Environmental Engineering Reference
In-Depth Information
Fig. 8
Annual course for selected water-soluble cations in TSP samples from site 4 (missing
values due to analytical problems)
ammonium and nitrate showed no correlation (r = 0.10, n = 53). Therefore, ammonium
in Beijing's aerosols seems to be mainly present in the form of ammonium sulphate.
Conclusion
All over the year 2006, particulate matter concentrations in Beijing were high and
thus atmospheric pollution was severe. PM
2.5
and TSP mass concentrations as well
as the concentrations of the different ions analyzed revealed a different annual
course. Seasonal differences are caused by meteorological influence, different air
mass origin and different source contributions. Also spatial differences could be
detected with higher particle concentrations in the city centre and lowest concentrations
in the outskirts northwest of the city.
Water-soluble ions displayed an important part of particulate matter in dust
samples from Beijing. Sulphate was the most abundant anion with highest concen-
trations in winter. Calcium was the dominant water-soluble cation in TSP samples.
Further knowledge of the temporal and spatial aerosol distribution and the corre-
sponding sources is important for the detailed assessment of the pollution of
Beijing's atmosphere.
Acknowledgements
This study was funded by the German Research Foundation as part of the
DFG project “Investigation of relevant processes of aerosol pollution in Beijing - source identifi-
cation, elemental composition and bio-availability with respect to different land use types”. Ion
chromatography for water-soluble cations was carried out at the German Weather Service (DWD)
in Freiburg, Germany. In this respect the authors want to express their special thanks to M. Fricker
for his support. All other analyses were performed at the Institute of Mineralogy and Geochemistry
at the Universität Karlsruhe, Germany.
