AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Accuracy and Reproducibility of DMS500 Fast Mobility Size Spectrometers Over 10 Years
Jonathan Symonds, CHRIS NICKOLAUS, Cambustion
Abstract Number: 714 Working Group: Instrumentation and Methods
Abstract Fast response particle mobility sizers, such as the Cambustion DMS500 and the TSI EEPS / FMPS have been commercially available for around 15 years. Compared with a Scanning Mobility Particle Sizer (SMPS), these instruments trade spectral resolution and absolute accuracy for a fast time response (up to 200 ms T10-90%). Some initial studies showed that early examples of these instruments were not as accurate as established methods of sizing, and instrument consistency was rather variable.
In response to these studies, a traceable calibration using aerosol sizing and number standards was developed for the DMS500. Recognising that soot agglomerates gain more charge in a corona charger compared with “compact” (near spherical) particles, separate calibrations were produced for soot and compact particles, via different data inversion matrices (Symonds and Reavell, 2006).
As it is a decade since traceable calibrations for compact and soot aerosols were pioneered for the DMS500, we here present a statistical analysis of the full corpus of instrument calibrations undertaken over that time.
The results show that in the last decade all DMS500s when challenged with 100 nm DMA selected aerosol exhibited a sizing error of less than 5% for NaCl aerosols, less than 10% for CAST soot aerosols and a number concentration error of less than 10% compared with a standard electrometer for both types of aerosol. Gradual improvement is observed over the decade. Over the last 3 years, the median deviation from the size and number standards at 100 nm is less than 1% for both types of aerosol, with upper and lower quartiles each within 2% of the median. Similar data across the full size range is presented.
Symonds, J.P.R. and Reavell, K.St.J. (2006). Calibration Of A Differential Mobility Spectrometer. European Aerosol Conference, Salzburg T02A034.