National Focal Centre (NFC) for Modelling and Mapping of Exceedances of Critical Loads and Critical Levels
NFC model code calculates exceedances of Critical Loads (for acidifying and for eutrophying air pollutants) and Critical Levels (for ammonia) to generate air pollution statistics. It is used by UK and devolved governments, statutory bodies, NGOs, environmental planners and consultants:
(1) to assess progress towards statutory targets;
(2) to assess development applications; and
(3) for UK reporting to the international Coordination Centre for Effects of the Air Convention (CLRTAP).
NFC is a largely GIS-based model that uses process understanding and measurements from atmospheric chemistry, soil chemistry and biodiversity, together with habitat maps, to generate high-profile air pollution statistics (e.g. % area where critical load is exceeded; excess nitrogen) for UK nations, habitats and protected areas.
Approaches to calculating and mapping exceedances of critical loads and critical levels were developed by CEH scientists in the 1990s. In the early 2000s, these approaches were formalised into a set of GIS-based calulations using ArcGIS. Recently the scripts were separated from ArcGIS and are now entirely in Python, greatly speeding up calculation times. From 2021-2022 a different atmospheric chemisty model and updated habitat maps were used. Revisions and updates are ongoing. Investment to date approx 5 person-years.
NFC integrates knowledge across UKCEH research capabilities, including: biodiversity, soil chemistry, atmospheric chemistry, and habitat mapping. While much of the relevant knowledge and data are in the public domain, it would be challenging for other organisations to replucate UKCEH's whole-system capability.
NFC was developed by UKCEH.
Access to NFC model code and input datasets is restricted to licenced users (see 'users'). NFC model outputs are openly available via the UKCEH Environmental Information Data Centre (EIDC), the UKEH APIS website, and Defra's annual Trends Report (e.g. https://uk-air.defra.gov.uk/library/reports?report_id=1020).
Development of NFC was funded by Defra (Air Quality and NFC contracts).
NFC is operated by UKCEH and its outputs are used primarily by policy and NGO audiences including: Defra; Natural England; JNCC; Natural Resources Wales; Nature Scotland; Department of Agriculture, Environment and Rural Affairs (DAERA, Northern Ireland); Plantlife; and the UK National Focal Centre for Critical Loads Mapping and Modelling (based at UKCEH Bangor).