Description of the instrument:

NO₂ is an important atmospheric trace gas that can be directly linked to certain health effects. It is the main precursor for ozone (O₃), which is directly responsible for the “summer smog” in the urban atmosphere. In addition, NO₂ provides information on the acidification of the environment (“acid rain”) through oxidation in HNO₃.
Urban NO₂ concentrations exceed the annual limit of approx. 200 µg/m3 (EU Directive 2010). The reasons for this are still the subject of controversial debate.
Due to this main reason, NO₂ is regularly measured in national network stations.
However, the common commercial instruments show significant and known interferences.

Properties:

• Very sensitive: detection limit 2 pptv (6 min. time resolution)
• Large application range: Measuring range 0.002-300 ppbv
• Air flow: 0.5 l/min.
• Time resolution: 3-6 min. (depending on the measuring range)
• Accuracy: approx. ± (10% + DL)
• Precision: approx. ± (1% + DL)
• Interference: negligible for all investigated conductive gases

Published literature:

• Development of a new Long Path Absorption Photometer (LOPAP) Instrument for the Sensitive Detection of NO₂ in the Atmosphere, Atmos. Meas. Tech., 2011, 4, 1663-1676.
• Interferences of commercial NO₂ instruments in the urban atmosphere and in a smog-chamber, Atmos. Meas. Tech., 2012, 5, 149-159.

In cooperation with:

Prof. Dr. Peter Wiesen /PD Dr. Joerg Kleffmann
Physical Chemistry/FB C
University of Wuppertal
Gauss Street 20
D-42097 Wuppertal
Germany
PHONE: +49 202 439 2515
FAX: +49 202 439 2505 or 2757
Email: wiesen@uni-wuppertal.de
kleffmann@uni-wuppertal.de
www.physchem.uni-wuppertal.de