SSSI NH3 Critical Levels: Ammonia Sensitivity for UK Nature Sites

SSSI NH3 Critical Levels is a geospatial layer from the UK Government Digital Service. It provides a Critical Level (CLe) for ammonia to assess potential impacts on Sites of Special Scientific Interest (SSSI). The layer includes the SSSI name, code, and an ammonia CLe value of 1 µg/m³, 3 µg/m³, or NS (Not Sensitive).

Use Cases

• Assess development impact on nitrogen-sensitive bryophytes and lichens based on the 1 µg/m³ CLe classification.
• Evaluate potential harm to invertebrate features dependent on nitrogen-sensitive vegetation based on the 3 µg/m³ CLe classification.
• Identify protected sites where ammonia is not a primary concern based on the NS (Not Sensitive) classification.
• Map ammonia sensitivity thresholds for UK SSSIs based on the site name and code attributes.

Strengths

• Provides a defined, standardized metric (Critical Level) for environmental impact assessment.
• Classifies site sensitivity into three distinct categories (1, 3, NS) with clear ecological rationales.
• Includes unique site identifiers (SSSI name and code) for linking with other datasets.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Last update date is unknown; freshness unverified.

Provenance

Source

Government Digital Service

Collection Method

Likely compiled by environmental agencies for regulatory assessment.

Time Range

null

Freshness

unknown

Geography

United Kingdom (specifically Sites of Special Scientific Interest)