Open AccessComparison of N<sub>2</sub>O<sub>5</sub> mixing ratios during NO3Comp 2007 in SAPHIR
Author(s) -
Hendrik Fuchs,
W. R. Simpson,
R. L. Apodaca,
T. Brauers,
R. C. Cohen,
John N. Crowley,
H.-P. Dorn,
W. P. Dubé,
Juliane L. Fry,
R. Häseler,
Yoshizumi Kajii,
Astrid KiendlerScharr,
Irena Labazan,
Jun Matsumoto,
Thomas F. Mentel,
Yoshihiro Nakashima,
Franz Rohrer,
A. W. Rollins,
G. Schuster,
Ralf Tillmann,
Andreas Wahner,
P. J. Wooldridge,
Steven S. Brown
Publication year - 2012
Publication title -
atmospheric measurement techniques
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.679
H-Index - 88
eISSN - 1867-8548
pISSN - 1867-1381
DOI - 10.5194/amt-5-2763-2012
Subject(s) - chemistry , analytical chemistry (journal) , aerosol , inlet , mixing (physics) , atmosphere (unit) , mixing ratio , laser , meteorology , environmental chemistry , optics , physics , mechanical engineering , organic chemistry , quantum mechanics , engineering
N2O5 detection in the atmosphere has been accomplished usingtechniques which have been developed during the last decade. Most techniquesuse a heated inlet to thermally decompose N2O5 to NO3, whichcan be detected by either cavity based absorption at 662 nm or bylaser-induced fluorescence. In summer 2007, a large set of instruments, whichwere capable of measuring NO3 mixing ratios, were simultaneouslydeployed in the atmosphere simulation chamber SAPHIR in Jülich, Germany.Some of these instruments measured N2O5 mixing ratios eithersimultaneously or alternatively. Experiments focused on the investigation ofpotential interferences from, e.g., water vapour or aerosol and on theinvestigation of the oxidation of biogenic volatile organic compounds byNO3. The comparison of N2O5 mixing ratios shows an excellentagreement between measurements of instruments applying different techniques(3 cavity ring-down (CRDS) instruments, 2 laser-induced fluorescence (LIF)instruments). Datasets are highly correlated as indicated by the square ofthe linear correlation coefficients, R2, which values were larger than0.96 for the entire datasets. N2O5 mixing ratios well agree withinthe combined accuracy of measurements. Slopes of the linear regression rangebetween 0.87 and 1.26 and intercepts are negligible. The most critical aspectof N2O5 measurements by cavity ring-down instruments is thedetermination of the inlet and filter transmission efficiency. Measurementshere show that the N2O5 inlet transmission efficiency can decreasein the presence of high aerosol loads, and that frequent filter/inletchanging is necessary to quantitatively sample N2O5 in someenvironments. The analysis of data also demonstrates that a generalcorrection for degrading filter transmission is not applicable for allconditions encountered during this campaign. Besides the effect of a gradualdegradation of the inlet transmission efficiency aerosol exposure, no otherinterference for N2O5 measurements is found