ACTRIS ACSM intercomparison – Part 2: Intercomparison of ME-2 organic source apportionment results from 15 individual, co-located aerosol mass spectrometers

Roman Fröhlich ,M J Cubison,A S H Prévôt,J K Esser-Gietl,M Bressi,Anna Ripoll ,Philip Croteau ,Jay G Slowik ,María Cruz Minguillón ,Wenche Aas ,Roland Sarda‐Estève ,Griša Močnik ,Mikko Äijälä ,Véronique Riffault ,Begoña Artı́ñano ,Nicolas Bonnaire ,Liine Heikkinen ,Laurent Poulain ,Max Priestman ,Claudio A Belis ,Andrés Alastuey ,Hartmut Herrmann ,Colin O’dowd ,Claudio Carbone ,Francesco Canonaco ,Valérie Gros ,Chris Rene Lunder ,Vincent Crenn ,John T Jayne ,Esther Coz ,David C Green ,Jurgita Ovadnevaitė ,Alfred Wiedensohler ,Olivier Favez ,Ettore Petralia ,Urs Baltensperger ,Ari Setyan ,Jean Sciare ,Carlo Bozzetti

doi:10.5194/amt-8-2555-2015

Abstract

Abstract. Chemically resolved atmospheric aerosol data sets from the largest intercomparison of the Aerodyne aerosol chemical speciation monitors (ACSMs) performed to date were collected at the French atmospheric supersite SIRTA. In total 13 quadrupole ACSMs (Q-ACSM) from the European ACTRIS ACSM network, one time-of-flight ACSM (ToF-ACSM), and one high-resolution ToF aerosol mass spectrometer (AMS) were operated in parallel for about 3 weeks in November and December~2013. Part 1 of this study reports on the accuracy and precision of the instruments for all the measured species. In this work we report on the intercomparison of organic components and the results from factor analysis source apportionment by positive matrix factorisation (PMF) utilising the multilinear engine 2 (ME-2). Except for the organic contribution of mass-to-charge ratio m/z 44 to the total organics (f44), which varied by factors between 0.6 and 1.3 compared to the mean, the peaks in the organic mass spectra were similar among instruments. The m/z 44 differences in the spectra resulted in a variable f44 in the source profiles extracted by ME-2, but had only a minor influence on the extracted mass contributions of the sources. The presented source apportionment yielded four factors for all 15 instruments: hydrocarbon-like organic aerosol (HOA), cooking-related organic aerosol (COA), biomass burning-related organic aerosol (BBOA) and secondary oxygenated organic aerosol (OOA). ME-2 boundary conditions (profile constraints) were optimised individually by means of correlation to external data in order to achieve equivalent / comparable solutions for all ACSM instruments and the results are discussed together with the investigation of the influence of alternative anchors (reference profiles). A comparison of the ME-2 source apportionment output of all 15 instruments resulted in relative standard deviations (SD) from the mean between 13.7 and 22.7 % of the source's average mass contribution depending on the factors (HOA: 14.3 ± 2.2 %, COA: 15.0 ± 3.4 %, OOA: 41.5 ± 5.7 %, BBOA: 29.3 ± 5.0 %). Factors which tend to be subject to minor factor mixing (in this case COA) have higher relative uncertainties than factors which are recognised more readily like the OOA. Averaged over all factors and instruments the relative first SD from the mean of a source extracted with ME-2 was 17.2 %.

Highlights

Measurements have shown that organic compounds constitute a major fraction of the total particulate matter (PM) all around the world (20–90 % of the submicron aerosol mass according to Kanakidou et al, 2005)
The algorithm has been heavily used for source identification and quantification with organic mass spectra measured by the Aerodyne aerosol mass spectrometer (AMS, Jayne et al, 2000; Drewnick et al, 2005; DeCarlo et al, 2006) and the related aerosol chemical speciation monitor (ACSM, Ng et al, 2011c; Fröhlich et al, 2013)
The median organic concentration calculated on a point-by-point basis of the 13 Q-aerosol chemical speciation monitors (ACSMs) is displayed as a black line with the interquartile range (IQR) (25–75 percentile) shaded in red and the 10–90 percentile range shaded in grey

Summary

Introduction

Measurements have shown that organic compounds constitute a major fraction of the total particulate matter (PM) all around the world (20–90 % of the submicron aerosol mass according to Kanakidou et al, 2005). Many POA sources have been identified (Zhang et al, 2011): hydrocarbon-like organic aerosol (HOA, Zhang et al, 2005a, b), biomass burning-related organic aerosol (BBOA, Alfarra et al, 2007; Aiken et al, 2010), cooking-related organic aerosol (COA, Slowik et al, 2010; Allan et al, 2010; Mohr et al, 2012; Canonaco et al, 2013; Crippa et al, 2014, 2013a), coal burning-related organic aerosol (CBOA, Hu et al, 2013b; Huang et al, 2014), nitrogen-enriched OA (NOA, Sun et al, 2011; Aiken et al, 2009) or local sources of primary organics (Timonen et al, 2013; Faber et al, 2013) Another marine source of secondary organic aerosol (MOA) related to MSA was reported by Crippa et al (2013b)

Methods

Results

Conclusion