Foreword: JEM Spotlight: Environmental monitoring of airborne nanoparticles

Omowunmi (Wunmi) A. Sadik

Wunmi Sadik is a Professor of Chemistry and the Director of the Center for Advanced Sensors and Environmental Systems at the State University of New York at Binghamton (SUNY-Binghamton). Sadik received her Ph.D. in Chemistry from the University of Wollongong in Australia and did her postdoctoral research at the US Environmental Protection Agency (US-EPA) in Las Vegas, Nevada. Dr Sadik has held appointments at Harvard University, Cornell University and Naval Research Laboratories in Washington, DC. Sadik has over 300 scientific publications and presentations in the areas of biosensors, environmental and materials chemistry. Her work in environmental chemistry utilizes electrochemical and spectroscopic techniques to study risk assessment, endocrine disrupters, and toxicity of synthetic and engineered nanomaterials. Sadik was the recipient of Harvard University's Distinguished Radcliffe Fellowship, National Science Foundation's Discovery Corps Senior Fellowship, SUNY Chancellor Award for Research, Chancellor's Award for Outstanding Inventor, and National Research Council COBASE fellowship.

There has been an explosion of interest in the science and technology of engineered nanomaterials. While nanomaterials have several applications and the benefits of nanotechnology are widely publicised, the discussion about the transformation of nanomaterials in the environment, and their potential impacts on human health has just begun. Nanoscale particles—whether ultrafine, engineered, intentional, or incidental—pose significant health effects. When inhaled, charged particles have been demonstrated to exhibit five to six-fold increases in the probability of being deposited in the lung than uncharged particles of the same size. In addition, these man-made nanoparticles are believed to have significant impacts on atmospheric properties and climate modification since they provide seeds for atmospheric nucleation processes.

Consequently, the environmental monitoring of nanoparticles is a critical research area for several reasons; and one which would greatly benefit from novel approaches to detect their presence and characterize their properties. First, the number of engineered nanomaterials currently on the market is large and is expected to increase rapidly as scientific knowledge increases and technological development advances. Second, there are a number of important, unresolved questions concerning the safety of these materials. Third, the potential exposure scenarios, and their interaction with the biological and environmental systems are largely unknown. Other issues relate to how these materials might move through various environmental or biological media or from one media to another.

Addressing the complex and critical issues surrounding the environmental transformation and toxicity of nanoparticles must be accompanied by the creation of new approaches or further developments of existing instrumentation. In the article by Morawska et al. (DOI: 10.1039/b912589m) provide a critical review of the current instrumental methods available for monitoring airborne nanoparticles is provided. The authors provide terminologies, definitions and distinctions between natural and anthropogenic sources, especially for engineered nanomaterials. Existing instrumental techniques for monitoring airborne particles were also compared with respect to their range of size, response time and working environments. Nanoparticle monitoring techniques reviewed include alcohol vs water-based condensation particle counters; differential mobility particle sizers, scanning mobility particle sizers and the Brunaeur, Emmet and Teller methods. The article also provides an in-depth comparison of a wide range of online and offline techniques by focusing on their strengths and limitations.

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