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 (ToFACSM),
and one high-resolution ToF aerosol mass specrometer
(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: hydrocarbonlike
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: 14.32.2 %, COA: 15.03.4 %, OOA:
41.55.7 %, BBOA: 29.35.0 %). 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 %.