A multimethodological approach to study the spatial distribution of air pollution in an Alpine valley during wintertime 1Institute of Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
2Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria
3Institut für Physik der Atmosphäre, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Oberpfaffenhofen, Germany
4MetAir AG, Menzingen, Switzerland
Received: 17 Nov 2008 – Published in Atmos. Chem. Phys. Discuss.: 09 Feb 2009 – Published: 26 May 2009Abstract. In order to investigate the spatial distribution of air pollutants in the Inn
valley (Tyrol, Austria) during wintertime, a joint field campaign of the
three research projects ALPNAP (Monitoring and Minimisation of
Traffic-Induced Noise and Air Pollution Along Major Alpine Transport Routes),
INNAP (Boundary Layer Structure in the Inn Valley during high Air Pollution)
and INNOX (NOx-structure in the Inn Valley during High Air
Pollution) was carried out in January/February 2006. In addition to
continuous ground based measurements, vertical profiles of various air
pollutants and meteorological parameters were obtained on six selected days.
For in-situ investigations, a tethered balloon was used to analyse the lowest
atmospheric layers, 0–500 m above the valley bottom (a.v.b.), and a
research aircraft sampled at 150–2200 m a.v.b. An aircraft equipped with
an aerosol backscatter lidar performed nadir measurements at 3000 m a.v.b.
Combined results from a typical day show a strongly polluted layer up to
about 125 m a.v.b. in the morning. Around midday concentrations on the
valley floor decrease indicating some vertical air exchange despite thermally
stable conditions. Strong vertical and horizontal gradients with enhanced
pollution levels along the sunny side of the valley up to 1300 m a.v.b.
were observed in the afternoon. This vertical mixing due to thermally or dynamically
driven slope winds reduces the concentration of air pollutants at the bottom of the valley and causes the formation of elevated pollution layers.
Citation: Schnitzhofer, R., Norman, M., Wisthaler, A., Vergeiner, J., Harnisch, F., Gohm, A., Obleitner, F., Fix, A., Neininger, B., and Hansel, A.: A multimethodological approach to study the spatial distribution of air pollution in an Alpine valley during wintertime, Atmos. Chem. Phys., 9, 3385-3396, doi:10.5194/acp-9-3385-2009, 2009.