10 July 2009 - The objective
of this investigation was to find a relatively
simple biological indicator for the nitrogen
load that can be used for monitoring.
The geographical and
seasonal variation in nitrogen content in
the lichen (Cladonia portentosa ) and ammonia
concentrations in air were measured during
a one year period at several locations.
The region covered a
triangle with approximately 50 km between
the locations, two inland heaths and one
dune heath. At one of the heaths and on
the dune heath samples were taken to investigate
the local variation within at distance of
a few kilometers. The seasonal variation
in the nitrogen content of the lichen was
small and a local variation was detectable,
even at the few kilometer scale.
Nitrogen content in
the lichen is a parameter monitored in the
surveillance program and these data compared
well to the data obtained in this investigation.
The seasonal variation of the concentration
of ammonia in air is very similar at the
different locations, though with a clear
difference in absolute values.
The nitrogen content
in the lichen shows a good correlation to
the yearly mean value of the measured ammonia
concentration in air at the different locations.
The total nitrogen deposition was calculated
by use of models and apart from ammonia
these results show very similar deposition
loads at the investigated locations. Considering
uncertainties in modeling, only the modeled
deposition of ammonia has a good correlation
to the nitrogen content in the lichens.
At locations with similar
background deposition of nitrogen compounds
the nitrogen content in the lichen (Cladonia
portentosa ) seems to be a good indicator
to detect local differences in ammonia concentrations
and ammonia depositions. It is not unambiguous
whether the nitrogen content of the lichens
also relates to the nitrogen deposition
as a hole.
Vegetation analysis
has been performed and showed relatively
high cover of grass species at the inland
heaths. The vegetation analysis is not regarded
as a suitable indicator for nitrogen deposition,
since other factors have an influence on
the diversity of species.
Contact: Senior scientist Helle Vibeke Andersen
Helle Vibeke Andersen,
Knud Erik Nielsen, Hans Jørgen Degn,
Camilla Geels, Per Løfstrøm,
Christian Damgaard & Jesper H. Christensen
2009.Lokal kvælstofdeposition og kvælstofindhold
i lav. Danmarks Miljøundersøgelser,
Aarhus Universitet. 46 s.- Faglig rapport
fra DMU nr. 732.
+ More
Emission factors for
PM2.5 and PM10 due to highway traffic
10 July 2009 - The emission
factors for PM2.5 and PM10 were determined
to 45 and 155 mg/(vehicle km), respectively
according to a new report from NERI. This
is comparable to the emission factors previously
determined for H. C. Andersens Boulevard
in Copenhagen and somewhat higher than found
at Jagtvej, Copenhagen.
A new report from NERI
presents the results from a measurement
campaign carried out at the Holbæk
Highway during 2008. The objective of the
campaign was to determine the emission factors
for PM2.5 and PM10 due to highway traffic.
The campaign included measurements of NOx,
NO, NO2, TEOM PM2.5, TEOM PM10, O3, particle
size distribution and local meteorology.
The emission factors
for PM2.5 and PM10 were determined to 45
and 155 mg/(vehicle km), respectively. This
is comparable to the emission factors previously
determined for H. C. Andersens Boulevard
in Copenhagen and somewhat higher than found
at Jagtvej, Copenhagen.
Contact: Senior scientist Thomas Ellermann
Thomas Ellermann, Steen
Solvang Jensen, Matthias Ketzel , Per Løfstrøm
and Andreas Massling 2009: Measurements
of air pollution from a Danish highway.
National Environmental Research Institute,
Aarhus University. 45 pp. Research Notes
from NERI No. 254.
+ More
Passive diffusion tube
samplers for determination of ammonia
9 July 2009 - Measurements
of atmospheric ammonia concentrations by
two types of passive diffusion tube samplers
(ALPHA and Radiello) have been compared
to active measurements obtained by the denuder
method. The comparison was made at several
locations over a one-year period, covering
different concentrations levels and seasons.
The passive diffusion
tube samples were found suitable for fortnight
to monthly sampling. Both types of passive
diffusion tubes showed a small systematic
overestimation of the ammonia concentration
compared to the denuder tubes and therefore
demand a correction. The precision is good
and both types of tubes are suitable for
measuring local gradients. Since the passive
diffusion tubes are independent of power
supply, they are very suitable for monitoring
purposes.
Contact: Senior scientist
Helle Vibeke Andersen
Helle Vibeke Andersen,
Per Løfstrøm, Lars Moseholm,
Thomas Ellerman & Knud Erik Nielsen
2009: Metodeafprøvning af passive
diffusionsopsamlere til koncentrationsbestemmelse
af ammoniak. National Environmental Research
Institute, Aarhus University. 31 p.- Technical
Report no.730.
