Simple Calculation of Atmospheric Impact Limits assessments for agricultural, combustion and industrial sources affecting designated ecological sites. We prepare SCAIL reports for IED permit applications, Habitats Regulation appropriate assessments, and planning applications near SSSIs and SACs.
The Simple Calculation of Atmospheric Impact Limits (SCAIL) tools — SCAIL-Agriculture and SCAIL-Combustion — are screening tools developed by the UK Centre for Ecology and Hydrology (UKCEH) and the National Atmospheric Emissions Inventory (NAEI) to assess the atmospheric deposition of nitrogen and acid compounds on sensitive habitats from agricultural and combustion sources respectively. SCAIL is the standard first-stage screening tool used by the Environment Agency, Natural England, Natural Resources Wales and NatureScot when evaluating applications for Environmental Permits, planning consents and variations that could affect designated sites including Sites of Special Scientific Interest (SSSIs) and Special Areas of Conservation (SACs). Where SCAIL indicates a potential exceedance of Critical Loads, more detailed modelling is generally required.
Habitats Regulations Assessment. For developments or operations that could affect a European designated site (SAC, SPA or Ramsar), a Habitats Regulations Assessment (HRA) is required. SCAIL outputs form a key part of the screening stage of the HRA process. We work with ecologists and legal advisors to ensure that atmospheric deposition evidence is prepared and presented correctly for HRA purposes.
A SCAIL assessment is typically required in the following circumstances:
We gather detailed information on emission sources: for agricultural sources, livestock numbers, building types and manure management systems; for combustion sources, fuel type, thermal input, stack parameters and operational hours. Emission factors are taken from the appropriate NAEI or IPCC source.
We identify all relevant designated sites within the assessment envelope using the MAGIC mapping system and SSSI and SAC boundary data from Natural England, NatureScot or NRW as appropriate. Habitat types and their Critical Loads are established from the UK Critical Loads databases.
SCAIL-Agriculture or SCAIL-Combustion is run for the relevant source-receptor combinations. Outputs include predicted deposition rates and concentrations, which are compared against Habitat-specific Critical Loads and Critical Levels.
Results are assessed for significance in the context of the relevant planning or permitting framework. Where SCAIL indicates a potential exceedance, we advise on whether more detailed modelling (AERMOD, ADMS) is required and can carry out that modelling where needed.
Full planning application air quality assessments for agricultural and industrial development.
Dust risk assessments for construction near ecologically sensitive sites.
Operational emission mitigation strategies for agricultural and combustion sources.
Tell us about your scheme and we will confirm requirements and provide a fixed-fee quotation within 24 hours.
Specialist air quality consultants for planning applications and workplace compliance across the UK. From initial scoping to submission-ready reports, we work closely with clients and local authorities to ensure a fast, smooth approval process.
