Abstract: An impactor, system and method for performing real-time measurements of particles in aerosol gases. The impactor comprises a plurality of cascading stages having impaction plates, mass-measurement mechanisms retained on the impaction plates, and a nozzle plate. A signal line associated with each of the plurality of cascading stages is configured to relay signals from the mass-measurement mechanism of the associated stage to a computer-based system configured to receive the transmitted signals from the signal lines, and to correlate changes in the resonant frequencies to particle concentrations in real time.

Abstract: An apparatus for the collection of particles from a gas containing particles which comprises a first means for directing the flow of said gas toward a second means for collection of at least a portion of said particles by the process of impaction, the first means containing inlet means which comprises at least one perforation having a length dimension which is greater than its width dimension and a third means between and contacting said first and second means and having an inner wall, which is a smooth closed curve, the third means being located relative to the inlet means and the third means having a configuration such that a substantial number of the streamlines of the flow of said gas after the impaction of at least a portion of said particles in said gas with the second means are in substantial parallelism to the curve of the wall of the third means; the first, second and third means forming an enclosed volume having the inlet means and outlet means for exit of the gas after the impaction of at least a p