This invention pertains to a CDC developed sonic aerosol generator that provides a controllable, stable concentration of particulate aerosol over a long period of time for aerosol exposure studies. Specifically, in situ testing data indicate uniform aerosol stability can be maintainable for greater than 30 hours at concentrations of 15 mg/m³ or more. Additionally, the technology was specifically developed for, and validated in, animal studies assessing exposure to airborne multi-walled carbon nanotubes (MWCNT). It has been suggested that workers may be at risk for exposure to nanosized particles during the manufacture, handling, and cleanup of engineered nanomaterials. Compared to other technologies, this CDC aerosol generator is particularly helpful when used for generating high testing concentrations of MWCNT aerosols that more accurately represent particulate levels that may be seen in a workplace environment.