Search

Abstract: Ammonia (NH3) emitted from animal agriculture is the most important gaseous pollutant in agro-systems. Experimental research, as compared with indirect estimation and hypothetical calculation, on NH3 from agriculture is critical for emission assessment, regulation, and abatement. Research involving field-scale monitoring of NH3 emissions from U.S. swine facilities has greatly expanded in the past 15 years. However, published NH3 calculation tools, including emission factors, and U.S. EPA (United States Environmental Protection Agency) inventories in this field were largely based on non-U.S. research. While seasonal and diurnal variations of NH3 concentrations and emissions are acknowledged, most field studies, which these tools depended on, produced data that only represented a fraction of the overall picture of NH3 emissions because of technological and financial limitations. Different methodologies and technologies have been used in NH3 emission investigations but not compared systematically. Methodology, equipment, and software used in sampling and measurement, and methodology and software used in data processing and emission rate calculation can introduce variations into the results. Because of the lack of standardized methods and procedures, it is difficult to identify and quantify measurement and calculation errors. Although a few comprehensive field studies have been conducted that were long enough to cover seasonal and even annual variations, and continuous enough to cover diurnal and dynamic emission variations, there is a considerable delay of in-depth interpretation and publication of data following comprehensive monitoring projects in the U.S. There is also a lag of adopting/updating the latest NH3 emission factors from comprehensive field studies in country-wide NH3 emission inventories. In addition, there have been discrepancies between data obtained from research and data published by governmental and other agencies. Future development in this field will require that methodologies and criteria be made to weigh data from different projects to develop emission factors, more emphasis be put on application of comprehensive research results, more intensive and extensive field monitoring be conducted, standards and protocols for monitoring and data calculation be developed, and more investment be made on post-measurement data processing/analyzing/interpretation and development of advanced computer software. [Copyright &y& Elsevier]

Manure-belt layer hen houses are a relatively newer design and are replacing the old high-rise layer hen houses for egg production in USA. However, reliable aerial pollutant emission data from comprehensive and long-term on-farm monitoring at manure-belt houses are scarce. This paper reports the emission factors and characteristics of ammonia (NH 3 ), hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), and particulate matter (PM 10 ) from two 250,000-bird capacity manure-belt layer hen houses (B-A and B-B) in northern Indiana, USA. The 2-year continuous field monitoring followed the Quality Assurance Project Plan of the National Air Emission Monitoring Study (NAEMS). Only days with more than 18 h (or 75%) of valid data were reported to avoid biased emission calculation. The results of 2-year average daily mean (ADM) gas emissions per hen from the two houses, excluding emissions from their manure shed, were 0.280 g for NH 3 , 1.952 mg for H 2 S, and 103.2 g for CO 2 . They were 67% lower for NH 3 , 77% higher for H 2 S, and 10% higher for CO 2 compared with reported emissions from high-rise layer hen houses. Emissions of NH 3 and CO 2 exhibited evident seasonal variations. They were higher in winter than in summer and followed the NH 3 and CO 2 concentration seasonal patterns. Annual emission differences were observed for all the four pollutants. Reduced emissions of the three gases were shown during periods of layer hen molting and flock replacement. The 2-year ADM PM 10 emission from B-B was 25.2 mg d −1 hen −1 . A unique weekly PM 10 emission pattern was identified for both houses. It was characterized with much lower Sunday emissions compared with the other single-day emissions of the week and was related to the weekly schedule of in-house production operations, including maintenance and cleaning. [ABSTRACT FROM AUTHOR]

Abstract: Indoor air pollutants at high concentrations in poultry houses can potentially affect workers'' health, and animal welfare and productivity. This paper presents research results of a 2-year continuous monitoring of ammonia (NH3), carbon dioxide (CO2), hydrogen sulfide (H2S), and particulate matter (PM) concentrations from to date the most comprehensive study on a single farm in two 180,000-bird high-rise (HR) and two 200,000-bird manure-belt (MB) layer hen houses located in Indiana, USA. Air was sampled at ventilation fans of the mechanically-ventilated houses. Concentrations of NH3 and CO2 were measured with photoacoustic multi-gas monitors. Concentrations of H2S and PM10 were monitored with pulsed fluorescence analyzers and Tapered Element Oscillating Microbalances (TEOM), respectively. The 2-year mean ± standard deviation concentrations at ventilation fans of the four layer hen houses were 48.9 ± 39 and 51.9 ± 40.7 ppm in HR, and 13.3 ± 9.1 and 12.9 ± 10.5 ppm in MB for NH3; 26.4 ± 17.6 and 24.9 ± 19 ppb in HR, 40.0 ± 21.1 and 41.2 ± 31.5 ppb in MB for H2S; 1755 ± 848 and 1804 ± 887 ppm in HR, and 2295 ± 871 and 2285 ± 946 ppm in MB for CO2; and 540 ± 303 and 552 ± 338 μg m−3 in HR, and 415 ± 428 and 761 ± 661 μg m−3 in MB for PM10. Compared with the MB houses, concentrations of the HR houses were higher for NH3, and lower for CO2, H2S, and PM10 (P < 0.05). High concentrations of NH3 detected in winter represent potential challenges to workers'' health and animal welfare. Variations in pollutant concentrations at the exhaust fans were affected by outdoor temperature, ventilation, bird condition, and farm operation. A new weekly variation, characterized by significantly lower PM10 concentrations on Sundays, was identified and was related to the weekly schedule of house operational activities. [Copyright &y& Elsevier]