Bealey, B.; Martin Hernandez, C.; Levy, P.E.; Stedman, J.R.

Deposition and concentration of nitrogen and sulphur for protected sites in the UK (2015-2017)

This dataset provides deposition values of sulphur and nitrogen deposition and concentration values for ammonia (NH3), sulphur dioxide (SO2) and nitrogen oxide (NOx) on the UK nature conservation protected sites, averaged over the years 2015 to 2017. The dataset also includes calculated minimum, maximum and gridded average values for each site. Protected nature sites covered are:
(i) Special Areas of Conservation (SAC)
(ii) Special Protection Areas (SPA)
(iii) Sites of Special Scientific Interest (SSSI).

The data consist of values of nitrogen and acid deposition, and concentrations of ammonia (NH3) based on the Concentration Based Estimated Deposition (CBED), and concentrations of NOX and SO2 using the Pollution Climate Mapping (PCM) model.

Nitrogen and acid deposition data is also given for specific habitat types including:
(i) moorland/short vegetation everywhere,
(ii) forest everywhere, and
(iii) the grid square average over multiple land cover types (i.e. arable, grassland, forest, moorland, urban)

These habitat-specific data are recommended for use with critical loads for the calculation of critical load exceedances using the relevant deposition/habitat type.

Publication date: 2020-02-17

Get the data

This dataset is available under the terms of the Open Government Licence

Format of the data: Comma-separated values (CSV)

You must cite: Bealey, B.; Martin Hernandez, C.; Levy, P.E.; Stedman, J.R. (2020). Deposition and concentration of nitrogen and sulphur for protected sites in the UK (2015-2017). NERC Environmental Information Data Centre.


© NERC (UK Centre for Ecology & Hydrology), Natural Resources Wales, Environment Agency, the Northern Ireland Environment Agency, Natural England, the Joint Nature Conservation Committee (JNCC), Scotland and Northern Ireland Forum for Environmental Research (SNIFFER), the Scottish Environment Protection Agency (SEPA), Scottish Natural Heritage (SNH)


Study area
Temporal extent
2015-01-01    to    2017-12-31

Provenance & quality

The Air Pollution Information System (APIS), through the 'Site Relevant Critical Loads' tool, provides critical loads for acidity and nitrogen and critical levels for ammonia, sulphur dioxide and nitrogen oxides for designated features within every SAC, SPA or A/SSSI in the UK. In addition, deposition and concentration data for nitrogen and sulphur pollutants are provided at each site to give an estimate of critical load/level exceedance.

The data provided is based on pollutant deposition gridded maps for nitrogen and acid deposition and concentration maps of ammonia, nitrogen oxides and sulphur, which are overlayed to a GIS shape file of site boundaries in the UK (e.g. SAC, SPA, SSSI). These gridded maps were then clipped to provide the pollutant values for each grid square including the area of the clipped grid. The resulting data was then queried to generate site statistics in the form of a minimum, maximum and area weighted average values for each of the pollutants.

For nitrogen and acid deposition values and ammonia concentrations, 3 year average pollutant maps were used at a resolution of 5 x 5 km from the CBED model for the years 2013-2015. For nitrogen dioxide and sulphur dioxide concentrations the 1 x 1 km PCM model was used based on the 3 year average (2013-2015). Deposition values are generated for specific habitat types (forest and semi-natural) to be used in critical load exceedance calculations.
The full methodology is available in the contextual metadata linked to this record.

The work of APIS is jointly funded between the Centre for Ecology & Hydrology and the UK pollution and conservation agencies including Natural Resources Wales (NRW), the Environment Agency, Northern Ireland Environment Agency, Natural England, the Joint Nature Conservation Committee (JNCC), the Scottish Environment Protection Agency (SEPA), and Scottish Natural Heritage (SNH).


This dataset is included in the following collections

Air Pollution Information System (APIS)

Supplemental information

Other useful information regarding this dataset:

APIS Site Relevant Critical Loads and Source Attribution

Correspondence/contact details

Dr. Bill Bealey
UK Centre for Ecology & Hydrology
Bush Estate
EH26 0QB
United Kingdom


Bealey, B.
Centre for Ecology & Hydrology
Martin Hernandez, C.
Centre for Ecology & Hydrology
Levy, P.E.
Centre for Ecology & Hydrology
Stedman, J.R.
Ricardo Energy & Environment

Other contacts

Environmental Information Data Centre
NERC Environmental Information Data Centre

Additional metadata

Topic categories
acid deposition,  atmospheric pollution,  critical loads,  ecosystem impacts from atmospheric pollution,  natura 2000,  nitrogen deposition,  Pollution source attribution
Environmental Monitoring Facilities
Spatial representation type
Tabular (text)
Spatial reference system
OSGB 1936 / British National Grid
Last updated
13 March 2020 14:31