English Abstract Samples obtained with an Annular Denuder System (ADS)
have been analysed by the Agricultural University of Wageningen and the
National Institute of Public and Environmental Protection on sulfate,
nitrite, nitrate, ammonium and hydronium. The ADS is used by both
institutes to determine concentrations of acidifying gases and aerosols in
ambient air. After sampling these gases and aerosols are dissolved in
deionized, distilled water and concentrations of the corresponding ions are
measured. For most of the ions different analytical methods used by the
Agricultural University of Wageningen on one hand and the National Institute
of Public Health and Environmental Protection on the other. In this
examination samples have been analysed by both institutes for comparison.
It has been set up both in order to examine the quality of the analysis
methods and to determine, whether the concentrations of gases and aerosols
measured by both institutes with their ADSs can be interchanged in further
research. Good agreement was found for sulfate, ammonium and hydronium,
Concentrations of nitrite measured by the Agricultural University of
Wageningen were 10 times lower than those determined by the National
Institute of Public Health and Environmental Protection. This difference
can be presumably attributed to a calibration or a calculation error. After
correction for this error the agreement was rather good. Nitrate
concentrations from denuder samples showed relatively large differences,
which may have been caused by instabilities in the corresponding solutions.
Due to this differences the corresponding nitric acid concentrations can not
be interchanged. Differences in nitrate concentrations from filter samples
were acceptable.
