Portable Aerosol Instrument Calibrator

FRED BRECHTEL, Andy Corless, Xerxes Lopez-Yglesias, Brechtel Mfg. Inc.

     Abstract Number: 167
     Working Group: Exhibitor and Instrument Application Showcase

Abstract
The proliferation of low-cost aerosol sensor networks and the field deployment of research-grade aerosol instruments motivates the development of a Portable, Low-cost, and EASy-to-use CALibration (PLEASCAL) system. The device described here is completely self-contained, with aerosol generator, dryer, charge neutralizer, particle size selector, and particle counter. PLEASCAL requires no external pumps or power and is the size of a piece of carry-on luggage.

PLEASCAL is built around a Brechtel Model 9404 mini-SEMS that has been modified to use an injection molded DMA. A Model 9403 advanced Mixing CPC is used as the particle detector. A micro-computer and software control PLEASCAL, communicates with the device under test, and generates a report with test results. Impactors are used to reduce the influence of multiply charged particles on the uncertainty in delivered mass concentrations. The complete system is packaged inside a small weatherproof pelican case.

PLEASCAL operates in two testing modes: monodisperse mode, where the device under test is challenged with known size, concentration, and composition aerosol generated by PLEASCAL; and polydisperse mode, where the polydisperse number size distribution is measured and the device under test is challenged with the same distribution. The system is designed to validate electrometers and CPCs (total number concentration), scanning electrical mobility sizers (number size distribution), mass spectrometers and other particle mass measurements (total mass for particles smaller than 500 nm), and light absorption photometers (light absorption coefficient and absorbing aerosol mass concentration).

To demonstrate PLEASCAL, example validation tests of a Model 1720 MCPC and a Model 2100 SEMS will be performed.