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| Titel |
Investigation of the Nitrogen Dioxide Pollution in Urban Areas using a New Portable ICAD Instrument |
| VerfasserIn |
Martin Horbanski, Denis Pöhler, Tim Adler, Johannes Lampel, Florian Kanatschnig, Tobias Oesterle, Miriam Reh, Ulrich Platt |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127774
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| Publikation (Nr.) |
 EGU/EGU2016-7684.pdf |
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| Zusammenfassung |
| Nitrogen oxides (NOx) and especially nitrogen dioxide (NO2), are still among of the most
problematic pollutants in urban areas not only in developing, but also in industrialized
countries. Despite the measures taken to reduce their emissions, NO2 concentrations in many
urban areas exceed the WHO recommended limits of 40 μg∕m3 for annual mean and
200 μg∕m3 for 1 hour mean. Additionally it is known that the NO2 concentration in
urban areas has a strong spatial and temporal variability, due to the large number
of NOx emitting point sources (mainly traffic) found in densely populated areas.
However, the layout of air monitoring networks in most urban areas, installed to
continuously monitor the officially prescribed NO2 limits, does not reflect the high spatial
variability because they only conduct measurements at a single or few selected
sampling points, mainly on major roads, which are often not representative for the
whole urban area. At present these uncertainties about the spatial NO2 distribution
constitute severe limitations for the assessment of health risks, for the quality of
chemical model calculations, and for developing effective measures to reduce NOx
emissions.
We developed a new light-weight and portable ICAD (Iterative Cavity Enhanced DOAS)
instrument which detects NO2 at a detection limit as low as 0.2 μg∕m3 with a high time
resolution of seconds. The instrument is based on the Cavity Enhanced (CE-) DOAS
technique, which directly identifies and quantifies NO2 by its differential optical absorption.
Therefore, it does not suffer from interferences by other trace gas species like O3 or NOy.
This is a great advantage over other NO2 instruments (e.g. solid state detectors or
chemiluminescence instruments).
We present the result of ICAD NO2 measurements, which we recently performed in more
than 10 German cities. The ICAD instrument was mounted on mobile platforms like cars and
bicycles, measuring the NO2 concentrations along carefully selected tracks. Also several
stationary measurements were performed at selected sites. We found that high NO2
concentrations exceeded pollution limits across extensive areas of the cities. Contrary to
expectations we found high NO2 concentrations also away from heavily traveled roads e.g. in
residential areas and close to kindergardens and schools and even indoors. Thus, the
exposure of the populations to NO2 is much higher than expected, which results
in higher health risks, particularly for children and elderly people who are risk
groups. |
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