of the 2001 World Trade Center attacks, with the aim to provide insights on issues related to military deployment to locations with hazardous agents. Issues covered include phases of exposure, materials of concern, detection equipment, and personal protection equipment. The focus is on human exposure issues, which are primarily associated with strategies 1 through 3 of the National Research Council's report entitled "Protecting Those Who Serve: Strategies to Protect the Health of Deployed U.S. Forces". Contact and duration of contact with hazardous substances are critical areas of concern, which require prevention and intervention procedures and protocols to reduce the incidence of acute and long-term health outcomes.

Exposure and dose estimation are essential to understanding the etiology of environmentally linked childhood diseases. The behavior of resuspended particulate matter (PM) suggests that stationary measurements may underestimate household exposures in young children (ages 6-36 months). Because of the size and weight of the sampling equipment, use of personal samplers in this age group is either difficult or impossible. The Pretoddler Inhalable Particulate Environmental Robotic (PIPER Mk IV) sampler has been developed to provide a surrogate method to ascertain personal exposures to PM for this age group. As part of a study of childhood asthma, 55 homes in central New Jersey were tested. Simultaneous sampling for inhalable PM using stationary (110 cm height) and PIPER mobile sampler were carried out. In homes with bare floors (N=21), the absolute difference was 3.9 μg/m3 (SE=3.01; p=0.217) and relative difference (PIPER/Stationary) was 1.12 (linearized SE=0.11). On carpets (N=34), the absolute difference was 54.1 μg/m3 (SE=13.50; p=0.0003), and the relative difference was 2.30 (linearized SE=0.34). The results confirm the importance of understanding the personal dust cloud caused by children's activity in a room, particularly when rugs or carpets are present.

In contrast to Cr(+3), Cr(+6) is carcinogenic and allergenic. Although Cr(+6) can occur naturally, it is thought that most soil Cr(+6) is anthropogenic, however, the extent of Cr(+6) in the background environment is unknown. Cr(+6)-containing chromite ore processing residue (COPR) from chromate manufacture was deposited in numerous locations in Jersey City (JC), New Jersey. In the 1990's, significantly elevated concentrations of total Cr (Cr(+6)+Cr(+3)) were found in house dust near COPR sites. We undertook a follow-up study to determine ongoing COPR exposure. We compared Cr(+6) in house dust in JC to selected background communities with no known sources of Cr(+6). Samples were collected from living areas, basements and window wells. Cr(+6) was detected in dust from all JC and background houses. In the JC homes, the mean (+ or - SD) Cr(+6) concentration for all samples was 3.9 + or - 7.0 microg/g (range: non-detect-90.4 microg/g), and the mean Cr(+6) loading was 5.8 + or - 15.7 microg/m(2) (range: non-detect-196.4 microg/m(2)). In background homes, the mean Cr(+6) concentrations of all samples was 4.6 + or - 7.8 microg/g, (range, 0.05-56.6 microg/g). The mean loading was 10.0 + or - 27.9 microg/m(2) (range, 0.22-169.3 microg/m(2)). There was no significant difference between Cr(+6) dust concentrations in Jersey City and background locations. Stratification by sample location within houses and sampling method gave similar results. Samples exceeding 20 microg/g were obtained only from single wood surfaces in different homes. Lower concentrations in window well samples suggests transport from outside is not the major source of indoor Cr(+6). Landscaping and groundcover may influence indoor Cr(+6). There appears to be a widespread low level background of Cr(+6) that is not elevated in Jersey City homes despite its historic COPR contamination. It is possible that house dust, in general, is a source of Cr(+6) exposure with potential implications for persistence of chromium allergic contact dermatitis., (Copyright 2010 Elsevier B.V. All rights reserved.)

This article discusses the gaps in our understanding of human exposures to nanoparticles stemming from the use of nanotechnology-based consumer products by the general public. It also describes a series of steps that could be taken to characterize such exposures. The suggested steps include classification of the nanotechnology-based products, simulation of realistic exposure patterns, characterization of emissions, analysis of the duration of activities resulting in exposures, and consideration of the bioaccessibility of nanoparticles. In addition, we present a preliminary study with nanotechnology-based cosmetic powders where particle release was studied under realistic powder application conditions. The data demonstrated that when nanotechnology-based cosmetic powders were used, there was a potential for inhaling airborne particles ranging in size from tens of nanometers to tens of micrometers.

This study presents the Individual Based Exposure Modeling (IBEM) application of MENTOR (Modeling ENvironment for TOtal Risk studies) in a hot spot area, where there are concentrated local sources on the scale of tens to hundreds of meters, and an urban reference area in Camden, NJ, to characterize the ambient concentrations and personal exposures to benzene and toluene from local ambient sources. The emission-based ambient concentrations in the two neighborhoods were first estimated through atmospheric dispersion modeling. Subsequently, the calculated and measured ambient concentrations of benzene and toluene were separately combined with the time-activity diaries completed by the subjects as inputs to MENTOR/IBEM for estimating personal exposures resulting from ambient sources. The modeling results were then compared with the actual personal measurements collected from over 100 individuals in the field study to identify the gaps in modeling personal exposures in a hot spot. The modeled ambient concentrations of benzene and toluene were generally in agreement with the neighborhood measurements within a factor of 2, but were underestimated at the high-end percentiles. The major local contributors to the benzene ambient levels are from mobile sources, whereas mobile and stationary (point and area) sources contribute to the toluene ambient levels in the study area. This finding can be used as guidance for developing better air toxic emission inventories for characterizing, through modeling, the ambient concentrations of air toxics in the study area. The estimated percentage contributions of personal exposures from ambient sources were generally higher in the hot spot area than the urban reference area in Camden, NJ, for benzene and toluene. This finding demonstrates the hot spot characteristics of stronger local ambient source impacts on personal exposures. Non-ambient sources were also found as significant contributors to personal exposures to benzene and toluene for the population studied.

To provide a scientific basis for the selection and use of continuous monitors for exposure and/or health effects studies, and for compliance and episode measurements at strategic locations in the State of New Jersey, we evaluated the performance of seven continuous fine particulate matter (PM2.5) monitors in the present study. Gravimetric samplers, as reference methods, were collocated with realtime instruments in both laboratory and field tests. The results of intercomparison of real-time monitors showed that the two nephelometers used in this study correlated extremely well (r2 approximately 0.97), and two tapered element oscillating monitors (TEOM 1400 and TEOM filter dynamics measurement system [FDMS]) correlated well (r2 > 0.85), whereas two beta gauges displayed a weaker correlation (r2 < 0.6). During a summertime controlled (laboratory) evaluation, the measurements made with the gravimetric method correlated well with the 24-hr integrated measurements made with the real-time monitors. The SidePak nephelometer overestimated the particle concentration by a factor of approximately 3.4 compared with the gravimetric method. During a summertime field evaluation, the TEOM FDMS monitor reported approximately 30% higher mass concentration than the Federal Reference Method (FRM); and the difference could be explained by the loss of semi-volatile materials from the FRM sampler. Results also demonstrated that 24-hr average PM2.5 mass concentrations measured by beta gauges and TEOM (50 degrees C) in winter correlated well with the integrated gravimetric method. Seasonal differences were observed in the performance of the TEOM (50 degrees C) monitor in measuring the particle mass attributed to the higher semi-volatile material loss in the winter weather. In applying the realtime particulate matter monitoring data into Air Quality Index (AQI) reporting, the Conroy method and the 8-hr end-hour average method were both found to be suitable.

There is growing scientific evidence linking early childhood exposure to environmental agents with asthma and other illnesses that may not appear until later in life. Unfortunately the direct measurement of personal exposures of children in the first year of life is not possible by existing methodologies. This study developed and evaluated a new methodology to better assess exposure of children to inhalable particles in the first year of life while involved in floor play in the home. We constructed the Pre-Toddler Inhalable Particulate Environmental Robotic (PIPER) sampler. Two series of measurements of inhalable particles were carried out. One collected filter samples of airborne inhalable particles and a second used a real-time total particle mass concentration monitor. Samples were collected for seven residential locations. Duplicate samples were collected with PIPER 20 cm above the floor and from an identical stationary monitor positioned at a height of 110 cm. The mean observed airborne inhalable particle concentrations measured by PIPER was 98.6 microg/ m3, whereas simultaneously collected stationary samples mean concentration was 49.8 microg/m3. The average observed ratio of PIPER samples to stationary samples was 2.4. A paired t test comparison of the two sampling methods indicated a statistically significant higher level of inhalable particle concentration measured by PIPER in comparison with the fixed sampler (P < 0.0001). Peak concentrations as measured by a real-time monitor were in excess of 3600 microg/m3. The results suggest that children playing on the floor are exposed to a higher concentration of total inhalable particles than previous methodologies estimate.

Airborne aldehyde and ketone (carbonyl) sampling methodologies based on derivatization with 2,4-dinitrophenylhydrazine (DNPH)-coated solid sorbents could unequivocally be considered the "gold" standard. Originally developed in the late 1970s, these methods have been extensively evaluated and developed up to the present day. However, these methods have been inadequately evaluated for the long-term (i.e., 24 h or greater) sampling collection efficiency (CE) of carbonyls other than formaldehyde. The current body of literature fails to demonstrate that DNPH-coated solid sorbent sampling methods have acceptable CEs for the long-term sampling of carbonyls other than formaldehyde. Despite this, such methods are widely used to report the concentrations of multiple carbonyls from long-term sampling, assuming approximately 100% CEs. Laboratory experiments were conducted in this study to evaluate the long-term formaldehyde and acetaldehyde sampling CEs for several commonly used DNPH-coated solid sorbents. Results from sampling known concentrations of formaldehyde and acetaldehyde generated in a dynamic atmosphere generation system demonstrate that the 24-hour formaldehyde sampling CEs ranged from 83 to 133%, confirming the findings made in previous studies. However, the 24-hour acetaldehyde sampling CEs ranged from 1 to 62%. Attempts to increase the acetaldehyde CEs by adding acid to the samples post sampling were unsuccessful. These results indicate that assuming approximately 100% CEs for 24-hour acetaldehyde sampling, as commonly done with DNPH-coated solid sorbent methods, would substantially under estimate acetaldehyde concentrations.

A sensitive, simple, and cost-effective passive sampling methodology was developed to quantify personal exposure to gaseous polycyclic aromatic hydrocarbons (PAHs). A Fan-Lioy passive PAH sampler (FL-PPS) is constructed from 320 sections of 1-cm long SPB-5 GC columns (0.75-mm i.d. and 7-microm film thickness), similar to a mini-honeycomb denuder. Given the unique feature of the GC column stationary phase, gaseous PAHs are collected on the inner surfaces of the columns by molecular diffusion and thermally desorbed to GC/MS for analysis. The sampling rates of FL-PPS were determined in the laboratory using a controlled test atmosphere containing eight PAHs for a range of face velocity, temperature, relative humidity, PAH concentration, and sampling duration. The sampling rate (mean, %RSD, cm3/min) was 26.7 (21%) for acenaphthylene, 37.6 (25%) for acenaphthene, 56.2 (13%) for fluorene, 49.1 (25%) for phenanthrene, 62.7 (22%) for anthracene, 65.4 (24%) for fluoranthene, and 64.4 (18%) for pyrene over a sampling duration of 8-48 h. The sampling rate for naphthalene was approximately 14.1 (12%) cm3/min over a sampling period of 8 h but decreased along with an increase of sampling time. The effects of temperature, humidity, face velocity, and PAH concentration on the sampling rate were not significant for all the compounds tested. A reasonable agreement (<30%) was obtained for most compounds measured by FL-PPS and a conventional active PAH sampling method colocated side-by-side in the field, but a sampling time of 24 h or longer was required for detection of less abundant PAHs in community settings.

Copper is an essential trace element and adverse health effects can potentially be associated with both very low and very high intakes. Accurate estimates of inhalation and ingestion (food and drinking water) exposures are therefore needed in order to realistically assess any effects of the distribution of copper intakes within the general population. The work presented here demonstrates an application of a customized subset of the MENTOR/SHEDS-4M computational system (Modeling ENvironment for TOtal Risk studies, employing the Stochastic Human Exposure and Dose Simulation approach, for Multimedia, Multipathway, Multiroute exposures to Multiple co-occurring contaminants. The application utilized data from the National Human Exposure Assessment Survey (NHEXAS) for USEPA Region V as well as from a variety of other available databases. The case study, using a statistical population-based modeling framework, was performed for Eaton County, MI. The results of the simulations, aggregated for six age subgroups of the general population, suggest that food intake is the major pathway for total copper exposure, while drinking water can have significant contributions at the tail of the distribution of intakes. Specifically, it was estimated that over 80% of the county population received potential doses of copper from food that were lower than the Institute of Medicine (IOM) Recommended Dietary Allowance (RDA) value of 900 microg/day. Furthermore, the total combined potential dose from food and water was only about two times greater than the recommended value only for individuals with intakes in the range above the 99th percentile of both food and water intakes. The values were well below the upper tolerable intake value of 10,000 microg/day. The inhalation route consistently acted as only a minor contributor to the total exposure.

Five methods of sampling lead-contaminated dust on carpets were evaluated and compared in 33 New Jersey homes of children with elevated blood lead levels. The five sampling methods were (1) wipe, (2) adhesive label, (3) C18 sheet, (4) vacuum, and (5) hand rinse. Samples were collected side by side on the same carpets within the homes. Among the five methods the wipe and vacuum methods showed high percentages of detectable samples, good reproducibility, and significant correlations with other methods. C18 sheets and adhesive labels collected the least quantity of lead dust, with high percentages of undetectable samples. Because of the limited ability of sampling lead on carpets and the relatively high cost for laboratory analysis, C18 sheets or adhesive labels are not considered feasible sampling techniques. The hand rinse method also was not feasible for carpet sampling, because it was difficult to conduct in the field and laboratory, and it was subject to inconsistency and cross contamination. Wipes, which collected lead dust from carpet surfaces, were believed to be the most appropriate method for measuring lead from carpets accessible to children. However, because of the low pickup from carpets, wipes may not be an appropriate measuring tool to assess the levels of total lead contamination in carpets. The authors recommend using surface wipe sampling to measure accessible lead from carpets for exposure assessment, and vacuum sampling to obtain the information on total lead accumulation.

The ability of questionnaires to predict children's exposure to pesticides was examined as part of the Minnesota Children's Pesticide Exposure Study (MNCPES). The MNCPES focused on a probability sample of 102 children between the ages of 3 and 13 years living in either urban (Minneapolis and St. Paul, MN) or nonurban (Rice and Goodhue Counties in Minnesota) households. Samples were collected in a variety of relevant media (air, food, beverages, tap water, house dust, soil, urine), and chemical analyses emphasized three organophosphate insecticides (chlorpyrifos, diazinon, malathion) and a herbicide (atrazine). Results indicate that the residential pesticide-use questions and overall screening approach used in the MNCPES were ineffective for identifying and oversampling children/households with higher levels of individual target pesticides.

Source types or source regions contributing to the concentration of atmospheric fine particles measured at Brigantine National Wildlife Refuge, NJ, were identified using a factor analysis model called Positive Matrix Factorization (PMF). Cluster analysis of backward air trajectories on days of high- and low-factor concentrations was used to link factors to potential source regions. Brigantine is a Class I visibility area with few local sources in the center of the eastern urban corridor and is therefore a good location to study Mid-Atlantic regional aerosol. Sulfate (expressed as ammonium sulfate) was the most abundant species, accounting for 49% of annual average fine mass. Organic compounds (22%; expressed as 1.4 x organic carbon) and ammonium nitrate (10%) were the next abundant species. Some evidence herein suggests that secondary organic aerosol formation is an important contributor to summertime regional aerosol. Nine factors were identified that contributed to PM2.5 mass concentrations: coal combustion factors (66%, summer and winter), sea salt factors (9%, fresh and aged), motor vehicle/mixed combustion (8%), diesel/Zn-Pb (6%), incinerator/industrial (5%), oil combustion (4%), and soil (2%). The aged sea salt concentrations were highest in springtime, when the land breeze-sea breeze cycle is strongest. Comparison of backward air trajectories of high- and low-concentration days suggests that Brigantine is surrounded by sources of oil combustion, motor vehicle/mixed combustion, and waste incinerator/industrial emissions that together account for 17% of PM2.5 mass. The diesel/Zn-Pb factor was associated with sources north and west of Brigantine. Coal combustion factors were associated with coal-fired power plants west and southwest of the site. Particulate carbon was associated not only with oil combustion, motor vehicle/mixed combustion, waste incinerator/industrial, and diesel/Pb-Zn, but also with the coal combustion factors, perhaps through common transport.

The explosion and collapse of the World Trade Center (WTC) was a catastrophic event that produced an aerosol plume impacting many workers, residents, and commuters during the first few days after 11 September 2001. Three bulk samples of the total settled dust and smoke were collected at weather-protected locations east of the WTC on 16 and 17 September 2001; these samples are representative of the generated material that settled immediately after the explosion and fire and the concurrent collapse of the two structures. We analyzed each sample, not differentiated by particle size, for inorganic and organic composition. In the inorganic analyses, we identified metals, radionuclides, ionic species, asbestos, and inorganic species. In the organic analyses, we identified polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, polychlorinated dibenzodioxins, polychlorinated dibenzofurans, pesticides, phthalate esters, brominated diphenyl ethers, and other hydrocarbons. Each sample had a basic pH. Asbestos levels ranged from 0.8% to 3.0% of the mass, the PAHs were > 0.1% of the mass, and lead ranged from 101 to 625 microg/g. The content and distribution of material was indicative of a complex mixture of building debris and combustion products in the resulting plume. These three samples were composed primarily of construction materials, soot, paint (leaded and unleaded), and glass fibers (mineral wool and fiberglass). Levels of hydrocarbons indicated unburned or partially burned jet fuel, plastic, cellulose, and other materials that were ignited by the fire. In morphologic analyses we found that a majority of the mass was fibrous and composed of many types of fibers (e.g., mineral wool, fiberglass, asbestos, wood, paper, and cotton). The particles were separated into size classifications by gravimetric and aerodynamic methods. Material < 2.5 microm in aerodynamic diameter was 0.88-1.98% of the total mass. The largest mass concentrations were > 53 microm in diameter. The results obtained from these samples can be used to understand the contact and types of exposures to this unprecedented complex mixture experienced by the surviving residents, commuters, and rescue workers directly affected by the plume from 11 to 12 September and the evaluations of any acute or long-term health effects from resuspendable dust and smoke to the residents, commuters, and local workers, as well as from the materials released after 11 September until the fires were extinguished. Further, these results support the need to have the interior of residences, buildings, and their respective HVAC systems professionally cleaned to reduce long-term residential risks before rehabitation.

The air pollution problem can be depicted as a system consisting of several basic components: source, concentration, exposure, dose, and adverse effects. Exposure, the contact between an agent (e.g., an air pollutant) and a target (e.g., a human respiratory tract), is the key to linking the pollution source and health effects. Human exposure to air pollutants depends on exposure concentration and exposure duration. Exposure concentration is the concentration of a pollutant at a contact boundary, which usually refers to the human breathing zone. However, ambient concentrations of regulated pollutants at monitoring sites have been measured in practice to represent actual exposure. This can be a valid practice if the pollutants are ones that are predominantly generated outdoors and if the monitoring sites are appropriately selected to reflect where people are. Results from many exposure studies indicate that people are very likely to receive the greatest exposure to many toxic air pollutants not outside but inside places such as homes, offices, and automobiles. For many of these pollutants, major sources of exposure can be quite different from major sources of emission. This is because a large emission source can have a very small value of exposure effectiveness, i.e., the fraction of pollutant released from a source that actually reaches the human breathing zone. Exposure data are crucial to risk management decisions for setting priorities, selecting cost-effective approaches to preventing or reducing risks, and evaluating risk mitigation efforts. Measurement or estimate of exposure is essential but often inadequately addressed in environmental epidemiologic studies. Exposure can be quantified using direct or indirect measurement methods, depending upon the purpose of exposure assessment and the availability of relevant data. The rapidly developing battery and electronic technologies as well as advancements in molecular biology are expected to accelerate the improvement of current methods and the development of new methods for future exposure assessment.

Background: The National Research Council (NRC) of the National Academy of Sciences recently published the report Exposure Science in the 21st Century: A Vision and a Strategy. The expert committee undertaking this report included expertise from ecology, chemistry, exposure science, toxicology, public health, bioethics, engineering, medicine, and policy. Objective: Our aim is to inform members of the scientific community in fields aligned with environmental and public health so they are more able to appreciate the full breadth of the vision and understand the framework developed in order to move the vision forward. Discussion: Although the NRC report was commissioned by the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences, it is solely the consensus product of the independent volunteer committee, whose findings were subject to the rigorous peer-review procedures of the NRC. In addition to reviewing the history and current status of exposure science, the report lays out a vision for the future and makes recommendations that include both short-term and long-term milestones. Conclusion: To accomplish the vision presented in the NRC report, resources will be needed to complete studies, develop and use analyses of exposure, and build databases associated with individual and population exposures, as well as to train the next generation of exposure scientists. Important excerpts as well as paraphrased statements from the report appear in this commentary; however, the general observations and comments are our own. [ABSTRACT FROM AUTHOR]

Background: The market of nanotechnology-based consumer products is rapidly expanding, and the lack of scientific evidence describing the accompanying exposure and health risks stalls the dis­cussion regarding its guidance and regulation.Objectives: We investigated the potential for human contact and inhalation exposure to nano­materials when using nanotechnology-based cosmetic powders and compare them with analogous products not marketed as nanotechnology based.Methods: We characterized the products using transmission electron microscopy (TEM) and laser diffraction spectroscopy and found nanoparticles in five of six tested products. TEM photomicrographs showed highly agglomerated states of nanoparticles in the products. We realistically simulated the use of cosmetic powders by applying them to the face of a human mannequin head while simultaneously sampling the released airborne particles through the ports installed in the mannequin's nostrils.Results: We found that a user would be exposed to nanomaterial predominantly through nanoparticle-containing agglomerates larger than the 1-100-nm aerosol fraction.Conclusions: Predominant deposition of nanomaterial(s) will occur in the tracheobronchial and head airways-not in the alveolar region as would be expected based on the size of primary nanoparticles. This could potentially lead to different health effects than expected based on the current understanding of nanoparticle behavior and toxicology studies for the alveolar region [ABSTRACT FROM AUTHOR]