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Guidelines for Air Emission Regulation

2. Contents and application of the guidelines

2.1 The contents of the guidelines

The Guidelines for Air Emission Regulation contain a complete description of how air pollution from installations should be regulated.

Central to these regulations is the use of mass flow limits, emission limit values, and contribution values (C-values). The mass flow limit determines whether it is necessary to clean the air emitted from an outlet, and the emission limit values determine the maximum concentration allowed after purification or abatement. These limits are described in Chapter 3 in these Guidelines.

The Danish EPA regularly sets up new contribution values for substances. The most recent information on C-values can be found in Sector Information Document (Orientering) No. 15/1996 published by the Danish EPA (in Danish). These C-values are based on the knowledge the Danish EPA possessed about the substances in question at the time of publication.

The Danish EPA will publish a new set of guidelines on C-values in August-September 2001. The Guidelines for Air Emission Regulation only include examples of C-values, and as these can be amended, the Danish EPA’s Information Document and new set of guidelines on C-values should always form the basis for using the values.

Chapter 4 includes calculation methods for outlet heights in order to comply with C-values. A computer-based model, the OML model, is used for these calculations.

When requirements for air pollution from an installation have been determined on the basis of Chapters 3 and 4, terms should be stipulated. Chapter 5 deals with designing terms, which type of terms can be applied and how to check compliance with these terms.

With regard to energy plants, the Danish EPA has chosen to prepare a separate chapter, Chapter 6, which includes a more detailed description of requirements for the different types of energy plant.

Furthermore, a special chapter, Chapter 7, has been prepared on requirements for the design and operation of tanks and silos.

Chapter 8 deals with measuring emissions from air-polluting installations. This chapter also establishes methods for sampling and analysis.

Chapter 9 includes conversion tables for surplus air and moisture content.

Chapter 10 on recommended emission limit values and inspection rules includes emission limit values, etc., for thermal and catalytic oxidation installations for the destruction of gaseous organic solvents.

2.2 How to apply the guidelines

The Guidelines for Air Emission Regulation basically apply to all installations emitting substances to the air.

However, if emission limit values for a certain type of plant, installation or sector have been determined in a Statutory Order, the limit values stipulated in this Order should be complied with, regardless of whether the Guidelines for Air Emission Regulation contain stricter or more lenient emission limit values of the substance in question. This is because, when it was issued, the Statutory Order took into account the technical and financial possibilities of lowering emissions of the relevant substances for the sector in question.

If sector guidelines have been prepared, they must form the basis of the requirements for the installation in connection with issuing an approval for the installation.

With regard to installations marked with an (i) and included in a BREF¹⁶, the Danish EPA will provide information on which requirements should be imposed on the installations described in the BREF.

Please note that the sections on outlet height, self-inspection, terms, etc., in the Guidelines for Air Emission Regulation are general and apply to all types of installations.

The Guidelines include minimum limits for emissions that require purification or abatement measures in order not to spend resources on limiting, monitoring, and controlling pollution of little significance to the environment.

A few small air outlets which cannot be integrated naturally into the overall discharge from an installation may be exempt from purification or abatement requirements, provided each outlet comprises less than 10 per cent of the mass flow limit for the substance(s) in question.

Diffused emissions, for example emissions from stock kept outdoors are not regulated by the guidelines. Instead, these emissions should be regulated through requirements for the operation and design of the installation.

These Guidelines do not regulate diffused pollution from installations affecting the indoor climate in adjacent residential housing in the same building.

The method of applying these guidelines when handling specific cases in pursuance of the Environmental Protection Act is explained in the following.

2.2.1 Application for approvals for new Listed Installations

As mentioned in Chapter 1, the approving authority must ensure that the establishment and operation of the installation in question is based on the BAT principle.

This means that the approving authority must first assess the possibility of limiting pollution by using cleaner technology.

Based on the information included in the application on the nature of substances emitted and the volume of these emissions, the approving authority will then assess whether purification or abatement measures should be implemented.

Purification or abatement measures are required if the mass flow limit is exceeded and if the current emission limit values cannot be complied with. In such instances the approval should contain terms including emission limit values and the maximum volume of air.

Mass-flow limits and emission limit values can be found in Chapter 3 of these Guidelines.

Required outlet heights are calculated on the basis of C-values for the substances in question. The calculation method is described in more detail in Chapter 4. C-values should always be complied with under normal operating conditions. Moreover, the approving authority should set up instructions for operation in extraordinary situations, including starting up, closing down, by-pass, etc.

2.2.2 Application for expansion or changes to Listed Installations

If a Listed Installation intends to expand or change its operations in a way that entails increased pollution, the expansion or changes must be approved in advance¹⁷. The terms of the expansion or change as regards air pollution must be determined in accordance with the same principles as described in the above for approvals for new installations.

In practice, determining the terms of an expansion or change that entails increased air pollution often causes difficulties. In particular, there has been some uncertainty as to whether requirements can only be made for the expansion or changes, or whether air pollution conditions for the entire installation should be included, when stipulating requirements.

Requirements for purification or abatement and outlet heights in connection with typical extensions and changes will be explained in the following. See also the definitions in Chapter 3.1. It is a requirement that all possibilities for introducing cleaner technology have been assessed prior to the extension or change, including whether

	opportunities for efficient use of energy and raw materials have been fully exploited,
	opportunities for substituting harmful or suspect substances with less harmful or suspect substances have been fully exploited,
	opportunities for optimising production processes have been fully exploited, e.g. by using closed processes or similar,
	production of waste can be avoided or, where this is not possible, whether opportunities for recycling or recirculation have been fully exploited.

Example 1.
A Listed Installation holding an approval wants to change the operation of an existing plant

Note that in some cases where an installation emits a new substance, it may be required that other substances from the same substance group are included in calculation of mass flow and emission concentration

Example 2.
A Listed Installation holding an approval wants to expand by adding a new plant with new outlets.

Note that in some cases where an installation emits a new substance, it is may be required that other substances from the same substance group are included in calculation of mass flow and emission concentration.

2.2.3 Regulation of existing Listed Installations

Application of the Guidelines to existing Listed Installations is explained in the following.

2.2.3.1 Listed Installations without an approval

Processing applications for approvals from existing Listed Installations is based on the same principles as processing applications from new installations. Depending on the scope and nature of pollution, a reasonable time limit for the implementation of any requirements for measures limiting pollution should be determined. In some cases a gradual reduction of pollution may be appropriate.

2.2.3.2 Reassessment of Listed Installations with an approval

2.2.3.2.1 Before expiry of the legal protection period

Within the first eight years¹⁹ of issuing an approval, new requirements may only be made to the installations, if²⁰

	new information has emerged about the harmful effects of pollution,
	pollution is harmful to the environment in a manner that could not be anticipated at the time of issuing the approval,
	pollution is greater than reported at the time of issuing the approval,
	significant changes to BAT enable considerable reduction of emissions without disproportionately raising costs,
	operation safety in connection with the process or activity requires that other techniques are applied, or
	new information on safety at risk installations21 has emerged.

The result is that, under certain circumstances, the authorities can serve orders to installations within the first eight years following the issue of an approval.

However, the publication of new guidelines, information on BREFs and sector-specific information documents, as well as stricter C-values do not in themselves give authorities the right to make new requirements within the legal protection period. This also applies to limit values, which have been tightened in these Guidelines compared to previous guidelines.

Please note also that terms for self-inspection in current guidelines can be reassessed at any time with a view to improving self-inspection at the installation, even though the legal protection period²² has not yet expired.

2.2.3.2.2 After expiry of the legal protection period

Regular reassessment of Listed Installations marked with an (i)

The supervising authority should reassess the entire installation on a regular basis and at least once every ten years. The terms of the approval should be changed as necessary to ensure that the operation of the installation remains based on the BAT principle²³. The first reassessment should take place when the legal protection period for the installation’s first approval expires. Note that installations must continue to limit pollution on the basis of developments in technology.

Reassessment of all other Listed Installations that are not marked with an (i)

Even though the Environmental Protection Act does not include an obligation to reassess approvals for Listed Installations not marked with an (i), there is clear authorisation to do so²⁴ and existing approvals should be reassessed on a regular basis. These installations should also live up to the BAT principle.

2.2.4 Regulation of non-Listed Installations

If an installation not requiring an approval causes significant pollution, the authorities can order it to implement measures to relieve the pollution²⁵.

The supervising authority should provide evidence that an installation is the cause of such high levels of pollution that measures to relieve pollution must be implemented. Such pollution levels may be:

	if mass flow limits and emission limit values have been exceeded simultaneously, or
	if the C-value has been exceeded considerably, or
	if limitation of emissions for Group 1 substances has not been implemented as stated in Chapter 3.

The supervising authority should collect information from the installation itself regarding

	which substances are emitted from the installation,
	the size of mass flow for each substance/substance group,
	concentration of each relevant substance, and
	whether the installation can comply with the current C-values.

If the mass flow limit is exceeded and if the current emission limit value is not complied with, there should be a requirement that emissions are reduced so as to ensure compliance with the current emission limit value.

If the C-values have been exceeded considerably, there should be requirements that they be complied with before a set date.

If limitation of emissions has not been implemented for Group 1 substances as stated in Chapter 3, requirements should be made for this.

Reasonable and realistic time limits should be set for implementation of possible purification or abatement measures.