Regulation from the State Secretary for Housing, Spatial Planning, and the Environment of 12 December 2006, no. BWL/2006333382, containing the determination of odour emission factors, minimum distances for fur-bearing animals, the method of calculating odour intensity and of the method of determining distance (Regulation on odour nuisance and livestock farming).

Directorate General Environmental Management

Directorate for Soil, Water and Rural Areas

Agriculture Department

Regulation from the State Secretary for Housing, Spatial Planning, and the Environment of 12 December 2006, no. BWL/2006333382, containing the determination of odour emission factors, minimum distances for fur-bearing animals, the method of calculating odour intensity and of the method of determining distance (Regulation on odour nuisance and livestock farming).

The State Secretary for Housing, Spatial Planning and the Environment;

Acting in agreement with the Minister of Agriculture, Nature and Food Quality;

Having regard to the articles 1.4 second paragraph and 10 of the Odour Nuisance and Livestock Farming Act;

Orders:

Article 1

In this regulation:

Annex means the annex accompanying this regulation;

Act means the Odour Nuisance and Livestock Farming Act;

Emission point means the point where a relevant quantity of odour:

a. occurs or is given off outside the whole of covered animal accommodation; or

b. occurs or is given off outside the covered part of the partially covered animal accommodation.

Article 2

1. The odour intensity caused by livestock farming is calculated taking into account the dispersal model ‘V-Stacks vergunning’.

2. The geometric average of the emission points is designated as the point where the odour from the animal accommodation occurs or is given off.

3. The odour intensity is determined on the closest outside surface of an odour sensitive object, calculated from the geometric average of the emission points.

4. If the animal accommodation is not covered, the odour intensity is determined at the nearest outer surface of an odour sensitive object, calculated from the point of the enclosure that is situated closest to the odour sensitive object in question.

5. The odour emission from a livestock farm is the sum of the calculated number of odour units per second per animal for the various animal categories, held in the separate animal accommodations.

6. The number of odour units per second per animal of an animal category is the number of animals of a particular category multiplied by the odour emission factor listed for that particular animal category in annex 1.

7. If no odour emission factor has been determined for a particular animal category, the animal category is not taken into account in the calculation of the odour intensity.

Article 3

The distance, provided for in article 4, paragraph 2, of the act is included in annex 2.

Article 4

1. The distance, provided for in articles 3, second and third paragraph, and 4, first paragraph, of the act are measured from the outer surface of the odour sensitive object to the nearest emission point.

2. If the animal accommodation is not covered, the distance is measured from the outer surface of an odour sensitive object to the point of the enclosure of the animal accommodation that is situated nearest to the odour sensitive object in question.

Article 5

This regulation comes into effect at the same time as the act.

Article 6

This regulation is referred to as: Regulation on odour nuisance and livestock farming.

This regulation will be placed accompanied by explanatory information in the Government Gazette.

The Hague,

State Secretary for Housing, Spatial Planning, and the Environment,

P.L.B.A. van Geel

Endnotes:

1. The odour emission is related to a stalling period of maximum three months in the winter.

2. The odour emission factor applies to breeding as well, so that this breeding does not count for the calculating of the odour emission.

3. A stalling system with drainage is not regarded as low-emission accommodation but as other accommodation.

4. a.e. is the abbreviation for ammonia emission.

5. For raising sows after first breeding, the odour emission factor for breeding sows is used.

Annex 2 , as provided for in article 3 (distances for fur-bearing animals)

The distances for fur-bearing animals (mink and fox) are defined accordingly.

Animal young and males are not included in the calculation.

If both mink and fox, or only fox, are being kept, in determining the distance 10 fox (breeding vixens) are equivalent to 15 mink (breeding sows). If (after any foxes present have been converted into minks in the calculations) more than 9,000 breeding sows are kept, the distance for every extra 3,000 breeding sows is increased by an extra 25 metres.

If the fur-bearing animals are kept in low-emission accommodations (a.e. £ 0.25 kg/animal place), the distances listed in the second row of the table (‘outside built-up area’) are lowered by 25 metres.
Explanation

1. General

The Odour Nuisance and Livestock Farming Act sets out an assessment framework for odour nuisance stemming from animal accommodation at livestock farms. Articles 1, 4, second paragraph and article 10 of the act stipulate that four topics are worked out by ministerial decree. This concerns the:

a. odour emission factors, in which the odour emission per animal according to animal category is determined, taking into account relevant parameters such as the accommodation system used (article 2, paragraph six of the regulation);

b. the manner of determining the odour intensity on an odour sensitive object (article 2);

c. the manner of determining the distance between an odour sensitive object and a livestock farm that keeps animals of a category for which no odour emission factor has been fixed (article 4); and

d. the minimum distance that must be maintained between a livestock farm where fur-bearing animals are kept and an odour sensitive object (article 3).

The four sections below devote attention to each of these topics.

2. Odour emission factors

The odour emission factors are almost all based on results from odour measurements in practical situations. In the past years a measuring programme has been carried out at stalling systems. The results up to 2003 – the year in which the predecessor of this regulation was drawn up – are set down in the reports ‘Geuremissies uit de veehouderij’ (Odour emissions from livestock farming), IMAG report 2001-14 and ‘Geuremissies uit de veehouderij II’, (Odour emissions from livestock farming II), IMAG, report 2002-09. Because of the importance of the odour emission factors for the implementation practice, a second opinion was commissioned at the time into the (determination of the) odour emission factors.[1]

Since 2003 new measurements have been carried out. The results of measurements from until 1 December 2006 have been incorporated in this regulation.

Results of measurements do not necessarily coincide with the actual emissions from a randomly chosen animal accommodation. The actual emission from a particular stalling system will vary above and below the emission ascertained during the measuring programme. That is the result of a great many factors that affect odour emission from a stalling system, including the inside temperature and the composition of the animal feed. The law is not based on this actual emission but on the emission that is set down in annex 1.

The odour emission factors are expressed as odour emission: as numbers of European odour units that are given off per animal per second (ou_E /sec/animal). The legal values are on the other hand expressed as odour concentration: as numbers of European odour units present per cubic metre of air.

The number structure of the animal categories and the distinction between low-emission and other accommodations correspond to the structure and distinction in the Regulation on ammonia and livestock farming. Unlike in the Regulation on ammonia and livestock farming, however, a separate odour emission factor is not, in principle, assigned to each stalling system, but rather to a cluster of stalling systems.

The reason for this difference is that the range of measurement results for the aspect odour is greater than for the aspect ammonia. The measurements show a wide variation in odour emission, both between comparable stalling systems and between comparable farms. The information available does not give rise to conclusions that are sufficiently statistically reliable with regard to the magnitude of the odour emission from an individual stalling system. Conclusions are possible – on the basis of a statistical analysis of the measurement results – if stalling systems are clustered.

Wherever possible the various types of accommodation (stalling systems) were divided into two clusters, low-emission accommodation and other accommodation. If it is assumed that a accommodation system that reduces ammonia emissions also reduces odour emission, statistical analysis of the whole data set of measurements shows that stalling systems that are designated as ‘low emission accommodations’ produce on average lower odour emission than ‘other accommodations.’ According to the analysis, the performance of low-emission accommodations is in general adequately distinguished with regard to other accommodations. The cluster low-emission accommodations therefore contains the stalling systems in which principles aimed at reducing ammonia emissions are applied.

In connection with the aforementioned, annex 1 indicates that accommodations are low-emission if a particular ammonia emission (a.e.) is not exceeded. These limits are the threshold values that were previously maintained by the ‘Stichting Groen Label’ (Green Label Foundation). The threshold values set down what extent of ammonia reduction was feasible in case of application of the most recent insights into the area of accommodation systems.

The cluster ‘other accommodations’ consists mainly of the stalling systems that are referred to in practice as conventional stalling systems.

The odour emission factors from annex 1 are almost all based on results of measurements. A few odour emission factors have been derived from emissions measured from other animal categories, if this was reliable taking into account the measurement results. The most important example is the odour emission factor for guinea fowl, which is derived from that for broilers. The motivation for this is that for a limited part of the year guinea fowl are in general kept in the same accommodations that broilers are kept for the rest of the year. The animal management and the composition of the feed are entirely or largely the same. Weight and other relevant species characteristics are predominantly in agreement as well.

3. Determining odour intensity

Calculating odour intensity (from ‘odour emission per animal’ to ‘odour intensity on an odour sensitive object’) consists of the following parts.

1. Odour emission per animal multiplied by the number of animals equals odour emission stemming from animal accommodation.

The odour emission factors from annex 1 are a reflection of the odour emission from a single animal in a certain animal category, taking into account the stalling system in use and air treatment techniques (air scrubbers).

2. Odour emission from animal accommodation multiplied by number of animal accommodations equals odour emission from livestock farming.

The term ‘odour emission from livestock farming’ does not exclude that there may be other sources of odour at the livestock farm, such as the slop feed kitchen or the manure silo. The Odour Nuisance and Livestock Farming Act however exclusively sets an assessment framework for the odour intensity stemming from animal accommodation.

3. Entering the odour emission from livestock farming into the dispersal model results in the odour intensity on the odour sensitive object.

The dispersal model calculates the dispersal of the odour between the emission point (animal accommodation) and the immission point (odour sensitive object). The dispersal model used is the computer programme ‘V-Stacks vergunning’, which was developed at the instructions of the ministry of Housing, Spatial Planning and the Environment and is available from Infomil in The Hague.

The following applies with regard to the ‘emission point.’

The use of a dispersal model implies a more precise, more detailed assessment of the odour intensity. In calculations in the past, the entire odour emission was attributed to the ventilator or ventilation opening (natural ventilation) that is situated closest to the odour sensitive object. Nowadays the calculation is based on the geometric average emission point of the stalling system. This can mean that a point where no actual emissions are given off may be designated as the emission point, as in the case that four ventilators are set up in a line in a stalling system, or in the -somewhat theoretical – case that the ventilation openings are situated on the four corners of the stalling system.

The relative contribution of the ventilators or ventilation openings does not need to be determined: all ventilators and ventilation openings are regarded as contributing in an equal quantity to odour emission. The so-called ‘building effect’ leads namely to the odour spreading from the stalling system as a diffuse cloud, in which the contributions of the various ventilators and ventilation openings cannot be distinguished. If however it emerges that no odour emission whatsoever stems from a particular ventilator or ventilation opening (for instance because a screened off part of the stalling system is regularly used as a storage place for agricultural vehicles) then this ventilator or ventilation opening may be left out of consideration, in line with jurisprudence.

Example:

For the sake of completeness, it is stressed that an emission point is by definition a point in a stalling system. In determining the emission point the barnyard belonging to the stalling system is left out of consideration. This is only otherwise in the rare occurrence that an animal accommodation exclusively consists of an open space, without stalling system or overhead cover. In the calculations the odour intensity is then determined from the point of the boundary of the animal accommodation (usually an enclosure or waterway) that is situated closest to an odour sensitive object.

A municipal council can, on grounds of article 6 of the Odour Nuisance and Livestock Farming Act, set a different value that departs from the value listed in article 3 of the law. Calculations for this purpose must be carried out with information on a number of livestock farms and odour sensitive objects. These calculations cannot be carried out with the dispersal model ‘V-Stacks vergunning’; another model, called ‘V-Stacks gebied’ (V-Stack area), has been developed for this purpose. The use of the latter model is not legally required, because the use of an alternative dispersal model is not inconvenient. It should be noted here however that the correlations between odour intensity and odour nuisance are determined using both models; in other words: if an alternative dispersal model is used, the correlations cannot simply be applied.

For the rest, the correlations will have to be listed in a separate publication, they are not essential to proper implementation of the law.

Both ‘V-Stacks vergunning’ and ‘V-Stacks gebied’ are simplifications of the New National Model that is the standard in industrial odour policy, but both models are focused on the specific circumstances in agriculture.

4. Determining distance

Pursuant to article 4, first paragraph of the act, the distance between a livestock farm and an odour sensitive object must be at least 100 metres (if the odour sensitive object is situated in the built-up area) or 50 metres (outside the built-up area). This distance is measured according to the same manner as the distance had to be measured under the old stench regulation (Regulation on livestock farming and stench nuisance 1996). The distance between animal accommodation and odour sensitive object is measured from the emission point that is situated closest to an odour sensitive object. In naturally ventilated stalling systems this point is usually the ventilation outlet or other opening from which relevant odour emissions (called ‘relevant ventilation losses’ in jurisprudence) occur. In mechanically ventilated stalling systems this point is usually the ventilator outlet nearest to an odour sensitive object, to the extent that relevant odour emissions do not occur at any shorter distance from the object.

For the sake of completeness it is noted that by definition the measurement is carried out from a point in the stalling system. In determining the emission point the extension belonging to the stalling system is not taken into consideration. This is only otherwise in the rare occurrence that an animal accommodation exclusively consists of an open space, without stalling system or overhead cover. In the calculations the odour intensity is then determined from the point of the boundary of the animal accommodation (usually an enclosure or waterway) that is situated closest to an odour sensitive object.

If a livestock farm keeps animals of a category for which an odour emission factor is fixed as well as animals of a category for which a minimum distance must be observed, the environmental aspect odour nuisance is assessed using two methods. The odour intensity stemming from animal accommodation is calculated by applying article 3 of the Odour Nuisance and Livestock Farming Act. If animals are also kept of an animal category for which no odour emission factor is determined, a distance of at least 100 or 50 metres must also be observed from the animal accommodations in which these animals are kept (article 4, first paragraph of the act).

5. Distances for fur-bearing animals

For the animal categories mentioned above, an odour emission factor is less opportune in connection with the size of the animal category in the Netherlands. Partly also because at present no measurement results, or only inadequate ones, are available, or the measurement results are such that they prevent an adequately motivated odour emission factor from being fixed. For these animal categories a minimum distance has been prescribed, differentiated according to type of environment (distinction between inside and outside the built-up area) but regardless of the number of animals kept and the type of animal accommodation. An exception to this general rule is the animal category fur-bearing animals.

For fur-bearing animals, minimum distances linked to the size of the livestock population do apply. In connection with the significant odour emission by fur-bearing animals, a minimum distance of 50 or 100 metres does not suffice. This regulation in essence includes the table that has been used since the Brochure on livestock farming and nuisance act from 1985. Since a representative spot check in eight municipalities has shown that most odour sensitive objects had to be placed in ‘category I’ or ‘category III’, in the past, the distances corresponding to each category have been adopted.

6. Explanatory notes to annex 1, list of odour emission factors

The various accommodation systems have been, where possible, divided up into the clusters low-emission accommodation or other accommodation. The odour emission factor is assigned to the cluster, and not to a specific type of accommodation system. An exception to this principle is found in animal category E 2 Laying chickens and (grand)parent animals of laying breeds: a separate odour emission factor has been assigned the manure storage system under the battery, a type of battery accommodation for laying chickens. It concerns a system that is now in limited use and that consequently falls so far outside the bandwidths of the cluster ‘other accommodations’ when it comes to the aspect odour emission that a separate odour emission factor is reasonable.

Odour emission factors have also been included for situations in which the most common techniques for reducing emissions – a chemical or biological air scrubber – are applied. A biological air scrubber performs better than a chemical one in reducing odour, according to measurements. One reason for this is that the acids in a chemical air scrubber used to remove ammonia do relatively little to reduce odour.

At present, biological air scrubbers are hardly used, if at all, in accommodation systems for chickens, turkeys, and guinea fowl. The presence of dust in these accommodation systems complicates the odour emission reducing effect of a biological air scrubber. That is why this regulation does not (yet) give an odour emission factor for these air scrubbers.

The ‘RAV no.’ in annex 1 refers to the corresponding category in the Regulation on ammonia and livestock farming. A stalling system is considered low-emission for the aspect odour if it is so for the aspect ammonia. An exception to this general rule is in the case of a stalling system with drainage used in pig farming. The emission reducing principle of the stalling system is based on the regular rinsing away of the manure to the central manure storage area. In this system peak emissions occur with a factor 3 to 3.5 higher than the average emission. In connection with these inherent peak emissions, the system cannot be regarded as low-emission, although it is designated as low-ammonia.

The State Secretary of Housing, Spatial Planning and the Environment,

P.L.B.A. van Geel

[1] Letter of 29 April 2004, Parliamentary documents II 2003/04, 29 200 XIV, no. 87

This text has been handed by Ms. Margrethe Bongers. Here at olores.org we would like to express our sincere gratitude and appreciation for her efforts in translating this document.