4
R. Timmermans et al.
1.1 Introduction
In the 2008 Air Quality Directive (2008/50/EG), the EU established limit values for
the PM10 concentration in ambient air. The daily limit of 50 µg/m
3 should not be
exceeded on more than 35 days a year, and the maximum allowed annual average
is 40 µg/m
3 . The daily limit value is still exceeded on too many days for a number
of observation stations in Germany. Although the number of exceedance days has
reduced in the last few years, there are still episodes with very high concentrations of
PM. High PM observations in Eastern Germany are often correlated to transport of
air masses from south-easterly direction. The pollution in these air masses mixes with
local pollution, adding up to levels exceeding the limit values for PM. This southeasterly transport occurs often with a high pressure system causing stable conditions
over Eastern Europe, which in winter means low temperatures in the area. When
Eastern Germany is more fed with westerly flows, this is usually during weather
conditions causing high atmospheric mixing, which leads to dilution of pollution.
The air quality guidelines state that for regions with exceedances associated
with long-range transport, the contribution of transboundary transport of PM to the
exceedance of limit values should be assessed and discussed between neighboring
countries. Unfortunately, separating national and foreign contributions as well as
source sectors using observation-based methods is hardly possible. This requires a
dedicated analysis using receptor-oriented approaches such as Positive Matrix Factorisation (PMF), ideally in combination with chemistry transport modelling aimed
at identifying the origin of air pollution.
1.2 Method
1.2.1 LOTOS-EUROS Model and Source Apportionment
In this study we have performed a source apportionment study using the LOTOSEUROS model and its source apportionment tool. LOTOS-EUROS is an open source
3D chemistry transport model. The grid model simulates air pollution concentrations
in the lower troposphere on a regular Eulerian grid with variable resolution over
Europe [1]. The model is used for a wide range of applications supporting scientific
research, regulatory programmes and air quality forecasts. The vertical layer structure
makes the model very efficient in use.
For the source apportionment a so-called labelling system is used to track the
impact of emission categories within a LOTOS-EUROS simulation. Besides species
concentrations the contributions of pre-defined source categories are calculated. The
labelling routine is implemented for primary, inert aerosol tracers as well as chemically active tracers containing a C, N or S atom, as these are conserved and traceable.
For details and validation of this source apportionment module we refer to [2].
R. Timmermans et al.
1.1 Introduction
In the 2008 Air Quality Directive (2008/50/EG), the EU established limit values for
the PM10 concentration in ambient air. The daily limit of 50 µg/m
3 should not be
exceeded on more than 35 days a year, and the maximum allowed annual average
is 40 µg/m
3 . The daily limit value is still exceeded on too many days for a number
of observation stations in Germany. Although the number of exceedance days has
reduced in the last few years, there are still episodes with very high concentrations of
PM. High PM observations in Eastern Germany are often correlated to transport of
air masses from south-easterly direction. The pollution in these air masses mixes with
local pollution, adding up to levels exceeding the limit values for PM. This southeasterly transport occurs often with a high pressure system causing stable conditions
over Eastern Europe, which in winter means low temperatures in the area. When
Eastern Germany is more fed with westerly flows, this is usually during weather
conditions causing high atmospheric mixing, which leads to dilution of pollution.
The air quality guidelines state that for regions with exceedances associated
with long-range transport, the contribution of transboundary transport of PM to the
exceedance of limit values should be assessed and discussed between neighboring
countries. Unfortunately, separating national and foreign contributions as well as
source sectors using observation-based methods is hardly possible. This requires a
dedicated analysis using receptor-oriented approaches such as Positive Matrix Factorisation (PMF), ideally in combination with chemistry transport modelling aimed
at identifying the origin of air pollution.
1.2 Method
1.2.1 LOTOS-EUROS Model and Source Apportionment
In this study we have performed a source apportionment study using the LOTOSEUROS model and its source apportionment tool. LOTOS-EUROS is an open source
3D chemistry transport model. The grid model simulates air pollution concentrations
in the lower troposphere on a regular Eulerian grid with variable resolution over
Europe [1]. The model is used for a wide range of applications supporting scientific
research, regulatory programmes and air quality forecasts. The vertical layer structure
makes the model very efficient in use.
For the source apportionment a so-called labelling system is used to track the
impact of emission categories within a LOTOS-EUROS simulation. Besides species
concentrations the contributions of pre-defined source categories are calculated. The
labelling routine is implemented for primary, inert aerosol tracers as well as chemically active tracers containing a C, N or S atom, as these are conserved and traceable.
For details and validation of this source apportionment module we refer to [2].