The influence of local winds on the spatial distribution of air pollutants in an Alpine valley

Abstract

The subject of our investigation is the wintertime boundary layer of the lower Inn Valley (Austria) during episodes of high air pollution. We investigate physical processes which are responsible for transport and redistribution of pollutants. Our study illuminates the influence of thermally driven winds (valley and slope winds), dynamically driven flows (e.g., foehn winds, low level cold-air advection) and related mechanically and thermally induced turbulence on the spatial structure of air pollutants. Our analysis is based on airborne and ground-based measurements collected on four winter days in 2007 during the joint field experiment of the three research projects INNAP, INNOX and ALPNAP. The dataset consists of airborne aerosol backscatter lidar data as well as airborne and ground-based in situ measurements of chemical and meteorological parameters. Our study highlights the strong case-to-case variability of the distribution of pollutants due to different meteorological background conditions and different types of local winds.