The second ACTRIS inter-comparison (2016) for Aerosol Chemical Speciation Monitors (ACSM): Calibration protocols and instrument performance evaluations

This work describes results obtained from the 2016 Aerosol Chemical Speciation Monitor (ACSM) intercomparison exercise performed at the Aerosol Chemical Monitor Calibration Center (ACMCC, France). Fifteen quadrupole ACSMs (Q_ACSM) from the European Research Infrastructure for the observation of Aerosols, Clouds and Trace gases (ACTRIS) network were calibrated using a new procedure that acquires calibration data under the same operating conditions as those used during sampling and hence gets information representative of instrument performance. The new calibration procedure notably resulted in a decrease in the spread of the measured sulfate mass concentrations, improving the reproducibility of inorganic species measurements between ACSMs as well as the consistency with co-located independent instruments. Tested calibration procedures also allowed for the investigation of artifacts in individual instruments, such as the overestimation of m/z 44 from organic aerosol. This effect was quantified by the m/z (mass-to-charge) 44 to nitrate ratio measured during ammonium nitrate calibrations, with values ranging from 0.03 to 0.26, showing that it can be significant for some instruments. The fragmentation table correction previously proposed to account for this artifact was applied to the measurements acquired during this study. For some instruments (those with high artifacts), this fragmentation table adjustment led to an “overcorrection” of the f44 (m/z 44/Org) signal. This correction based on measurements made with pure NH4NO3, assumes that the magnitude of the artifact is independent of chemical composition. Using data acquired at different NH4NO3 mixing ratios (from solutions of NH4NO3 and (NH4)2SO4) we observe that the magnitude of the artifact varies as a function of composition. Here we applied an updated correction, dependent on the ambient NO3 mass fraction, which resulted in an improved agreement in organic signal among instruments. This work illustrates the benefits of integrating new calibration procedures and artifact corrections, but also highlights the benefits of these intercomparison exercises to continue to improve our knowledge of how these instruments operate, and assist us in interpreting atmospheric chemistry. © 2019, © 2019 Author(s). Published with license by Taylor & Francis Group, LLC.

Funding text #1 aLaboratoire de Météorologie Physique (LaMP), Aubiere, France; bInstitut National de l’Environnement Industriel et des Risques (INERIS), Verneuil-en-Halatte, France; cLaboratoire des Sciences du Climat et de l’Environnement (LSCE), CNRS-CEA-UVSQ, Gif-sur-Yvette, France; dAerodyne Research, Inc, Billerica, Massachusetts, USA; eEnvironment Energy and Water Research Center, The Cyprus Institute, Nicosia, Cyprus; fEstonian Environmental Research Center (EERC), Tallinn, Estonia; gFinnish meteorological institute (FMI), Helsinki, Finland; hIERSD, National Observatory of Athens, Athens, Greece; iDepartment of the Environment, Centre for Energy, Environment and Technology Research (CIEMAT), Madrid, Spain; jDeutscher Wetterdienst, Meteorologisches Observatorium Hohenpeißenberg, Hohenpeißenberg, Germany; kInstitute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland; lLeibniz Institute for Tropospheric Research, Leipzig, Germany; mEnvironmental Research Group, MRC-HPA Centre for Environment and Health, King’s College London, London, United Kingdom; nInstitute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, Spain; oLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland; pNational Institute of R&D for Optoelectronics (INOE), Ilfov, Romania; qProambiente S.c.r.l CNR Research Area, Bologna, Italy Funding text #2 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654109. The US Department of Energy Small Business Innovative Research program (award number DE-SC0017041) provided support for development of ACSM calibration procedures. CNRS, CEA, and INERIS are acknowledged for financial support of the ACMCC. The intercomparison campaign and the following data treatment have been conducted in collaboration with the French reference laboratory for air quality monitoring (LCSQA), funded by the French Ministry of Environment. COST action CA16109 Chemical On-Line cOmpoSition and Source Apportionment of fine aerosoLs COLOSSAL grant is gratefully acknowledged for the support of data workshops. M.C. Minguillón acknowledges the Ramón y Cajal fellowship awarded by the Spanish Ministry of Economy, Industry and Competitiveness. The CIEMAT participation has been partially funded by MINECO/AEI/FEDER, UE (CGL2017-85344-R and CGL2017-90884-REDT) and TIGAS-CM (Y2018/EMT- 5177) Project. PSI is grateful for financial support by the Federal Office for the Environment in Switzerland.

Peer reviewed