Characterizing aerosolized particulate as part of a nanoprocess exposure assessment

Characterizing a process aerosol in the nanoscale beyond numeric concentration can assist in hazard assessment and in separating aerosolized process material from background aerosol. Size and size distribution, chemical composition, solubility, shape, and surface area may become important categorization parameters of exclusion/inclusion for purposes of exposure control. Various particle parameters are presented using examples from a process simulation. The process aerosol was composed of insoluble carbon particles plus environmental background constituents at an average air concentration of 2.76E+5 particles/cubic centimeter (p/cm3). Greater than 70% of the carbon particulate was blade-like in shape, 50% of which had a height dimension < or =100 nm. The equivalent spherical mobility diameter of 0.8% of the particulate was < or =100 nm in size. The carbon blades had a root-mean-square roughness of 75 nm and an average fractal dimension of 2.25. Obtaining these measures characterizes the aerosol and identifies parameters that may be important toxicologically.