NORA Manufacturing Sector Strategic Goals
927Z2MK - Nanoaerosol Monitoring Methods
Principal Investigator (PI)
Primary Goal Addressed
Secondary Goal Addressed
Attributed to Manufacturing
Worker exposure to nanomaterials is a global concern. Nanotechnology's promise is introducing many new materials, yet little is known about their health and environmental impacts. This project will contribute new methods to characterize the physical and chemical properties of nanoaerosols/nanomaterials. Metrics include particle mass, surface area, number, size distribution, composition, and morphology. Because the potential adverse health effects of nanoscale materials are not yet known, multiple exposure metrics are needed. This information can provide critical insights on particle toxicity because these properties dictate biological reactivity. Multiple measurements also should provide a better understanding of the physical processes that contribute to workplace exposure. The methods produced can be applied to existing and emerging nanoaerosols/nanomaterials, exposure monitoring, and evaluation of exposure controls.
The explosive growth in nanotechnology is introducing many new materials at a rapidly increasing rate, yet research on their potential health and environmental risks lags far behind. Consumers and the environment may be at risk during the life cycle of nanomaterial products, but workers who produce and handle raw nanomaterials are at greater risk. Factors such as transient exposure to high concentrations of nanomaterials at various stages of production and processing may contribute substantially to this risk.
Traditionally, toxicant mass has been used as an exposure metric, but other metrics (e.g., particle number or surface area) may be more relevant measures of nanoaerosol toxicity. Currently, monitoring includes all three metrics: mass, surface area, and number. Aerosol mass concentration can be determined by traditional filter capture, while direct-reading instruments (e.g., aerosol photometer) can be used for qualitative assessments. Aerosol surface area can be monitored in real-time with a relatively new technique known as diffusion charging. This technique may be a promising tool for workplace assessments. Particle number concentration can be monitored with a handheld condensation particle counter. Particle size distribution also is an important aerosol property. Instruments such as an electrical low pressure impactor (ELPI, Dekati) or a fast, mobility-based measurement (DMS50, Cambustion) provide rapid (about one second) measurement of the particle size distribution, which is often required because workplace particle concentrations can change significantly within short time scales.
Real-time aerosol instrumentation provides useful data, but it cannot distinguish engineered nanomaterials from 'background' particles (e.g., from combustion sources). Therefore, more specific markers must be determined. This can be accomplished through simple filter collection and/or size-resolved particle sampling with cascade impactors. After sampling, the collected material is analyzed by appropriate analytical techniques. Lastly, capture and subsequent analysis of particles by electron microscopy with elemental detection capability provides particle size and shape (morphology) information and the composition of single particles.
This project supports the need for sensitive, selective methods to characterize the physical and chemical properties of nanoaerosols/nanomaterials. Evaluating the effects of nanomaterials on the human health and the environment may require considerable knowledge about their properties. Multiple analytical tools and methods are required for the broad range of nanomaterials being produced. Methods to determine the composition, size distribution, surface area, and dispersion of nanoscale aerosols are being investigated, as are aerosol generation methods and nanoparticle transport. Off-line and on-line (real-time) methods are being developed/evaluated for use in toxicology and field studies. Field research is being conducted to better understand nanomaterial release and exposure, and to identify controls and work practices that reduce workers' exposures. This research will contribute important methods and data needed to establish recommendations for safe workplace production and handling of nanomaterials and directly addresses the Institute's strategic goals for nanotechnology.
The main objective of this research is to develop new methods to characterize the physical and chemical properties of nanoaerosols/nanomaterials. Multiple methods (mass, surface area, number, size distribution, chemical analysis, microscopy) are needed for a comprehensive exposure picture. This research is at the core of the Institute's strategic goals for nanotechnology.
As recognized in a recent NNI report on engineered nanomaterials, evaluating the effects of nanomaterials on the environment and human health may require considerable knowledge about their properties. A broad array of analytical tools and methods are required because of the wide range of nanomaterial properties and types. Methods to determine the composition, size distribution, surface area, shape, and dispersion of nanoscale particles are being investigated.
Field research also is being conducted to better understand nanomaterial release and exposure, and to help identify controls and work practices that reduce workers' exposures. This work is contributing important data, methods, and information needed to establish recommendations for safe production and handling of nanomaterials.
A highly successful project outcome will be new methods to characterize and monitor nanoaerosols/nanomaterials, a better understanding of the physical, chemical, and toxicological properties of nanoscale particles, and a substantial reduction in workers' exposures. The intermediate outcomes of this project can be substantiated mainly through communication with stakeholders and other clear evidence of output use. This includes adoption of controls/methods by industry based on survey findings and recommendations, use of methods/guidance by the research community to fill current knowledge gaps, application by industrial hygienists/employers of the outputs for hazard identification and workplace monitoring, use of outputs by regulatory agencies for standards setting and environmental/occupational monitoring, and citations of this research by other investigators.
The adverse health effects of ultrafine particles such as urban air pollution and diesel emissions are well known. According to the World Health Organization, transport-related pollution results in 80,000 premature deaths in Europe annually. Unlike ultrafine particles (diameters less than 100 nanometers), little is known about the risks of engineered nanoparticles. Nanotechnology is projected to have a one trillion dollar impact on the global economy and employ about two million workers by year 2015. New materials are being introduced at a rapidly increasing rate, yet research on their potential risks lags far behind. This project supports multiple investigations on nanoaerosols/nanomaterials. Objectives include new methods for nanoparticle characterization, better understanding of particle property-toxicity relationships, and new exposure data. Laboratory and field studies are being conducted to investigate nanomaterial release, exposure, and control. Results will greatly benefit other researchers; they also will benefit employers and workers through application to exposure assessment and control.
The project is aligned with strategic goals (SGs) for the Manufacturing sector and the Respiratory Diseases, Exposure Assessment, Global, and Nanotechnology cross sectors. It specifically addresses the following intermediate and activity/output goals:
Respiratory Diseases (SGs 1, 2, 5)
Intermediate Goal 2.3 (09PPRDRIG2.3): prevent and reduce "fiber"-induced respiratory diseases.
Intermediate Goal 5.1 (09PPRDRIG5.1): determine potential respiratory toxicities of nanomaterials. Activity/Output Goal 1.1 (09PPRDRAOG5.1.1): perform basic in vitro and in vivo toxicology studies to evaluate for respiratory toxicity of nanoparticles and, if present, to characterize nanoparticle characteristics and mechanisms of action underlying toxic effects.
Intermediate Goal 5.2 (09PPRDRIG5.2): characterize respiratory exposures and measures used to reduce exposures…in work settings where engineered nanomaterials are produced or used. Activity/Output Goal 2.1 (09PPRDRAOG5.2.1): develop partnerships and conduct field evaluations of facilities where nanomaterials are produced or used.
Intermediate Goal 5.3 (09PPRDRIG5.3): develop guidance for facilities that produce or use nanomaterials.
Exposure Assessment (SG2)
Intermediate Goal 2.10 (09PPEXAIG2.10): Develop reference materials and values for use in exposure assessment studies. Activity/Output 2.10.1 (09PPEXAAOG2.10.1): Development of reference materials or values either through partnerships, literature reviews or direct synthesis of the reference materials.
Intermediate Goal 2.11 (09PPEXAIG2.11): Address critical exposure assessment needs in emerging areas such as nanotechnology…Activity/Output 2.11.1 (09PPEXAAOG2.11.1): Development of exposure assessment tools to characterize and evaluate the exposure to these emerging areas. Activity/Output 2.11.2 (09PPEXAAOG2.11.2): Application of exposure assessment tools to these emerging areas.
Nanotechnology (SGs 1, 4)
Intermediate Goal 1.1 (09PPNAN1G1.1): Determine the key factors influencing the generation, dispersion, deposition, and re-entrainment of nanomaterials in the workplace, including the role of mixed exposures.
Intermediate Goal 1.2 (09PPNANIG1.2): Quantitatively assess exposures to nanomaterials in the workplace including inhalation and dermal exposure. Determine how exposures differ by work task or process.
Intermediate Goal 5.2 (09PPNANIG5.2): Develop new measurement methods.