Livestock excreta and manure stored in housing, in manure stores, in beef feedlots, or cattle hardstandings are the most important sources of ammonia (NH3) in the atmosphere. There is a need to quantify the emission, to assess the effect of emission on NH3 and ammonium ( NH 4 + ) deposition to ecosystems and on the health risks posed by NH 4 + ‐based particles in the air. To obtain a reliable estimate of the emission from these sources, the processes involved in the transfer of NH3 from the manure to the free atmosphere have to be described precisely. A detailed knowledge of the processes of NH3 transfer from the manure and transport to the free atmosphere will contribute to development of techniques and housing designs that will contribute to the reduction of NH3 emission to the atmosphere. For this reason, this review presents the processes and algorithms involved in NH3 emission from livestock manure in livestock buildings and manure stores for pigs and cattle. Emission from poultry buildings and following land application of manure, although significant sources of NH3, have been reported in earlier reviews and are not included here. A clear description of the features that contribute to the total NH3 emission from buildings will include information on stock class, diet and excreta composition, the distribution of emitting surfaces and knowledge of their mass transfer characteristics in relation to the building as a whole, as well as environmental variables. Other relevant information includes the quantity and composition of excreta produced by different classes of livestock and the influence of feeding regime; the influence of environmental variables on the production of NH3 from excreta; how excreta is distributed and managed in livestock buildings; and factors that affect mass transfer of NH3 in the building to the atmosphere outside. A major factor is the pH of the manure. There is a great need for algorithms that can predict pH as affected by feeding and management. This chapter brings together published estimates of NH3 emissions and abatement techniques, and relates these to the factors listed above (excreta, NH3 production, building, and mass transfer).

Algorithms determining ammonia emission from buildings housing cattle and pigs and from manure stores

Ammonia emissions from pig houses: Influencing factors and mitigation techniques

A report for the Rural Industries Research and Development Corporation

Thermal behaviour of growing pigs in response to high temperature and humidity

Ammonia emissions from swine feeding operations depend on the housing type; animal size, age, and type; manure
management, storage, and treatment; climatic variables; and manure utilization or land application techniques. Techniques
or methods for estimating or quantifying NH3 flux from a source to the atmosphere include nitrogen mass balance,
micrometeorology, flux chambers, models, and emission factors. Of these techniques, emission factors, once established,
provide the most convenience in estimating emissions. However,it is important to understand how a particular emission factor
is determined and whether it accurately reflects a composite or average emission for all the variable conditons. Using an
average ammonia emission factor multiplied by pig inventory to determine a regional or national ammonia emission inventory
may be misleading, especially in the U.S. where existing emission factors were developed using data from swine facilities in
Western Europe. 
Housing, manure management practices, and climate vary among different regions of the U.S. and can be very different
from those in Western Europe. In addition, ammonia concentrations and emission estimations have been determined with a
variety of methods, making it difficult to compare results. To determine representative ammonia emissions from confined swine
feeding operations, it is important that emission factors be specific enough to account for animal type and size, housing
system, manure storage and treatment, land application, and climatic effects. This article describes the strengths and
limitations of emission factors as currently used and provides recommendations for determining realistic ammonia emission
factors for swine feeding operations. Because of the limited nature of the data published in the literature, emission factors
for different animal management systems could not be presented. 
Regulators, consultants, cooperative extension personnel, and other leaders in the agricultural community with interest
in ammonia emissions should be aware of the lack of reliable U.S. data available for calculating accurate emission factors.
The scientific research community should standardize methods for measurement, calculation, and reporting of ammonia
emissions.

A review of ammonia emissions from confined swine feeding operations

A 2(4) factorial experiment with six pens per treatment was conducted to examine the factors affecting the excretory behavior of growing-finishing pigs. The factors investigated were partition type (open or closed), pig density (9 or 14 pigs/pen, size: 2 m x 4.5 m), position of nipple drinker in the pen (back wall of the pen or side in front of slatted area), and prior experience of pigs (training or no training). A total of 1,104 pigs at a weight interval of 28.4 +/- .2 to 91.4 +/- .4 kg were used in this study. Pen cleanliness was assessed by a dung scoring system, and growth rate was determined over the growing-finishing period. Partition type, nipple drinker position, or prior training of pigs had no effect on growth rate. Stocking pigs at 14 pigs/pen reduced growth rate (P < .05) compared with 9 pigs/pen (.80 vs .83 kg/d). Significant differences for pen dirtiness were found for partition type. Pens with closed partitions were cleaner than those with open partitions (P = .0001) and pens became significantly dirtier as pigs grew older or heavier (P < .01). There was a significant interaction effect between pen partition and pig density as well as an interaction among pen partition, pig density, and water position (P < .05).

Factors affecting excretory behavior of pigs

In order to assess the effects of ventilation rate, temperature, relative humidity and source of air on bioaerosol levels and dust with particle size < 10 μm, a total of 120 pigs housed in 12 pens in two separate rooms were used. Pigs averaged 30 kg initially and the trials were discontinued when 20% of the pigs were marketed. A six-stage Andersen sampler and a light scattering particle counter were used to determine bioaerosols and respirable dust (0.1–10 μm), respectively. Total bioaerosols were assessed using Trypticase Soy Agar. Potato Dextrose Agar was used for fungal aeorsols and Baird-Parker Agar used for isolation of Staphylococcus aureus. Moulds amounted to less than 1% of total microorganisms. Gram positive bacteria made up 72% of the bacterial isolates. Respirable dust was not correlated with respirable bioaerosols. Ventilation rate (2, 5 or 8 changes h−1) did not affect bioaerosol level or respirable dust. Total bioaerosols were significantly reduced (P < 0.05) in higher temperatures only. Rel...

W. D. Morrison

Papers

Factors affecting excretory behavior of pigs

Concentration of respirable dust and bioaerosols and identification of certain microbial types in a hog-growing facility