Towards development of a deposition monitoring network for air pollution of Europe (LIFE II)
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Series / Report no.
Open Access
Type
Report
Language
en
Date
2000-08-31
Research Projects
Organizational Units
Journal Issue
Title
Towards development of a deposition monitoring
network for air pollution of Europe (LIFE II)
Translated Title
Naar een depositiemonitoring netwerk voor
luchtverontreiniging in Europa (LIFE II)
Published in
Abstract
In het kader van het LIFE II project gefinancierd door
de Europeesche Commissie DG XI, zijn vanaf de zomer van 1996 tot en met 1998
de fluxen gemeten van NH3, SO2 en NOx. Deze fluxen dienden als referentie
voor te ontwikkelen goedkope meetmethoden, die geschikt zijn om een
uitgebreid Europees monitoring netwerk mee uit te rusten. Verder werden de
gemeten fluxen gebruikt voor het verbeteren van parameterisaties die de
fluxen van deze componenten beschrijven. De flux metingen zijn onderworpen
aan een selectie om aan de eisen van de flux-gradient theorie te voldoen en
om nauwkeurige gradienten te kunnen bepalen. Elk jaar blijven er minder
data over door dalende SO2 concentraties en steeds meer apparaat-uitval
(NH3). De droge depositieflux van NH3 was erg hoog in 1997 (2729
mol/ha/jr), waarschijnlijk veroorzaakt door extremen in metingen. De nieuwe
parameterisatie van de droge depositiesnelheid voor NH3 is uitgebreid met
een compensatiepunt, zodat ook emissiefluxen berekend kunnen worden
gedurende perioden met lage achtergrondconcentraties. De parameterisatie is
verbeterd, maar emissiefluxen worden nogsteeds niet goed gerepresenteerd.
De kwaliteit van de metingen is niet goed genoeg om nieuwe parameterisaties
mee af te leiden, of oudere concepten zoals co-depositie en verhoogde
depositie bij nat blad oppervlak te valideren.
In the framework of the LIFE II project, financed by the European Commission DG XI, fluxes of NH3, SO2 and NOx were measured from July 1996 to November 1998. The interpretation of the flux measurements at the Speulder forest should lead to a) primary wet and dry deposition fluxes of the measured components and b) yearly averaged fluxes. These fluxes should serve as a reference method for newly designed monitoring systems that can be applied on many locations for a reasonable price. Furthermore the deposition characteristics at one of the three core-sites: Speuld for the RIVM should be determined and the measured fluxes should be used for improvement and further evaluation of the deposition models. The gradient measurements were subjected to a selection to comply with the conditions of the flux gradient method and to be able to determine fluxes accurately. Each year, less valid hours remain, caused by a decrease in concentrations (SO2) and increasing instrumental failure (NH3). The dry deposition flux of NH3 was extremely high in 1997 (2729 mol/ha/yr), probably caused by extremes in the measurements. The new dry deposition velocity parameterisations of NH3 (by TNO) is capable of producing emission fluxes during periods of low ambient NH3 concentrations, through the incorporation of the compensation point. It can be seen that this parameterisation is better, although negative measured fluxes (emission fluxes) are still not reproduced very well. The quality of the measurements was not high enough to extract new parameterisations or to validate older concepts like co-deposition or even enhanced deposition at wet leaf surfaces.
In the framework of the LIFE II project, financed by the European Commission DG XI, fluxes of NH3, SO2 and NOx were measured from July 1996 to November 1998. The interpretation of the flux measurements at the Speulder forest should lead to a) primary wet and dry deposition fluxes of the measured components and b) yearly averaged fluxes. These fluxes should serve as a reference method for newly designed monitoring systems that can be applied on many locations for a reasonable price. Furthermore the deposition characteristics at one of the three core-sites: Speuld for the RIVM should be determined and the measured fluxes should be used for improvement and further evaluation of the deposition models. The gradient measurements were subjected to a selection to comply with the conditions of the flux gradient method and to be able to determine fluxes accurately. Each year, less valid hours remain, caused by a decrease in concentrations (SO2) and increasing instrumental failure (NH3). The dry deposition flux of NH3 was extremely high in 1997 (2729 mol/ha/yr), probably caused by extremes in the measurements. The new dry deposition velocity parameterisations of NH3 (by TNO) is capable of producing emission fluxes during periods of low ambient NH3 concentrations, through the incorporation of the compensation point. It can be seen that this parameterisation is better, although negative measured fluxes (emission fluxes) are still not reproduced very well. The quality of the measurements was not high enough to extract new parameterisations or to validate older concepts like co-deposition or even enhanced deposition at wet leaf surfaces.
Description
Publisher
TNO
ECN
ITE
Engeland
IFT
Duitsland
ECN
ITE
Engeland
IFT
Duitsland
Sponsors
EC DG XI
DGM