Estimation of surface area concentration of workplace incidental nanoparticles based on number and mass concentrations
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Surface area was estimated by three different methods using number and/or mass concentrations obtained from either two or three instruments that are commonly used in the field. The estimated surface area concentrations were compared with reference surface area concentrations (SAREF) calculated from the particle size distributions obtained from a scanning mobility particle sizer and an optical particle counter (OPC). The first estimation method (SAPSD) used particle size distribution measured by a condensation particle counter (CPC) and an OPC. The second method (SAINV1) used an inversion routine based on PM1.0, PM2.5, and number concentrations to reconstruct assumed lognormal size distributions by minimizing the difference between measurements and calculated values. The third method (SAINV2) utilized a simpler inversion method that used PM1.0 and number concentrations to construct a lognormal size distribution with an assumed value of geometric standard deviation. All estimated surface area concentrations were calculated from the reconstructed size distributions. These methods were evaluated using particle measurements obtained in a restaurant, an aluminum die-casting factory, and a diesel engine laboratory. SAPSD was 0.7–1.8 times higher and SAINV1 and SAINV2 were 2.2–8 times higher than SAREF in the restaurant and diesel engine laboratory. In the die casting facility, all estimated surface area concentrations were lower than SAREF. However, the estimated surface area concentration using all three methods had qualitatively similar exposure trends and rankings to those using SAREF within a workplace. This study suggests that surface area concentration estimation based on particle size distribution (SAPSD) is a more accurate and convenient method to estimate surface area concentrations than estimation methods using inversion routines and may be feasible to use for classifying exposure groups and identifying exposure trends.
KeywordsSurface area concentration Surface area estimation Nanoparticles Inversion method Occupational health and safety
We thank TSI, Inc. for the instrumentation and technical support for this study, in particular Dr. Avula Sreenath’s help with calibration data and the Campus Club at the University of Minnesota, QX Inc., and the Center for Diesel Research in Department of Mechanical Engineering at University of Minnesota for allowing us to collect samples in their workplaces. Financial support for this project was provided by 3 M Company and the Midwest Center for Occupational Health and Safety (MCOHS) paper.
- Accuratus (2009) Aluminum oxide, Al2O3. http://www.accuratus.com/alumox.html. Accessed 19 April 2010
- Bell TE (2007) Understanding risk assessment of nanotechnology. National Nanotechnology Initiative web. http://www.nano.gov/Understanding_Risk_Assessment.pdf. Accessed 19 April 2010
- Faux SP, Tran CL, Miller BG, Jones AD, Monteiller C, Donaldson K (2003). In vitro determinants of particulate toxicity: the dose-metric for poorly soluble dusts. Research Report 154, Suffolk, UK, Health and Safety ExecutiveGoogle Scholar
- Hach (2010) Met One HHPC-6 Handheld optical particle counter http://www.hach.com/fmmimghach?/19588%7C1. Accessed 22 May 2011
- ICRP (1994) International Commission on Radiological Protection Publication 66 Human Respiratory Tract Model for Radiological Protection. Pergamon, Elsevier Science Ltd., OxfordGoogle Scholar
- Kuehn TH (2008) Characterization of effluents from additional cooking appliances. Report 1375. ASHRAEGoogle Scholar
- NIOSH (1994) Particulates not otherwise regulated, total (0500). In: NIOSH Manual of Analytical Methods, National Institute for Occupational Safety and Health (NIOSH), CincinnatiGoogle Scholar
- Ramachandran G, Adgate JL, Pratt GC, Sexton K (2003) Characterizing indoor and outdoor 15-minute average PM2.5 concentrations in urban neighborhoods. Aerosol Sci Technol 37:33–45Google Scholar
- Rappaport SM, Kupper LL (2008) Quantitative exposure assessment, Lulu PressGoogle Scholar
- Sreenath A (2009) Personal communication. TSI Inc.Google Scholar
- Woo KS, Chen DR, Pui DYH, Wilson WE (2001) Use of continuous measurements of integral aerosol parameters to estimate particle surface area. Aerosol Sci Technol 34:57–65Google Scholar