 |
| Titel |
Intercomparison of four different in-situ techniques for ambient formaldehyde measurements in urban air |
| VerfasserIn |
C. Hak, I. Pundt, S. Trick, C. Kern, U. Platt, J. Dommen, C. Ordóñez, A. S. H. Prévôt, W. Junkermann, C. Astorga-Lloréns, B. R. Larsen, J. Mellqvist, A. Strandberg, Y. Yu, B. Galle, J. Kleffmann, J. C. Lörzer, G. O. Braathen, R. Volkamer |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 5, no. 11 ; Nr. 5, no. 11 (2005-11-02), S.2881-2900 |
| Datensatznummer |
250003135
|
| Publikation (Nr.) |
 copernicus.org/acp-5-2881-2005.pdf |
|
|
|
|
|
| Zusammenfassung |
| Results from an intercomparison of several currently used in-situ techniques
for the measurement of atmospheric formaldehyde (CH2O) are presented.
The measurements were carried out at Bresso, an urban site in the periphery
of Milan (Italy) as part of the FORMAT-I field campaign. Eight instruments
were employed by six independent research groups using four different
techniques: Differential Optical Absorption Spectroscopy (DOAS), Fourier
Transform Infra Red (FTIR) interferometry, the fluorimetric Hantzsch
reaction technique (five instruments) and a chromatographic technique
employing C18-DNPH-cartridges (2,4-dinitrophenylhydrazine). White type
multi-reflection systems were employed for the optical techniques in order
to avoid spatial CH2O gradients and ensure the sampling of nearly the
same air mass by all instruments. Between 23 and 31 July 2002, up to 13 ppbv
of CH2O were observed. The concentrations lay well above the detection
limits of all instruments. The formaldehyde concentrations determined with
DOAS, FTIR and the Hantzsch instruments were found to agree within ±11%,
with the exception of one Hantzsch instrument, which gave
systematically higher values. The two hour integrated samples by DNPH
yielded up to 25% lower concentrations than the data of the continuously
measuring instruments averaged over the same time period. The consistency
between the DOAS and the Hantzsch method was better than during previous
intercomparisons in ambient air with slopes of the regression line not
significantly differing from one. The differences between the individual
Hantzsch instruments could be attributed in part to the calibration
standards used. Possible systematic errors of the methods are discussed. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|