Environmental Engineering Reference
In-Depth Information
The present study focuses on the UK and considers the individual contribution of
emissions from a number of major point sources (power stations), distributed
sources as well as international shipping and import from European sources.
2. Description of Model and Input Data
The FRAME model (Dore et al
.
, 2007) is a Lagrangian atmospheric transport
model employing annually averaged statistical meteorology. It's main features
include: 5 km horizontal resolution covering the British Isles; vertical resolution
varying from 1 m at the surface to 100 m near the top of the boundary layer;
vertical diffusion calculated with k-theory eddy diffusion; dry phase and aqueous
phase chemistry of sulphur and nitrogen; wet removal calculated by constant
drizzle using scavenging coefficients driven by a map of annual rainfall for the
UK; gaseous dry deposition calculated using a canopy resistance parameterisation;
a plume rise module to calculate 'effective stack height' of point source emissions;
boundary concentrations generated from a European scale simulation on the
EMEP 50 km grid. The model was found to give a good representation of aerosol
and gas concentrations of nitrogen and sulphur compounds as well as wet deposition
when compared with measurements from the UK national monitoring networks
(Dore et al
.
, 2007).
A detailed data base of emissions for the year 2005 including stack parameters
for point sources was compiled for the UK. Distributed emissions were obtained
from the National Atmospheric Emissions Inventory (www.naei.org.uk). The
model was applied to perform 160 individual simulations, each with a different
point source or area emissions source abated. The sources comprised: 100 indi-
vidual point sources, 21 groups of combined minor point sources, 37 sources of
area emissions disaggregated according to region and emission classification as
well as international shipping and import from other European countries.
3. Discussion and Conclusion
The results of the simulations were used to apportion deposition in the UK to
emissions from UK sources, European sources and international shipping. The
results from FRAME showed good agreement with the EMEP source-receptor
matrices. FRAME estimated that international shipping contributed 18% and 15%
respectively to total sulphur and oxidised nitrogen deposition in the UK, compared
with 19% and 18% for EMEP. FRAME calculated that emissions from the UK
contributed 59% of sulphur, 58% of oxidised nitrogen and 70% of reduced nitrogen
deposition, as compared with 56%, 42% and 73% for EMEP. Total deposition to
the UK was dominated by wet deposition with reduced and oxidised nitrogen
making similar contributions to total nitrogen deposition.
