The Impacts of air pollutants on the Scottish and Northern Irish Environments

May 2002


1.1 Purpose of project

  1. Air quality standards currently in use by regulators have principally been calculated to protect human health. It was recognised by staff at SEPA, SNH and Northern Ireland EHS that there was a need for local staff to take into account the potential effects that issuing of air emission authorisations might have on habitats and species. It was agreed that a database of air pollution information and standards to protect habitats and species was required as a support tool. This would be relevant in particular for staff with pollution expertise to provide information on impacts on habitats and species, and for staff with conservation expertise to provide information on the different air pollutants. In addition to this main task, a number of research needs for further development and assessment of air pollution impacts have been identified.
  2. The work was carried out by a consortium of Centre for Ecology and Hydrology (CEH - formerly ITE), the University of Edinburgh, Macaulay Land Use Research Institute (MLURI) and the University of Ulster.

Development of the database

  1. The concept and design for the database was agreed with SNIFFER members, in particular regarding database platform, scope of pollutants, habitats and species and system structure. For convenience, the developed database is referred to as the SNIFFER Air Pollution Information System (APIS).
  2. The overall database structure consists of a) overviews, b) the database query section, c) a help guide, glossary and unit conversion table and d) listing of relevant literature. It is built using Microsoft Access 97. In addition, a runtime version has been developed and made available on CD.
  3. The relational database allows interrogation by a) pollutant (e.g. SO2, O3 etc), b) habitat or species and c) air pollution issues (e.g. acidification, eutrophication).
  4. The overview sections cover short summaries on a) pollutants and their impacts, b) receptors and their key air pollution concerns, c) regulations (e.g. Habitats Directive) and d) air pollution issues.
  5. The pollutants covered in the database include: SO2, NOx, NH3, O3, and acid and nitrogen deposition processes. Literature reviews on these pollutants were conducted for the agreed habitats and species. In addition, other pollutants such as toxic substances, greenhouse gases (methane, carbon dioxide, CFCs etc), radioactive particles, VOCs, heavy metals and POPs, are covered briefly in the overview sections to provide simple explanations and allow clarification of the differences between these and the air pollutions that have local and regional impacts.
  6. The habitats covered are based on the Biodiversity Action Plan (BAP) and Habitat Directive (HD) lists, with additional habitats of key concern for air pollution impacts which are not on these lists for Scotland and Northern Ireland (e.g. urban woodlands and arable land).
  7. Due to the fact that lists of species could become extremely long, species are included where: a) a key species with an air pollution interest (e.g. brown trout), b) data are available in literature or c) air pollution is noted as a concern for a rare species listed under BAPs. Note: some species, which do not merit a separate inclusion, have been summarised into species groups (e.g. fungi).
  8. The third way in which the relational database can be search is by the major air pollution issues. This was an additional search mechanism requested by SNIFFER partners during the project and may be considered as particularly relevant for policy issues.

Population of the database

  1. The database was populated through joint literature review by the contractors on the different aspects. In particular, a special data entry form for the Access database was constructed to facilitate populating the database.
  2. The literature survey covered a wide range of sources including peer-reviewed scientific literature, government reports and other sources (e.g. web material) where available. A key part of the review was to provide transparency and access to the original source literature. Overall, the database contains over 600 references (Sept 2001), which are given as full citations.
  3. The literature has been analysed particularly with a view to the impacts and concerns in Scotland and Northern Ireland. Much information is only available at a general (e.g. UK, or NW Europe) level or from isolated experimental studies. However, the particular relevance for Scotland and Northern Ireland has been drawn out where this is has consequences for the impacts assessment.

Additional features: Critical Limits information

  1. 14. There are two main ways in which pollutants impact on habitats and species: a) direct exposure to a pollutant concentration (with an effects threshold referred to as a Critical Level) and b) indirect deposition of pollutant (with an effects threshold referred to as a Critical Load). A brief description of the effects of the critical load/level being exceeded, or other relevant comments specific to this critical load/level value is provided, with a full citation of the original literature.
  2. 15. A key finding of the work is that for many habitats there is a large uncertainty regarding Critical Loads for specific habitats or species. In such cases, the most similar or relevant ecological habitat has been assigned, and this clearly noted for transparency.

Additional features: Qualitative impact assessment

  1. 16. A feature of the database is the facility to scale in an approximate qualitative manner the level of impact of an air pollutant, habitat interaction or air pollutant species interaction, in Scotland and Northern Ireland. Although this should be treated only as a broad indication, it is especially relevant given that the database does not currently include gridded spatial information, but rather focuses on the generic levels of concern.
  2. 17. The impact scale considers an overall assessment of the impacts in Scotland and Northern Ireland derived from the product of the magnitude of impact and the geographical scale of impact. Combined these are used to consider whether, for example, there is a more severe impact on a local level or a smaller impact over a wider area. This is visualised in an impacts matrix, following the principles of risk assessment.

Help in using the database

  1. In addition, a help guide is provided to support users on installation and use of the database. This provides a walk-through of the database, by examples, of the full functionality of SNIFFER APIS.

Needs for research and further development

  1. The analysis of this project has shown in particular the paucity of available information on air pollution for a comprehensive list of habitats in Scotland and Northern Ireland. While much is known from experimental studies on individual example habitats, the studies have not covered all habitats comprehensively. This introduces uncertainties in assessing the level of threat for habitats where there is little available information (so that estimates can only be made by analogy to the most similar studied habitat). While it would be impossible to conduct comprehensive research on all habitats, there is a need to assess the uncertainties where information is lacking and the implications of this for regulatory environmental impact assessment of air pollutants.
  2. Related to the lack of comprehensive information on impacts of air pollutants on habitats is the lack of information for rare species. Most air pollution research has been conducted on key species in major habitats. It is currently unknown whether many priority BAP species are more sensitive to air pollution. This might be expected for rare stress tolerater species limited to specific environmental niches. Such differences in sensitivity would have major implications for the whole critical loads assessment. Experimental studies are also required.
  3. The database provides a tool that is highly suited to further development and expansion. In particular, the system would benefit from incorporating spatial information (e.g. on deposition and critical loads).
  4. It is recognised that there are limitations to the Microsoft Access runtime version. Current work includes the re-building of the database into a webenabled version of the database, which would be accessible through an Internet browser.
  5. Other future work on the database could cover inclusion of further pollutants and their impacts on the natural environment (e.g. heavy metals, POPs, dust and acid halogen gases), as well as information on biomonitoring of air pollutants. In addition, there is scope for the database to incorporate information on health and the effects of air pollutants on built environment.


Air Pollution impacts, Habitats, Species, Air pollutants, relational database, critical loads

Copies of this reports are available from the Foundation, price 15.00, less 20% to FWR members.

N.B. The report is available for download from the SNIFFER Website