An Aerosol Mobility Imager for Rapid Size Distribution Measurement

Atmospheric aerosols influence the earths radiation balance through direct scattering and absorption of radiation, and through alteration in the formation, brightness and extent of clouds. The concentrations and size distribution of aerosols aloft is important to these effects. Needed is a method to capture the size-resolved vertical profiles of those particles in the 10 600 nm size range that dominate the numbers of particles that are, or grow to become cloud condensation nuclei. Obtaining such data with finer spatial resolution requires rapid measurements, with averaging times of the order of one second or less. This proposal combines two technologies, a mobility separation and imaging system that instantly captures the size distribution of particles, and a laminar flow water condensation methodology that would eliminate the toxic fluids currently used with the imaging system. The current mobility separation and imaging technology is fast, but requires the use of butanol, which is both toxic and flammable. The aim of this project is to develop a water-based, environmentally acceptable, compact instrument that will provide rapid, high-resolution, mobility-based particle size distributions in the 10 nm 1000 nm size range. Commercial Applications and Other Benefits: Commercial applications span a wide range of industrial and research uses for which rapid size distributions are needed, including atmospheric research, combustion source characterization, nanoparticle fabrication, microenvironmental monitoring, rapid testing of filters and respirators. Moreover, this instrument will allow scientists to better assess the magnitude of airborne particles on cloud formation and global climate