Division 4.9.2 Techniques for ammonia and dust monitoring

United Kingdom

Technique	Description
Estimation by using a mass balance based on the excretion and the total (or ammoniacal) nitrogen present at each manure management stage.	Ammonia emissions are estimated based on the amount of nitrogen excreted by each animal category and using the total nitrogen (or the total ammoniacal nitrogen — TAN) flow and the volatilisation coefficients (VC) over each manure management stage (housing, storage, landspreading). The equations applied for each of the manure management stages are: E_housing = N_excreted · VC_housing E_storage = N_storage · VC_storage E_spreading = N_spreading · VC_spreading where: E is the annual NH₃ emission from the animal house, manure storage or landspreading (e.g. in kg NH₃/animal place/year). N is the annual total nitrogen or TAN excreted, stored or applied in landspreading (e.g. in kg N/animal place/year). If appropriate, nitrogen additions (e.g. related to litter, recycling of scrubbing liquids) and/or nitrogen losses (e.g. related to manure processing) can be considered. VC is the volatilisation coefficient (dimensionless, related to the housing system, manure storage or landspreading techniques) representing the proportion of TAN or total N emitted to air. VC are derived from measurements designed and performed according to a national or an international protocol (e.g. VERA protocol) and validated for a farm with an identical type of technique and similar climatic conditions. Alternatively, information to derive VC can be taken from European or other internationally recognised guidance. The mass balance considers especially any significant change to the type of livestock reared at the farm and/or to the techniques applied for housing, storage and landspreading.
Calculation by measuring the ammonia (or dust) concentration and the ventilation rate using ISO, national or international standard methods or other methods ensuring data of an equivalent scientific quality.	Ammonia (or dust) samples are taken on six days, as a minimum, distributed over one year. Sampling days are distributed as follows: For animal categories with a stable emissions pattern (e.g. laying hens), the sampling days are randomly selected in every two-month period. The daily average is calculated as a mean over all sampling days. For animal categories with a linear increase in emissions during the rearing cycle (e.g. fattening pigs), the sampling days are equally distributed over the growing period. In order to achieve this, half the measurements are performed in the first half of the rearing cycle, and the remainder in the second half of the rearing cycle. The sampling days in the second half of the rearing cycle are equally distributed within the year (same number of measurements per season). The daily average is calculated as a mean over all sampling days. For animal categories with an exponential increase in emissions (e.g. broilers), the rearing cycle is divided into three periods of equal length (same number of days). One measurement day falls in the first period, two measurements in the second period, and three measurements in the third period. In addition, sampling days in the third period of the rearing cycle are equally distributed within the year (same number of measurements per season). The daily average is calculated as the average of the three periodic means. Sampling is based on 24-hour sampling periods and is performed at the air inlet/outlet. Ammonia (or dust) concentration at the air outlet is then measured, corrected for the concentration of the incoming air, and daily ammonia (or dust) emissions are derived by measuring and multiplying the ventilation rate and the ammonia (or dust) concentration. From the daily average of ammonia (or dust) emissions, the yearly average ammonia (or dust) emissions from an animal house can be calculated, if multiplied by 365 and corrected for any non-occupation periods. The ventilation rate, necessary to determine the emission mass flow, is determined either by calculation (e.g. fan wheel anemometer, records of ventilation control system) in forced ventilated houses, or by means of tracer gases (excluding the use of SF₆ and any gas containing CFCs) in naturally ventilated houses which allow a proper mixing of air. For plants with multiple air inlets and outlets, only those sampling points considered representative (in terms of expected mass emissions) of the plant are monitored.
Estimation by using emission factors.	Ammonia (or dust) emissions are estimated on the basis of emission factors derived from measurements designed and performed according to a national or an international protocol (e.g. VERA protocol) in a farm with an identical type of technique (related to the housing system, manure storage and/or landspreading) and similar climatic conditions. Alternatively, emission factors can be taken from European or other internationally recognised guidance. The use of emission factors considers especially any significant change to the type of livestock reared at the farm and/or to the techniques applied for housing, storage, landspreading.

Technique

Description

Estimation by using a mass balance based on the excretion and the total (or ammoniacal) nitrogen present at each manure management stage.

Ammonia emissions are estimated based on the amount of nitrogen excreted by each animal category and using the total nitrogen (or the total ammoniacal nitrogen — TAN) flow and the volatilisation coefficients (VC) over each manure management stage (housing, storage, landspreading).

The equations applied for each of the manure management stages are:

E_housing = N_excreted · VC_housing
E_storage = N_storage · VC_storage
E_spreading = N_spreading · VC_spreading

where:

is the annual NH₃ emission from the animal house, manure storage or landspreading (e.g. in kg NH₃/animal place/year).

is the annual total nitrogen or TAN excreted, stored or applied in landspreading (e.g. in kg N/animal place/year). If appropriate, nitrogen additions (e.g. related to litter, recycling of scrubbing liquids) and/or nitrogen losses (e.g. related to manure processing) can be considered.

is the volatilisation coefficient (dimensionless, related to the housing system, manure storage or landspreading techniques) representing the proportion of TAN or total N emitted to air.

VC are derived from measurements designed and performed according to a national or an international protocol (e.g. VERA protocol) and validated for a farm with an identical type of technique and similar climatic conditions. Alternatively, information to derive VC can be taken from European or other internationally recognised guidance.

The mass balance considers especially any significant change to the type of livestock reared at the farm and/or to the techniques applied for housing, storage and landspreading.

Calculation by measuring the ammonia (or dust) concentration and the ventilation rate using ISO, national or international standard methods or other methods ensuring data of an equivalent scientific quality.

Ammonia (or dust) samples are taken on six days, as a minimum, distributed over one year. Sampling days are distributed as follows:

For animal categories with a stable emissions pattern (e.g. laying hens), the sampling days are randomly selected in every two-month period. The daily average is calculated as a mean over all sampling days.
For animal categories with a linear increase in emissions during the rearing cycle (e.g. fattening pigs), the sampling days are equally distributed over the growing period. In order to achieve this, half the measurements are performed in the first half of the rearing cycle, and the remainder in the second half of the rearing cycle. The sampling days in the second half of the rearing cycle are equally distributed within the year (same number of measurements per season). The daily average is calculated as a mean over all sampling days.
For animal categories with an exponential increase in emissions (e.g. broilers), the rearing cycle is divided into three periods of equal length (same number of days). One measurement day falls in the first period, two measurements in the second period, and three measurements in the third period. In addition, sampling days in the third period of the rearing cycle are equally distributed within the year (same number of measurements per season). The daily average is calculated as the average of the three periodic means.

Sampling is based on 24-hour sampling periods and is performed at the air inlet/outlet. Ammonia (or dust) concentration at the air outlet is then measured, corrected for the concentration of the incoming air, and daily ammonia (or dust) emissions are derived by measuring and multiplying the ventilation rate and the ammonia (or dust) concentration. From the daily average of ammonia (or dust) emissions, the yearly average ammonia (or dust) emissions from an animal house can be calculated, if multiplied by 365 and corrected for any non-occupation periods.

The ventilation rate, necessary to determine the emission mass flow, is determined either by calculation (e.g. fan wheel anemometer, records of ventilation control system) in forced ventilated houses, or by means of tracer gases (excluding the use of SF₆ and any gas containing CFCs) in naturally ventilated houses which allow a proper mixing of air.

For plants with multiple air inlets and outlets, only those sampling points considered representative (in terms of expected mass emissions) of the plant are monitored.

Estimation by using emission factors.

Ammonia (or dust) emissions are estimated on the basis of emission factors derived from measurements designed and performed according to a national or an international protocol (e.g. VERA protocol) in a farm with an identical type of technique (related to the housing system, manure storage and/or landspreading) and similar climatic conditions. Alternatively, emission factors can be taken from European or other internationally recognised guidance.

The use of emission factors considers especially any significant change to the type of livestock reared at the farm and/or to the techniques applied for housing, storage, landspreading.