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The new UFP 330: Sample conditioning
L. Hillemann
1
, A. Zschoppe
2
, B. Wehner
3
and H. Gerwig
4
1
Institute of Process Engineering and Environmental Technology, TU Dresden, 01062 Dresden, Germany
2
Topas GmbH, Wilischstr. 1, 01279 Dresden, Germany
3
Leibniz-Institute for Tropospheric Research, 04318 Leipzig, Germany
4
LfUG - Saxon State Agency for Environment and Geology, Section Air Quality, 01109 Dresden, Germany
Keywords: number size distribution, instrumentation, ambient aerosol
Submicron particles belong to the most
problematic pollutants in ambient air especially in
urban areas. In contrast to other species the
concentration of these particle fraction has increased
in recent years.
Basing on their ability to reach the deep lung and
even to enter body tissue submicron particles show
adverse health effects. This dose-relationship seems
to be particularly evident for particles smaller than
1 μm (Peters, 1997).
Currently the particulate matter in ambient air
is quantified by the mass concentration of different
particle size fractions like PM10 or PM2.5. Shifting
this upper cut to lower sizes towards ultrafine
particles is not possible due to the lack in both highly
sensitive mass detection methods and in suitable
separation methods.
One possible solution of the problem can be
the measurement of the number concentration. In the
past this has been done by many groups adapting
highly sensitive particle counters to the requirements
of routine measuring networks. A suitable
commercial device for this purpose has not been
available up to now.
Figure 1. Sampling system for aerosol spectrometers
In the European project UFIPOLNET a new
particle spectrometer has been developed making a
trade-off between the required accuracy of the results
and the suitability for field use. This includes on the
one hand rough environmental conditions and on the
other hand a low maintenance effort.
Figure 2. Relation between particle size and electrical
mobility using a diffusion-based charger.
One important part of the newly developed
spectrometer is the sampling system being
substantially different from systems used for gaseous
or particle mass sampling. Its main function is the
separation of particles exceeding the working range
of the device. Due to the used diffusion charging
process coarse particles would otherwise interfere the
measured mobility spectrum.
Furthermore it includes a dryer to reduce
humidity in the sampled aerosol and a equalization
tank to average dynamic concentration peaks. The
measured particle number concentrations have to be
corrected for the transmission efficiency of this
components. This data will be presented in detail.
UFIPOLNET
(www.ufipolnet.eu)
is financed by the
LIFE financial instrument of the European
Community under No. LIFE04 ENV/D/000054.
A. Peters et al. Respiratory effects are associated
with the number of ultrafine particles (1997),
Am
J Respir Crit Care Med
, 155, 1376-1383.