Potential for Ammonia Generation and Emission in Broiler Production Facilities in Brazil

Air quality is one of the main factors that must be guaranteed in animal production. However, the measurement of pollutants is still a problem in several countries because the available methods are costly and do not always apply to the reality of the constructive typology adopted, as in countries with a hot climate, which adopt predominantly open facilities. Thus, the objective of the present study was to develop predictive models for the potential generation and emission of ammonia in the production of broiler chickens with different types of litter, different reuse cycles and under different climatic conditions. Samples of poultry litter from thirty commercial aviaries submitted to different air temperatures were analyzed. The experiment was conducted and analyzed in a completely randomized design, following a factorial scheme. Models were developed to predict the potential for generation and emission of ammonia, which can be applied in facilities with ambient conditions of air temperature between 25 and 40 °C and with wood shaving bed with up to four reuse cycles and coffee husks bed with up to six reuse cycles. The developed and validated models showed high accuracy indicating that they can be used to estimate the potential for ammonia generation and emission.

Quantification of methane emitted by ruminants: a review of methods

The contribution of greenhouse gas (GHG) emissions from ruminant production systems varies between countries and between regions within individual countries. The appropriate quantification of GHG emissions, specifically methane (CH4), has raised questions about the correct reporting of GHG inventories and, perhaps more importantly, how best to mitigate CH4 emissions. This review documents existing methods and methodologies to measure and estimate CH4 emissions from ruminant animals and the manure produced therein over various scales and conditions. Measurements of CH4 have frequently been conducted in research settings using classical methodologies developed for bioenergetic purposes, such as gas exchange techniques (respiration chambers, headboxes). While very precise, these techniques are limited to research settings as they are expensive, labor-intensive, and applicable only to a few animals. Head-stalls, such as the GreenFeed system, have been used to measure expired CH4 for individual animals housed alone or in groups in confinement or grazing. This technique requires frequent animal visitation over the diurnal measurement period and an adequate number of collection days. The tracer gas technique can be used to measure CH4 from individual animals housed outdoors, as there is a need to ensure low background concentrations. Micrometeorological techniques (e.g., open-path lasers) can measure CH4 emissions over larger areas and many animals, but limitations exist, including the need to measure over more extended periods. Measurement of CH4 emissions from manure depends on the type of storage, animal housing, CH4 concentration inside and outside the boundaries of the area of interest, and ventilation rate, which is likely the variable that contributes the greatest to measurement uncertainty. For large-scale areas, aircraft, drones, and satellites have been used in association with the tracer flux method, inverse modeling, imagery, and LiDAR (Light Detection and Ranging), but research is lagging in validating these methods. Bottom-up approaches to estimating CH4 emissions rely on empirical or mechanistic modeling to quantify the contribution of individual sources (enteric and manure). In contrast, top-down approaches estimate the amount of CH4 in the atmosphere using spatial and temporal models to account for transportation from an emitter to an observation point. While these two estimation approaches rarely agree, they help identify knowledge gaps and research requirements in practice.

Key Factors in Measuring Ammonia Emissions with Dynamic Flux Chamber in Barns

In this study, measurement methods for estimating the NH3 emissions in barns and the development of different emission factors were reviewed, and the factors to be considered when applying a dynamic flux chamber approach were analyzed. First, one of the factors to be considered when applying the dynamic flux chamber was determined as the stabilization time in the chamber. As a result of the experiment, it was confirmed that the concentration in the chamber stabilized after 45 min. This is considered to take longer than the stabilization time of 20 min suggested in the previous study. The second is the choice of the measurement method. This method includes real-time measurement and the indophenol method. As a result of the experiment in both methods, the ammonia flux showed a difference of about 10%, so both methods are considered to be considered. Therefore, it is judged that the methodology should be selected according to the situation, such as weather or electric power secured at the barn site. In the future, if studies on whether the stabilization time in the chamber can be changed according to seasonal factors and ambient temperature, and based on a sufficiently large sample size, the results will contribute to improving the reliability of the estimated ammonia(NH3) emissions and the development of an emissions factor for use in the livestock sector in Korea.

Air temperature, carbon dioxide, and ammonia assessment inside a commercial cage layer barn with manure-drying tunnels

Understanding the air temperature distribution, ammonia (NH₃) and carbon dioxide (CO₂) levels in poultry housing systems are crucial to poultry health, welfare, and productivity. In this study, 4 Intelligent Portable Monitoring Units and 7 temperature sensors were installed inside and between the cages and above 2 minimum ventilation fans of a commercial stacked-deck cage laying hen house in the Midwest United States (425,000 laying hens) to continuously monitor the interior environment over a 6-month period. During cold conditions (March 12th–May 22nd), there was a variation noted, with barn center temperatures consistently being highest in the longitudinal and lateral direction (P < 0.001) and the top floor deck warmer than the bottom floor (P < 0.05). During hotter conditions (May 23rd–July 26th), the interior thermal environment was more uniform than during the winter, resulting in a difference only in the longitudinal direction. The daily CO₂ and NH₃ concentrations were 400 to 4,981 ppm and 0 to 42.3 ppm among the 4 sampling locations, respectively. Both CO₂ and NH₃ decreased linearly with increasing outside temperatures. The mean NH₃ and CO₂ concentrations varied with sampling locations and with the outside temperatures (P < 0.001). For CO₂, the minimum ventilation sidewall had lower values than those measured in the barn’s center (P < 0.05) during cold weather, while the barn center and the manure room sidewall consistently measured the highest concentrations during warmer weather (P < 0.05). For NH₃, the tunnel ventilation inlet end consistently had the lowest daily concentrations, whereas the in-cage and manure drying tunnel sidewall locations measured the highest concentrations (P < 0.001). Higher NH₃ and CO₂ concentrations were recorded within the cage than in the cage aisle (P < 0.05). The highest NH₃ concentration of 42 ppm was recorded above the minimum exhaust fan adjacent to the manure drying tunnel, which indicated that higher pressure (back pressure) in the manure drying tunnel allowed air leakage back into the production area through nonoperating sidewall fan shutters.

Modeling and measurements of ammonia from poultry operations: Their emissions, transport, and deposition in the Chesapeake Bay

The goal of this study is to determine how much ammonia/nitrogen is being deposited to the Maryland Eastern Shore land and the Chesapeake Bay from poultry operations on Maryland's Eastern Shore. We simulated the fate of ammonia/nitrogen emitted (using emission factors from the U.S. EPA in conjunction with Carnegie-Mellon University) from 603 poultry facilities using the air quality model, AERMOD. The model domain was approximately 134 km by 230 km (and covers the full land area of Maryland's Eastern Shore), with a horizontal resolution of 2 km by 2 km. Ammonia concentration observations were made at 23 sites across Maryland's Eastern Shore during two periods (September and October 2017) in order to calibrate the model. An ammonia deposition velocity of 2.4 cm/sec was selected based on the sensitivity analysis of results for the simulation of a large poultry facility, and this value fell within the range of measurements reported in the scientific literature downwind of Concentrated Animal Feeding Operations (CAFOs). The ammonia deposition velocity of 2.4 cm/s leads to an estimated total annual ammonia deposition of 11,100 Megagrams/year (10,600 Mg/yr deposition to land, and 508 Mg/yr deposition to water (1 Mg = 1,000,000 g = 1.1023 US Tons)). In addition, model simulations indicate that ~72.4% of ammonia emissions from poultry animal feeding operations would be deposited within the modeling domain. However, this deposited ammonia/nitrogen may be transported through waterways from the land mass and ground water to the Chesapeake Bay. A comprehensive sensitivity analysis of the assumed ammonia deposition velocity (ranging from 0.15 to 3.0 cm/s) on estimated ammonia annual deposition is provided. Using the lower limit of an ammonia deposition velocity of 0.15 cm/s gives much smaller estimated total annual ammonia deposition of 2,040 Mg/yr (1,880 Mg/yr deposition to land and 163 Mg/yr deposition to water).

Effects of carbon dioxide on turkey poult performance and behavior

Appropriate ventilation of poultry facilities is critical for achieving optimum performance. Ventilation promotes good air exchange to remove harmful gases, excessive heat, moisture, and particulate matter. In a turkey brooder barn, carbon dioxide (CO2) may be present at higher levels during the winter due to reduced ventilation rates to maintain high temperatures. This higher CO2 may negatively affect turkey poult performance. Therefore, the objective of this study was to evaluate the effects of subjecting tom turkey poults (commercial Large White Hybrid Converters) to different constant levels of atmospheric CO2 on their growth performance and behavior. In three consecutive replicate trials, a total of 552 poults were weighed post-hatch and randomly placed in 3 environmental control chambers, with 60 (Trial 1) and 62 (Trials 2 and 3) poults housed per chamber. They were reared with standard temperature and humidity levels for 3 wks. The poults were exposed to 3 different fixed CO2 concentrations of 2,000, 4,000, and 6,000 ppm throughout each trial. Following each trial (replicate), the CO2 treatments were switched and assigned to a different chamber in order to expose each treatment to each chamber. At the end of each trial, all poults were sent to a local turkey producer to finish growout. For each trial, individual body weight and group feed intake were measured, and mortality and behavioral movement were recorded. Wk 3 and cumulative body weight gain of poults housed at 2,000 ppm CO2 was greater (P < 0.05) than those exposed to 4,000 and 6,000 ppm CO2. Feed intake and feed conversion were unaffected by the different CO2 concentrations. No significant difference in poult mortality was found between treatments. In addition, no effect of CO2 treatments was evident in the incidence of spontaneous turkey cardiomyopathy for turkeys processed at 19 wk of age. Poults housed at the lower CO2 level (2,000 ppm) demonstrated reduced movement compared with those exposed to the 2 higher CO2 concentrations.

Nitrous oxide, ammonia and methane from Australian meat chicken houses measured under commercial operating conditions and with mitigation strategies applied

Greenhouse gas (GHG) and ammonia emissions are important environmental impacts from meat chicken houses. This study measured ammonia (NH3), nitrous oxide (N2O) and methane (CH4) in two trials from paired, commercial meat chicken houses using standard (control) and mitigation strategies. In Trial 1, emissions from houses with standard litter depth of 47 mm (LD47) or increased litter depth of 67 mm (LD67) were compared. When standardised to a 42-day-old bird, emissions were 11.9 g NH3/bird, 0.30 g N2O/bird and 0.16 g CH4/bird from the LD47 and 11.7 g NH3/bird, 0.69 g N2O/bird and 0.12 g CH4/bird from the LD67. Emissions per kilogram of manure N were 0.14 and 0.11 for NH3-N, 0.003 and 0.005 N2O-N and CH4 conversion factors were 0.08% and 0.05%. Total direct and indirect GHG emissions reported in carbon dioxide equivalents were found to be higher in LD67 in response to the elevated direct N2O emissions. Trial 2 compared the impact of reduced crude protein (CP19.8) and a standard diet (CP21.3) developed using least-cost ration formulation, on emissions. Emissions per bird for the CP19.8 diet were 7.7 g NH3/bird, 0.39 g N2O/bird and 0.14 g CH4/bird, while emissions from birds fed the CP21.3 diet were 10.6 g NH3/bird, 0.42 g N2O/bird and 0.19 g CH4/bird. Significant differences were observed only in the NH3 results, where emissions were reduced by 27% for the low-CP diet. Because of the low emission levels, total mitigation potential from indirect GHG emissions was relatively small in Trial 2, corresponding to 11 t carbon dioxide equivalents/year per million birds.

Research and demonstration to improve air quality for the U.S. animal feeding operations in the 21st century - a critical review

There was an increasing interest in reducing production and emission of air pollutants to improve air quality for animal feeding operations (AFOs) in the U.S. in the 21st century. Research was focused on identification, quantification, characterization, and modeling of air pollutions; effects of emissions; and methodologies and technologies for scientific research and pollution control. Mitigation effects were on pre-excretion, pre-release, pre-emission, and post-emission. More emphasis was given on reducing pollutant emissions than improving indoor air quality. Research and demonstrations were generally continuation and improvement of previous efforts. Most demonstrated technologies were still in a limited scale of application. Future efforts are needed in many fundamental and applied research areas. Advancement in instrumentation, computer technology, and biological sciences and genetic engineering is critical to bring major changes in this area. Development in research and demonstration will depend on the actual political, economic, and environmental situations.

Volatile gas concentrations in turkey houses estimated by Fourier Transform Infrared Spectroscopy (FTIR)

1. The aim of the present study was to estimate gas concentrations in commercial turkey houses by Fourier Transform Infrared Spectroscopy (FTIR). 2. The experiment was conducted in 5 buildings of a commercial turkey farm. The measurements of gases were carried out every 3 weeks of the growth cycle. 3. The results demonstrate that ammonia and carbon dioxide are the prevalent gases released during the entire production cycle in turkey houses. The mean concentrations of the above compounds ranged between 4-31 ppm and 220-2058 ppm, respectively. Thiols, nitriles, amines, aldehydes, hydrocarbons and other organic and inorganic compounds also occurred in turkey houses, but they were emitted periodically and their mean concentrations were significantly lower in comparison with CO2 and NH3. 4. Lower ventilation ratio and higher moisture of excreta in the first half of the growth period accelerated the release of some gases, whereas gradual faeces and urine accumulation contributed to an increase in the concentration of selected organic compounds. 5. A portable FTIR analyser is a useful device for measuring gas concentrations in commercial turkey farms, and it supports determinations of tolerable emission limits in turkey production.