Emissions of ammonia, methane, carbon dioxide, and nitrous oxide from dairy cattle housing and manure management systems

Concentrated animal feeding operations emit trace gases such as ammonia (NH?), methane (CH?), carbon dioxide (CO?), and nitrous oxide (N?O). The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. The objective of this study was to determine the emission rates of NH?, CH?, CO?, and N?O from three source areas (open lots, wastewater pond, compost) on a commercial dairy located in southern Idaho. Gas concentrations and wind statistics were measured each month and used with an inverse dispersion model to calculate emission rates. Average emissions per cow per day from the open lots were 0.13 kg NH?, 0.49 kg CH?, 28.1 kg CO?, and 0.01 kg N?O. Average emissions from the wastewater pond (g m(-2) d(-1)) were 2.0 g NH?, 103 g CH?, 637 g CO?, and 0.49 g N?O. Average emissions from the compost facility (g m(-2) d(-1)) were 1.6 g NH?, 13.5 g CH?, 516 g CO?, and 0.90 g N?O. The combined emissions of NH?, CH?, CO?, and N?O from the lots, wastewater pond and compost averaged 0.15, 1.4, 30.0, and 0.02 kg cow(-1) d(-1), respectively. The open lot areas generated the greatest emissions of NH?, CO?, and N?O, contributing 78, 80, and 57%, respectively, to total farm emissions. Methane emissions were greatest from the lots in the spring (74% of total), after which the wastewater pond became the largest source of emissions (55% of total) for the remainder of the year. Data from this study can be used to develop trace gas emissions factors from open-lot dairies in southern Idaho and potentially other open-lot production systems in similar climatic regions.     

Nitrogen cycling through swine production systems: ammonia, dinitrogen, and nitrous oxide emissions

Ammonia (NH(3)) emissions from animal systems have become a primary concern for all of livestock production. The purpose of this research was to establish the relationship of nitrogen (N) emissions to specific components of swine production systems and to determine accurate NH(3) emission factors appropriate for the regional climate, geography, and production systems. Micrometeorological instrumentation and gas sensors were placed over two lagoons in North Carolina during 1997-1999 to obtain information for determining ammonia emissions over extended periods and without interfering with the surrounding climate. Ammonia emissions varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Conversion of significant quantities of ammonium NH(4)(+) to dinitrogen gas (N(2)) were measured in all lagoons with the emission rate largely dependent on NH(4)(+) concentration. Lagoon NH(4)(+) conversion to N(2) accounted for the largest loss component of the N entering the farm (43% as N(2)); however, small amounts of N(2)O were emitted from the lagoon (0.1%) and from field applications (0.05%) when effluent was applied nearby. In disagreement with previous and current estimates of NH(3) emissions from confined animal feeding operation (CAFO) systems, and invalidating current assumptions that most or all emissions are in the form of NH(3), we found much smaller NH(3) emissions from animal housing (7%), lagoons (8%), and fields (2%) using independent measurements of N transformation and transport. Nitrogen input and output in the production system were evaluated, and 95% of input N was accounted for as output N from the system.     

Modelling deposition and air concentration of reduced nitrogen in Poland and sensitivity to variability in annual meteorology

The relative contribution of reduced nitrogen to acid and eutrophic deposition in Europe has increased recently as a result of European policies which have been successful in reducing SO(2) and NO(x) emissions but have had smaller impacts on ammonia (NH(3)) emissions. In this paper the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model was used to calculate the spatial patterns of annual average ammonia and ammonium (NH(4)(+)) air concentrations and reduced nitrogen (NH(x)) dry and wet deposition with a 5 km × 5 km grid for years 2002-2005. The modelled air concentrations of NH(3) and dry deposition of NH(x) show similar spatial patterns for all years considered. The largest year to year changes were found for wet deposition, which vary considerably with precipitation amount. The FRAME modelled air concentrations and wet deposition are in reasonable agreement with available measurements (Pearson's correlation coefficients above 0.6 for years 2002-2005), and with spatial patterns of concentrations and deposition of NH(x) reported with the EMEP results, but show larger spatial gradients. The error statistics show that the FRAME model results are in better agreement with measurements if compared with EMEP estimates. The differences in deposition budgets calculated with FRAME and EMEP do not exceed 17% for wet and 6% for dry deposition, with FRAME estimates higher than for EMEP wet deposition for modelled period and lower or equal for dry deposition. The FRAME estimates of wet deposition budget are lower than the measurement-based values reported by the Chief Inspectorate of Environmental Protection of Poland, with the differences by approximately 3%. Up to 93% of dry and 53% of wet deposition of NH(x) in Poland originates from national sources. Over the western part of Poland and mountainous areas in the south, transboundary transport can contribute over 80% of total (dry + wet) NH(x) deposition. The spatial pattern of the relative contribution of national sources to total deposition of NH(x) may change significantly due to the general circulation of air.     

Reduction of ammonia emission by shallow slurry injection: injection efficiency and additional energy demand

Ammonia (NH3) emission from livestock production causes undesirable environmental effects and a loss of plant-available nitrogen. Much atmospheric NH3 is lost from livestock manure applied in the field. The NH3 emission may be reduced by slurry injection, but slurry injection in general, and especially on grassland, increases the energy demand and places heavy demands on the slurry injection techniques used. The reduction in NH3 emission, injection efficiency, and energy demand of six different shallow slurry-injection techniques was examined. The NH3 emission from cattle slurry applied to grassland was reduced by all the injectors tested in the study, but there were major differences in the NH3 reduction potential of the different types of injectors. Compared with the trailing hose spreading technique, the NH3 loss was reduced by 75% when cattle slurry was injected using the most efficient slurry injection technique, and by 20% when incorporated by the least efficient injection technique. The reduction in NH3 emission was correlated with injection depth and the volume of the slot created. The additional energy demand for reducing ammonia emissions by slurry injection was approximately 13 000 kJ ha(-1) for a 20% reduction and 34 000 kJ ha(-1) for a 75% reduction. The additional energy demand corresponds to additional emissions of, respectively, 5.6 and 14.5 kg CO2 per ha injected.     

Crusting of stored dairy slurry to abate ammonia emissions: pilot-scale studies

Storage of cattle slurry is a significant source of ammonia (NH3) emissions. Emissions can be reduced by covering slurry stores, but this can incur significant costs, as well as practical and technical difficulties. In this pilot-scale study, slurry was stored in small tanks (500 L) and the effectiveness of natural crust development for reducing NH3 emissions was assessed in a series of experiments. Also, factors important in crust development were investigated. Measurements were made of crust thickness and specially adapted tank lids were used to measure NH3 emissions. Slurry dry matter (DM) content was the most important factor influencing crust formation, with no crust formation on slurries with a DM content of <1%. Generally, crusts began to form within the first 10 to 20 d of storage, at which time NH3 emission rates would decrease. The formation of a natural crust reduced NH3 emissions by approximately 50%. The type of bedding used in the free stall barn did not influence crust formation, nor did ambient temperature or air-flow rate across the slurry surface. There was a large difference in crust formation between slurries from cattle fed a corn (Zea mays L.) silage-based diet and those fed a grass silage-based diet, although dietary differences were confounded with bedding differences. The inclusion of a corn starch and glucose additive promoted crust formation and reduced NH3 emission. The maintenance of a manageable crust on cattle slurry stores is recommended as a cost-effective means of abating NH3 emissions from this phase of slurry management.     

Ammonia emissions from swine houses in the southeastern United States

Ammonia (NH3) from confined animal feeding operations is emitted from several sources including lagoons, field applications, and houses. This paper presents studies that were conducted to evaluate NH3 emissions from swine finisher and sow animal houses in the southeastern USA. Management and climate variables including animal weight, feed consumption, housing gutter water temperature, total time fans operated per day, house air temperature, house ambient NH3 concentration, and animal numbers were measured to determine their individual and combined effect on NH3 emissions. Ammonia emissions varied on daily and seasonal bases with higher emissions during warmer periods. For finishers, the summertime housing emissions on a per-animal basis were 2.4 times higher than wintertime (7.0 vs. 3.3 g NH3 animal(-1) d(-1)) or 3.2 times higher when compared on an animal unit (AU) basis (1 AU = 500 kg) because of climate and animal size differences between measurement periods. For summertime, the emission factor for the finishing pigs was 7.8 times higher than for sows on an animal basis and 25.6 times higher on an AU basis. Simple models were developed for housing emissions based on (i) all measured factors that were independent of each other and (ii) on three commonly measured management factors. The two models explained 97 and 64%, respectively, of variations in emissions. Ammonia emissions were found to be somewhat less than other studies on the same type housing due to more representative housing concentration measurements and calibration of exhaust fans; thus, emission factors for these type houses will be less than previously thought.     

Dependence of ammonia emissions from housing on the time cattle spent inside

Buildings housing cattle contribute 19% (42 kt NH3-N yr(-1)) of total UK ammonia (NH3) emissions. In the UK there is not usually an abrupt switch from cattle being kept inside to when they are turned out to graze 24 h a day. Moreover, during the summer dairy cows return to the farm twice a day to be milked and may spend some time inside buildings. Hence, there is uncertainty over the treatment of the transitional and summer periods when inventorying NH3 emissions. The aim of this study was to measure, under controlled and replicated conditions, the relationship between the number of hours cattle spend in buildings and the NH3 emissions from those buildings. Our results indicate that NH3 emissions decrease as the proportion of the day cattle spend in the buildings decreases, although the trend is not linear. Daily emission rates from cattle housed for 2 h ranged from 1.6 to 6.2 g NH3-N lu(-1) whereas emissions from cattle housed for 24 h ranged from 8.1 to 24.1 g NH3-N lu(-1). To significantly reduce NH3 emissions in comparison to those from buildings where cattle are housed for 24 h, the occupancy would have to be reduced to no more than 6 h each day. Thus, the strategy of extending the grazing season by allowing cattle to graze for c. 4 to 12 h during the winter is unlikely to reduce NH3 emissions from buildings or overall.     

Quantifying ammonia emissions from a cattle feedlot using a dispersion model

Livestock manure is a significant source of ammonia (NH3) emissions. In the atmosphere, NH3 is a precursor to the formation of fine aerosols that contribute to poor air quality associated with human health. Other environmental issues result when NH3 is deposited to land and water. Our study documented the quantity of NH3 emitted from a feedlot housing growing beef cattle. The study was conducted between June and October 2006 at a feedlot with a one-time capacity of 22,500 cattle located in southern Alberta, Canada. A backward Lagrangian stochastic (bLS) inverse-dispersion technique was used to calculate NH3 emissions, based on measurements of NH3 concentration (open-path laser) and wind (sonic anemometer) taken above the interior of the feedlot. There was an average of 3146 kg NH3 d(-1) lost from the entire feedlot, equivalent to 84 microg NH3 m(-2) s(-1) or 140 g NH3 head(-1) d(-1). The NH3 emissions correlated with sensible heat flux (r2 = 0.84) and to a lesser extent the wind speed (r2 = 0.56). There was also evidence that rain suppressed the NH3 emission. Quantifying NH3 emission and dispersion from farms is essential to show the impact of farm management on reducing NH3-related environmental issues.     

秦皇岛市农业面源污染特征分析

对2011年秦皇岛市农业污染源进行分析并测算各污染物排放量,结果表明,农业面源COD排放量为38768．27t,NH3-N为7593．71t,TN为15684．63t,TP为7821．18t;昌黎县是秦皇岛市农业面源污染最重的污染区域;农村生活源对COD排放量的贡献率最大,种植业对NH3-N、TN和TP排放量的贡献率最大。     

Modeling China's semiconductor industry fluorinated compound emissions and drafting a roadmap for climate protection

Fluorinated compounds (FC) are high-global warming potential (GWP) greenhouse gases used and emitted during the manufacture of silicon semiconductor devices. Following the U.S. EPA's PFC Emissions Vintage Model (PEVM), uncontrolled FC emissions are modeled as proportional to total manufactured layer area (TMLA) of silicon. FC emissions of World Semiconductor Council (WSC) charter member countries (Europe, Japan, Korea, Taiwan and the United States), which voluntarily committed in 1999 to lower FC emissions by 2010 to 10% of baseline year emissions, are modeled for the period 1995–2020. For this same period, emissions from Chinese manufacturers under alternative emission reduction scenarios are modeled. If Chinese manufacturers were to adopt a baseline year of 2005 and a reduction target of 10% below baseline year emissions to be achieved by 2020, emissions would be 3.4 MMTCO₂eq, comparable to the similarly projected controlled emissions of an average WSC charter member country (=16.3/5 MMTCO₂eq) in 2020. The relative stringency of the alternative reduction scenarios considered for China vary between 50 and 95% reduction compared to business as usual (BAU). This is comparable to the stringency of the WSC charter members’ goals for which FC emission reduction technologies are currently available.