Emissions calculations in EMIT
Sources with known emission rates can be imported directly,
for example, the emissions from Part A industrial sources can be
downloaded from the Environment
Agency website.
However, explicit emissions from most sources
are not known. This means that emissions have to be estimated. This
can be done in one of two ways.
Firstly, emissions can be calculated from activity
data, such as traffic flows for road and rail traffic,
and fuel consumption for industrial sources. The table to the
right gives examples of activity data for various sources whose
emissions can be estimated in EMIT
(some or all of the activity data listed may be required to
estimate emissions).
In order to calculate emissions from activity data, associated
emission factor datasets are required. A range
of datasets are held in EMIT,
including:
-
Road traffic 
The latest DMRB emission factors (February
2003) and the new NAEI factors are included
to estimate moving vehicle emissions; also, datasets to
estimate emissions from hot soak, cold starts, and road
wear are in EMIT.
-
|
Activity data
used in EMIT
Example sources |
Example activity data |
Agriculture |
Number of animals
Land area
Fuel used |
Industrial plants |
Amount of raw materials consumed
Amount of product
Fuel consumption |
Road and rail traffic |
Traffic flows
Fleet compositions
Number of vehicle kilometres
Number of trips |
Air traffic |
Number of Landing/Take off cycles
Fuel consumption |
Electricity |
Number of kWhr used
Fuel consumption |
Landfill |
Volume of landfill |
Commercial and domestic heating |
House type
Fuel type
Insulation
Heating efficiency |
|
-
-
Industrial processes
Hundreds of emissions factors for industrial sources have
been included using data from the UK
EFD, UK
GHG and IPCC inventories.
-
Electricity 
Datasets have been included in EMIT
to estimate emissions from electricity, both in terms of the fuel
used for power generation, and also using ‘end-use’
values of electricity consumption in terms of the number of kWhr
used.
-
Domestic dwellings
An emission factor dataset to estimate the CO2
emissions from domestic properties based on the Government’s
Standard Assessment Procedure for Energy Rating of Dwellings
has been included within the EMIT
database.
Secondly, emissions can be estimated as a scaling
of a national emissions figure by a local statistic. For example, the
local population is often a good indicator of emissions – if you
were to scale the total emissions from landfill sites in the UK by the
ratio of the local to national population, this would give an estimate
of the emissions from landfill that could be attributed to the local
population.
Pollutants
Emission factors are included for the following gaseous pollutants:
8 local Air Quality Strategy (AQS) pollutants: |
oxides of nitrogen ('NOx' and nitrogen
dioxide), particulate matter (PM10), sulphur dioxide,
carbon monoxide, lead benzene and 1,3-butadiene |
6 greenhouse gases: |
carbon dioxide, methane, nitrous oxide, sulphur
hexaflouride, hydrofluorocarbons and perfluorocarbons |
5 other pollutants: |
volatile organic compounds (VOC), mercury, total
suspended particulates (TSP) and Benzo[a]pyrene |
Import and Export
Emissions data in the following formats can be imported directly into
EMIT:
Once data manipulations and calculations within EMIT
have been performed as required, emissions data can be exported from
EMIT as ArcView
shape files. For major roads data, these files can be imported
directly into noise mapping software that implements the UK noise
standard Calculation of Road Traffic Noise (CRTN).
Alternatively, the data can be exported to a format that
can be imported directly into CERC’s air quality management tool,
ADMS-Urban for use in local
air quality assessments of AQS pollutants, or to the industrial assessment
model, ADMS 4.
Emissions totals are displayed in the
EMIT interface, and
can be copied and pasted into other packages for editing, use in reports
and so forth. For Greenhouse Gas inventories, the
totals are not only displayed for each of the 6 greenhouse gases explicitly,
but also in terms of their Global Warming Potential.
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