The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ...ventilation rate. The aim of this research was to assess the performance of a low-cost Non-Dispersive Infra-Red (NDIR) sensor for intensive spatial field monitoring of CO2 concentrations in a NV dairy cow house. This was achieved by comparing NDIR sensors with two commonly applied methods, a Photo-Acoustic Spectroscope (PAS) Gas Monitor and an Open-Path laser (OP-laser). First, calibrations for the NDIR sensors were obtained in the laboratory. Then, the NDIR sensors were placed in a dairy cow barn for comparison with the PAS and OP-laser methods. The main conclusions were: (a) in order to represent the overall barn CO2 concentration of the dairy cow barn, the number of NDIR sensors to be accounted for average concentration calculation was dependent on barn length and on barn area occupation; and (b) the NDIR CO2 sensors are suitable for multi-point monitoring of CO2 concentrations in NV livestock barns, being a feasible alternative for the PAS and the OP-laser methods to monitor single-point or averaged spatial CO2 concentrations in livestock barns.
This study aimed to investigate the impact of decreased crude protein (CP) levels (by 2% units) or acidifying diets (by adding 10 g benzoic acid/kg diet in combination with replacing a part of CaCO
...by about 10 g Ca-formate/kg diet) on urine, feces and manure composition and ammonia emissions from growing and finishing pig houses. Yorkshire x F1(Landrace x Yorkshire) pigs (n = 576) with an initial body weight of 24.9 ± 3.4 kg were randomly allocated to four treatments of (i) a control diet with normal protein content and no acidifying components added; (ii) a diet with 2% units CP reduction; (iii) a diet with an acidifying effect on the manure; (iv) or a diet consisting of a combination of diet (ii) and (iii). Pigs were housed in four mechanically ventilated and temperature-controlled rooms. Results showed that decreasing the dietary CP levels by 2% units reduced the ammonia emission from the floor by 46% (
= 0.06) and from the pig house by 31% (
= 0.08). Decreased CP diets reduced the total N in feces and in manure and NH
-N in the manure, as well as the ammonia concentration at 1 cm and 10 cm above the manure surface (
< 0.05). However, acidifying diets failed to reduce ammonia emissions from the floor and the pig house (
> 0.05). Reducing dietary crude protein is, therefore, a solution to reducing ammonia emissions from pig houses.
Living in livestock-dense areas has been associated with health effects, suggesting airborne exposures to livestock farm emissions to be relevant for public health. Livestock farm emissions involve ...complex mixtures of various gases and particles. Endotoxin, a pro-inflammatory agent of microbial origin, is a constituent of livestock farm emitted particulate matter (PM) that is potentially related to the observed health effects. Quantification of livestock associated endotoxin exposure at residential addresses in relation to health outcomes has not been performed earlier.
We aimed to assess exposure-response relations for a range of respiratory endpoints and atopic sensitization in relation to livestock farm associated PM10 and endotoxin levels.
Self-reported respiratory symptoms of 12,117 persons participating in a population-based cross-sectional study were analyzed. For 2494 persons, data on lung function (spirometry) and serologically assessed atopic sensitization was additionally available. Annual-average PM10 and endotoxin concentrations at home addresses were predicted by dispersion modelling and land-use regression (LUR) modelling. Exposure-response relations were analyzed with generalized additive models.
Health outcomes were generally more strongly associated with exposure to livestock farm emitted endotoxin compared to PM10. An inverse association was observed for dispersion modelled exposure with atopic sensitization (endotoxin: p = .004, PM10: p = .07) and asthma (endotoxin: p = .029, PM10: p = .022). Prevalence of respiratory symptoms decreased with increasing endotoxin concentration at the lower range, while at the higher range prevalence increased with increasing concentration (p < .05). Associations between lung function parameters with exposure to PM10 and endotoxin were not statistically significant (p > .05).
Exposure to livestock farm emitted particulate matter is associated with respiratory health effects and atopic sensitization in non-farming residents. Results indicate endotoxin to be a potentially plausible etiologic agent, suggesting non-infectious aspects of microbial emissions from livestock farms to be important with respect to public health.
•Quantification of residential exposure to livestock farm emissions established•Land-use regression and dispersion modelling of particulate matter and endotoxin•Associations of exposure and health analyzed in a large population-based study•Respiratory health and atopic sensitization associated with endotoxin exposure•Highlights public health relevance of microbial air pollution from livestock farms
Given the current scarcity of empirical data on ammonia (NH3) emissions from dairy cattle under different management-based mitigation techniques, a modeling approach to assess potential NH3 emission ...reduction factors is needed. This paper introduces a process-based model that estimates NH3 emission reduction factors for a dairy cattle barn featuring single or multiple management-based NH3 emission mitigation techniques, as compared to another barn, to which no mitigation measure is applied. The model accounts for the following emission mitigation measures: (a) floor scraping, (b) floor type, (c) floor flushing with water and (d) indoor acidification of manure. Model sensitivity analysis indicated that manure acidification was the most efficient NH3 emission reduction technique. A fair agreement was observed between reduction factors from the model and empirical estimates found in the literature. We propose a list of combinations of techniques that achieve the largest reductions. In order of efficiency, they are: (a) floor scraping combined with manure acidification (reduction efficiency 44–49%); (b) solid floor combined with scraping and flushing (reduction efficiency 21–27%); (c) floor scraping combined with flushing and (d) floor scraping alone (reduction efficiency 17–22%). The model is currently being used to advise the Flemish Government (Belgium), on the performance of certain NH3 emission reduction systems for dairy barns in Flanders.
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•Modeled NH3 emission reduction factors agreed with empirical data from literature.•Scraping and flushing of floor, floor type and manure acidification were modeled.•Floor scraping combined with manure acidification yielded the highest emission reductions.
Measuring gaseous and particulate emissions from livestock houses has been the subject of intensive research over the past two decades. Currently, there is general agreement regarding appropriate ...methods to measure emissions from mechanically ventilated buildings. However, measuring emissions from naturally ventilated buildings remains an elusive target primarily because there is no reference method for measuring building ventilation rate. Ventilation rates and thus building emissions estimates for naturally ventilated buildings are likely to contain greater errors compared with those from mechanically ventilated buildings. This work reviews the origin and magnitude of errors associated with emissions from naturally ventilated buildings as compared to those typically found in mechanical ventilation. Firstly, some general concepts of error analysis are detailed. Then, typical errors found in the literature for each measurement technique are reviewed, and potential sources of relevant systematic and random errors are identified. The emission standard uncertainty in mechanical ventilation is at best 10% or more of the measured value, whereas in natural ventilation it may be considerably higher and there may also be significant unquantifiable biases. A reference method is necessary to obtain accurate emissions estimates, and for naturally ventilated structures this suggests the need for a new means of ventilation measurement. The results obtained from the analysis of information in this review will be helpful to establish research priorities, and to optimize research efforts in terms of quality of emission measurements.
► Recent research on uncertainties of emissions measured in animal houses is reviewed. ► For mechanical ventilation, errors can be quantified and reduced to acceptable levels. ► For natural ventilation, errors are higher and significant biases may be committed. ► Error analysis is critical for sound conclusions and to establish research priorities.
In the Netherlands, emissions from animal houses represent a major source of ambient particulate matter (PM). The objective of the present paper was to provide accurate and up to date concentrations ...and emission rates of PM10 and PM2.5 for commonly used animal housing systems, under representative inside and outside climate conditions and ventilation rates. We set up a national survey which covered 13 housing systems for poultry, pigs, and dairy cattle, and included 36 farms. In total, 202 24-h measurements were carried out, which included concentrations of inhalable PM, PM10, PM2.5, and CO2, ventilation rate, temperature, and relative humidity. On an animal basis, geometric mean emission rates of PM10 ranged from 2.2 to 12.0 mg h−1 in poultry and from 7.3 to 22.5 mg h−1 in pigs. The mean PM10 emission rate in dairy cattle was 8.5 mg h−1. Geometric mean emission rates of PM2.5 ranged from 0.11 to 2.41 mg h−1 in poultry and from 0.21 to 1.56 mg h−1 in pigs. The mean PM2.5 emission rate in dairy cattle was 1.65 mg h−1. Emissions are also reported per Livestock Unit and Heat Production Unit. PM emission rates increased exponentially with increasing age in broilers and turkeys and increased linearly with increasing age in weaners and fatteners. In laying hens, broiler breeders, sows, and dairy cattle, emission levels were variable throughout the year.
•We conducted a national emission survey in 36 farms.•The survey covered 13 housing systems for poultry, pigs, and dairy cattle.•This paper reports climate conditions, ventilation rates, and dust emissions.•Geometric mean emission rates of PM10 ranged from 2.2 to 22.5 mg h−1 animal−1.•Geometric mean emission rates of PM2.5 ranged from 0.11 to 2.41 mg h−1 animal−1.
The removal of ammonia (NH3) by a full scale packed-bed biotrickling filter (packing volume: 3.8 m3; water buffer tank: 20 m3) under fluctuating loading conditions was studied. The unit was operated ...at an animal house for treatment of exhaust air at an average air contact time of 1.2 s. Continuous long-term ammonia measurements showed average inlet and outlet air concentrations of 14 ppm and 2.4 ppm, respectively, and a removal efficiency of 82%. The average temperature of the water was 16 °C, the pH 6.6, the ammonium concentration 1.9 g N l−1, and the nitrate concentration 1.8 g N l−1; no nitrite was detected. The average ammonia loading and removal rate were 29 and 24 g NH3 m−3 h−1, respectively. A daily and seasonal pattern could be observed in the ammonia removal performance. With increasing outside temperature ammonia loading rate, ammonia removal rate, and ammonia outlet concentration increased, resulting in a net decrease of the ammonia removal efficiency. This phenomenon might be explained by the existence of equilibrium between the ammonia concentration in the outlet air and the concentration of dissolved ammonia in the water, which is influenced by fluctuating air and water temperature. A nitrogen balance indicated that 86% of the removed ammonia-N was discharged or accumulated in the water as ammonium and nitrate, and 5% was emitted as nitrous oxide (N2O). The fluctuating removal patterns that were found suggest that current regulatory performance monitoring practices need to be improved.
► Ammonia removal performance driven by day–night and seasonal variations. ► Ammonia scrubber outlet concentration eventually determined by water discharge rate and temperature. ► Regulatory performance monitoring practices need to be improved.
The present study evaluated the performance of four systems for abatement of particulate matter (PM) emission inside full-scaled commercial poultry houses: a fixed oil spraying system (OSF) inside ...two broiler farms and one laying hen house, an autonomously driving oil spraying vehicle (OSV) in one laying hen house, a negative air ionisation system (NAI) inside two broiler farms, and a positive air ionisation system (PAI) inside two laying hen houses. The systems were evaluated using case-control approaches. At each farm, six 24-h measurements were scheduled of PM10, PM2.5, ammonia, odour, and carbon dioxide concentrations (the latter for estimation of the ventilation rate and herewith emissions). This paper presents the layout of the systems, compares their performance in practice with that under experimental conditions, discusses improvement possibilities, reports the baseline emission rates of the poultry houses, and discusses the validity of the case-control approaches. The emission reductions of PM10 and PM2.5 were: 60% and 53% for the OSF in broilers (at 12 mL m−2 d−1), 21% and 31% for the OSF in laying hens (at 15 mL m−2 d−1), 32% and 38% for the OSV in laying hens (at 30 mL m−2 d−1), 49% and 68% for the NAI in broilers, and 6% and zero for the PAI in laying hens. None of the systems significantly reduced the emission rate of odour or ammonia. On the basis of this work, emission reduction factors of the OSF, OSV, and NAI have been adopted in Dutch regulations.
•We evaluated 4 abatement systems in 8 poultry farms using case-control designs.•Litter oiling systems (fixed; vehicle) reduced PM10 emission by 21–60%.•A negative air ionisation system reduced PM10 emission in broilers by 49%.•A positive air ionisation system reduced PM10 emission in layers by 6%.•Baseline house emissions of PM10, PM2.5, NH3, and odour are reported.
Odor and lateralization (irritation) thresholds (LTs) for ammonia vapor were measured using static and dynamic olfactometry. The purpose of the study was to explore the test–retest reliability and ...comparability of dynamic olfactometry methodology, generally used to determine odor thresholds following European Committee for Standardization guidelines in the context of odor regulations to outside emissions, with static olfactometry. Within a 2-week period, odor and LTs for ammonia were obtained twice for each method for 24 females. No significant differences between methods were found: mean odor detection thresholds (ODTs) were 2.6 parts per million (ppm) for either method (P = 0.96), and mean LTs were 31.7 and 60.9 ppm for the static and dynamic method, respectively (P = 0.07). Test–retest reliability was higher for the dynamic than for the static method (r = 0.61 vs. 0.14 for ODTs and r = 0.86 vs. 0.45 for LTs). The choice of optimal method for any application, however, depends not only on psychometric factors but also on practical factors such as physicochemical properties of the compound, availability of equipment and expertise, task efficiency, and costs.
In Europe, dynamic olfactometry, as described by the European standard EN 13725, has become the preferred method for evaluating odor emissions emanating from industrial and agricultural sources. Key ...elements of this standard are the quality criteria for trueness and precision (repeatability). Both are linked to standard values of n-butanol in nitrogen. It is assumed in this standard that whenever a laboratory complies with the overall sensory quality criteria for n-butanol, the quality level is transferable to other, environmental, odors.
Although olfactometry is well established, little has been done to investigate inter laboratory variance (reproducibility). Therefore, the objective of this study was to estimate the reproducibility of odor laboratories complying with EN 13725 as well as to investigate the transferability of n-butanol quality criteria to other odorants.
Based upon the statistical analysis of 412 odor measurements on 33 sources, distributed in 10 proficiency tests, it was established that laboratory, panel and panel session are components of variance that significantly differ between n-butanol and other odorants (α = 0.05). This finding does not support the transferability of the quality criteria, as determined on n-butanol, to other odorants and as such is a cause for reconsideration of the present single reference odorant as laid down in EN 13725.
In case of non-butanol odorants, repeatability standard deviation (sr) and reproducibility standard deviation (sR) were calculated to be 0.108 and 0.282 respectively (log base-10). The latter implies that the difference between two consecutive single measurements, performed on the same testing material by two or more laboratories under reproducibility conditions, will not be larger than a factor 6.3 in 95% of cases.
As far as n-butanol odorants are concerned, it was found that the present repeatability standard deviation (sr = 0.108) compares favorably to that of EN 13725 (sr = 0.172). It is therefore suggested that the repeatability limit (r), as laid down in EN 13725, can be reduced from r ≤ 0.477 to r ≤ 0.31.
•We investigated variance components using 412 odor measurements.•Measurements were according to EN 13725 and comprised non-butanol and butanol odors.•Panel, panel session and laboratory differed significantly for both groups.•Transferability of quality criteria to non-butanol odors was not supported.•Reproducibility factor for non-butanol and n-butanol proved to be 6.3 and 4.3.
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