Chemistry Reference
In-Depth Information
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
2 Source Apportionment Approaches . . . . . . . . . . . . . . . . . . . . . . .................................. 197
2.1 Spatial Increment Approach .......................................................... 197
2.2 Lenschow Approach . ................................................................. 198
2.3 Mass Closure/Tracer Based Approaches . ........................................... 199
2.4 Statistical Receptor Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
2.5 Dispersion and Chemical Transport Models ......................................... 200
2.6 Back-Trajectory Modelling ........................................................... 201
3 Source Apportionment Studies Carried Out in Germany ................................. 202
3.1 Overview .............................................................................. 202
3.2 General Source Apportionment Results for Germany ............................... 203
3.3 Main Sources and Processes in Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
4 Resume and Outlook . . . . . . . . . . ............................................................. 213
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
1
Introduction
Source apportionment of airborne dust is a technique allowing us to identify and
quantify sources contributing significantly to ambient air pollution. Airborne particles
have various environmental and health effects. They are, by Aeolian transport of
particles, important nutrient sources but also cause negative health effects for humans
especially after inhalation. Sources and meteorological conditions significantly
influence ambient particle concentrations and hence human and environmental expo-
sure. Exposure also varies significantly throughout Europe, and within each country.
In case of Germany, a large fraction of the population lives in urban agglomerations
which historically have been centred along trading routes, rivers and industrial (coal
mining and steel production) areas. Thirteen of the EU's 50 largest cities by population
are located in Germany. Hence identification and quantification of source
contributions to ambient particles is of interest especially for urban areas with their
high population density and proximity to significant sources of air pollution.
Although the air quality situation has been improving throughout the recent
decades (cf. Fig.
1
), these agglomeration areas still face air quality problems. Dust,
with high levels of coarse particles, and sulphur dioxide led to frequent (winter)
smog episodes in the middle of the twentieth century. At present, fine dust (PM10,
PM2.5, particles with aerodynamic diameters
m
m, respectively) and
nitrogen dioxide pose the major issues. In cities, the latter pollutant is largely
influenced by automotive traffic; a multitude of sources, however, is contributing
to the PM levels. This complicates the development of mitigation actions and calls
for deeper insights into the source-receptor relationships.
<
10 and
<
2.5
