Abstract: A constant flow rate controller apparatus for an aerosol sampler using a filter includes an enclosed channel for channeling a stream of air, a filter positioned in the channel to capture and retain particles while allowing the stream of air to flow therethrough, an air or vacuum pump to pull the air through the filter, and a flow controller that maintains a constant volumetric flow rate of air through the sampler and filter, regardless of how much particulate matter is deposited on the filter or how much pressure drop across the filter changes due to particulate loading. The filter can be a substantially non-fibrous, porous, this film membrane medium, for which the flow controller of this invention is particularly beneficial, or it can be a more conventional fibrous medium.

Abstract: A volume flow control device for an aerosol sampler is disclosed. The device includes a mechanism for drawing the aerosol through the sampler. A critical flow venturi is disposed downstream in the sampler for maintaining a predetermined volume flow of aerosol through the sampler. The aerosol drawing mechanism is adapted to create a vacuum downstream of the venturi.

Abstract: An ambient aerosol sampling device according to the disclosure herein includes a cyclonic fractionator comprised of an inner tube positioned partially inside a larger diameter middle tube that is plugged at the bottom. A still larger sized outer tube is positioned over the middle tube to receive air flow out of the middle tube and direct it to a conventional filter substrate. A plurality of vanes are positioned at the inlet of the inner tube to impart a vertical motion to an air stream flowing therein. A protective cover is positioned over the vanes and cyclonic fractionator, and an aerodynamic deflector at the bottom of the cover and air ramp inside the cover provides an omni-directional inlet pathway to draw air into the sampling device and to guide the airstream into the vanes.