Vertical distribution of air pollutants at the Gustavii Cathedral in Göteborg, Sweden

Atmospheric trace gases and particles were measured at two heights at the Gustavii Cathedral in Göteborg, Sweden, during 7 weeks in September and October 1999. The Gustavii Cathedral is situated in the city centre of Göteborg, which is near the harbour area and encircled by heavy traffic some hundred metres away. The main body of the church is as high as the surrounding buildings, while the tower extends well above. The sampling points were placed on the west wall of the tower at 10 and 32 m height, i.e. well below and above the roof top level of surrounding buildings, respectively. Sulphur dioxide and nitric acid were sampled using the denuder technique and analysed by Ion Chromatography, IC. Total suspended particulates (TSP) were sampled using filter cups and subsequently analysed by energy dispersive X-ray fluorescence spectroscopy (EDXRF). In addition to the diurnal sampling of species, nitrogen oxides were measured using chemiluminescence detectors. Additional data from the Environmental Office in Göteborg was used in the analysis. Differences between the concentrations measured at the upper and lower levels were calculated and their variation and dependence on meteorological factors were evaluated. On the average larger concentrations were found at the lower level for soil derived elements and TSP, while nitric acid and nitric oxide showed larger concentrations at the upper level. Sulphur dioxide and nitrogen dioxide, as well as many of the elements in the TSP, showed equal concentrations at the two levels. However, depending on wind direction the measured differences of nitrogen oxides could be both positive and negative.