1. Topic

2. Introduction

Air quality can be affected not only from traffic-related emission sources, but also from residential heating area sources and industrial emission sources. Over the last decades important improvements have been achieved in industry regarding several major polluting substances, and gradually the environmental impact has shifted towards so-called diffuse sources of pollution (such as traffic and household consumption of chemicals). Nevertheless, industrial production processes still account for a considerable share of the overall pollution in Europe (for pollutants such as greenhouse gases, acidifying substances, volatile organic compounds and waste), and it is very important to further reduce their contribution to "un-sustainability".

The most important EU Directives concerning emissions of air pollutants from industrial facilities are the ‘Pollution from Large Combustion Plants’ Council Directive (88/609/EEC), the ‘Volatile organic compounds (VOCs) resulting from the storage of petrol and its distribution from terminals to service stations’ European Parliament and Council Directive (94/63/EC), the ‘Volatile organic compounds (VOCs) resulting from certain industrial activities in certain installations’ Council Directive (1999/13/EC) and the ‘Integrated pollution prevention and control’ or IPPC Council Directive (96/61/EC).

The IPPC Directive is about minimising pollution from various point sources throughout the European Union. All installations covered by Annex I of the Directive are required to obtain an authorisation (permit) from the authorities in the EU countries. Unless they have a permit, they are not allowed to operate. The permits must be based on the concept of Best Available Techniques (or BAT), which is defined in Article 2 of the Directive. Since the permits must be based on BAT, the licensing authorities need some assistance to find out which techniques are BAT. This exchange of information between experts from the EU Member States, industry and environmental organisations is co-ordinated by the European IPPC Bureau and it has been divided into some 30 sectors along the lines of Annex I of the Directive. For each sector it takes around two years to complete the work and to produce a so-called BREF (BAT reference document). All BREFs will be completed by the end of 2005, but several are now finalised and are downloadable from the BREF site of the IPPC Bureau and available on CD. Policy-makers as well as the public at large need better information about the amount of pollution that different installations are responsible for: that is why the Directive provides for the setting up of a European Pollutant Emission Register (also known as EPER).

3. Discussion

Emission estimates are important for developing emission control strategies, determining applicability of permitting and control programs, ascertaining the effects of sources and appropriate mitigation strategies, and a number of other related applications by an array of users, including federal, state, and local agencies, consultants, and industry. The estimation of air emissions from industrial facilities can be computed by using emission factors and/or emission models. An emission factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. At European level, the UNECE/EMEP Task Force on Emissions Inventories and Projections has prepared the CORINAIR Emission Inventory Guidebook, designed to provide a comprehensive guide to the state-of-the-art of atmospheric emissions inventory methodology (see the Topic on How to develop urban Emission Inventories?) for each of the emission-generating activities (for the industrial facilities see Group 1: Combustion in energy and transformation industries, Group 3: Combustion in manufacturing industry, Group 4: Production processes Group 5: Extraction & distribution of fossil fuels and geothermal energy Group 6: Solvent and other product use, Group 9: Waste treatment and disposal). Other relevant references for emission factors are EMEP/CORINAIR 2003; IPCC Revised 1996 “Guidelines for National Greenhouse Gas Inventories” and US EPA’s Compilation of Air Pollution Emission Factors, AP-42.

At U.S.A. level, the Emissions Modelling Clearing House (EMCH) has been designed to support and promote emission modelling activities both internal and external to U.S.-Environmental Protection Agency. Some examples of emission models are the Landfill Air Emissions Model (a PC-based software for estimating emissions of CH₄, CO₂, NMVOC and hazardous air pollutants from municipal solid waste landfills), and the EMS-HAP, an emissions model that prepares annual toxics emission inventory data, for subsequent air quality modelling using, for example, the ISCST3 Gaussian model (Industrial Source Complex, Short Term, version 3: it is the recommended model for a wide range of regulatory applications to study the impact of industrial sources). Moreover the CALPUFF Lagrangian dispersion model, developed by EPA, has been adopted by the U.S. Environmental Protection Agency (U.S. EPA) in its Guideline on Air Quality Models as the preferred model for assessing long range transport of pollutants and their impacts on Federal Class I areas and on a case-by-case basis for certain near-field applications involving complex meteorological conditions. CALPUFF model need to be driven by an emission inventory and CALMET 3-D meteorological diagnostic model. CALMET also drives CALGRID 3D Eulerian photochemical model recommended by EEA (European Environment Agency).

4. Recommendation / Conclusion

· When using official Emission Factors’ Guidebook (such as the CORINAIR), it should be advisable to check the emission factors against any more specific information available in the country. Data from source-specific emission tests or continuous emission monitors are usually preferred for estimating a source’s emissions because those data provide the best representation of the tested source's emissions. However, test data from individual sources are not always available and, even then, they may not reflect the variability of actual emissions over time. Thus, emission factors are frequently the best or only method available for estimating emissions, in spite of their limitations.

· Emission factors are generally provided as mean values representative of a large scale (National) situation. When local emission inventories are to be performed an uncertainty analysis (e.g. Montecarlo method) of emission estimations can be advisable. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per tonne of coal burned). Emission factors can be used in some permitting applications, such as in applicability determinations and in establishing operating permit fees. Source-specific tests or continuous emission monitors can determine the actual pollutant contribution from an existing source better than can emission factors. Even then, the results will be applicable only to the conditions existing at the time of the testing or monitoring. To provide the best estimate of longer-term (e. g., yearly or typical day) emissions, these conditions should be representative of the source's routine operations.

· A material balance approach also may provide reliable average emission estimates for specific sources. For some sources, a material balance may provide a better estimate of emissions than emission tests would. In general, material balances are appropriate for use in situations where a high percentage of material is lost to the atmosphere (e. g., sulphur in fuel, or solvent loss in an uncontrolled coating process.) In contrast, material balances may be inappropriate where material is consumed or chemically combined in the process, or where losses to the atmosphere are a small portion of the total process throughput. As the term implies, one needs to account for all the materials going into and coming out of the process for such an emission estimation to be credible.

· Direct surveys combining questionnaires and some chimney emission measures can be the most accurate approach to estimate and validate industrial sources emissions on a regional or sub-regional scale.

5. Examples / Further Reading

Examples are provided by:

Example from Bristol - Industrial emissions modelling

Sardinia Industrial emissions

SO2 emmisions in Porto Marghera industrial area Venice: A model approach in risk assessment

6. Additional Documents / Web Links

Background references on Emission Factors

· CORINAIR Emission Inventory Guidebook (3^rd edition): http://reports.eea.eu.int/EMEPCORINAIR3/en

· U.S.-EPA: http://www.epa.gov/ttn/chief/

Background references on IPPC and Best Available Technologies (BAT)

· The IPPC Directive: http://europa.eu.int/comm/environment/ippc/index.htm

· The BAT reference documents (BREFs): http://eippcb.jrc.es/pages/FActivities.htm

· The European Union Network for the Implementation and Enforcement of Environmental Law (IMPEL) network (forum for discussion between national authorities about general issues linked to the implementation and enforcement of the Directive): http://europa.eu.int/comm/environment/impel/index.htm

· The EPER European Pollutant Emission Register: http://europa.eu.int/comm/environment/ippc/eper/index.htm

Last Updated

25th January 2005