Source Attribution

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Introduction

The FRAME model was used to generate individual deposition footprints of sulphur and nitrogen resulting from gaseous emissions from 42 different sources. The analysis was based on emissions in 2012. The emission sources are described in the emissions data tab.

The results are presented in a series of tabs , summarising the source attribution for nitrogen deposition, sulphur deposition and acid deposition respectively. The deposition is based on the maximum deposition values each source contributes at any one of the grid squares (5km x5 km) that overlap the site boundaries. The deposition values presented here are grid averages and not habitat specific depositions. Each tab provides a selection of expandable tables and pie charts as follows:

  • A table providing a breakdown of total deposition at the site, showing the sources ranked by their contribution. For each source, the relative proportion which is from short vs long-range sources is shown as well as a breakdown by pollutant (e.g. NOy/NHx). The data presented in the table are illustrated in a series of pie charts showing:
    • Total deposition source apportionment
    • Source apportionment for local sources
    • Source apportionment for long-range sources
    • Source apportionment Reduced Nitrogen deposition
    • Source apportionment Oxidised Nitrogen deposition.
  • A table providing a breakdown of total deposition at a site apportioned to sources defined also by “region” – either a country of the UK or international sources (e.g. livestock in Wales). The data presented in the table are illustrated in a series of pie charts showing:
    • Source apportionment of total deposition by regionally defined source
    • Source apportionment for local sources by regionally defined source
    • Source apportionment for long-range sources by regionally defined source
    • Source apportionment Reduced Nitrogen deposition by regionally defined source
    • Source apportionment Oxidised Nitrogen deposition by regionally defined source.

Method

By running the FRAME model successively and abating at each run the individual emission sources, we calculated the difference to estimate that source’s footprint. For each grid square (5 km), the pollutant species for SO2, NOx and NHx deposition from all sources were calculated. We then outputted the relative contribution of each source to the total deposition in each grid square (5 km). A further post-processing procedure was applied to the deposition data (that is used for calculations of critical loads exceedance) to 'calibrate' the deposition data relative to the CBED approach. The recent CBED deposition data for the years 2011-2013 was used for the calibration procedure.

The source attribution pages now give an estimate of how much of each source is from short or longer distance sources. For example, you can get an indication of how much from the “livestock source” is from local or distant sources. Users are warned that this is an approximation and should indicate if local sources should be considered further. It is based on outputting data for multiple pollutant species (e.g. wet NH3, dry NH3, wet NH4+ and dry NH4+). Dry deposition of the primary pollutant ammonia gas is mostly local as it is rapidly dispersed vertically and horizontally. However ammonia can be transported long distances at higher levels, especially if it doesn't react with acid gases, and then be deposited. As a consequence a proportion of emissions from long-range may be incorrectly classified as “local” in this method.

The tables and pie charts below show the source apportionment for nitrogen deposited onto the . Click on the to expand the table/charts. To aid viewing, you can hover over each slice in the pie charts.

The tables and pie charts below show the source apportionment for sulphur deposited onto the . Click on the to expand the table/charts. To aid viewing, you can hover over each slice in the pie charts.

The tables and pie charts below show the source apportionment for acid deposited onto the . Click on the to expand the table/charts. To aid viewing, you can hover over each slice in the pie charts.

Some of the following source emissions have been grouped for combined/area sources to a UK aggregate. For further information on terminology please read the emissions modelling page.

SOURCE/SOURCE GROUPSO2 2012 T/SNOX 2012 T/NNH3 2012 T/N
Energy Production and Transformation1028931-
Commercial Industry and Residential Combustion21489175601666
Industrial Combustion1475014648-
Industrial Processes123804
Offshore-17-
Solvent use--989
Road transport405996986564
Other transport19674243670
Waste treatment and disposal881456-
Natural-255-
Livestock--156100
Fertiliser--31300
Non-agricultural abatable--9300
Non-agricultural non-abatable--23300
Non-agricultural waste--13400
Drax3647542144-
Longannet3480016600-
Ferrybridge C1665916042-
Eggborough1621515103-
Ratcliffe on Soar1352416475-
Ashington133004700-
Fiddlers Ferry1197716160-
Stanlow102503534-
Fawley Refinery1018338941
West Burton832018000-
Scunthorpe7507512450
Teesside7460204025
Cottam679020600-
Grangemouth61782815-
Port Talbot565350248
Pembroke Plant554315764
Whitwell487258850
South Killingholme Refinery451927671
Aberthaw B394632000-
Milford Haven38992805307
Kilroot27193358-
Rugeley B229910898-
Europe import  
International Shipping3852987713-