The REDMAAS 2014 intercomparison campaign: CPC, SMPS, UFPM and neutralizers

Abstract

The Spanish network on environmental DMAs (Red Española de DMAs Ambientales, REDMAAS), working since 2010, is currently formed by six groups involved in the measurement of atmospheric aerosol size distributions by means of Differential Mobility Analyzers (DMAs). One of its activities is an annual intercomparison of mobility size spectrometers (SMPS and UFPM). In this work we show the results obtained in the 2014 campaign: the verification of DMA calibrations with latex, the results of the CPC and SMPS + UFPM intercomparisons, and a comparison of the new TSI 3087 X-ray and the former TSI 3077 85Kr neutralizers. The concentrations measured by different types of CPC were within the range of 10% of the average value. CPCs working at higher flow rates measured slightly higher concentrations, probably related to the smaller losses in the lines. All the SMPS worked at the same sampling and sheath flow rates (1:10 lpm). Four of the SMPS gave very good results for particles larger than 20 nm. The UFPM measured particle number concentrations in the average +/-10% band measured by the SMPS. Instruments working with the X-ray neutralizer measured higher concentrations than with the 85Kr neutralizers. This could mean that particle losses are smaller inside this neutralizer.