Novel Active Personal Nanoparticle Sampler for the Exposure Assessment of Nanoparticles in Workplaces Chuen-Jinn Tsai,* ,† Chun-Nan Liu, † Shao-Ming Hung, † Sheng-Chieh Chen, † Shi-Nian Uang, ‡ Yung-Sung Cheng, § and Yue Zhou § † Institute of Environmental Engineering, National Chiao Tung University (NCTU), Hsinchu, 1001 University Road, 30010, Taiwan ‡ Institute of Occupational Safety and Health (IOSH), Council of Labor Affairs, Executive Yuan, 99, Lane 407, Hengke Road, Shijr, Taipei, 22143, Taiwan § Lovelace Respiratory Research Institute, 2425 Ridgecrest, Albuquerque 87108, United States * S Supporting Information ABSTRACT: A novel active personal nanoparticle sampler (PENS), which enables the collection of both respirable par- ticulate mass (RPM) and nanoparticles (NPs) simultaneously, was developed to meet the critical demand for personal sampling of engineered nanomaterials (ENMs) in workplaces. The PENS consists of a respirable cyclone and a micro-orifice impactor with the cutoff aerodynamic diameter (d pa50 ) of 4 μm and 100 nm, respectively. The micro-orifice impactor has a fixed micro-orifice plate (137 nozzles of 55 μm in the inner diameter) and a rotating, silicone oil-coated Teflon filter sub- strate at 1 rpm to achieve a uniform particle deposition and avoid solid particle bounce. A final filter is used after the im- pactor to collect the NPs. Calibration results show that the d pa50 of the respirable cyclone and the micro-orifice impactor are 3.92 ± 0.22 μm and 101.4 ± 0.1 nm, respectively. The d pa50 at the loaded micro-Al 2 O 3 mass of 0.36-3.18 mg is shifted to 102.9-101.2 nm, respectively, while it is shifted to 98.9-97.8 nm at the loaded nano-TiO 2 mass of 0.92-1.78 mg, respectively. That is, the shift of d pa50 due to solid particle loading is small if the PENS is not overloaded. Both NPs and RPM concentrations were found to agree well with those of the IOSH respirable cyclone and MOUDI. By using the present PENS, the collected samples can be further analyzed for chemical species concentrations besides gravimetric analysis to determine the actual exposure concentrations of ENMs in both RPM and NPs fractions in workplaces, which are often influenced by the background or incident pollution sources. ■ INTRODUCTION The development and commercialization of nanotechnology have been growing very rapidly over the past few decades. As more engineered nanomaterials (ENMs) are being incorporated into products or devices, concerns about potential environmental and occupational health implications also increase. In particular, workers in the nanotechnology-based industry deserve more attention as they may have the greatest risk to expose to ENMs that lead to adverse health effects. 1-3 Furthermore, many toxicological and epidemiological studies have shown that inhaled ENMs pose a higher adverse effect than that of large particles, because the number and surface area concentrations of ENMs are much higher than those of large particles with the same mass. 1 Therefore, the assessment of the potential occupational health risks due to the exposure to ENMs is essential to ensure their safe manufacturing and handling in the workplaces. Personal sampling is a better way to ensure accurate re- presentation of the worker’s exposure to ENMs than sampling at a fixed location. 1 However, commercial samplers that sample particles in the nanosized range such as the micro-orifice uniform deposit impactor (MOUDI), 4 the low pressure impactor (LPI), 5 or the electrical low pressure impactor (ELPI), 6 and so forth are too heavy to be used as a personal sampler. The Marple personal cascade impactor was developed as a personal cascade impactor with the d pa50 of 21 to 0.4 μm in its 0-8 stages and an after filter, which does not cover the nanosized range. 7 Therefore, many studies have been devoted to the development of a personal nanoparticle sampler. For example, a thermal precipitator (TP) was designed as a personal sampler to deposit nanoparticles uniformly on a colder plate by a uniform temperature gradient. 8,9 The morphology, crystallography, and chemical composition of the deposited particles could be further analyzed by using scanning electron microscopy (SEM) or transmission electron microscopy Received: December 20, 2011 Revised: March 5, 2012 Accepted: March 21, 2012 Published: March 21, 2012 Article pubs.acs.org/est © 2012 American Chemical Society 4546 dx.doi.org/10.1021/es204580f | Environ. Sci. Technol. 2012, 46, 4546-4552