Abstract: Method for the online measurement of the number, surface area and volume distribution of nanoparticle aerosol aggregates relates the number and size of primary particles that compose the aggregates and the aggregate mobility diameter. The number distribution of nanoparticle aggregates is obtained by calculations based on the drag on the aggregates and the aggregate charging efficiency. The aggregate surface area and volume are obtained by summing over the surface areas and volume of the primary particles that compose the aggregate. The aggregate surface area and volume distribution is then obtained by multiplying the aggregate surface area, volume and the aggregate number distribution.

Abstract: A catalytic reactor bed in which support particles in the free molecule size range of 50 to 500 .ANG.ngstroms are attached to an anchor surface to form a dendritic network which extends from 10 microns to 300 microns outward from the anchor surface. Catalyst particles which are also in the free molecule in the size range of 10 to 80 .ANG.ngstroms are attached to and dispersed throughout the support particle network. A process for making the reactor bed using binary gas phase nucleation of support particle and catalyst particle precursors is also disclosed.

Abstract: A system is provided for analyzing the particles in aerosols, as in making air pollution studies, which enables the making of rapid chemical analyses of particles. The system includes an apparatus for producing a controlled stream of individual particles to be analyzed from an environment, and an apparatus for vaporizing and ionizing the particles while they move in free flight, for analysis by a mass spectrometer. The apparatus for producing a stream of particles includes a capillary tube through which the air with suspended particles moves, a skimmer device having a small opening spaced from an end of the capillary tube to receive particles passing through the tube, and a vacuum pump for pumping air out of the space between the tube and skimmer. The vacuum pump serves to remove much of the gas from around the particles, while also creating an inflow of air and particles through the capillary tube.