Aerosol Dynamics Inc.

Tsi, Inc.

Other

University of California

University System of Maryland

Virginia Tech Intellectual Properties Inc

Colorado State University Research Foundation

Research Triangle Institute

Brookhaven Science Associates, Lcc

Research Triangle, Inc.

Susanne Vera Hering

Gregory Stephen Lewis

Steven Russel Spielman

David S Ensor

Howard Jerome Walls

Frederick R Quant

Karin K Foarde

Arantzazu Eiguren Fernandez

Daniel C Bjorkquist

Nathan Michael Kreisberg

Robert Caldow

Richard Remiarz

Sreenath Avula

George John Chancellor

Sean Morell

Mark Richard Stolzenburg

Tyler Anderson

Philip Bourgeois

Kenneth Farmer

Charles Sherman Henry

Scott Noblitt

Kenneth Rudolph Farmer, Ii

Donald K Milton

Jian Wang

Melissa Grose

Somayeh Youssefi

Chongai Kuang

Jeffrey Lee Collett, Jr

Allen H Goldstein

Gabriel Isaacman-VanWertz

David Workman

Mark R Stolzenberg

Dan Bjorkquist

A method and apparatus to create water vapor supersaturation and particulate counts from an air sample. The method and apparatus include introducing an air sample into a chamber connected to an optical detector and an outlet by pumping at the outlet. The method further includes passing air through the chamber and optical detector in a steady flow, and subsequently closing the inlet while continuing the pumping to expand the air sample and exhaust a portion of the air sample through the optical detector. The walls of the particle chamber are wetted with a fluid such as water, and one portion of the wall is warmer than the other portions such that there is some condensational growth prior to the expansion, and yet more condensational growth during the expansion. The cycles are repeated by continuously repeating the introducing, passing and closing.

Pulsed diffusion condensation particle counter

A method and apparatus to create water vapor supersaturation and particulate counts from an air sample. The method and apparatus include introducing an air sample into a chamber by passing a flow into the chamber through the inlet by pumping at the outlet. The method further includes closing the inlet while continuing the pumping to exhaust the air sample from the chamber through the outlet. The pumping is performed at a rate operable to reduce pressure inside the chamber such that the air sample in the central portion of the chamber cools, and water vapor from walls of the chamber has time to diffuse into the air sample in the chamber from the walls. The cycles are repeated by continuously repeating the introducing and closing. The walls of the chamber may be wet or dry.

Pulsed condensation particle counter

An approach for counting particles suspended in a flow of gas or liquid in instruments that direct the flow through an illuminated region. Pulses are detected when the signal is below a threshold amplitude and moves above the threshold amplitude. This movement above the threshold creates a dead time during which only one pulse is detected until the signal amplitude moves sufficiently below the threshold such that a subsequent particle creates a distinct pulse. After counting the number of pulses, and determining the measured live time that the signal is below the threshold value, an initial particle concentration is calculated, and the calculation corrected for coincidence by calculating an actual live time as a measured live time minus a constant multiplied by the number of distinctly counted pulses, where the constant has the units of time. From this, particle concentrations in a volume can be determined.

Pulse counting coincidence correction based on count rate and measured live time

A method and apparatus for evaluating the chemical composition of airborne particles by sequentially collecting and analyzing airborne particles in-situ. The method includes: collecting particles; enlarging the particles through water condensation; accelerating the enlarged particles onto a surface to collect enlarged particles; and analyzing the enlarged particles by: isolating the surface; passing a carrier gas over the surface; heating the surface to thermally desorb collected particles into the carrier gas; transporting this evolved vapor into detectors; and assaying the evolved vapor as a function of a desorption temperature. The apparatus includes: a sample flow inlet; a condensational growth tube; a collection and thermal desorption (CTD) cell; a carrier gas source; a heater coupled to the CTD; one or more gas detectors; and a controller configured to operate valves, the heater, the growth tube, and the CTD cell in at least an in-situ sequential collection mode and analysis mode.

Volatility-resolved chemical characterization of airborne particles

A system includes a first and second condensation particle counter, each counter having an inlet port, a growth column, and an optical element for counting particles detected at the respective inlet ports. The counters are configured to include a wick in which the wick is wetted by water. A differential pressure sensor is coupled to the first inlet port and coupled to the second inlet port. The sensor is configured to provide a pressure signal. A processor is coupled to memory and configured to receive the first signal, the second signal, and the pressure signal and generate an output corresponding to a ratio of the first signal and the second signal and correlate the ratio with the pressure signal. A housing is configured to receive the first counter, the second counter, the differential pressure sensor, the processor, and the memory.

In situ respirator fit testing

A particle growth apparatus includes a temperature-controlled humidifier coupled to a water-based condensation growth system. The humidifier may include a tube of sulfonated tetrafluoroethylene-based fluoropolymer-copolymer and surrounded by a region containing water or water vapor. The apparatus includes a wetted wick and wick sensor in the condensation growth system, configured such that the gas sample flows through the sulfonated tetrafluoroethylene-based fluoropolymer-copolymer tube into the condensation growth system.

Humidity conditioning for water-based condensational growth of ultrafine particles

A wick liquid sensor suitable for use in a particle condensation device is provided. The sensor includes a light source configured to illuminate a surface of the wick. A detector is configured to detect wick reflected light from the light source and determine the intensity of reflected light. The wick is formed from a porous media that is wettable by the liquid, and becomes translucent when filled with the liquid. The amount of reflectivity decreases as the saturation content of the liquid in the wick increases.

Wick moisture sensor for airborne particle condensational growth systems

Various embodiments include methods and systems for reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into multiple wicks used for transporting separate portions of an aerosol sample flow, with the wicks extending from a wick stand on a first end to a flow joiner on a second end, combining particles from the separate portions of the aerosol sample flow into a single aerosol stream within the flow joiner prior to transporting the combined aerosol sample stream into a particle detection chamber within the CPC, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water in a collection reservoir, and after receiving a signal corresponding to the excess volume of water, draining the excess volume of water from the collection reservoir. Other methods, systems, and apparatuses are disclosed.

Condensation particle counter false count performance

An apparatus and method for creating enlarged particles in a flow. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. A heater heats a first portion of the tube along a first, longitudinal portion of the tube, and a cooler cools a second, longitudinal portion of the tube along at least a second portion of the tube. The method includes heating a first portion of the tube along a first longitudinal portion of the tube, and simultaneously cooling a second portion of the tube along at least a second longitudinal portion of the tube. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.

Apparatus for sustained super-saturations for condensational growth of particles

An apparatus and method for condensationally enlarging particles in a flow of air or other gas. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. The walls of the tube are wetted with a condensing fluid. The walls of the first portion of the coiled tube are held a temperature that is lower than the highest temperature in the second portion of the tube. The tube may have a third vapor recovery portion with wall temperature lower than the highest temperature in the second portion, and which optionally may not be coiled. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.

Coiled system for condensational growth of ultrafine particles

An aerosol collection system and method. The system includes a bio-aerosol delivery device configured to supply bioparticles in a gas stream, a moisture exchange device including a partition member coupled to the gas stream and configured to humidify or dehumidify the bioparticles in the gas stream, and an aerosol collection medium downstream from the moisture exchange device and configured to collect the bioparticles. The method includes delivering bioparticles in a gas stream, humidifying or dehumidifying the bioparticles in the gas stream by transport of water across a partition member and into a vapor phase of the gas stream, and collecting the bioparticles by a collection medium.

Fiber sampler for recovery of bioaerosols and particles

Various embodiments include methods of reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into one or more wicks, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water into a collection reservoir, and draining the excess volume of water from the collection reservoir. Other methods and apparatuses are disclosed.

The present invention relates to systems and methods for collecting and analyzing bioaerosols, including exhaled breath aerosol from a subject. The collection system comprises an inlet portion configured to receive a gaseous fluid containing water vapor and aerosol particles. A primary passage for gaseous fluid flow is in fluid communication with the inlet portion and configured to channel the gaseous fluid flow therethrough. An outlet portion is in fluid communication with the primary passage. A sample collection region is provided, which is configured to receive from the outlet portion aerosol particles from the gaseous fluid, wherein the aerosol particles are impacted onto a layer of ice.

Aerosol collection system and method

Growing community of inventors

Berkeley, CA, United States of America

Susanne Vera Hering