Mobility particle size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions

Abstract

Abstract. Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental setup, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer.We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data.Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research) and AC-TRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around ±10 % after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30 %, which could not be explained. The network reference mobility spectrometers with identical design agreed within ±4 % in the peak particle number concentration when all settings were done carefully. The consistency of these reference instruments to the total particle number concentration was demonstrated to be less than 5 %.Additionally, a new data structure for particle number size distributions was introduced to store and disseminate the data at EMEP (European Monitoring and Evaluation Program). This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between different networks and sites, and their transparency and traceability back to raw data.

Surface tension prevails over solute effect in organic-influenced cloud droplet activation

“…see Standard Deviation in figure box). The intercomparison confirmed that MHD SMPS system errors were well within general uncertainties derived for this type of instrument (±10 % for size in the range of 20 -200 nm and ±4 % for number) 45 .…”

Comparative assessment of GRASP algorithm for a dust event over Granada (Spain) during ChArMEx-ADRIMED 2013 campaign

“…Table 1 summarizes the instrumentation on board the ATR-42 airplane used in this study. The scanning mobility particle sizer (SMPS) with an accuracy of 5 % (Wiedensohler et al, 2012) and the ultra high-sensitivity aerosol spectrometer (UHSAS) with an accuracy of 10 % (Cai et al, 2008) are used for measuring aerosol number size distribution in the submicron range. The wing-mounted Forward Scattering Spectrometer Probe (FSSP-300) with an accuracy of 30 % (Baumgardner et al, 1992) and the in-cabin GRIMM OPC (sky OPC 1.129) with an accuracy of 10 % were used to measure the optical size distributions in the diameter nominal size range between 0.28 and 20 µm and between 0.3 and 32 µm, respectively.…”

Influence of cloud processing on CCN activation behaviour in the Thuringian Forest, Germany during HCCT-2010

“…On top of the container a PM 10 inlet followed by a self-regenerating diffusion drier was placed (Tuch et al, 2009), maintaining the relative humidity of the aerosol flow below 20 %. Inside the container -besides other instrumentation -a Mobility Particle Size Spectrometer (MPSS-type TROPOS; details of this instrument in Wiedensohler et al, 2012) was used to determine the particle number size distributions between 10 and 850 nm, and a Cloud Condensation Nucleus counter (CCNc, CCN-100, DMT Boulder, Roberts and Nenes, 2005) in combination with a differential mobility analyser (DMA) was used to measure CCN distributions between 25 and 300 nm.…”