There is increasing interest among dairy farmers in The Netherlands for animal friendly housing systems that at the same moment reduce the ammonia emission compared to currently available systems. Therefore, there is a need for a relatively cheap and easy measuring method to investigate the potential effect of new emission reduction systems. In 2008 and 2009 Wageningen UR Livestock Research preformed emission measurements on 3 different ammonia emission reduction systems using a dynamic flux chamber. All systems were meant for use in a free stall housing system for dairy cows. Two of the emission reduction systems were concrete floors and one was an emission reduction system covering the slurry in the pits. The experiments were conducted at three different practical dairy farms in the Netherlands, one for each system. Emission of the reduction system was related to emission of a references floor. In all cases a concrete slatted floor with slurry pits was used as a reference. Emission levels ranged from 39% to 71% of the emission of the reference system. The two systems based on reduction of floors emissions seemed to have more perspective than the system based on reduction of pit emissions. A complete closing of the pits is however an important condition. Because of the case-control character of the flux chamber measurements the results can not be translated directly to full scale emission factors for dairy housing neither can they be used for between farms comparison

Dooren, H.J.C., van

Mosquera, J.

English

Wageningen Yield 

CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 1 
 
XVIIth World Congress of the International Commission  
of Agricultural and Biosystems Engineering (CIGR) 
Hosted by the Canadian Society for Bioengineering (CSBE/SCGAB) 
Québec City, Canada   June 13-17, 2010  
MEASUREMENT OF AMMONIA EMISSIONS FROM THREE AMMONIA 
EMISSION REDUCTION SYSTEMS FOR DAIRY CATTLE USING A 
DYNAMIC FLUX CHAMBER 
 
H.J.C. VAN DOOREN1, J. MOSQUERA
 
1 
1 Wageningen UR Livestock Research, PO Box 65, 8200 AB, Lelystad. HendrikJan.vanDooren@wur.nl   
1 
 
J. Mosquera, Julio.Mosquera@wur.nl 
CSBE101322 – Presented at Section II: Farm Buildings, Equipment, Structures and 
Livestock Environment Conference 
 
ABSTRACT There is increasing interest among dairy farmers in The Netherlands for 
animal friendly housing systems that at the same moment reduce the ammonia emission 
compared to currently available systems. Therefore, there is a need for a relatively cheap 
and easy measuring method to investigate the potential effect of new emission reduction 
systems. In 2008 and 2009 Wageningen UR Livestock Research preformed emission 
measurements on 3 different ammonia emission reduction systems using a dynamic flux 
chamber. All systems were meant for use in a free stall housing system for dairy cows. 
Two of the emission reduction systems were concrete floors and one was an emission 
reduction system covering the slurry in the pits. The experiments were conducted at three 
different practical dairy farms in the Netherlands, one for each system. Emission of the 
reduction system was related to emission of a references floor. In all cases a concrete 
slatted floor with slurry pits was used as a reference. Emission levels ranged from 39% to 
71% of the emission of the reference system. The two systems based on reduction of 
floors emissions seemed to have more perspective than the system based on reduction of 
pit emissions. A complete closing of the pits is however an important condition. Because 
of the case-control character of the flux chamber measurements the results can not be 
translated directly to full scale emission factors for dairy housing neither can they be used 
for between farms comparison. 
 
Keywords: ammonia emission, flux chamber, cattle housing.  
INTRODUCTION 
Agriculture is the most important source of ammonia (NH3) emissions in the Netherlands. 
In 2008, approximately 90% of the Dutch ammonia emissions originated from 
agricultural activities (PBL, 2010). In 2008 cattle husbandry in total (including beef 
cattle, veal calves and suckling cows) was responsible for 49% of the total ammonia 
emission from agriculture. Dairy cattle emitted 33% of the total agricultural ammonia 
emission and 67% of the total ammonia emission from cattle husbandry. More than half 
(52%) of the ammonia emission from dairy cattle comes from housing and slurry storage. 
Although absolute emissions decreased over the last decades the relative contribution was 
constant. In the light of the expected increase of dairy cattle production there is an urgent 
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 2 
need for housing systems with lower ammonia emissions. For the development and 
assessment of new open housing types it is of most importance to have an approved 
measuring method. For mechanically ventilated buildings adequate methods are available 
(Mosquera et al., 2002a and Mosquera et al., 2002b). Emission points are well defined 
and ventilation rates and gas concentrations can be measured with sufficient accuracy. 
Ventilation rates from naturally ventilated livestock housings can be measured using the 
tracer gas technique. This can be an artificial tracergas like SF6 or an already available 
gas like CO2. This technique presumes a good mixing of tracergas and target gas (i.e. 
ammonia). This is no longer guaranteed in very open buildings. One other possibility is 
the use of flux chambers that determine emissions at floor level. In 2008 and 2009 
Wageningen UR Livestock Research preformed emission measurements on several 
ammonia emission reduction systems using the flux chamber technique. All systems were 
meant for use in a free stall housing system for dairy cows. The open flux chamber used 
in these measurements is described in Mosquera et al. (2009). Question all three 
measuring projects was how the emission level of the reduction systems relates to a 
reference. The results of three emission reduction systems will be described here.  
MATERIAL AND METHODS  
Two of the emission reduction systems, identified as A and B, were concrete floors and 
one was an emission reduction systems covering the slurry in the pits, identified as C. 
Reduction principle of both A and B is based on a fast removal of urine and a separate 
removal of the feces by scrapers. Floor A is a complete solid floor closing the pits, floor 
B has slots between solid floor element to drain urine and feces to the pits. Both floors 
have a pattern of grooves to prevent cow slip incidence. The experiments were conducted 
at three different practical diary farms in the Netherlands, one for each systems. Emission 
of all reduction systems was related to emission of a references floor. In all cases a 
concrete slatted floor with slurry pits was used as a reference.  
 
Figure 1. Open flux chamber.  
The dimensions of the flux chamber were 2.37 m x 2.32 m x 0.40 m. The flux Q (g m-2 h-
1) from the emitting surface A (5.50 m2) was calculated by multiplying the ventilation 
rate φ (m3 h-1) and the difference in concentration between the incoming (Cin) and 
outgoing (Cout) air from the chamber: 
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 3 
( )
A
CCQ inuit −⋅= φ  
The concentration of NH3 in the in- and outgoing air in the flux chamber was measured 
by using a photoacoustic monitor (Innova 1312). A fan (Fancom FMS 35) with a 
diameter of 35 cm and a ventilation capacity of 3000 m3 h-1 was installed in the tube of 
the outgoing air. The ventilation rate inside the chamber was determined by using a fan-
wheel anemometer coupled to the used Fancom fan. The fan-wheel anemometer was 
calibrated at the start of the measurements, resulting in the following calibration line: 
Ventilation rate [m3 h-1] = 1,89 * [pulses/s] * 60 [s/min] / 4 [pulses/turnover] + 21 
During measurements the fan was adjusted at 30% of its maximum ventilation capacity. 
Besides, the temperature (oC) and relative humidity (%) were measured for all 
measurements close to the place where the chamber was placed by using a Rotronic 
Hygromer®. This sensor had an accuracy of respectively ± 1,0 °C and ± 2 % for 
temperature and relative humidity. The signal of the Rotronic and fan-wheel anemometer 
were registered every 5 minutes by a data acquisition system (Koenders CR-10). When 
relevant a section of the underlying pits was divided from the rest of the pits by sheets of 
plywood. In that cases measured emissions are a combination of emission from floor 
surface and pits.  
RESULTS AND DISCUSSION  
System A was measured on the 25th of September and the 2nd and 9th of October 2009. 
System B was measured on the 16th of October and 3rd of November 2009. System C was 
measured from the 3rd  to the 6th of November 2008. Table 1 shows the average climatic 
conditions and the average ventilation rates through the flux chamber.  
Table 1.Average climatic conditions (Temperature and Relative Humidity), number of 
replications and flux chamber ventilation rates of different reduction systems. Significant 
differences (p<0.05) between measurements within a system are represented by different 
superscripts. s.e.d.: standard error of differences. 
Measure Replications T [o RH [%] C] Ventilation [m3 h-1
References A 
]  
6 14.5±2.1 69.9±4.9a 888±1.4a 
System A 
a 
5 17.0±2.1 61.3±4.9a 888±1.4a 
Reference B 
a 
4 10.8±0.9 79.8±7.5a 889±0.5a 
System B 
a 
4 11.5±0.9 76.6±7.5a 889±0.5a 
System B+ 
a 
1 10.1 90.7 884 
Reference C 7 12.5±1.2 85.3±5.6a 889±0.5a 
System C 
a 
7 11.9±1.2 84.8±5.6a 889±0.5a 
 
a 
The flux chamber ventilation rate ranged from 29-30% of the maximum ventilation 
capacity resulting in an air velocity of 0.24-0.26 m s-1 above the floor surface. That is a 
typical air velocity measured at the floor level on cattle houses. Temperature (T) and 
relative humidity (RH) are in a close range and typical for autumn climatic conditions in 
The Netherland. Within farms differences of temperature, relative humidity and 
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 4 
ventilation rate between reduction system and references for were not significant 
(p<0.005).  
Table 2. Ammonia emissions and relative emission compared to reference measurements 
of different systems. Significant differences (p<0.05) between measurement within a 
system are represented by different superscripts. s.e.d.: standard error of differences. 
Measure NH3 [mg m-2 h-1 Relative emission [%] ] 
References A 2771 100 a 
System A 1081 39 b 
s.e.d. A 374.9  
Reference B 1138 100 a 
System B 1432 126 b 
s.e.d. B 84.4  
System B+ 599 53 
Reference C 1248 100 a 
System C 889 71 b 
s.e.d. 82.3  
 
Table 2 shows the ammonia emission of the different systems together with the emission 
related to the within farm references. Absolute levels of reduction systems differed 
significantly (p<0.05) from their references. Emission levels of system A and C were 
39% and 71% respectively, related to their references. Emission level of reduction system 
B however was 125% related to the reference. An additional measurement of system B 
(B+) while the slot was covered showed substantially lower emission (48%). This 
differences between results of B and B+ probably has to do with the use of open flux 
chambers on floors with a relatively small air exchange area between pit headspace and 
the rest of the air in the barn. Due to the small air exchange the concentration of ammonia 
in de pit head space above the slurry is high during practical circumstances. Applying a 
small under pressure during flux chamber measurements gives probably an 
overestimation of the contribution of the slurry pit to the total ammonia emission. Figure 
2 shows the emission levels of the different reduction systems and their references per 
replicated measurement. 
0
500
1000
1500
2000
2500
3000
3500
1 2 3 4 5 6
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is
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 N
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]
Reference A Reduct ion Technique A  
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 5 
0
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1 2 3 4
Number measurement
Em
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Reference B Reduct ion Technique B Reduct ion Technique B+  
0
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Number measurement
Em
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]
Reference C Reduct ion Technique C  
Figure 2. Ammonia emission level of the different reduction systems and paired 
references per replicated measurement.  
CONCLUSIONS 
Two systems (A and C) showed a significant reduction of the ammonia emissions with 
emission levels of 39% and 71% of the ammonia emission from the reference system. 
One system (B) showed a significant increase of the ammonia emissions with emission 
levels of 125% of the ammonia emission from the reference system. First measurement 
showed that system B has a promising reduction option by closing the slots between floor 
elements. Because of the case-control character of the flux chamber measurements the 
results can not be translated directly to full scale emission factors for dairy housing 
neither can they be used for between farms comparison. 
Acknowledgements. Klaas Blanken, Henk Gunnink and Jos Huis in ‘t Veld are 
acknowledged for their contribution to the measurements. 
REFERENCES 
Mosquera, J., P. Hofschreuder, J.W. Erisman, E. Mulder, C.E. van ’t Klooster, N. Ogink, 
D.Swierstra, N. Verdoes. 2002a. Meetmethode gasvormige emissies uit de 
veehouderij, Wageningen, IMAG rapport 2002-12 (In Dutch). 
CIGR XVIIth World Congress – Québec City, Canada – June 13-17, 2010 6 
Mosquera, J., P.Hofschreuder, A. Hensen. 2002b. Application of new measurement 
techniques and strategies to measure ammonia emissions from agricultural activities. 
Wageningen, IMAG Rapport 2002-11. 
Mosquera, J., G.J. Kasper, K. Blanken, F. Dousma, A.J.A. Aarnink. 2009. Development 
of a fast measurement method for the determination of ammonia emission reduction 
from floor related measures. Report 291, Wageningen UR Livestock Research, 15p. In 
Dutch with English summary.  
PBL. 2010. Emissieregistratie, Planbureau voor de Leefomgeving. Bilthoven. 
www.emissieregistratie.nl. 


CIGR XVIIth World Congress – Québec City,

Development of a fast measurement method for the determination of ammonia emission reduction from floor related measures.

Emissieregistratie, Planbureau voor de Leefomgeving.

Meetmethode gasvormige emissies uit de veehouderij, Wageningen, IMAG rapport 2002-12

Measurement of ammonia emissions from three ammonia emission reduction systems for dairy cattle using a dynamic flux chamber

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Measurement of ammonia emissions from three ammonia emission reduction systems for dairy cattle using a dynamic flux chamber

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