(ENVIRON) Quantifying particle number and specific surface area (SSA) of manufactured nanoparticles

Nanoscience and nanotechnology are concerned with the nanoscale which is usually defined as being between 1 and 100 nm in size. The synthesis and use of nanoparticle (NP) and other nanomaterials (NMs) are significant parts of nanotechnology and there are clearly many economic, environmental and social benefits from the use of NMs as detailed in recent reports from Royal Society and Royal Academy of Engineering and the Royal Commission for Environmental Pollution (http://www.nanotec.org.uk/finalReport.htm; http://www.nanotec.org.uk/finalReport.htm) in energy, in healthcare and in other sectors. However, use of NPs, particularly on the vast scale at which is currently occurring and projected for the future, has led to significant concerns about their human and environmental health effects from the reports mentioned and from others such as the EU SCENIHR (http://ec.europa.eu/health/ph_risk/committees/04_scenihr/docs/scenihr_o_012.pdf) and more widely. Ideally, we require full exploitation of the benefits of nanotechnology while ensuring the environment is not adversely affected. Understanding and quantifying the environmental effects of NMs requires understanding the physico-chemical properties of relevant NPs. Of particular relevance for this project, the appropriate metrics for characterising NP concentration (mass, particle number of surface area) has been questioned and it is recognised that the mass concentration used for conventional chemicals may be inappropriate. The appropriate metrics to use in NP studies is an important policy issue; of the 19 Research Objectives (ROs) produced by the UK government (DEFRA's NRCG http://www.defra.gov.uk/environment/nanotech/research/pdf/nanoparticles-riskreport07.pdf), one is: To identify the most appropriate metrics and appropriate methods for the measurement and characterisation of NPs. This proposal is of both scientific and policy/regulatory importance and will seek to define and test some of the appropriate methods to quantify these two metrics. Objectives 1) To perform a comparative study to quantify particle number concentration. 2) To investigate SSA measurement methods for NPs in liquid. 3) To apply number and SSA techniques to NMs in complex media.