Intercomparisons of Mobility Size Spectrometers and Condensation Particle Counters in the Frame of the Spanish Atmospheric Observational Aerosol Network

Abstract

REDMAAS (Red Española de DMAs Ambientales), the Spanish network of environmental Differential Mobility Analyzers (DMAs), currently consists of six research groups involved in the measurement of atmospheric aerosol size distributions by means of DMAs. The aim of this network is to guarantee the good quality and comparability of the routine measurements carried out at each different location and in diverse environments across Spain. In order to reach this objective, one of its main activities is an annual intercomparison of mobility size spectrometers used within the network (five units Scanning Mobility Particle Sizers (SMPS) and one Ultrafine Particle Monitor (UFPM)). Here we report the main results obtained during the 2010-1012 campaigns, including a study on particle deposition in dryers used in ambient air sampling systems. In general, all instruments showed a good performance with deviations in an accepted tolerance. The intercomparisons have been proven to be a useful exercise to detect instrument problems, such as incorrect calibrations. DMA calibration checks were performed with polystyrene latex (PSL) reference particles. Deviations of less than 1% were observed during the first year, which increased to a value of 4.7% during the last campaign. Some differences among the responses of different Condensation Particle Counter (CPC) models were encountered, being mainly connected to the intrinsic characteristics of each counter. The comparison of the UFPM with the CPCs has given good results. The SMPS intercomparisons, especially for particles Downloaded by [University of Otago] at 00:40 27 July 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT3 above 20 nm, have been within +/-15% tolerances. Regarding the particle deposition in dryers used in sampling systems, particle penetration was lower than predicted by the recommended model. This result was probably due to the fact that not all the possible mechanisms were considered in the model.---

Temporal and spatial variability of atmospheric particle number size distributions across Spain

“…The consistency of the functioning of the instruments over time has been tested during the intercomparison campaigns of the REDMAAS conducted annually since 2010 (Gómez-Moreno et al, 2015). The measured range of particle sizes varied from 7.37 to 855.78 nm depending on the SMPS model and measurement configuration (Table S2).…”

“…In the case of the TSI-UFPM, its measurement size resolution ranged from 20-500 nm into 6 size channels (N20-30, N30-50, N50-70, N70-100, N100-200 and N>200 nm where N is the number of particles and its subscript the particle size range). Given that these are different measurement systems (SMPS and UFPM), instrument comparability was discussed in Gómez-Moreno et al (2015). The comparison showed that the measured distributions from both instruments are in good agreement.…”

“…In 2010, the significant number of Spanish sites monitoring atmospheric aerosol size distributions and the need to exchange scientific and technical information about these measurements promoted the creation of the Spanish Network of Environmental DMAs (REDMAAS) with the participation of the interested research centres. A main purpose was to provide a set of recommendations and unifying criteria concerning instrumentation, calibration and measurement protocols (Gómez-Moreno et al, 2015). Currently REDMAAS is formed by seven observation sites operated by six research groups.…”

Mobility particle size spectrometers: Calibration procedures and measurement uncertainties

“…Although these MPSSs are designed to operate autonomously with minimum attention, quality assurance measures are required on a regular basis to ensure the delivery of reliable data. Comparisons between different MPSS instrument types and individuals have been reported in numerous studies (e.g., Dahmann et al 2001;Khlystov et al 2001;Helsper et al 2008;G omez-Moreno et al 2015). Specific recommendations for a complete system of quality assurance measures, and well-founded estimates of the measurement uncertainties have, however, been missing in the literature.…”

On the concentration and size distribution of sub-micron aerosol in the Galápagos Islands

“…The difference in total particle concentration between the UCPC and SMPS systems gives the particles in the (3e9) nm size range. The responses of the SMPS and the UCPC were cross-compared previous to the CHARLEX campaign following the guidelines of the Spanish Network on Environmental DMAs (G omez-Moreno et al, 2015). Additionally, both UCPCs were compared at their arrival at the Galapagos Islands, showing deviations below 8%.…”