Elevated NH sub(3) and NO sub(2) Air Concentrations and Nitrogen Deposition Rates in the Vicinity of a Highway in Southern Bavaria

• Published in: Atmospheric environment (1994) 2005-08, Vol.39 (25), p.4531-4531
• Main Authors: Kirchner, Manfred, Jakobi, Gert, Feicht, Ernst, Bernhardt, Markus, Fischer, Anton
• Format: Article
• Language: English
• ISSN: 1352-2310
• DOI: 10.1016/j.atmosenv.2005.03.052

At two sites along highway A91 from Munich to Garmisch-Partenkirchen, Germany, atmospheric ammonia and nitrogen dioxide concentrations were measured, along with N deposition rates. A grassland transect was located 40 km south of Munich, and a forest transect was established 5 km south of the city. Precipitation samples were collected in the open field and as throughfall, and soil samples were collected for analysis. The NH sub(3) concentrations exhibited a clear daily variation with higher values during the day. The concentrations of both NH sub(3) and NO sub(2) were significantly higher near the highway compared with locations approximately 500 m from the roadway, but the N deposition gradient was marked only for the grassland transect, where total deposition ranged 23.0 25.6 and 16.8 22.0 kg/ha/yr in the vicinity of the highway and 500 m from the highway, respectively. While the atmospheric concentrations of NH sub(3) and NO sub(2) were significantly lower than critical levels, the N input significantly exceeded the critical loads for bogs and spruce forests. At the forest transect, high nitrate export in seepage was observed near the highway.