Aerosol particle analyzer for measuring the amount of analyte in airborne particles

An aerosol-particle analyzer (APA) for measuring the amount of an analyte in particles in a gas comprising:

• (a) an analysis liquid chosen such that when the analysis liquid is mixed with the particles, an optical property of the analysis liquid varies according to the amount of the analyte in the particles;
• (b) a charged droplet generator, having a charged droplet generator output, that generates a charged droplet of the analysis liquid (CDAL) and ejects it out of said charged-droplet generator output when signaled to do so;
• (c) a charger, enclosed in a gas-tight enclosure, having a gas input and charged particle output, arranged to:
• (i) accept the gas and the particles therein through said gas input;
• (ii) impart an electrical charge to any of said particles accepted, such that the now charged particles will have a charge opposite that of the CDAL;
• and
• (iii) permit the gas containing the charged particles to exit through the charged particle output;
• (d) a particle-droplet-collision subsystem (PDCS) consisting of an electrodynamic levitator enclosed in a gas-tight container, having a charged-droplet input connected to the charged-droplet generator output, a charged particle input connected via gas-tight connection to the charged particle output, a PDCS CDAL output, and a vacuum connection that:
• (i) accepts the CDAL via the charged-droplet input;
• (ii) accepts the gas containing the charged particles via the charged particle input;
• (iii)levitates the CDAL into a position where the gas containing the charged particles drawn from the charger flows past it so that the charged particles, collide with and combine with the CDAL in part because they are electrically attracted to the oppositely charged CDAL;
• and
• (iv) ejects the CDAL that has combined with the charged particles, in a desired direction via the PDCS CDAL output;
• (e) a vacuum pump connected to the PDCS vacuum connection that draws the gas and particles into the charger gas input and through the charger and then on into the PDCS, where the gas and any particles not combined with the CDAL are then evacuated;
• (f) a droplet analysis subsystem (DAS), having an input orifice for accepting the CDAL that has combined with the charged particles consisting of:
• (i) an electrodynamic levitator that levitates the CDAL that has combined with the charged particles ejected by the PDCS and holds them while the reaction between the CDAL and the analyte occurs;
• (ii) a means to control the motion of the particles in the electrodynamic levitator;
• (iii) a container that surrounds the levitated CDAL and that is substantially airtight, except for the orifice through which the CDAL enter, so that the CDAL does not evaporate quickly, and so that air currents do not push the CDAL out of the electrodynamic levitator;
• (iv) a means to detect changes in the optical property of the levitated CDAL, so that the amount of analyte in the CDAL, and in the particles that combined with the CDAL, can be determined from these measurements of the optical property;
• and
• (v) a receptacle to collect and store the CDAL after the optical property of the CDAL has been measured.