On the characterization of environmental nanoparticles.

The presence and release of nanoparticles into the environment has important implications for human health and the environment. This article highlights and describes techniques that are effective in the characterization of anthropogenic and naturally occurring nanoparticles. Particle attributes like size, size distribution, shape, structure, microstructure, composition, and homogeneity are critically important to determining the potential impact of such materials on health and the environment. Many techniques yield data for a collection of nanoparticles; while others yield data for individual nanoparticles; and still others yield data showing the size, distribution of chemical species, and variations in structure and microstructure for a single nanoparticle. All are important in the context of environmental nanoparticles. Many of these techniques are complementary, and depending on the information required, the ideal characterization usually employs multiple techniques.