Field evaluation of a Portable Fine Particle Concentrator (PFPC) for ice nucleating particle measurements
The custom-built Portable Fine Particle Concentrator (PFPC) is evaluated for the measurement of ice nucleating particles (INPs) in the atmosphere. The concentrations of INPs in remote regions of the atmosphere are very low, often close to instrumental detection limits. The PFPC is a dual slit-nozzle virtual impactor where particles are concentrated from an input flow of 250 LPM (litres per minute) into an output flow of 10 LPM. The enrichment factors (EFs) for ambient particles with diameters between 0.4 and 2.5 µm were found to be 21 ± 5 at sea level and 18 ± 2 at a field station 3580 meters above sea level for the PFPC operated in horizontal configuration. Similar enhancement factors (16 ± 5) in the concentrations of INPs measured by the Horizontal Ice Nucleation Chamber at the high-altitude station were observed when the air mass was characterized by high numbers of particles larger than 0.5 µm. When the number size distribution was dominated by particles smaller than 0.5 µm, the INP EF was considerably lower. Corroborating short-term measurements were provided by additional INP-measuring instruments, the Fast Ice Nucleus CHamber and the Frankfurt Ice Deposition Freezing Experiment. Results from two aerosol mass spectrometers also indicate significant particle enhancement using the PFPC. These results indicate that the PFPC can be usefully deployed to improve the detection efficiency of ambient INP measurements.
Copyright © 2019 American Association for Aerosol Research
Funding
The CLACE/INUIT field project was funded by DFG (FOR 1525). JS and HCC acknowledge funding by DFG (SCHN1138/2-2). RK and JC acknowledge funding from DFG (RO 5045/1-2). HB and DW acknowledge funding from DFG (BI 462/3-2). This evaluation of the Portable Fine Particle Concentrator is part of a project that has received funding from the European Union’s horizon 2020 research and innovation program under grant agreement No 654109, and from NSERC (Canada). Travel for the main author was supported through the Beatrice and Arthur Minden Graduate Research Fellowship at the School of the Environment, University of Toronto. ZAK and LL acknowledge funding from Global Atmospheric Watch, Switzerland (MeteoSwiss GAW-CH+ 2014-2017). PSI has received financial support for this project from MeteoSwiss (GAW-CH and GAW-CH+) the ACTRIS research infrastructure funded by the European Union. (H2020-INFRAIA-2014-2015; grant agreement no. 654109) and the Swiss State Secretariat for Education, Research and Innovation (SERI) (contract number 15.0159-1).
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