Dr. Constantinos Sioutas, Sc.D., is the first holder of the Fred Champion Professorship in Civil and Environmental Engineering at the University of Southern California (USC). His research has followed an integrated approach to the problem of the well-publicized and significant effects of particulate air pollution on health and the environment. His research has focused on investigations of the underlying mechanisms that produce the health effects associated with exposure to air pollutants generated by a variety of sources. He has developed many state-of-the-art technologies used by many academic institutions and national laboratories for aerosol sampling and characterization. He has authored 280 peer-reviewed journal publications, 5 book chapters and holds 13 U.S. patents in the development of instrumentation for aerosol measurement and emissions control. He is the recipient of the AAAR David Sinclair award in 2015, the Hagen Smit award of Atmospheric Environment for seminal publications, the 2010 Scientific and Technological Achievement Award by the U.S. Environmental Protection Agency, a Fulbright fellow and a trustee of his undergraduate alma mater, the Aristotle University of Thessaloniki in Greece.
Numerous epidemiological studies have shown a relationship between ambient particulate pollution and adverse health effects on humans. Nonetheless, our understanding of how particle properties such as particle size, surface area and chemistry affect their toxic properties remains rather limited. In this tutorial we will discuss conventional and state-of-the-art technologies used for the evaluation of toxicological properties of PM. We will first start with traditional particle collection methods, such as filtration, impaction and the use of liquid impinger- BioSampler techniques. Despite their simplicity, we will demonstrate that these methods may suffer from shortcomings related to alterations of the physical and/or chemical characteristics of the sampled aerosol. We will then present state-of-the-art technological improvements of these conventional methods, such as particle concentrators that have been widely used in different aerosol study applications. We will present results from numerous studies showing that these concentrators can effectively preserve the physical, chemical and redox properties of PM during the concentration enrichment process, thereby making them a significant advancement in many aerosol research applications, including enhancement of signal-to-noise ratios of on-line aerosol monitors, uses in molecular/cellular in-vitro toxicity assays and real-time in-vivo exposures, as well as direct PM collection in aqueous solutions for chemical and toxicological analysis. We will then present applications and modifications of these systems for innovative particle-into-liquid collection that can achieve a much better recovery of both soluble and insoluble species of PM compared to conventional filtration/impaction methods, and demonstrate how this increased recovery translates into better and more accurate ways of assessing the toxicological properties of PM. We will finally present major findings from recent health studies utilizing these technologies to expose cells or animals to urban aerosols of various sizes and chemical composition, and discuss how these particle attributes affect the observed health outcomes.