Diurnal and seasonal variations of odor and gas emissions from a naturally ventilated free-stall dairy barn on the Canadian prairies
Notice bibliographique
Résumé
This study characterized the seasonal concentration (C) and emission (E) patterns of odor, ammonia (NH3), and hydrogen sulfide (H2S) over the course of a whole year and their diurnal patterns in cold, warm, and mild seasons for a naturally ventilated free-stall dairy barn. It was found that seasonal odor and NH3 and H2S emissions varied greatly: from 17.2 to 84.4 odor units (OU) sec−1 AU−1 (AU: animal unit, 500 kg of animal body mass), from 0.27 to 0.92 mg sec−1 AU−1, and from 3 to 105 μg sec−1 AU−1, respectively. The overall concentrations of odor and NH3 were higher in the winter, whereas the emissions were higher in the mild and warm seasons. Diurnal variation was most significant for odor emission (OE) in the mild season when the ratio of maximum (279.2 OU sec−1 AU−1) to minimum value (60.5 OU sec−1 AU−1) was up to 4.6. The indoor air quality was also evaluated by considering not only the health effect of individual gases, but also the additive effect of NH3 and H2S. Results showed that the indoor air quality was poorest in cold seasons when NH3 C could exceed the threshold limit set out in occupational health regulation, and in fact could worsen due to the additive effect of the two gases. Further, it was suggested NH3 was a good indicator for predicting odor concentration (OC) or OE. The impact of climatic parameters on odor and gases were also examined, and it was found ventilation rate (VR) negatively affected OC and NH3 C, but positively impacted OE and NH3 E. Using 70% of the total data, a multilinear model for OE was developed as a function of VR and indoor relative humidity and was validated to be acceptable using the rest of the data.Implications: Diurnal and seasonal variations of odor, NH3, and H2S concentrations and emissions were monitored for a naturally ventilated dairy barn in a cold region. The emission factors were calculated and indoor air quality was evaluated. The overall odor and NH3 concentrations were higher in winter, whereas emissions were higher in the mild and warm seasons. Diurnal variation was most significant for odor emission in the mild season, when the ratio of maximum to minimum value was up to 4.6. The results can be used to estimate odor and gas emissions from other dairy barns in Canada and other cold regions.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».