Combined evaluations of meteorological parameters, traffic noise and air pollution in an Alpine valley

Kurzfassung

Concurrent measurements of meteorological parameters, traffic flow and vehicle composition, NOx concentrations and noise levels have been performed during a consecutive 166-hour (approx. one week) episode in the Austrian Inn valley. The study elaborates the meteorologically induced effects on the transport and dispersion of air pollutants (NOx) and the propagation of sound waves from the motorway in the valley towards two receptor/receiver sites, one at the valley bottom, the other one at an elevated slope position. Due to complex transmission effects only a small portion of the observed variations in the air and noise pollution at the two sites can be explained by the varying emission at the motorway. With the help of simple models it is shown that by adding merely one or two meteorological parameters a substantially larger portion of the variation can be explained. The vertical temperature gradient turned out to be the meteorological key parameter. It controls the mixing volume (confined by the valley sides and the mixing-layer top) and the sound wave refraction which strongly determine air pollution and noise level, respectively.