*The seminar will be in English, the event is open to the public.

Abstract 
Suspended particles in the breathing air can have adverse effects upon human health and climate. These environmental effects depend primarily on the size and composition of the particles, which can abruptly change depending on the vapor water content of the air and their hygroscopicity (i.e., their ability to take up water). For example, ammonium sulfate particles are dry when the relative humidity (RH) of the atmosphere is lower than 35%, but they become larger aqueous-solution droplets when the RH increases above 80%. At intermediate RH values, the particles can be in either the dry or the aqueous-solution state depending on their RH history. Knowing the size and the amount of water that airborne particles contain at different RH conditions is therefore crucial for understanding both their behavior in the atmosphere and their transport through the human respiratory system.

Laboratory-generated aerosol nanoparticles of well-defined size and composition, on the other hand, can be used to develop novel nanomaterials for a wide range of applications. For instance, aerosol nanoparticles can be used to fabricate semiconducting nanomaterials for gas sensors used in environmental monitoring. Compared to other methods in the field of nanotechnology, aerosol-based tools offer many advantages including low cost, good control over nanoparticle size and composition, as well as high purity. In addition, they offer simple ways for producing versatile nanoporous structures with granular and/or dendritic morphologies, thereby allowing good control over their surface-to-volume ratio. By further annealing the resulting nanomaterials one can also control their morphology and crystal structure, which in turn affects their ability to adsorb/desorb specific gas molecules thereby making them highly selective gas sensors.

In this presentation I will give a brief description of state-of-the-art instruments for measuring the size and hygroscopicity of airborne nanoparticles, and describe novel aerosol-based techniques for fabricating materials for gas sensors. Presenting recent results from field and laboratory experiments, I will then show how recent developments in the field pave the way towards dense spatially distributed (both horizontally and vertically) measurements that are highly needed for understanding the impacts of atmospheric aerosol particles. I will summarize by addressing the current challenges and discuss future directions.

About the Speaker
George Biskos received his Ph.D. in 2004 from Cambridge University (UK), after which he spent three years as a Research Associate at Harvard University (USA). Currently he is a faculty member at the Cyprus Institute (Cyprus) and at Delft University of Technology (The Netherlands).

His research interests span over the broader area of aerosol science and technology, ranging from the development of instrumentation for measuring airborne particles, to atmospheric aerosol chemistry and aerosol-based nanotechnology.

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This event is part of the CyI Seminar Series.  View all CyI events.