Instrument Description:

    The Model 3091 (Figure 1-1) spectrometer measures submicrometer aerosol particles over a wide range from 5.6 to 560 nm. Due to its unique design, the FMPS™ spectrometer is capable of making particle size distribution measurements with one-second resolution, enabling users to visualize particle events in real time.

 

Theory of Operation:

    The Model 3091 Fast Mobility Particle Sizer™ (FMPS™)spectrometer builds on a tradition of TSI electrical-basedmeasurements including the Electrical Aerosol Analyzer (EAA 3030)and Electrostatic Classifier (3071, 3080/3081/3085).It is based on this fast-responseinstrument. Conceptually these instruments are similar to a DMA.But, rather than particles being drawn to the center, as in a DMA,the particles are repelled outward to electrodes.

 

    The FMPS™ spectrometer performs particle size classification basedon differential electrical mobility classification (as with the SMPS™).The charged aerosol enters the analyzer column near on-axis andabove the central rod. The particles are deflected radially outwardand collected on electrically isolated electrodes that are located atthe outer wall (see Figure 1-2). The particle number concentrationis determined by measurement of the electrical current collected ona series of electrodes.

 

Applications:

- Particle formation and growth studies.

- Indoor air quality tests.

- Environmental research.

- Inhalation toxicology studies.

- Urban canyon studies.

- Transient emission studies from stacks, boilers, and wood
burners.

- Mobile test laboratories.

- Electric vehicle measurement platforms.

- Roadside measurements (in trailer or enclosure) to evaluate the
effect of individual vehicles passing monitoring location.

Figure 1-1Model 3091 Fast Mobility Particle Sizer™ Spectrometer	Figure 1-2Schematic of theFMPSinstrument