Abstract
Abattoirs remain poorly characterised in terms of odour and volatile emissions despite their potential environmental, social, and economic impacts. This study characterised volatile organic compounds (VOCs) in a commercial cattle abattoir and assessed associations with animal welfare and production factors. Air samples were collected from the lairage and stun box throughout the working week and analysed using TD-GC-TOF-MS. A total of 200 compounds were identified, including alcohols, aldehydes, alkanes, amines, aromatic hydrocarbons, esters, ketones, nitriles, phenols, halogenated compounds, and silicones. Tweedie generalised linear models identified significant associations between VOC concentrations and production variables. Alcohol concentrations were 36% higher when overnight cattle were present (p = 0.030). Esters and nitriles increased by 41% with batch number (p < 0.05), while alkanes were 3.5-fold higher during morning periods (p = 0.015). Ketones increased with batch size (+15%, p = 0.010) and over time (p = 0.017), whereas aromatic hydrocarbons declined over time (p < 0.001). Machine learning models further demonstrated relationships between VOC profiles, production day, and shift hours. These findings indicate that abattoir VOC emissions are influenced by operational and animal-related factors and may provide useful indicators of environmental conditions, animal welfare, and occupational exposure.
