Abstract: Methods and systems for sorting particles entrained in a gaseous stream are disclosed. A representative system, among others, includes a particle scanner, a sorter, which is in pneumatic communication with the particle scanner, and a controller, which is in electrical communication with the particle scanner and sorter. The particle scanner is adapted to receive a gaseous stream and measure a characteristic of a particle entrained in the gaseous stream. The controller is adapted to classify the scanned particle according to the measured characteristic of the particle. The sorter includes an electrically controlled valve. Responsive to the particle being classified as belonging to a first category, the controller signals the valve to deflect the trajectory of the particle.

Abstract: Aerosol particle analyzer (APA) for measuring an analyte in airborne particle is described. Airborne particles are first given an electrical charge and then drawn in air past an oppositely charged volume of an analysis liquid that exposed to the air at a small hole in a container, such as a capillary, that holds that analysis liquid. Electrostatic forces enhance the rate that the airborne particles collide with the small exposed volume of the analysis liquid in the hole. If the particles that collide with the analysis liquid contain the analyte, an optical property of the analysis liquid, such as the fluorescence, varies according to the amount of the analyte in the particles. This optical property is measured and the amount of analyte in the particles is determined from the measured optical property.

Abstract: An aerosol-into-liquid collector (ALC) for collecting gas-borne particles from a large volume of gas such as air into a small volume of liquid is described. The ALC uses a linear quadrupole to concentrate particles flowing in a gas and to help direct these concentrated particles toward a small volume of collection liquid so that these particles tend to combine with a small volume of collection liquid that can then be drawn from the ACL for further analysis. The particles in the gas are typically given a charge that is opposite to that of the charge imparted to the volume of collection liquid so that electrostatic forces help draw particles from the flowing gas into the small volume of liquid. The linear quadrupole focuses toward it axis particles that have the charge, mass and mobility to be stable in the linear quadrupole.

Abstract: Aerosol particle analyzer (APA) for measuring the amount of analyte in airborne particle is described. The APA uses an analysis liquid. In most embodiments, this analysis liquid is chosen so that when it is mixed with the particles, an optical property of the analysis liquid (AL) varies according to the amount of the analyte in the particles. Airborne particles are drawn into the instrument, and detected using optical methods such as light scattering or laser-induced fluorescence. When a particle of interest is detected, a charged droplet of the analysis liquid (CDAL) is ejected so that it collides with the detected particle and moves into a horizontally oriented linear quadrupole that is in an airtight container, except for small orifices to let the CDAL enter and exit.

Abstract: Aerosol particle analyzer (APA) for measuring the amount of analyte in airborne particle is described. The APA uses an analysis liquid. When this analysis liquid is mixed with the particles, an optical property of the analysis liquid (CDAL) varies according to the amount of the analyte in the particles. A charged droplet of the analysis liquid is levitated. Airborne particles are drawn into the instrument and given a charge that is opposite that of the CDAL, and made to flow near the CDAL so that electrostatic forces greatly increase the probability that the CDAL and charged particles will combine. Then the CDAL is ejected into a horizontally oriented linear quadrupole that is in an airtight container, except for a small orifice to let the CDAL enter. The CDAL is levitated in a high humidity environment so that it evaporates slowly, so that there is time for the reaction between the analyte, if any, and the CDAL can take place, and so that the optical property, typically fluorescence, can be measured.

Abstract: Characterizing individual airborne particles in real time according to their absorption of optical energy at one or more wavelengths. The instrument can measure the two-dimensional angular optical scattering (TAOS) and/or the one-dimensional angular optical scattering (ODAOS) at one or more wavelengths. When two wavelengths are used, one is chosen to be on an absorption peak, the other is off of the absorption peak (preferably in the absorption valley).

Abstract: A Fluorescence Particle Spectrometer (FPS) performs real-time measurement of the fluorescence spectra of aerosol particles in the size range 1-10 ?m diameter. The FPS has a sufficiently high sample rate (estimated to be a few liters/min) to measure aerosol within buildings (from 1 up to 600 particle fluorescence spectra per minute) at practical rates. A virtual impactor first concentrates aerosol particles, which are then drawn under negative pressure through an aerodynamic focusing nozzle in the inlet of the instrument, through the sample region, providing further concentration. The rate of particle spectra measured by the FPS increases significantly when the particle inlet is within a few meters of some common sources of indoor biological particles.

Abstract: A Fluorescence Particle Spectrometer (FPS) performs real-time measurement of the fluorescence spectra of aerosol particles in the size range 1-10 &mgr;m diameter. The FPS has a sufficiently high sample rate (estimated to be a few liters/min) to measure aerosol within buildings (from 1 up to 600 particle fluorescence spectra per minute) at practical rates. A virtual impactor first concentrates aerosol particles, which are then drawn under negative pressure through an aerodynamic focusing nozzle in the inlet of the instrument, through the sample region, providing further concentration. The rate of particle spectra measured by the FPS increases significantly when the particle inlet is within a few meters of some common sources of indoor biological particles.

Abstract: Characterizing individual airborne particles in real time according to their absorption of optical energy at one or more wavelengths. The instrument can measure the two-dimensional angular optical scattering (TAOS) and/or the one-dimensional angular optical scattering (ODAOS) at one or more wavelengths. When two wavelengths are used, one is chosen to be on an absorption peak, the other is off of the absorption peak (preferably in the absorption valley).