National Air Emissions Monitoring Study Research Articles

USEPA CALPUFF validation and dispersion modeling of beef cattle feedlot PM10 and PM2.5 emissions factors

Beef cattle feedlots are major sources of criteria air pollutants in the United States. To aid stakeholders in air quality modeling, emissions factors for animal waste-producing facilities are under development by the U.S. Environmental Protection Agency (USEPA). However, beef cattle feeding operations (feedlots) are not among facilities surveyed under the associated USEPA National Air Emissions Monitoring Study (NAEMS). Authors aim to supplement NAEMS through development and validation of particulate matter (PM10 and PM2.5) emission factors from a previous sampling campaign of five large feedlots in the Southern High Plains of North America via USEPA's CALPUFF dispersion model. PM concentrations were higher overall during the warm season (March–August; PM10 = 692 ± 507, PM2.5 = 114 ± 110 μg/m3) relative to cool season (November–January; PM10 = 102 ± 105, PM2.5 = 12.2 ± 8.6 μg/m3), and overall median PM10 and PM2.5 emission factors were 48.2 (day = 33.8, night = 72.4) and 5.22 (day = 8.4, night = 3.1) mg/m2/hr, respectively. Validated emissions factors were then used to model diurnal peaks and long-range transport (100 km maximum extent). Peak concentrations were most frequently observed between 2000 and 0600 h (93.9%; mean 1-hr peak ± SD = 1119 ± 1240 μg/m3) for PM10 and 1600-0600 h (80.0%; mean 1-hr peak ± SD; 178 ± 174 μg/m3) for PM2.5. Four of five feedlots exceeded ≥1 primary PM National Ambient Air Quality Standard (NAAQS) at receptors (2-m height) over a 5-km spatial extent during the modeling period (November 2010–August 2011). Moreover, present estimates of feedlot-derived inhalable PM represent human and environmental exposure pathways currently exempt from Clean Air Act monitoring and reporting standards, and spatial interpolation of federal air quality monitors cannot adequately characterize inhalable PM concentrations in non-metropolitan municipalities and unincorporated rural communities.

Characteristics of Particulate Matter Emissions from Swine and Poultry Production Houses in the United States

HighlightsParticulate matter (PM) data were analyzed to identify PM emission characteristics among different animal types.The PM concentrations were higher in broiler chicken and swine farrowing houses and were higher in winter.The PM emissions were also higher in broiler chicken houses and swine farrowing rooms.The PM in the layer chicken house in Indiana had narrower distributions with a greater percentage of smaller particles.Abstract. Understanding the characteristics of particulate matter (PM) emissions from animal feeding operations (AFOs) is essential to address the associated health and environmental impacts and to develop control strategies to mitigate such impacts. This article reports a study of PM concentrations and emission characteristics from 26 poultry and swine production houses to investigate the similarities and differences in PM emission characteristics, e.g., concentrations, emission rates, and particle size distribution (PSD), among different animal and housing types. Concentration and emission data for PM2.5, PM10, and total suspended particulates (TSP) collected by the National Air Emission Monitoring Study (NAEMS) were used to compare the differences among different production practices and animal types. The PSDs of the PM were examined based on the PM2.5/PM10 and PM10/TSP emission rate ratios. It was discovered that the concentrations of PM varied among animal types. For poultry, the concentrations of PM were higher in broiler houses than in other poultry houses. For swine, the average concentrations of PM were higher in farrowing rooms than in swine barns. Moreover, the PM concentrations in poultry and swine houses exhibited significant seasonal trends, with higher concentrations in winter and lower concentrations in summer, which were in a reverse relationship with ventilation rates. The PM emissions also varied among animal types. For poultry, the PM emissions were significantly higher for poultry production houses in California. For swine, the PM emissions were significantly higher for farrowing rooms than other swine houses. The PSD of PM varied among animal types, with mass median diameters (MMD) in the ranges of 6.51 to 13.62 µm for poultry houses and 7.94 to 17.19 µm for swine houses. The geometric standard deviations (GSD) were in the ranges of 1.66 to 2.71 and 1.65 to 2.9 for poultry and swine PM, respectively. The PM in the layer house in Indiana had a narrower distribution (smaller GSD) with a greater percentage of smaller particles than the other poultry houses, while the PM in the broiler house in California had a broader distribution (larger GSD) than the other poultry houses. For swine, the PM in the sow barn in North Carolina had a narrower distribution (smaller GSD) than the other swine houses, while the PM in the farrowing houses in Oklahoma had a broader distribution (larger GSD) than the other swine houses. The knowledge gained from this research may provide insights for addressing the PM emissions from various animal production systems. Keywords: Concentration and emission, Particulate matter, PM2.5, PM10, Poultry, swine, PSD, TSP.

Comparison of direct and indirect determinations of dynamic ventilation rate in a modern dairy free stall barn

Reliable estimation of the ventilation rate (VR) in intensive livestock buildings is necessary for studying building environmental control strategies and predicting indoor air quality and air emissions. As direct air exchange measurements are time-consuming and expensive, it is environmentally inefficient to measure livestock building VR continuously in practice. Hence, indirect VR estimation methods have been widely used in modelling environmental control and air emissions, and also to measure airflow in the field. The accuracy of indirect measurement methods needs to be evaluated by comparing with direct measurements. In this study, the direct and indirect methods of determining hourly and daily mean VRs were applied to a mechanically-ventilated dairy free stall barn monitored by the 24-month National Air Emissions Monitoring Study. The direct method was used to continuously monitor fan rotational speeds, and differential static pressures, coupled with periodic in-situ fan performance assessments, to calculate the VR. The indirect method consisted of estimating the VR using CO2 concentration measurements and the CO2 mass balance method. The average daily and hourly means (mean±SD) of directly measured barn ventilation rates for two years were (246±73) m3/s and (245±77) m3/s, respectively. The average daily and hourly means (mean±SD) of barn ventilation rates estimated by the CO2 mass balance method were (287±93.4) m3/s and (287±118) m3/s, respectively. Correlation analyses showed a strong correlation between the indirect CO2 mass balance method and direct measurement methods (r=0.93 for daily means and r=0.85 for hourly means). Keywords: dynamic ventilation rate, modern dairy, free stall barn, carbon dioxide, mass balance, dairy cow, direct and indirect determination, comparison DOI: 10.25165/j.ijabe.20201306.5767 Citation: Zou B, Heber A J, Shi Z X, Du S H, Jin Y, Lim T T. Comparison of direct and indirect determinations of dynamic ventilation rate in a modern dairy free stall barn. Int J Agric & Biol Eng, 2020; 13(6): 41–46.

Factors and characteristics of ammonia, hydrogen sulfide, carbon dioxide, and particulate matter emissions from two manure-belt layer hen houses

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 (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), and particulate matter (PM10) 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 NH3, 1.952 mg for H2S, and 103.2 g for CO2. They were 67% lower for NH3, 77% higher for H2S, and 10% higher for CO2 compared with reported emissions from high-rise layer hen houses. Emissions of NH3 and CO2 exhibited evident seasonal variations. They were higher in winter than in summer and followed the NH3 and CO2 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 PM10 emission from B-B was 25.2 mg d−1 hen−1. A unique weekly PM10 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.

Variations of Ammonia Emissions from Cattle Operations: Effects of Air Temperature and Dietary Crude Protein Content

<abstract> <b><sc>Abstract.</sc></b> The objective of this study was to conduct a systematic review of the published literature on ammonia (NH₃) emissions from beef feedlots and dairy barns using a meta-analytical approach in order to improve the estimation of emission rates, to understand the sources of variation, and to specifically quantify the effects of air temperature and dietary crude protein (CP) on NH₃ emissions. Emissions from lagoons or other manure storage facilities were not included. The review compiled results from 91 studies (published from 1997 to 2016) and from the five dairy sites in the National Air Emissions Monitoring Study (NAEMS). Based on the results, the average NH₃ emission rate was 105.9 g d^-1 animal^-1 for beef feedlots and 125.6 g d^-1 animal^-1 for open-lot dairy barns, which were much higher than the emission factors proposed by the U.S. Environmental Protection Agency. Expressing NH₃ emissions as the NH₃-N loss as a percentage of nitrogen (N) intake can address the effect of N feed intake, can reduce uncertainties in estimation of emissions, and can be used as a key parameter in establishing emission inventories and evaluating mitigation strategies. The average NH₃-N loss as a percentage of N intake was 53.1%, 15.6%, 8.7%, and 5.1% for beef feedlots, open-lot dairy barns, free-stall dairy barns, and tie-stall dairy barns, respectively. Results showed that the measured NH₃ emission rates could be affected by measurement method. The chamber method tends to underestimate, while the N balance method tends to overestimate. Proper adjustment and validation may be needed when using the tracer ratio method in free-stall/tie-stall barns in order to avoid potential overestimation. Regression models were developed to quantify the effects of air temperature and dietary CP on emissions from various types of cattle operations. The sensitivity of NH₃ emission rate to air temperature obtained for various operations was consistent (2.33, 2.39, and 2.66 g d^-1 animal^-1 per °C, respectively, for beef feedlots, open-lot dairy barns, and free-stall/tie-stall dairy barns with natural ventilation). Higher dietary CP resulted in significantly higher NH₃ emission rates and also corresponded with higher NH₃-N loss as a percentage of N intake for beef feedlots and free-stall/tie-stall dairy barns with natural ventilation. The sensitivity of emission rates to dietary CP obtained for various types of dairy cattle operations was consistent (9.91, 12.68, and 10.40 g d^-1 animal^-1 per 1% CP, respectively, for beef feedlots, open-lot dairy barns, and free-stall/tie-stall dairy barns with natural ventilation). The average NH₃ emission rate for barns with mechanical ventilation was less than half that for barns with natural ventilation. When developing mitigating strategies, managing N intake and improving feed efficiency seem to represent the greatest opportunities.

The National Air Emissions Monitoring Study’s Southeast Layer Site: Part V. Hydrogen Sulfide and Volatile Organic Compounds

Aerial pollutants generated from intensive poultry and livestock production raise concerns of health and welfare for the surrounding communities. This article reports emission rates of hydrogen sulfide (H 2 S) and concentrations of volatile organic compounds (VOCs) from two tunnel-ventilated high-rise houses at a layer site in North Carolina that were tested by the National Air Emissions Monitoring Study (NAEMS). Hydrogen sulfide concentrations exhibited significant seasonal and diurnal variations. The minimum and maximum average hourly mean (AHM) concentrations by hour of day occurred at 15:00-16:00 and 6:00-7:00, respectively. The lowest and highest daily mean concentrations during the annual cycle were observed in summer and winter, respectively. The AHM H 2 S concentrations were 1.04 ±0.83 ppb for inlet air and 9.52 ±6.35 and 9.43 ±6.01 ppb, respectively, for exhaust air from the two production houses. The diurnal and seasonal patterns of H 2 S emission rates from the two production houses were also similar. Slight increases in H 2 S emission rates occurred at 12:00 to 14:00. Higher H 2 S emission rates occurred in summer. The AHM hen-specific H 2 S emission rates from the two production houses were 618 ±517 and 698 ±620 I¼g d -1 hen -1 , respectively. Factors significantly affecting H 2 S emissions were hen activity, house exhaust air temperature, and ambient air temperature. Time-integrated samples of VOCs were collected over 24 h periods seven times in one production house from 12 April 2009 to 18 September 2009. Of 77 target compounds, the ten most abundant compounds were 2-butanone, iso-propanol, dimethyl sulfide, hexanal, acetic acid, 2,3-butanedione, pentane, acetaldehyde, pentanal, and phenol. Differences in VOC concentrations were observed between the layer room and the manure pit. The highest total VOC concentration was detected in samples taken from the manure pit exhaust air.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 3. Chemical Emissions

This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). The objective of this study was to measure odor emissions and corresponding concentrations and emissions of target odorous gases. Odor and odorous gas measurements at four NAEMS sites (dairy barns in Wisconsin-WI5B and Indiana-IN5B, swine finisher barn in Indiana-IN3B and swine gestation/farrowing barns in Iowa-IA4B) were conducted during four-13 weeks periods over ~1 year. Odorous gas samples were collected every two weeks using sorbent tubes and analyzed by the automated one-step thermal desorption-GC-MS-Olfactometry. In this paper, we summarize measured concentrations and emissions of 15 odorous gases from four sites. The average volatile fatty acids (VFAs) concentrations ranged between1.1 and 121 µg m -3 . The average phenolics and indolics concentrations varied from 0.03 to 42 µg m -3 . The total volatile organic compound VOC emission rates for 15 compounds for four sites ranged between 8.89 and 546 mg/hr-m 2 . Only acetic acid (p<0.05) and propanoic acid (p<0.1) had a seasonal significant difference for IA4B. For IN3B, 4-ethyl phenol and indole and most of VFAs (except hexanoic and heptanoic acid) have the seasonal significant differences. At the WI5B dairy site, there were five VFAs (acetic, propanoic, 2-methyl propanoic, butyric and 3-methylbuanoic acid) and one phenolics ( 4-methyl phenol) showing a seasonal significant difference. Only three compounds (2methoxyphenol, 1-(2-aminophenyl)-ethanone and indole) had a seasonal significant difference for IN5B. Between dairy sites (WI5B vs. IN5B), acetic, propanoic, 2-methyl propanoic, butyric, and 3-methyl butanoic acids were significantly different. Most of odorants were significantly different except heptanoic acid, 1-(2-aminophenyl)-ethanone and 3-methyl indole, between the two swine sites (IA4B vs. IN3B). Between the two different species (Dairy vs. Swine), five odorants including acetic and heptanoic acid, phenol, 4-ethylphenol, 1-(2-aminophenyl) ethanone were not significantly different, whereas the other 10 compounds measured were.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 5. Simultaneous Chemical and Sensory Analysis with Gas Chromatography-Mass Spectrometry-Olfactometry

Simultaneous chemical and sensory analyses using gas chromatography-mass spectrometry-olfactometry (GC-MS-O) for air samples collected at barn exhaust fans were used for quantification and ranking of the odor impacts of target odorous gases. Fifteen target odorous VOCs (odorants) were selected. Air samples were collected at dairy barns in Wisconsin and Indiana and at swine barns in Iowa and Indiana over a one-year period. The livestock facilities with these barns participated in the National Air Emissions Monitoring Study (NAEMS). Gas concentrations, odor character and intensity, hedonic tone, and odor peak area of the target odorants in air samples were measured simultaneously with GC-MS-O. The four individual odorants emitted from both dairy and swine sites with the largest odor impacts (measured as odor activity value, OAV) were 4-methyl phenol, butanoic acid, 3-methyl butanoic acid, and indole. The total odor (limited to target VOCs and referred to as the measured concentrations, odor intensities, and OAVs) emitted from the swine sites was generally greater than that from the dairy sites. The Weber-Fechner law was used to correlate measured odor intensities with chemical concentrations. Odorants with higher mean OAV followed the Weber-Fechner law much better than odorants with lower mean OAV. The correlations between odor intensities and chemical concentrations were much better for the swine sites (typically p 2 = 0.16 to 0.51) than for the dairy sites (typically p > 0.05 and R 2

Methane and nitrous oxide analyzer comparison and emissions from dairy freestall barns with manure flushing and scraping

Continuous methane (CH4) and nitrous oxide (N2O) emission measurements were conducted at two crossflow-ventilated dairy freestall barns located in the state of Wisconsin, USA during a 19-month period from 2008 to 2010. The two cross-flow mechanically ventilated buildings (275 and 375 cow capacities) were evaluated in the National Air Emissions Monitoring Study. In September of 2008, the barns' manure collection systems were changed from flushing open gutter using manure basin effluent to a tractor scrape. A photoacoustic multi-gas analyzer (PAMGA) and a direct methane/non-methane hydrocarbon analyzer (GC-FID) provided side-by-side measurements of methane (CH4) for 13 months. The PAMGA also measured nitrous oxide (N2O), and a side-by-side comparison was performed with a gas-filter correlation analyzer (GFC) for six months. Barn ventilation rates were measured by recording run times of the 127-cm diameter exhaust fans. All 125 belt-driven exhaust fans were identical, and in situ airflow measurements using the Fan Assessment Numeration System (FANS) were conducted once at the beginning and twice during the test. Daily CH4 and N2O emission rates were calculated over approximately 19 and 6 month periods respectively, on per barn, head, animal unit, floor area space and barn capacity bases. The differences between the analyzers' concentration measurements were compared in conjunction with water vapor and other gases. The analyzer type had a significant impact on the average CH4 emission rate (p < 0.001) and the average N2O emission rate (p < 0.05). Based on the CH4 measurements with the GC-FID, average daily mean CH4 emissions were approximately 290 g AU−1 d−1 (390 g cow−1 d−1) with very limited seasonal effects. Little variation was observed in CH4 emission rates before and after the change in manure collection method, suggesting that most of the CH4 emissions were enteric losses directly from the cows. The average daily mean N2O emission rates based on the GFC were very low, with an approximate rate of only 690 mg AU−1 d−1 (970 mg cow−1 d−1). The change in manure collection had no apparent effect on N2O emission.

Ventilation rate measurements at a mechanically-ventilated pig finishing quad barn

With concentrated animal feeding operations (CAFOs) becoming larger and more intensive, air pollutant emissions from these facilities are of increasing concern for regulators and the public, and on-farm measurements of emissions are needed. A critical step in determining air pollutant emissions from the barns at these facilities is the accurate assessment and continuous monitoring of the barn ventilation rates. One of the most recent efforts to accurately determine barn ventilation rate was to continuously monitor fan operation, differential static pressure, fan speed, and air density related environmental variables, coupled with in-situ fan performance assessments at a range of static pressures, as applied in the 24-month National Air Emissions Monitoring Study (NAEMS). Uncertainty analyses associated with these calculations aided in characterising and qualifying the measurements. This paper describes methods used in the NAEMS to determine ventilation rates of four rooms (rooms 5–8) in a mechanically-ventilated pig finishing quad barn. The overall 2-yr average daily dry-standard ventilation rates (mean ± SD) were 13.5 ± 11.3, 13.8 ± 11.6, 14.5 ± 12.9, and 13.6 ± 12.9 m3 [dry-standard] s−1 for rooms 5–8, respectively. Thorough uncertainty analyses demonstrated that the estimated uncertainty of the ventilation rate (dry-standard) under typical site conditions decreased from 9.4% to 4.1% between the minimum (3.7 m3 [ds] s−1) and maximum (45.2 m3 [ds] s−1) capacities of the ventilation system. These results confirmed that larger numbers of operating fans lead to lower relative uncertainties for barn ventilation rates and that the uncertainty of ventilation rate measurements can be reduced by improved and more frequent in-situ fan calibrations.

Ammonia and hydrogen sulfide emissions from swine production facilities in North America: A meta-analysis1

Literature on NH3 and H2S emissions from swine production facilities in North America was reviewed, and a meta-analysis was conducted on measured emissions data from swine houses and manure storage facilities as well as concentration data in the vicinity of swine production facilities. Results from more than 80 studies were compiled with results from the 11 swine sites in the National Air Emissions Monitoring Study (NAEMS). Data across studies were analyzed statistically using the MIXED procedures of SAS. The median emission rates from swine houses across various production stages and manure handling systems were 2.78 and 0.09 kg/yr per pig for NH3 and H2S, respectively. The median emission rates from swine storage facilities were 2.08 and 0.20 kg/yr per pig for NH3 and H2S, respectively. The size of swine farm that may trigger the need to report NH3 emissions under the Emergency Planning and Community Right-to-Know Act (EPCRA) is 3,410 pigs on the basis of the median NH3 emission rate (4.86 kg/yr per pig), but the threshold can be as low as 992 pigs on the basis of the 90th-percentile emission rates (16.71 kg/yr per pig). Swine hoop houses had significantly higher NH3 emission rate (14.80 kg/yr per pig) than other manure-handling systems (P < 0.01), whereas deep-pit houses had the highest H2S emission rate (16.03 kg/yr per pig, P = 0.03). Farrowing houses had the highest H2S emission rate (2.50 kg/yr per pig), followed by gestation houses, and finishing houses had the lowest H2S emission rate (P < 0.01). Regression models for NH3 and H2S emission rates were developed for finishing houses with deep pits, recharge pits, and lagoons. The NH3 emission rates increased with increasing air temperature, but effects of air temperature on H2S emission rates were not significant. The recharge interval of manure pits significantly affected H2S but not NH3 emission rates. The H2S emission rates were also influenced by the size of the operation. Although NH3 and H2S concentrations at the edge of swine houses or lagoons were often higher than corresponding acute or intermediate minimum risk levels (MRL), they decreased quickly to less than corresponding chronic or intermediate MRL as distances from emission sources increased. At the distances 30 to 1,185 m from emission sources, the average ambient concentrations for NH3 and H2S were 46 ± 46 µg/m(3) and 4.3 ± 8.6 µg/m(3) respectively.

The National Air Emissions Monitoring Study�s Southeast Layer Site: Part I. Site Characteristics and Monitoring Methodology

Abstract. Air emissions from animal feeding operation (AFO) facilities have been of increasing concern. While the EPA was pressured to put more stringent regulations on the AFO industry, there was an absence of suitable emission data to support regulatory decisions for different AFOs due to limitations of past studies and the absence of standard measurement protocols that link an emission rate to the different activities responsible for the emissions. In 2005, the EPA announced the AFO Air Quality Compliance Agreement, under which a two-year National Air Emissions Monitoring Study (NAEMS) was initiated. The NAEMS Southeast Layer Site was designed to collect baseline air emissions from high-rise tunnel-ventilated layer houses. The target emissions at this site were ammonia (NH 3 ), hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), volatile organic compounds (VOCs), and particulate matter (PM), including PM 2.5 , PM 10 , and total suspended particulate (TSP). In addition, operational and environmental variables (e.g., animal activity, room temperature and relative humidity (RH), house ventilation rate, ambient temperature and RH, wind speed and direction, and solar radiation) were monitored to address their impacts on the emissions. Information about house inventory and major farm management activities was also collected. This article documents site characteristics and monitoring methods for the NAEMS at the Southeast Layer Site. Baseline emissions of PM and gaseous pollutants, house ventilation rates, and apparent impacts of farm management activities are reported in parts II through VI of this series.

The National Air Emissions Monitoring Study’s Southeast Layer Site: Part II. Particulate Matter

Abstract. The National Air Emissions Monitoring Study (NAEMS) was established by the U.S. EPA and the U.S. livestock and poultry industries to address the lack of scientific air emission data needed for properly assessing compliance with federal air laws and regulations. A North Carolina egg layer farm (NC2B) was one of 20 NAEMS monitored farms. Emission rates of particulate matter (PM 2.5 , PM 10 , and TSP) from two high-rise layer houses at NC2B were determined based on continuous measurements of PM concentrations and house ventilation rates over a two-year period. The overall average PM 2.5 emission rate of both houses combined was 0.37 ±3.06 mg d -1 hen -1 with no significant difference between houses. The average PM 10 emission rates were 16.2 ±13.7 and 19.3 ±15.9 mg d -1 hen -1 from houses 3 and 4, respectively, and 17.8 ±14.9 mg d -1 hen -1 for both houses combined. The average TSP emission rates were 39.1 ±32.8 and 47.1 ±37.6 mg d -1 hen -1 for houses 3 and 4, respectively, and 43.1 ±35.5 mg d -1 hen -1 for both houses combined. The median hourly mean emission rates were 0.61, 14.7, and 31.7 mg d -1 hen -1 from house 3 and 0.72, 17.1, and 42.4 mg d -1 hen -1 from house 4 for PM 2.5 , PM 10 , and TSP, respectively. Significant temporal variations in PM concentrations and emissions were observed. Significant differences in PM concentrations were also observed between the manure pit and layer room. The PM emissions exhibited significant correlations with hen activity and house exhaust air temperature. An empirical PM emissions model was developed based on multiple regression analysis to predict PM emissions from this monitoring site.

The National Air Emissions Monitoring Study’s Southeast Layer Site: Part III. Ammonia Concentrations and Emissions

Abstract. This article reports two years of quality-assured measurements of concentrations and baseline emissions of ammonia (NH 3 ) at two tunnel-ventilated high-rise houses (houses 3 and 4) located at an egg production facility in North Carolina. The study was conducted as part of the National Air Emissions Monitoring Study (NAEMS). The inside NH 3 concentrations, as represented by the exhaust air, were characterized by significant diurnal and seasonal variations. The lowest exhaust concentrations (17.0 ±14.0 ppm in house 3; 15.8 ±13.0 ppm in house 4) were observed in early afternoon (i.e., 2:00 p.m. to 3:00 p.m.) at the maximum diurnal ventilation rate. The highest concentrations (29.5 ±22.7 ppm in house 3; 28.8 ±22.2 ppm in house 4) occurred in early morning (i.e., 2:00 a.m. to 3:00 a.m.) when the ventilation rate was the lowest. Similarly, the concentrations were lowest during summer and maximum ventilation rates, and highest during winter and minimum ventilation rates. The average NH 3 concentrations were 0.7, 22.9, and 20.7 ppm for inlet air and the exhausts of houses 3 and 4, respectively. The average daily mean NH 3 emission rate of house 3 (fully occupied and active) was 0.599 ±0.200 g d -1 hen -1 (197 ±66.3 g d -1 AU -1 , 18.2 ±6.04 g d -1 m -2 ) at an average ambient temperature of 16.7°C and that of house 4 was 0.600 ±0.250 g d -1 hen -1 (197 ±82.3 g d -1 AU -1 , 18.2 ±7.53 g d -1 m -2 ) at an average ambient temperature of 16.3°C. Ammonia emission rates exhibited less daily and seasonal variation than inside NH 3 concentrations. Slightly elevated NH 3 emission rates were observed in early afternoon (12:00 noon to 2:00 p.m.), when house temperatures were relatively high. No significant differences in emissions between summer and winter were observed. Factors significantly affecting hen-specific NH 3 emissions included house ventilation rate, ambient and exhaust air temperatures, exhaust air humidity ratio, hen population, hen activity, feed and water consumption rates, and manure accumulation time. Among all these factors, house exhaust temperature had the greatest effect on NH 3 emission rate, followed by manure accumulation time.

The National Air Emissions Monitoring Study’s Southeast Layer Site: Part IV. Effects of Farm Management

<abstract><title><italic>Abstract.</italic></title> The effects of house lighting, forced molting, manure removal, and flock replacement on air pollutant concentrations and emissions from high-rise tunnel-ventilated layer houses were evaluated. Air pollutants included ammonia (NH₃), carbon dioxide (CO₂), and particulate matter (PM, including PM₁₀, PM_2.5, and total suspended particulate, TSP). Emission rates were determined based on ventilation rates and pollutant concentrations, which were monitored for two years. House lighting schedules, molting, manure removal, and flock replacement activities were documented by the producer. Hen activity was monitored continuously using commercial motion detectors and was observed to be much higher during light periods as compared with dark periods. The TSP and PM₁₀ emissions during light periods were about five times greater than during dark periods, whereas NH₃ and CO₂ emissions during light periods were about 20% higher. The NH₃ and CO₂ concentrations and emission rates decreased during molting and then increased afterward. Ammonia emission was directly proportional to hen body weight and feed consumption. Compared with NH₃, CO₂ concentrations and emissions showed more variations during molting. During manure pit cleanouts, NH₃ and CO₂ emissions decreased from 0.62 to 0.21 g d^-1 hen^-1 and from 78 to 64 g d^-1 hen^-1, respectively. After the manure pits were emptied, NH₃ and CO₂ emissions increased steadily during the first 3 to 7 d of manure accumulation and then remained relatively constant. Manure pit cleanout activities caused high PM emission. Particulate matter emission decreased gradually after the pits were cleaned. No significant changes in egg production, mortality, water consumption, or feed consumption were observed during manure removals. When compared with occupied houses, empty house emission rates of PM₁₀, TSP, and NH₃ each decreased by more than 90%, and CO₂ decreased by more than 70%.

Ammonia and hydrogen sulfide emissions from swine production facilities in North America: a meta-analysis (2013)

Ammonia (NH3) and hydrogen sulfide (H2S) emissions from swine production facilities receive considerable attention due to human health and environmental implications. Accurate quantification of farm emissions is essential to ensure compliance with regulatory requirements. The objectives of this study were to provide a review of the literature on NH3 and H2S emissions from swine production facilities in North America with a meta-analysis that integrates results of independent studies, including measured emissions data from both swine houses and manure storage facilities as well as concentration data in the vicinity of swine production facilities. Results from more than 80 studies were identified through a thorough literature search, and the data were compiled together with results from the 11 swine sites in the National Air Emissions Monitoring Study (NAEMS). Data across studies were analyzed statistically using the MIXED procedures of SAS. Median emissions rates from swine houses were 2.78 and 0.09 kg/year per pig for NH3 and H2S, respectively. Median emissions rates from swine storage facilities were 2.08 and 0.20 kg/year per pig for NH3 and H2S, respectively. The Emergency Planning and Community Right-to-Know Act (EPCRA) require reporting of NH3 and H2S emissions that exceed 100 lb/d. The size that may trigger the need for a farm to report NH3 emissions is 3,410 pigs based on median NH3 emissions rates in the literature, but the threshold can be as low as 992 pigs based on 90th-percentile emissions rates. Swine hoop houses had significantly higher NH3 emission rates than other manure-handling systems (P < 0.01), whereas deep pit houses had the highest H2S emission rates (P = 0.03). Farrowing houses had the highest H2S emission rates, followed by gestation houses, and finishing houses had lowest H2S emission rates (P < 0.01). Regression models for NH3 and H2S emission rates were developed for finishing houses with deep pits, recharge pits, and lagoons. The NH3 emission rates increased with increasing air temperature, but effects of air temperature on H2S emission rates were not significant. The recharge interval of manure pits significantly affected H2S but not NH3 emission rates. The H2S emission rates were also influenced by the size of the operation. Although NH3 and H2S concentrations at the edge of swine houses or lagoons were often higher than corresponding acute or intermediate minimum risk levels (MRLs), they decreased quickly to be less than corresponding chronic or intermediate MRLs as distances from emission sources increase. At distances 30 to 1,185 m from emission sources, the average ambient concentrations for NH3 and H2S were 66 ± 66 ppb and 3.1 ± 6.2 ppb, respectively.; Swine Day, Manhattan, KS, November 21, 2013

Emissions monitoring at a deep-pit swine finishing facility: Research methods and system performance

This paper describes part of a comprehensive National Air Emissions Monitoring Study (NAEMS) conducted at a swine finishing farm located in the state of Indiana, in the United States. The NAEMS was a 2-year study of emissions from animal feeding operations that produce pork, chicken meat, eggs, and milk. It provided emission data for the U.S. Environmental Protection Agency (EPA) to develop tools for estimating emissions from livestock farms. The study in Indiana focused on quantifying and characterizing emissions of gases, particulate matter (PM), and volatile organic compounds (VOCs) from a swine finishing quad (four 1000-head rooms under one roof). Long-term continuous and quasi-continuous measurements were conducted with 157 on-line measurement variables using an array of instruments and sensors for gas and PM concentrations, fan operation, room static pressures, indoor temperature and humidity, animal activity and feeding times, and weather conditions. Pig inventory and weight, feed type and quantity, and manure accumulation and composition were also documented. Systematic tests of the measurement system were conducted. Monitoring methodologies, instrumentation applications, equipment maintenance, quality controls, and system performances are presented and can be used as a reference in assessing research quality and improving future environmental studies on livestock facilities. Implications: Aerial pollutant emissions became a major environmental issue for livestock operations after farms increased significantly in size. Gas and particulate matter emissions from livestock production may cause various environmental impacts such as odor and noxious gas exposure in neighboring areas. In this study, comprehensive and long-term emissions of gases and PM at a Midwestern U.S. commercial swine finishing farm were continuously monitored for 2 years. The methodologies, quality assurance procedures, and results of this study can be used to plan future emission monitoring projects, improve baseline emission databases, and validate emission models.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 6. Odor Activity Value

There is a growing concern with air and odor emissions from agricultural facilities. A supplementary research project was conducted to complement the U.S. National Air Emissions Monitoring Study (NAEMS). The overall goal of the project was to establish odor and chemical emission factors for animal feeding operations. The study was conducted over a 17-month period at two freestall dairies, one swine sow farm, and one swine finisher facility. Samples from a representative exhaust airstream at each barn were collected in 10 L Tedlar bags and analyzed by trained human panelists using dynamic triangular forced-choice olfactometry. Samples were simultaneously analyzed for 20 odorous compounds (acetic acid, propanoic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, guaiacol, phenol, 4-methylphenol, 4-ethylphenol, 2-aminoacetophenone, indole, skatole, dimethyl disulfide, diethyl disulfide, dimethyl trisulfide, hydrogen sulfide, and ammonia). In this article, which is part 6 of a six-part series summarizing results of the project, we investigate the correlations between odor concentrations and odor activity value (OAV), defined as the concentration of a single compound divided by the odor threshold for that compound. The specific objectives were to determine which compounds contributed most to the overall odor emanating from swine and dairy buildings, and develop equations for predicting odor concentration based on compound OAVs. Single-compound odor thresholds (SCOT) were statistically summarized and analyzed, and OAVs were calculated for all compounds. Odor concentrations were regressed against OAV values using multivariate regression techniques. Both swine sites had four common compounds with the highest OAVs (ranked high to low: hydrogen sulfide, 4-methylphenol, butyric acid, isovaleric acid). The dairy sites had these same four compounds in common in the top five, and in addition diethyl disulfide was ranked second at one dairy site, while ammonia was ranked third at the other dairy site. Summed OAVs were not a good predictor of odor concentration (R2 = 0.16 to 0.52), underestimating actual odor concentrations by 2 to 3 times. Based on the OAV and regression analyses, we conclude that hydrogen sulfide, 4-methylphenol, isovaleric acid, ammonia, and diethyl disulfide are the most likely contributors to swine odor, while hydrogen sulfide, 4-methyl phenol, butyric acid, and isovaleric acid are the most likely contributors to dairy odors.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 1. Project Overview, Collection Methods, and Quality Control

Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include inputs to odor setback models, while chemical emission factors may be compared with regulation thresholds as a means of demonstrating potential health impacts. Acompanion study of the National Air Emissions Monitoring Study (NAEMS) included measurements necessary for establishing odor and chemical emission factors for confined animal feeding operations. This additional investigation was conducted by the University of Minnesota, Iowa State University, West Texas A&M Agri-Life Center, and Purdue University. The objectives were to (1) determine odor emission rates across swine and dairy facilities and seasons using common protocols and standardized olfactometry methods, (2) develop a chemical library of the most significant odorants, and (3)correlate the chemical library with the olfactometry results. This document describes the sampling and quality assurance methods used in the measurement and evaluation of odor and chemical samples collected at two freestall dairy farms, one sow (gestation/farrowing) facility, and one finishing pig site. Odor samples were collected in Tedlar bags and chemical samples were collected in sorbent tubes at barn inlet and exhaust locations using the NAEMS multiple-location gas sampling systems. Quality assurance protocols included interlaboratory comparison tests, which were evaluated to identify variations between olfactometry labs. While differences were observed, the variations among the labs and samples appeared random and the collected odor data were considered reliable at a 0.5% level of statistical significance. Overall, the study took advantage of groundbreaking opportunities to collect and associate simultaneous odor and chemical information from swine and dairy buildings while maintaining accordance with standard methods and comparability across laboratories.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 2. Odor Emissions

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions considering variations in seasons, animal types, and olfactometry laboratories. Odor emissions from four of 14 NAEMS sites with nine barns/rooms (two dairy barns at the WI5B and IN5B sites, two pig finishing rooms at IN3B, and two sow gestation barns and a farrowing room at the IA4B site) were measured during four 13-week cycles. Odor emissions were reported per barn area (OU h-1 m-2), head (OU h-1 head-1), and animal unit (OU h-1 AU-1). The highest overall odor emission rates were measured in summer (1.2 105 OU h-1 m-2, 3.5 105 OU h-1 head-1, and 6.2 105 OU h-1 AU-1), and the lowest rates were measured in winter (2.5 104 OU h-1 m-2, 9.1 104 OU h-1 head-1, and 1.5 105 OU h-1 AU-1). The highest ambient odor concentrations and barn odor emissions were measured from the sow gestation barns of the IA4B site, which had unusually high H2S concentrations. The most intense odor and the least pleasant odor were also measured at this site. The overall odor emission rates of the pig finishing rooms at IN3B were lower than the emission rates of the IA4B sow gestation barns. The lowest overall barn odor emission rates were measured at the IN5B dairy barns. However, the lowest ambient odor concentrations were measured at the ventilation inlets of the WI5B dairy barns.